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WO2016082220A1 - 多视频流的传输方法和设备 - Google Patents

多视频流的传输方法和设备 Download PDF

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Publication number
WO2016082220A1
WO2016082220A1 PCT/CN2014/092577 CN2014092577W WO2016082220A1 WO 2016082220 A1 WO2016082220 A1 WO 2016082220A1 CN 2014092577 W CN2014092577 W CN 2014092577W WO 2016082220 A1 WO2016082220 A1 WO 2016082220A1
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WO
WIPO (PCT)
Prior art keywords
frame
intra prediction
period
station
service period
Prior art date
Application number
PCT/CN2014/092577
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English (en)
French (fr)
Inventor
李德建
刘培
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to CN201480026399.9A priority Critical patent/CN105830445B/zh
Priority to PCT/CN2014/092577 priority patent/WO2016082220A1/zh
Priority to EP14907163.1A priority patent/EP3214839B1/en
Publication of WO2016082220A1 publication Critical patent/WO2016082220A1/zh
Priority to US15/607,238 priority patent/US10079997B2/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/14—Systems for two-way working
    • H04N7/15—Conference systems
    • H04N7/152—Multipoint control units therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
    • H04N21/262—Content or additional data distribution scheduling, e.g. sending additional data at off-peak times, updating software modules, calculating the carousel transmission frequency, delaying a video stream transmission, generating play-lists
    • H04N21/26275—Content or additional data distribution scheduling, e.g. sending additional data at off-peak times, updating software modules, calculating the carousel transmission frequency, delaying a video stream transmission, generating play-lists for distributing content or additional data in a staggered manner, e.g. repeating movies on different channels in a time-staggered manner in a near video on demand system
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/63—Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
    • H04N21/637—Control signals issued by the client directed to the server or network components
    • H04N21/6373—Control signals issued by the client directed to the server or network components for rate control, e.g. request to the server to modify its transmission rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/63—Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
    • H04N21/647—Control signaling between network components and server or clients; Network processes for video distribution between server and clients, e.g. controlling the quality of the video stream, by dropping packets, protecting content from unauthorised alteration within the network, monitoring of network load, bridging between two different networks, e.g. between IP and wireless
    • H04N21/64784—Data processing by the network
    • H04N21/64792—Controlling the complexity of the content stream, e.g. by dropping packets
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/14—Systems for two-way working
    • H04N7/15—Conference systems
    • H04N7/155—Conference systems involving storage of or access to video conference sessions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
    • H04N7/181—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast for receiving images from a plurality of remote sources

Definitions

  • the present invention relates to communication technologies, and in particular, to a method and device for transmitting multiple video streams.
  • Wireless Local Area Networks have the advantages of low cost and convenient deployment, which can meet the technical and cost requirements of wireless video surveillance networks.
  • the demand for high-definition video streams is increasing, and the data rate of high-definition video streams is relatively high, resulting in higher network load for multiple video surveillance terminals transmitting HD video streams concurrently.
  • a typical data rate for a high-definition video conference in a 720p encoding format is 0.5 Mbps-2.5 Mbps, assuming an average rate of about 1.5 Mbps for a high-definition video stream of 720p encoding format, and an aggregate data rate of 22.5 Mbps for 15 video monitoring terminals.
  • the 8MHz channel (Modulation and Coding Scheme, MCS) design of the 802.11ah standard physical layer even 15 stations (Station, referred to as STA) can adopt high-order 64-QAM (code rate). 2/3), the maximum network aggregate throughput is only 23.4Mbps. Therefore, when running wireless HD video surveillance services on the 779-787 MHz band allocated below 1 GHz in China, the wireless video surveillance network will often run in a saturated state due to the limited available bandwidth. The load variation range of the wireless video surveillance network running in saturation cannot be too large, otherwise the peak throughput of the network will exceed the load tolerance of the network.
  • MCS Modulation and Coding Scheme
  • the mainstream video coding standard adopts H.264, and the video coding output includes an intra frame (intra frame, I frame for short), a predictive frame (referred to as P frame) and bidirectional prediction.
  • the peak load rate of the network is too high, which exceeds the network load tolerance, which may not satisfy the delay QoS requirements of multiple real-time video data streams.
  • the method and device for transmitting multiple video streams provided by the embodiments of the present invention are such that the transmission time of the I frames of the STAs is staggered, so that the network load is balanced, and the delay QoS of each STA is guaranteed to meet the requirements.
  • a first aspect of the present invention provides an access point, including:
  • a processing module configured to allocate an initial transmission time and a transmission period of the intra prediction frame to the at least two stations associated with the access point, where the transmission time of the intra prediction frame in the at least two stations is adjacent
  • the interval of the initial transmission time of the intra prediction frame of the two stations is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations, and the intraframe of any two adjacent stations
  • the interval between the initial transmission times of the predicted frames is greater than 0;
  • a transceiver module configured to send an initial transmission time and a transmission period of an intra prediction frame to each of the at least two stations;
  • the processing module is further configured to allocate a service period of the intra prediction frame and a service period of the forward prediction frame to the stations according to an initial transmission time and a transmission period of the intra prediction frame of each station, where Each station exclusively enjoys the channel during the service period of the intra prediction frame and the service period of the forward prediction frame, wherein the interval T of the service period of the intra prediction frame of any two adjacent stations satisfies the following condition: Min ⁇ T ⁇ T max , T min and T max are determined by the access point according to an initial transmission time and a transmission period of an intra prediction frame of each station;
  • the transceiver module is further configured to send, to the stations, an allocation result of a service period of the intra prediction frame of each station and a service period of the forward prediction frame.
  • Tmin and Tmax are calculated by the following formula:
  • T min min ⁇
  • T max max ⁇
  • N GOP (1) and N GOP (2) are respectively the length of the image group of any two adjacent stations, and F is the frame rate of any two adjacent stations, T 1 and T 2 The initial transmission time of the intra prediction frame of any two adjacent stations.
  • the intra prediction of the two adjacent two sites The initial transmission time of the frame is the same.
  • the initial transmission of the intra prediction frame of the two adjacent two sites is:
  • the processing module is further configured to:
  • the intraframe Predicting a frame interval request frame to request at least one of the two adjacent stations to adjust a transmission period of its own intra prediction frame, so that the adjacent two stations adjust the intra prediction
  • the interval of the initial transmission time of the frame is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations;
  • the transceiver module is specifically configured to:
  • the initial transmission time of the intra prediction frame of each station is adjusted, the initial transmission included in the frame interval setting request of the first intra prediction frame is Setting an initial transmission time of the intra prediction frame, the frame interval setting request of the second intra prediction frame is sent to the stations, and the frame interval setting request of the second intra prediction frame includes the The transmission period of the intra prediction frame of each station is such that each station adjusts the transmission period of the respective intra prediction frame to the transmission period included in the frame interval setting request of the second intra prediction frame.
  • the processing module is specifically configured to:
  • an allocating unit configured to: according to the service period of the intra prediction frame of each station and the service period of the forward prediction frame, and the interval of the service period of the intra prediction frame of any two adjacent stations, Each station allocates a service period of the intra prediction frame and a service period of the forward prediction frame.
  • the processing module is further configured to:
  • a channel contention period for each of the stations Assigning, to each of the beacon intervals, a channel contention period for each of the stations, the channel contention period being used when the stations are in the intra-frame prediction period of the own frame and the service period of the forward prediction frame
  • the data is transmitted using the channel contention period, and the channel contention period is shared by the stations.
  • the transceiver module is further configured to:
  • the contention period control signaling is used to prohibit a first station or all stations in the stations from being in the first of the respective beacon intervals
  • the channel is accessed during the channel competition period before the service period, and the first service period of each station is the service period of the intra prediction frame or the service period of the forward prediction frame.
  • the access point allocates intra prediction to each station
  • the service period of the frame is greater than the service period of the forward predicted frame allocated for the respective stations.
  • the processing module is further configured to:
  • the transceiver module is further configured to send a reference user priority of each site to the sites, so that the sites set channel competition access parameters of the channel competition period according to respective reference user priorities. And a priority of the intra predicted frame and the forward predicted frame.
  • the processing module is further configured to:
  • the service period of the frame, the adjusted base user priority of the site is higher than the reference user priority before the adjustment;
  • the transceiver module is further configured to notify the site of the adjustment result of the processing module
  • the processing module is further configured to:
  • the service period of the intra predicted frame is equal to the service period of the pre-adjusted frame before the adjustment
  • the service period of the forward predicted frame after the station is restored is equal to the service period of the forward predicted frame before the adjustment
  • the reference user priority after the site is restored is equal to the reference user priority before the adjustment.
  • the transceiver module is further configured to notify the site of the recovery result of the processing module.
  • the access point when the access point sends the intra prediction frame or the forward prediction frame, the access The application layer of the point carries a frame type parameter in the intra prediction frame and the forward prediction frame delivered to the medium access control MAC layer, so that the MAC layer of the access point is according to the frame type parameter. Determining that the received data frame is the intra predicted frame or the forward predicted frame.
  • a second aspect of the present invention provides a site, including:
  • a receiving module configured to receive an initial sending time and a sending period of an intra prediction frame sent by the access point
  • the receiving module is further configured to receive an allocation result of a service period of the intra prediction frame and a service period of a forward prediction frame sent by the access point, a service period of the intra prediction frame, and the foregoing
  • the service period to the predicted frame is that the access point allocates for the station within each beacon interval according to an initial transmission time of the station and a transmission period of the intra prediction frame;
  • a sending module configured to send the intra prediction frame during a service period of the intra prediction frame according to an initial transmission time of the intra prediction frame and a transmission period of the intra prediction frame, where The forward predicted frame is transmitted to a service period of the predicted frame.
  • the receiving module is specifically configured to:
  • each of the beacon intervals further includes a channel competition period allocated by the access point, when the site is in the When the service period of the intra prediction frame and the service period of the forward prediction frame fail to transmit all the buffered data, the station transmits data using the channel contention period, and the channel contention period is described. All sites associated with the access point are shared.
  • the receiving module is further configured to:
  • the contention period control signaling is used to prohibit Stopting the station accessing the channel during a channel contention period prior to the first service period within each beacon interval, the first service period of the station being a service period of the intra prediction frame Or the service period of the forward predicted frame.
  • the station further includes: a setting module
  • the receiving module is further configured to receive a user reference priority reference user priority sent by the access point;
  • the setting module is configured to set a channel contention access parameter of the channel competition period according to the user reference priority reference user priority, and compete for a channel during the competition period according to the channel contention access parameter;
  • the setting module is further configured to set a priority of the intra prediction frame and a priority of the forward prediction frame according to the user reference priority reference user priority, where the forward prediction frame is prioritized
  • the priority of the intra-predicted frame is the same as the priority of the forward-predicted frame, and the priority of the re-transmitted frame of the station is higher than that of the non-retransmitted frame. priority.
  • the receiving module is further configured to:
  • the adjustment result includes: the adjusted frame of the station a service period of the intra prediction frame, a service period of the adjusted forward prediction frame, and an adjusted reference user priority, wherein a service period of the intra-frame-adjusted frame of the station is greater than an intra-predicted frame before adjustment During the service period, the service period of the forward-adjusted frame of the site is greater than the service period of the forward-predicted frame before the adjustment, and the adjusted priority of the reference user of the site is higher than the priority of the reference user before the adjustment.
  • the receiving module is further configured to:
  • the recovery result includes: after the site is restored a service period of the intra predicted frame, a service period of the restored forward predicted frame, and a restored reference user priority, wherein the service period of the intra predicted frame after the station is restored, and the like
  • the service period of the forward predicted frame after the site is restored is equal to the service period of the forward predicted frame before the adjustment
  • the reference user after the site is restored is prior to the service period of the intra-predicted frame before the adjustment
  • the level is equal to the reference user priority before the adjustment.
  • the access point is allocated to the site
  • the service period of the intra prediction frame is greater than the service period of the forward prediction frame.
  • an application layer of the station may Carrying a frame type parameter in the intra prediction frame and the forward prediction frame to the medium access control MAC layer, so that the MAC of the station determines, according to the frame type parameter, that the received data frame is the Intra prediction frame or the forward predicted frame.
  • a method for transmitting a multiple video stream according to a third aspect of the present invention includes:
  • the access point allocates an initial transmission time and a transmission period of the intra prediction frame to the at least two associated sites, wherein the intra prediction of any two stations adjacent to the transmission time of the intra prediction frame in the at least two stations
  • the interval of the initial transmission time of the frame is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations, and the initial transmission time of the intra prediction frame of any two adjacent stations The interval is greater than 0;
  • the access point allocates a service period of the intra prediction frame and a service period of the forward prediction frame to the stations according to an initial transmission time and a transmission period of the intra prediction frame of each station, where each station is The service period of the intra prediction frame and the service period of the forward prediction frame are exclusive channels, wherein the interval T of the service period of the intra prediction frame of any two adjacent stations satisfies the following condition: T min ⁇ T ⁇ T max , T min and T max are determined by the access point according to an initial transmission time and a transmission period of an intra prediction frame of each station;
  • the access point sends, to the stations, an allocation result of a service period of the intra prediction frame of each station and a service period of the forward prediction frame.
  • Tmin and Tmax are calculated by the following formula:
  • T min min ⁇
  • T max max ⁇
  • N GOP (1) and N GOP (2) are respectively the length of the image group of any two adjacent stations, and F is the frame rate of any two adjacent stations, T 1 and T 2 The initial transmission time of the intra prediction frame of any two adjacent stations.
  • the intra prediction of the two adjacent two sites is the same.
  • the initial transmission time of the intra prediction frame of the two adjacent two stations The interval is:
  • the method further includes:
  • the access point When the access point detects that the initial transmission time interval of the intra prediction frame of any two adjacent stations is equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations The access point requests at least one of the two adjacent stations to adjust a transmission period of its own intra prediction frame by transmitting an interval request frame of the intra prediction frame, so that the adjacent The interval of the initial transmission time of the intra prediction frame adjusted by any two stations is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations;
  • the access point when the access point detects the minimum value of the interval of the service period of the intra prediction frame of any two adjacent stations, min ⁇
  • the access point is The initial transmission time and transmission period of the intra prediction frame sent by each station, including:
  • the access point separately sends a frame interval setting request of the first intra prediction frame to the each station, where the frame interval setting request of the first intra prediction frame includes an initial sending time of each station, so that Each station sets an initial transmission time of its own intra prediction frame according to a respective initial transmission time;
  • the station indicates that each station sets its own intra prediction according to the initial transmission time included in the frame interval setting request of the first intra prediction frame.
  • the initial transmission time of the frame the access point sends a frame interval setting request of the second intra prediction frame to the stations, where the frame interval setting request of the second intra prediction frame includes the sites.
  • the transmission period of the intra prediction frame is such that the stations adjust the transmission period of the respective intra prediction frame to the transmission period included in the frame interval setting request of the second intra prediction frame.
  • the initial transmission time and the transmission period of the intra prediction frame of each station, the service period of the intra prediction frame and the service period of the forward prediction frame are allocated to the stations, including:
  • the access point calculates a service period of the intra prediction frame of each station according to an average length of intra prediction frames of each station and an average transmission rate of each station, and according to the sites Calculating a service period of the forward predicted frame of each station, respectively, an average length of the forward predicted frame and an average transmission rate of each station;
  • the access point according to the service period of the intra prediction frame of each station and the service period of the forward prediction frame, and the interval of the service period of the intra prediction frame of any two adjacent stations are Each station allocates a service period of the intra prediction frame and a service period of the forward prediction frame.
  • the method further includes:
  • the access point allocates a channel contention period for the stations in each of the beacon intervals, and the channel contention period is used when the stations predict the frame service period and forward prediction in their own intraframes When the entire data of the cache is not transmitted during the service period of the frame, the data is transmitted using the channel contention period, and the channel contention period is shared by the stations.
  • the method further includes: the access point sending a competition period to each of the stations Controlling signaling, the contention period control signaling is used to prohibit some or all of the stations from accessing the channel during the channel competition period before the first service period in the respective beacon intervals.
  • the first service period of each station is a service period of an intra prediction frame or a service period of a forward prediction frame.
  • the access point allocates an intra prediction to each of the stations
  • the service period of the frame is greater than the service period of the forward predicted frame allocated for the respective stations.
  • the method further includes:
  • the access point sets a reference user priority for each site according to the importance of the video monitoring area of each site or the content of the monitoring content;
  • the access point sends the reference user priority of each site to the sites, so that the sites set channel competition access parameters of the channel competition period according to respective reference user priorities, and The priority of the intra prediction frame and the forward prediction frame.
  • the method further includes:
  • the access point detects whether the video surveillance content of each site changes in motion
  • the access point detects a motion change of the video surveillance content of any one of the sites, the access point adjusts a service period and a forward prediction frame of the intra prediction frame allocated by the site.
  • Service period, and adjusting a reference user priority of the station the service period of the adjusted intra prediction frame of the station is greater than the service period of the intra prediction frame before the adjustment, the adjusted forward prediction frame of the station.
  • the service period is greater than the service period of the forward predicted frame before the adjustment, and the adjusted base user priority of the site is higher than the reference user priority before the adjustment;
  • the access point notifies the site of the adjustment result
  • the method further includes:
  • the access point restores a service period of the intra prediction frame of the site, a service period of the forward predicted frame, and a reference user priority of the user, where
  • the service period of the intra-predicted frame after the station is restored is equal to the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-predicted frame after the station is restored is equal to the forward prediction before the adjustment
  • the service period of the frame, the reference user priority after the site is restored is equal to the reference user priority before the adjustment.
  • the access point notifies the site of the recovery result.
  • the access point when the access point sends the intra prediction frame or the forward prediction frame, the access The application layer of the point carries a frame type parameter in the intra prediction frame and the forward prediction frame delivered to the medium access control MAC layer, so that the MAC layer of the access point is according to the frame type parameter. Determining that the received data frame is the intra predicted frame or the forward predicted frame.
  • a fourth aspect of the present invention provides a method for transmitting a multiple video stream, including:
  • the station receives an initial transmission time and a transmission period of the intra prediction frame sent by the access point;
  • a service period of the intra prediction frame sent by the access point and a service period of a forward prediction frame, a service period of the intra prediction frame, and a service of the forward prediction frame The period is that the access point allocates for the station within each beacon interval according to an initial transmission time of the station and a transmission period of the intra prediction frame;
  • the forward predicted frame is transmitted during the service period of the frame.
  • the station receives an initial transmission time of an intra prediction frame sent by an access point, and a sending period of the intra prediction frame.
  • the frame interval setting request of the second intra prediction frame includes a transmission period of the intra prediction frame of the station.
  • each of the beacon intervals further includes a channel competition period allocated by the access point, when the site is in the When the service period of the intra prediction frame and the service period of the forward prediction frame fail to transmit all the buffered data, the station transmits data using the channel contention period, and the channel contention period is described. All sites associated with the access point are shared.
  • the method further includes:
  • the station Receiving, by the station, a contention period control signaling sent by the access point, where the contention period control signaling is used to prohibit a channel competition period of the station before the first service period in each beacon interval
  • the channel is accessed internally, and the first service period of the station is a service period of the intra prediction frame or a service period of the forward prediction frame.
  • the method further includes:
  • the priority of the reference priority reference user is the same, the priority of the intra prediction frame is higher than the priority of the forward prediction frame, and the priority of the retransmission frame of the station is higher than the priority of the non-retransmission frame.
  • the method further includes:
  • the adjustment result includes: the site adjustment a service period of the subsequent intra prediction frame, a service period of the adjusted forward prediction frame, and an adjusted reference user priority, wherein the station adjusts the frame of the intra prediction frame
  • the service period is greater than the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-adjusted frame of the station is greater than the service period of the forward-predicted frame before the adjustment
  • the adjusted priority of the reference user is high.
  • the method further includes:
  • the recovery result includes: the site a service period of the restored intra prediction frame, a service period of the restored forward prediction frame, and a restored reference user priority, wherein a service period of the intra predicted frame after the station is restored is equal to the pre-adjustment a service period of the intra predicted frame, a service period of the forward predicted frame after the station is restored is equal to a service period of the forward predicted frame before the adjustment, and the reference user priority after the station is restored is equal to the adjustment Previous base user priority.
  • the access point is allocated to the station
  • the service period of the intra prediction frame is greater than the service period of the forward prediction frame.
  • the method further includes:
  • an application layer of the station may deliver the intra prediction frame and the forward prediction frame to a medium access control MAC layer.
  • the AP sets the initial transmission time and the transmission period of the I frame of the at least two associated STAs, and makes the I frame of any two STAs adjacent to the transmission time of the I frame.
  • the interval of the initial transmission time is not equal to the difference of the transmission period of the I of the two adjacent STAs, and the service period of the I frame is allocated to each STA according to the initial transmission time and the transmission period of the I frame of each STA.
  • each STA enjoys the channel exclusively during the service period of the I frame and the service period of the P frame, so that the transmission time of the I frame of each STA is staggered, so that the network load is balanced, and the network load is always in the network load capacity. Within the limit, thus ensuring that the delay of each STA meets the QoS requirements.
  • 1 is a schematic diagram of wireless channel division
  • FIG. 2 is a schematic structural diagram of an access point according to Embodiment 1 of the present invention.
  • Figure 3 is an I frame interval report field format
  • FIG. 4 is a schematic structural diagram of a VTSPEC element
  • FIG. 5 is a schematic diagram showing an allocation result of a service period of an I frame and a service period of a P frame;
  • FIG. 6 is a schematic structural diagram of a priority allocation element of a STA
  • Figure 7 is a schematic structural view of a motion detection report element
  • FIG. 8 is a schematic structural diagram of a station according to Embodiment 4 of the present invention.
  • FIG. 9 is a schematic structural diagram of a station according to Embodiment 5 of the present invention.
  • FIG. 10 is a flowchart of a method for transmitting multiple video streams according to Embodiment 6 of the present invention.
  • FIG. 11 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 7 of the present invention.
  • FIG. 12 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 8 of the present invention.
  • FIG. 13 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 9 of the present invention.
  • FIG. 14 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 10 of the present invention.
  • FIG. 15 is a schematic structural diagram of an access point according to Embodiment 11 of the present invention.
  • FIG. 16 is a schematic structural diagram of a station according to Embodiment 12 of the present invention.
  • the method of each embodiment of the present invention is applied in the field of wireless video surveillance, wireless personal area network
  • the Wireless Personal Area Network (WPAN) standard working group has begun to develop a video personal area network (Vedio Personal Area Network, VPAN) standard for applications such as wireless video surveillance.
  • the standard focuses on indoor and outdoor wireless HD video surveillance applications, with the goal of developing national standards for wireless video surveillance networks that are medium-sized and support multiple concurrent HD video streams for concurrent transmission.
  • 802.11ah divides the channel of China's 779-787MHz frequency band into eight 1MHz channels, four 2MHz, two 4MHz channels and one 8MHz channel. As shown in Figure 1, Figure 1 is a schematic diagram of wireless channel division.
  • 802.11ah divides China's 755-779MHz frequency band into 24 channels with a bandwidth of 1MHz. According to the channel division method of 802.11ah, the maximum channel bandwidth of the IoT band below 1 GHz used in various control devices in China is only 8 MHz (779-787 MHz band).
  • the video surveillance terminal is usually a station STA.
  • the typical data rate of a high-definition video conference in the 720p encoding format is 0.5 Mbps-2.5 Mbps. It is assumed that the average rate of the high-definition video stream of the 720p encoding format is about 1.5 Mbps, and the aggregate data rate of the 15 STAs will reach 22.5 Mbps.
  • high-definition video stream compression coding is divided into two types: fixed bit rate (CBR) and variable bit rate (VBR), and CBR video compression coding quality is lower than VBR video compression. Coding quality.
  • CBR fixed bit rate
  • VBR variable bit rate
  • Coding quality For VBR video compression coding, the data rate is closely related to the speed of monitoring content. For the monitoring picture with faster change, the video stream rate will show a large range of variation.
  • H.264 is a mainstream video coding standard widely used in the industry, and its video coding output includes an intra frame (intra frame, I frame for short), a predictive frame (P frame) and a bidirectional predictive interpolated code frame.
  • I frame intra frame
  • P frame predictive frame
  • B frame bidirectional predictive interpolated code frame
  • I frame size is generally 8 to 10 times the size of the P frame and the B frame. Therefore, at a uniform frame interval, the coded output rate of the I frame is much higher than that of the P frame and the B frame.
  • the B frame is used as a bidirectional prediction frame, which is not suitable for real-time applications, and is generally not used in video coding of video surveillance applications.
  • a wireless video surveillance network if the I frames of different STAs are sent at the same time or in a similar time, the peak rate of the network load is too high, which exceeds the network load tolerance, and the delay of some or all STAs cannot meet the QoS requirements.
  • FIG. 2 is a schematic structural diagram of an access point according to Embodiment 1 of the present invention. As shown in FIG. 2, the access provided in this embodiment is provided.
  • the points include: a processing module 11 and a transceiver module 12.
  • the processing module 11 is configured to allocate, for the at least two stations associated with the access point, an initial transmission time and a transmission period of the intra prediction frame, where the transmission time of the intra prediction frame in the at least two stations is The interval of the initial transmission time of the intra prediction frame of any two stations of the neighbor is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations, and any two adjacent stations The initial transmission time interval of the intra prediction frame is greater than zero.
  • An Access Point is a network-side device that can provide wireless signal transmission and reception services for a station (STA).
  • the wireless signal provided by each AP can cover a certain range of locations.
  • the STAs in the coverage area access the network through the AP, and the AP and the multiple STAs connected thereto form a basic service set (BSS).
  • BSS basic service set
  • the STA associated with the AP refers to the STA in the BSS of the AP.
  • the I frame is periodically transmitted.
  • the initial transmission time of the I frame of each STA refers to the transmission time of the first I frame sent when the I frame of each STA operates according to a specific transmission period.
  • the AP initially sets the transmission time and the transmission period for the I frame of each STA, so that the transmission time of the I frame of each STA is shifted.
  • the initial transmission time of the I frame of each STA needs to satisfy the following condition: in each STA, the initial transmission time interval of the I frame of any two STAs adjacent to the transmission time of the I frame is not equal to the adjacent The difference between the transmission periods of the I frames of any two STAs.
  • any two adjacent STAs refer to two STAs adjacent to the transmission time of the I frame.
  • n 0, 1, 2, ..., N GOP (1) and N GOP (2) are the length of Group of Pictures (GOP) of STA1 and STA2, respectively, and how many image frames are represented by GOP
  • GOP Group of Pictures
  • the time interval is:
  • t 1 -t 2 (mN GOP (1)/F+T 1 )-(nN GOP (2)/F+T 2 )
  • the minimum value of the interval of the transmission time of the I frame of STA1 and STA2 is:
  • the minimum interval of the transmission time of the I frame of STA1 and STA2 is the interval of the initial transmission time of STA1 and STA2.
  • the initial transmission time interval of the intra prediction frames of any two adjacent STAs is the same.
  • the interval of the initial transmission time of the intra prediction frames of any two adjacent STAs may be different.
  • the initial transmission time interval of the intra prediction frames of any two adjacent STAs is:
  • K is the total number of STAs
  • F is the frame rate of each STA.
  • the preset frame interval can also be determined by other means, which is only an example in this embodiment, and is not limited thereto.
  • the initial transmission time interval of the intra prediction frames of any two adjacent STAs is: For example, if the STA rate of each STA is 30 fps, the GOP value of each STA is 20, and the number of STAs is 10, the AP can allocate a service period for one STA i for transmission every 1/15 second. An I frame.
  • the transceiver module 12 is configured to send an initial transmission time and a transmission period of the intra prediction frame to each of the at least two stations.
  • the transceiver module 12 After the processing module 11 allocates an initial transmission time and a transmission period to each STA, the transceiver module 12 notifies each STA. Specifically, the transceiver module 12 is configured to:
  • each STA sends a frame interval setting request of the first I frame, and the frame interval setting request of the first I frame includes an initial transmission time of each STA, so that each STA sets its own I frame according to the initial transmission time. Initial send time. After setting the initial transmission time of its own I frame, each STA returns the frame interval setting response of the first I frame to the AP.
  • Table 1 is a schematic diagram of a frame format of a frame interval setting request of the first I frame.
  • the frame interval setting request of the first I frame includes four fields, and the information represented by each is: category, action, and session order.
  • the category is used to indicate the category of the frame interval setting request of the first I frame
  • the session token field is set to a value selected by the STA that transmitted the frame to uniquely identify the session.
  • the interval field of the new I frame indicates that the STA immediately adjusts the I frame interval performed by the current video compression coding to the value of the interval field of the new I frame after receiving the frame interval setting request frame.
  • the AP may set the difference between the transmission time of the request frame and the initial transmission time of the I frame of the desired STA according to the frame interval of the I frame, and set the value of the interval field of the new I frame.
  • the frame interval setting response of the first I frame returned by each STA is received, and the frame interval setting response of the first I frame includes an adjustment result of the initial transmission time of the I frame of each STA.
  • the STA may set the initial transmission time to the initial transmission time included in the frame interval setting request of the first I frame according to the indication of the AP, or may not.
  • the STA will return the frame interval setting response of the first I frame to the AP for the initial transmission time of its own I frame.
  • Table 2 shows the frame format of the frame interval response of the first I frame. As shown in Table 2, the frame interval setting response of the first I frame also includes four fields: category, action, session token, and interval report of the I frame. .
  • FIG. 3 is an I frame interval report field format, and the interval report field of the I frame includes three fields: an I frame interval response, an unset reason, a desired GOP value, and an I frame interval response field occupying 1 bit.
  • the value indicates that the STA has set the initial transmission time of its own I frame according to the initial transmission time in the frame interval setting request of the first I frame, and the reason field is not set to be reserved.
  • the value of the interval response field of the I frame is not 1, it indicates that the STA does not set the initial transmission time of the I frame according to the initial transmission time in the frame interval setting request of the first I frame, and the value of the reason field that is not set.
  • the expected GOP value field is the GOP value expected by the STA.
  • the transceiver module 12 The STA sends a frame interval setting request of the second I frame, and the frame interval setting request of the second I frame includes a transmission period of the I frame of each STA, so that each STA adjusts the transmission period of the respective I frame to the second I frame.
  • the frame interval sets the transmission period included in the request.
  • the frame format of the frame interval setting request of the second I frame is the same as the frame format of the frame interval setting request of the first I frame, except that the generation interval field of the new I frame in the frame interval setting request of the second I frame is The value is the transmission period of the STA's I frame.
  • the processing module 11 is further configured to allocate, for each station, a service period of the intra prediction frame and a service period of the forward prediction frame according to an initial transmission time and a transmission period of the intra prediction frame of each station, where each The station exclusively enjoys the channel during the service period of the intra prediction frame and the service period of the forward prediction frame, wherein the interval T of the service period of the intra prediction frame of any two adjacent stations satisfies the following condition: T min ⁇ T ⁇ T max , T min and T max are determined by the access point according to an initial transmission time and a transmission period of an intra prediction frame of each station.
  • T min ⁇ T ⁇ T max are initial transmission times of the intra prediction frame of the AP according to each STA.
  • the transmission period is determined.
  • T min and T max are calculated by the following formula:
  • T min min ⁇
  • T max max ⁇
  • the length of the GOP of any two adjacent STAs, F is the frame rate of any two adjacent STAs, and T 1 and T 2 are the initial transmissions of the I frames of any two adjacent STAs, respectively.
  • Time, the sum of the transmission times of each data frame in one GOP of one STA is equal to the length of the transmission period of the STA.
  • the processing module 11 allocates a service period (Service Period, SP for short) and a service period of the P frame for each STA according to the initial transmission time and the transmission period of the I frame of each STA, and the I frame of each STA.
  • the service periods of the STAs of the STAs do not overlap in time, and the service periods of the P frames of the STAs do not overlap in time.
  • the service period of the I frame of each STA and the service period of the P frame are the contention free slots, and each STA is in the I frame.
  • Exclusive channel for service period and P frame service period The size of the service period of the I frame of each STA and the service period of the P frame may be set according to actual needs.
  • the size of the I frame of one STA is 8-10 times of the P frame. Therefore, the AP can be set at the time of setting.
  • the service period of the I frame of the STA is set to be greater than the service period of the P frame.
  • the service period of the I frame of the STA may be the same as the service period of the P frame, which is not limited by the present invention.
  • the interval of the service period of the I frame allocated by the processing module 11 for each STA needs to meet certain conditions: the minimum value of the interval of the I frame of any two adjacent STAs is min ⁇
  • ) max ⁇
  • represents the interval of the initial transmission time of the I frame of any two adjacent STAs
  • /F is the position of any two adjacent STAs The difference between the transmission periods of I frames.
  • the transceiver module 12 is further configured to send, to the stations, an allocation result of a service period of the intra prediction frame of each station and a service period of the forward prediction frame.
  • the processing module 11 allocates the service period of the I frame and the service period of the P frame to each STA, and then receives The transmitting module 12 notifies each STA of the allocation result, and each STA transmits an I frame according to the service period of the I frame allocated to itself, and transmits a P frame during the service period of the P frame allocated to itself, without performing channel competition.
  • the processing module sets the initial transmission time and the transmission period of the I frame of each STA associated with the AP, so that the initial transmission time interval of the I frame of any two STAs adjacent to the transmission time of the I frame is not Equal to the difference of the transmission period of the I of the two adjacent STAs, and then, according to the initial transmission time and the transmission period of the I frame of each STA, the service period of the I frame and the service period of the P frame are allocated to each STA.
  • Each STA enjoys the channel exclusively during the service period of the I frame and the service period of the P frame, so that the transmission time of the I frame of each STA is staggered, so that the network load is balanced, and the delay QoS of each STA is guaranteed to meet the requirements.
  • An access point is provided in the second embodiment of the present invention.
  • the structure of the access point in this embodiment may be referred to the structure of the access point in the first embodiment.
  • the access point provided in this embodiment is in the first embodiment.
  • the processing module 11 is further configured to:
  • the processing module 11 receives a Video Traffic Specification (VTSPEC) element sent by each STA, where the VTSPEC element includes a nominal length, a maximum length, a nominal length of the P frame, and a maximum of the I frame of the corresponding STA. Length and average send rate.
  • the AP determines the average length of the I frame of each STA according to the nominal length and the maximum length of the I frame of each STA, and determines the average length of the P frame of each STA according to the nominal length and the maximum length of the P frame of each STA.
  • VTSPEC Video Traffic Specification
  • FIG. 4 is a schematic structural diagram of a VTSPEC element.
  • the VTSPEC element includes the following fields in sequence: element ID, length, service flow information, nominal I frame MSDU length, maximum I frame MSDU length, and nominal P frame MSDU. Length, maximum P frame MSDU length, minimum service interval, maximum service interval, inactive interval, pause interval, service start time, minimum data rate, average data rate, peak data rate, burst length, delay limit, minimum PHY rate, excess bandwidth tolerance, media time.
  • the nominal I frame MSDU length field includes an unsigned integer specifying the nominal size of the MSDU or A-MSDU of the I frame belonging to the service flow, in units of octets.
  • the Maximum I Frame MSDU Length field contains an unsigned integer specifying the maximum value of the MSDU or A-MSDU of the I frame belonging to the service flow in octets.
  • the nominal P frame MSDU length and the maximum P frame MSDU length field also respectively contain an unsigned integer for specifying the nominal size or maximum value of the MSDU or A-MSDU of the I frame belonging to the service flow, to eight
  • the bit group is a unit.
  • the processing module 11 is further configured to separately calculate a service period of the intra prediction frame of each station according to an average length of intra prediction frames of each station and an average transmission rate of each station, and according to the foregoing The average length of the forward predicted frame of the station and the average transmission rate of the stations respectively calculate the service period of the forward predicted frame of each station.
  • the processing module 11 is further configured to determine, according to an initial sending time and a sending period of the intra prediction frame of each station, an interval of a service period of the intra prediction frame of any two adjacent stations.
  • the minimum interval of the service period of the I frame of any two adjacent STAs is min ⁇
  • the maximum value of the service period interval of the I frame of any two adjacent STAs is max ⁇
  • the interval of the service period of the I frame of any two adjacent STAs may be equal to or greater than the minimum value.
  • the service period of the I frame of any two adjacent STAs is the same. For the calculation of the interval of the service period of the I frame, refer to the related description in the first embodiment, and details are not described herein again.
  • the processing module 11 is further configured to: according to the service period of the intra prediction frame of each station and the service period of the forward prediction frame, and the interval of the service period of the intra prediction frame of any two adjacent stations is Each of the stations allocates a service period of the intra prediction frame and a service period of the forward prediction frame.
  • the processing module 11 is further configured to: in each of the beacons
  • the channel competition period is allocated to the stations in the interval, and specifically, the allocation unit 133 may be allocated, where the channel contention period is used when the stations in the frame predict the service period of the frame and the service period of the forward prediction frame.
  • the channel contention period may be pre-allocated by the AP in the BI, or may be a time after the service period of the remaining I frame and/or the service period of the P frame are dynamically released by some lightly loaded STAs.
  • the transceiver module 12 is further configured to: further send, to each STA, a contention period control signaling, where the contention period control signaling is used to prohibit each STA Some STAs or all STAs access the channel during the channel competition period before the first service period in the respective BI, and the first service period of each STA is the service period of the I frame or the service period of the P frame.
  • the contention control signaling is included in the control field of the scheduling element when the AP is in the scheduling service period of the STA, and is represented by 1 bit. When the contention control signaling is set to 1, it indicates that the STA is prohibited from being in its first service period. The previous channel contends to access the channel, otherwise the STA is allowed to access the channel during the channel contention period prior to its first service period.
  • T BI is the length of one BI
  • C is the proportional coefficient
  • T I (i) represents the length of the I frame of the i th STA
  • T P (i) represents the length of the P frame of the i th STA
  • i 1, 2..., K
  • C is related to the rate dynamic range of the STA. The larger the rate variation range of the STA, the smaller the C is, and the smaller the rate variation range of the STA is, the larger the C is.
  • the remaining time in the BI that is not allocated as the service period can be used to allocate as a channel competition period (CP), that is, the length of the channel competition period is (1-C) ⁇ T BI to satisfy
  • CP channel competition period
  • the channel contention period is shared by each STA, and each STA performs a contention channel in the channel usage period. Data is sent.
  • C is equal to 1, all time in the BI is allocated as the service period, and no channel competition period is reserved.
  • FIG. 5 is a schematic diagram of the service period of the I frame and the service period of the P frame.
  • the BTP is a Beacon Transmission Period
  • the ATP indicates an Announce Transmission Period, ATP.
  • SP 1 is the service period of the P frame of STA1
  • SP 2 is the service period of the P frame of STA2
  • SP N is the STA of the Nth P frame.
  • the service period, SP 3 is the service period of the I frame of STA3
  • CP 1 and CP 2 are the channel competition periods.
  • STA 3, STA 4, ... STA N are prohibited from using CP 1, but STA1 and STA 2 can use CP 1.
  • the processing module 11 is further configured to: when detecting that an initial transmission time interval of an I frame of any two adjacent STAs is equal to a difference of a transmission period of an I frame of any two adjacent STAs, Sending an interval request frame of the I frame to request at least one of the two adjacent STAs to adjust the transmission period of the I frame, so that the initial transmission time of the adjusted I frame of any two adjacent STAs The interval is not equal to the difference of the transmission period of the I frame of any two adjacent STAs.
  • the processing module sets an initial transmission time and a transmission period of the I frame of each STA associated with the AP, and the processing module allocates an I frame for each STA in the BI according to the initial transmission time and the transmission period of the I frame of each STA.
  • each STA exclusively enjoys the channel during the service period of the I frame and the service period of the P frame, and each STA contends for the channel during the channel contention period, thereby making the I frame of each STA
  • the transmission time is staggered, so that the network load is balanced, ensuring that the peak load of the network does not exceed the network load tolerance, thereby ensuring that the delay QoS of each STA meets the requirements, and by assigning the channel competition period to the STA in the BI, the SP duration cannot be satisfied.
  • the required STAs can compete for access channels during the channel contention period as needed, so that the remaining data of the cache can be transmitted.
  • the carrier Sense Multiple Access/Collision Avoidance (CSMA-CA) collision probability increases to avoid the video service homogeneity.
  • the AP should first set a User Priority (UP) for each STA from the importance of the STA.
  • the STA sets the video stream according to its own reference user priority. The priority of the same type of frame.
  • UP User Priority
  • the third embodiment of the present invention provides an access point.
  • the structure of the access point provided by the embodiment of the present invention can be referred to the structure of the access point in the first embodiment.
  • the access point in this embodiment is implemented.
  • the processing module 11 of the access point of the second embodiment is further configured to: set a reference user priority for each station according to the importance of the video monitoring area of each site or the content of the monitoring content.
  • this embodiment can adopt a 4-level user priority (UP): tight, high, medium, and low:
  • UP 4-level user priority
  • Urgent (Level 4): Emergency Signaling/Reporting, Data
  • the transceiver module 12 is further configured to send a reference user priority of each site to the sites, so that the sites set channel competition for the channel competition period according to respective reference user priorities. Incoming parameters, and priorities of the intra predicted frame and the forward predicted frame.
  • the transceiver module 12 may carry the priority of each STA in the STA priority allocation element, and the STA priority allocation element may be included in the beacon frame.
  • FIG. 6 is a schematic structural diagram of a priority allocation element of an STA, where the STA priority allocation element includes: an element ID, a length, a reference user priority of STA1, a reference user priority of STA2, ... STA N Baseline user priority.
  • the value of each STA priority field is as follows: When set to 1, it indicates that the STA's reference user priority is level 1. When set to 2, it indicates that the STA's reference user priority is level 2. When set to 3, the STA's reference user priority is set. The level is level 3. When set to 4, the base user priority of the STA is level 4.
  • the access parameters of the STA include: a minimum contention window CWmin, a maximum contention window CWmax, and an arbitration frame. Inter-Interval Space (AIFS) and Transmission Opportunity (TXOP).
  • AIFS Inter-Interval Space
  • TXOP Transmission Opportunity
  • the STA must consider the homogenous characteristics of the video stream service when setting these channel contention access parameters.
  • the parameter values of the STAs cannot be too different, and the gaps between the different levels of the priority parameters are appropriately opened, which can avoid the collision of different STAs and effectively reduce the delay of the high-priority video service.
  • Table 3 is a schematic diagram of channel contention access parameters of STAs of different priorities:
  • the user priority setting method of the STA belongs to the application layer, and the STA can set the user of all the local data frames according to the high level instruction (the SME issues the primitive including the priority configuration parameter) or the receiving the AP instruction (such as the STA priority allocation element). priority.
  • the user priority of the STA is divided into an internal data frame priority and a data frame priority between the STAs.
  • each data frame (I frame or P frame) within the same video stream is sent in the first-in first-out order in the time of entering the buffer queue. This is because for an I frame or a P frame of the same STA, each I frame or P frame corresponds to an image of the video, and the I frame and the P frame have the same delay QoS requirement, and the video encoding generation order should be followed. Perform first-in, first-out caching and sending.
  • the STA needs to buffer the I frame and the P frame into two queues respectively, wherein the priority of the I frame is higher than the priority of the P frame.
  • the priority setting method of the data frame is as follows: (1) the priority of the P frame of the STA is the same as the priority of the reference user of the STA, the priority of the I frame is higher than the priority of the P, and the priority of the retransmission frame is higher than that of the non-weight. Priority of the frame to be transmitted; (2) After detecting the motion, the STA can increase the priority of all data frames by the same number of levels; (3) Retransmit the data frame should raise the priority. The effect of priority on reducing the probability of access collision is reflected in the fact that the data frames of different STAs have different priorities.
  • the processing module 11 is further configured to: detect whether the video surveillance content of each site changes in motion. If the video surveillance content of any one of the sites is detected And a motion change occurs, adjusting a service period of the intra prediction frame allocated by the station and a service period of the forward prediction frame, and adjusting a reference user priority of the station, where the station adjusts the intra prediction frame
  • the service period is greater than the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-adjusted frame of the station is greater than the service period of the forward-predicted frame before the adjustment
  • the adjusted priority of the reference user is high.
  • the baseline user priority before adjustment is used to: detect whether the video surveillance content of each site changes in motion. If the video surveillance content of any one of the sites is detected And a motion change occurs, adjusting a service period of the intra prediction frame allocated by the station and a service period of the forward prediction frame, and adjusting a reference user priority of the station, where the station adjusts the intra prediction frame
  • the transceiver module 12 is further configured to notify the site of the adjustment result of the processing module 11.
  • Motion changes in the appearance of content in still images are important events in video surveillance applications.
  • the monitoring terminal in the video surveillance for security finds that there is a person movement in the still image, or the monitoring terminal in the traffic monitoring finds that the vehicle motion appears in the still image, the importance of the monitoring terminal is greatly improved, resulting in
  • the QoS requirements such as packet loss rate and delay are also significantly higher than other monitoring terminals. Therefore, in this embodiment, the AP needs to detect whether the video monitoring content of each STA changes.
  • the motion detection of the video surveillance content may be performed on the STA or the AP side.
  • the motion detection report element may specifically notify the other party of the motion detection result.
  • the motion detection report element can be included in an announcement frame or an information response frame.
  • 7 is a schematic structural diagram of a motion detection report element.
  • the motion detection report element provided in this embodiment includes the following fields: element ID, length, detected motion, service period delay request, and STA priority. If the motion monitoring content motion of the STA is detected, the motion field is set to 1 to indicate that the video monitoring content of the STA has undergone a motion change. Otherwise, the motion monitoring content of the STA does not change.
  • the service period extension request field is set to 1, indicating that the requesting AP temporarily extends the service period of the I frame of the STA and the service period of the P frame in the subsequent BI; the service period extension request field When set to 0, it indicates that the requesting AP recovers the service period of the original I frame and the service period length of the P frame.
  • the STA priority field is used by the AP to indicate the increased priority level that the STA should set in the subsequent BI. When the STA priority field is set to 0, it indicates that the STA maintains the current priority.
  • the STA After receiving the motion detection report element sent by the AP, the STA allocates more scheduling time slots for the data of the STA that detects the motion according to the data frame priority rule between the STAs, that is, increases the service period of the I frame of the STA. Length and length of the service period of the P frame, the service period of the I frame is increased The amplitude depends on the variation range of the video surveillance content, and the AP can obtain the experience value according to the dynamic change history data of different STA monitoring rates, thereby determining the service period length and required of the I frame required after the motion monitoring content movement of each STA is changed. The length of the service period of the P frame. In addition, the AP raises the priority of the STA of the STA, and the priority of the I frame of the STA and the priority of the P frame are both increased by the same level, and the delay QoS of the STA is preferentially guaranteed.
  • the processing module 11 is further configured to: after the video surveillance content of the site does not undergo motion change, restore a service period of the intra prediction frame of the site, a service period of the forward predicted frame, and a reference user of the user.
  • a priority wherein a service period of the intra-predicted frame after the station is restored is equal to a service period of the intra-predicted frame before the adjustment, and a service period of the forward-predicted frame after the station is restored is equal to the pre-adjustment
  • the service period of the forward predicted frame, the reference user priority after the site is restored is equal to the pre-adjusted reference user priority.
  • the transceiver module 12 is further configured to notify the site of the recovery result of the processing module 11.
  • the AP After the AP detects that the video surveillance content of the STA does not move, the AP should restore the length of the service period of the I frame of the STA and the length of the service period of the P frame, and restore the reference user priority of the STA, thereby The priority of all data frames is restored to before the boost.
  • the video coding rate of these STAs is significantly increased due to the motion change of the video surveillance content of some STAs, which leads to insufficient time resources.
  • the AP should set the STA's video coding quantization parameter QP to reduce the coding rate of some STAs with lower priority. Frame rate, or set the encoding mode to a lower rate CBR encoding.
  • the processing module sets the reference user priority for each STA, so that each STA sets its own access parameters according to the respective reference user priorities, and contends the channel competition period according to the access parameters. Since the access parameters of users of different priorities are different, it is possible to reduce the collision probability when each STA competes for a channel competition period.
  • the processing module further detects whether the video surveillance content of each STA changes in motion. After the motion monitoring content of the STA changes, the service period and the P frame of the I frame of the STA are correspondingly increased. The service period and the priority of the STA are raised to preferentially guarantee the delay QoS of the STA.
  • the application layer of the access point may be in the frame delivered to the media access control MAC layer. Carrying a frame type parameter in the predicted frame and the forward predicted frame to make the MAC layer root of the access point
  • the received data frame is determined to be the intra predicted frame or the forward predicted frame according to the frame type parameter.
  • FIG. 8 is a schematic structural diagram of a site according to Embodiment 4 of the present invention. As shown in FIG. 8, the site provided in this embodiment includes: a receiving module 21 and a sending module 22.
  • the receiving module 21 is configured to receive an initial sending time and a sending period of the intra predicted frame sent by the access point.
  • the receiving module 21 is specifically configured to: receive a frame interval setting request of a first intra prediction frame sent by the access point, where a frame interval setting request of the first intra prediction frame includes an initial sending of the site And receiving a frame interval setting request of the second intra prediction frame sent by the access point, where the frame interval setting request of the second intra prediction frame includes a transmission period of the intra prediction frame of the station.
  • the receiving module 21 is further configured to receive an allocation result of a service period of the intra prediction frame and a service period of a forward prediction frame sent by the access point, a service period of the intra prediction frame, and the The service period of the forward prediction frame is that the access point allocates for the station within each beacon interval according to an initial transmission time of the station and a transmission period of the intra prediction frame;
  • the sending module 22 is configured to send the intra prediction frame during a service period of the intra prediction frame according to an initial transmission time of the intra prediction frame and a transmission period of the intra prediction frame, where The forward predicted frame is transmitted during the service period of the forward predicted frame.
  • the sending module sends an I frame during the service period of the AP allocation I frame according to the initial sending time and the sending period of the I frame allocated by the AP, and sends the P frame during the service period of the P frame, and the AP is allocated.
  • the STAs of each STA are made to load balance, and the delay QoS of each STA is guaranteed to meet the requirements.
  • FIG. 9 is a schematic structural diagram of a site according to Embodiment 5 of the present invention.
  • the site in this embodiment includes the access point allocation in each beacon interval on the basis of the site in Embodiment 4.
  • Channel competition period when the station fails to transmit all the data buffered during the service period of the intra prediction frame and the service period of the forward prediction frame, the station uses the channel competition period Data is transmitted, the channel contention period being shared by all sites associated with the access point.
  • the receiving module 21 is further configured to: receive contention period control signaling sent by the access point, where the contention period control signaling is used to prohibit the station from being in each of the beacon intervals.
  • the channel is accessed during a channel competition period before the first service period, and the first service period of the station is the service period of the intra prediction frame or the service period of the forward prediction frame.
  • the site further includes: a setting module 23.
  • the receiving module 21 is further configured to receive a user reference priority reference user priority sent by the access point.
  • the setting module 23 is configured to set a channel contention access parameter of the channel contention period according to the user reference priority reference user priority, and compete for a channel during the contention period according to the channel contention access parameter.
  • the setting module 23 is further configured to set a priority of the intra prediction frame and a priority of the forward prediction frame according to the user reference priority reference user priority, where the forward prediction frame is The priority is the same as the priority of the user reference priority reference, the priority of the intra prediction frame is higher than the priority of the forward prediction frame, and the retransmission frame of the station has a higher priority than the non-retransmission frame.
  • the specific implementation manner of the setting module 23 for setting the channel contention access parameter of the channel competition period according to the user reference priority reference user priority may refer to the related description in the third embodiment, and details are not described herein again.
  • the receiving module 21 is further configured to: receive an adjustment result sent by the access point, where the adjustment result is sent after the access point detects a motion change of the video surveillance content of the site,
  • the adjustment result includes: a service period of the adjusted intra prediction frame, a service period of the adjusted forward prediction frame, and an adjusted reference user priority, where the site-adjusted intra prediction frame
  • the service period is greater than the service period of the intra-predicted frame before the adjustment
  • the service period of the adjusted forward prediction frame is greater than the service period of the forward-predicted frame before the adjustment
  • the adjusted base user priority of the station Higher than the pre-adjusted baseline user priority.
  • the receiving module 21 is further configured to: receive a recovery result sent by the access point, where the recovery result is sent after the access point detects that the video surveillance content of the site does not move.
  • the recovery result includes: a service period of the intra predicted frame after the station is restored, a service period of the restored forward predicted frame, and a restored reference user priority, wherein the intra prediction after the station is restored
  • the service period of the frame is equal to the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-predicted frame after the station is restored is equal to the service period of the forward-predicted frame before the adjustment, after the site is restored
  • the baseline user priority is equal to the pre-adjusted baseline user priority.
  • the service period of the intra prediction frame allocated by the access point to the station is greater than the service period of the forward prediction frame.
  • the application layer of the station transmits the intra prediction frame to the medium access control MAC layer and the
  • the forward prediction frame carries a frame type parameter, so that the MAC of the station determines, according to the frame type parameter, that the received data frame is the intra predicted frame or the forward predicted frame.
  • the setting module sets an access parameter of the channel competition period according to the reference user priority of the STA, and contends the channel competition period according to the access parameter. Since the access parameters of users of different priorities are different, it is possible to reduce the collision probability when each STA competes for a channel competition period.
  • the AP also detects whether the video surveillance content of the STA changes in motion, correspondingly increases the service period of the I frame of the STA and the service period of the P frame, and raises the priority of the STA, thereby giving priority to Guarantee the STA's delay QoS.
  • parameter interaction between a MAC layer management entity (MLME) of a STA and a video encoder is implemented by a packet management parameter transmitted by an MLME_SAP (Service Access Point).
  • MLME_SAP Service Access Point
  • the MLME may deliver the initial transmission time and the transmission period of the I frame carried by the MLME_SAP to the STA management entity (SME), and the SME adjusts and sets the video encoder. Input parameters.
  • the STA In order to enable the STA's MAC layer to distinguish between I and P frames, the STA must set the following packet parameter set for the MSDU that is passed to the MAC layer by the upper layer:
  • the set of primitive parameters between the MAC layer and the SME or high-level application TXLIST, RXLIST.
  • the TXLIST includes: a frame type (FRAME_TYPE), a delay QoS (Latency_QoS), a set GOP value (GOP_SET), and an RXLIST includes: motion detection (Motion_Detected), a requested GOP value (GOP_Requested).
  • FIG. 10 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 6 of the present invention. As shown in FIG. 10, the method in this embodiment may include the following steps:
  • Step 101 The AP allocates an initial transmission time and a transmission period of the I frame to the at least two associated STAs, where the initial transmission time of the I frame of any two STAs adjacent to the transmission time of the I frame in the at least two STAs is The interval is not equal to the difference of the transmission period of the I frame of any two adjacent STAs, and the interval of the initial transmission time of the I frame of any two adjacent STAs is greater than 0.
  • the initial transmission time of the intra prediction frames of the two adjacent stations is the same.
  • the initial transmission time interval of the intra prediction frame of the two adjacent stations is:
  • Step 102 The AP sends an initial transmission time and a transmission period of the I frame to each of the at least two STAs.
  • the access point separately sends a frame interval setting request of the first intra prediction frame to each station, where the frame interval setting request of the first intra prediction frame includes an initial sending time of each station, so that each station The initial transmission time of the own intra prediction frame is set according to the respective initial transmission time.
  • the access point receives a frame interval setting response of the first intra prediction frame returned by each station, where the frame interval setting response of the first intra prediction frame includes an initial transmission time of the intra prediction frame of each station. Adjust the results.
  • each station sets its own intra prediction frame according to the initial transmission time included in the frame interval setting request of the first intra prediction frame.
  • the initial transmission time the access point sends a frame interval setting request of the second intra prediction frame to each station, and the frame interval setting request of the second intra prediction frame includes a transmission period of the intra prediction frame of each station, Each station is caused to adjust the transmission period of the respective intra prediction frame to the transmission period included in the frame interval setting request of the second intra prediction frame.
  • Step 103 The AP allocates the service period of the I frame and the service period of the P frame for each STA according to the initial transmission time and the transmission period of the I frame of each STA, and each STA is independent in the service period of the I frame and the service period of the P frame.
  • the AP allocates the service period of the I frame and the service period of the P frame for each STA according to the initial transmission time and the transmission period of the I frame of each STA, and each STA is independent in the service period of the I frame and the service period of the P frame.
  • T min ⁇ T ⁇ T max , T min and T max are the intra prediction frames of the access point according to each station.
  • T min and T max are calculated by the following formula:
  • T min min ⁇
  • T max max ⁇
  • N GOP (1) and N GOP (2) are respectively the length of the image group of any two adjacent stations, and F is the frame rate of any two adjacent stations, and T 1 and T 2 are respectively The initial transmission time of the intra prediction frame of any two adjacent stations.
  • Step 104 The AP sends an allocation result of the service period of the I frame of each STA and the service period of the P frame to each STA.
  • the AP After allocating the service period of the I frame and the service period of the P frame for each STA, the AP notifies each STA of the allocation result, and each STA transmits an I frame according to the service period of the I frame allocated to itself, and allocates the P to itself.
  • a P frame is sent during the service period of the frame, and channel competition is not required.
  • the AP sets the initial transmission time and the transmission period of the I frame of the associated STAs, so that the initial transmission time interval of the I frames of any two STAs adjacent to the transmission time of the I frame is not equal to the adjacent one.
  • the difference between the transmission periods of I of any two STAs, and the service period of the I frame and the service period of the P frame are allocated to each STA according to the initial transmission time and the transmission period of the I frame of each STA, and each STA is in the I frame.
  • the service period and the service period of the P frame are exclusive channels, so that the transmission time of the I frames of each STA is staggered, so that the network load is balanced, and the delay QoS of each STA is guaranteed to meet the requirements.
  • the method in this embodiment can be performed by the access point provided in the first embodiment.
  • the specific implementation is the same as the principle.
  • FIG. 11 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 7 of the present invention.
  • the method of an embodiment may include the following steps:
  • Step 201 The AP allocates an initial transmission time and a transmission period of the I frame to the associated STAs, where the initial transmission time interval of the I frames of any two STAs adjacent to the transmission time of the I frame is not equal to the adjacent arbitrary The difference between the transmission periods of the I frames of the two STAs, and the interval between the initial transmission times of the I frames of any two adjacent STAs is greater than zero.
  • Step 202 The AP sends an initial transmission time and a transmission period of the I frame to each STA.
  • Step 203 The AP acquires an average length of an I frame of each STA and an average length of the P frame, and an average transmission rate of each STA.
  • Step 204 The AP calculates the service period of the I frame of each STA according to the average length of the I frame of each STA and the average transmission rate of each STA, and the average length of the P frames of each STA and the average transmission rate of each STA.
  • the service period of the P frame of each STA is calculated separately.
  • Step 205 The AP determines an interval of service periods of I frames of any two adjacent STAs according to an initial transmission time and a transmission period of the I frame of each STA.
  • Step 206 The AP allocates the service period of the I frame and the service of the P frame to each STA according to the service period of the I frame of each STA and the service period of the P frame, and the interval of the service period of the I frame of any two adjacent STAs. Period, and each channel is assigned a channel contention period within each beacon interval.
  • Step 207 The AP sends the service period of the I frame of each STA, the service period of the P frame, and the allocation result of the channel competition period to each STA.
  • the service period of the I frame allocated by the AP for each STA is greater than the service period allocated for the P frame allocated to each STA, and the channel contention period is reserved, and the channel contention period is used when each STA is in its own I frame.
  • the channel contention period may be pre-allocated by the AP in the BI, or may be a time after the service period of the remaining I frame and/or the service period of the P frame are dynamically released by some lightly loaded STAs.
  • the AP when the AP allocates a channel contention period in the BI, the AP also sends a contention period control signaling to each STA, where the contention period control signaling is used to prohibit some STAs or all STAs in each STA from being in the respective BIs.
  • the channel is accessed during the channel competition period before the first service period, and the first service period of each STA is the service period of the I frame or the service period of the P frame.
  • the AP sets the initial transmission time and the transmission period of the I frame of each associated STA, and allocates the service period of the I frame to each STA in the BI according to the initial transmission time and the transmission period of the I frame of each STA.
  • each STA exclusively enjoys the channel during the service period of the I frame and the service period of the P frame, and each STA contends for the channel during the channel competition period, so that the transmission time of the I frame of each STA is staggered.
  • the network load is balanced, ensuring that the peak load of the network does not exceed the network load tolerance, thereby ensuring that the delay QoS of each STA meets the requirements and passes
  • the STA allocates a channel contention period in the BI, so that each STA whose SP duration cannot meet the transmission requirement can compete for the access channel during the channel contention period as needed, so that the remaining data of the buffer can be transmitted.
  • the method in this embodiment can be performed by the access point in the second embodiment.
  • the specific implementation is similar to the technical solution.
  • the first embodiment and the second embodiment may further include the following steps: when the AP detects that the initial transmission time of the I frame of any two adjacent STAs is equal to the interval When the difference between the transmission periods of the I frames of any two adjacent STAs, the AP requests the at least one STA of any two adjacent STAs to adjust the transmission period of the I frame by transmitting the interval request frame of the I frame. The interval of the initial transmission time of the I frame adjusted by the two adjacent STAs is not equal to the difference of the transmission period of the I frame of any two adjacent STAs.
  • the AP when the AP detects the minimum interval of the service period of the I frame of any two adjacent STAs, min ⁇
  • the transmission period is such that the minimum value of the interval of the service period of the adjusted I frame of any two adjacent STAs is not less than the interval threshold.
  • FIG. 12 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 8 of the present invention. As shown in FIG. 12, the method provided in this embodiment may include the following steps:
  • Step 301 The AP allocates an initial transmission time and a transmission period of the I frame to the associated STAs.
  • the initial transmission time interval of the I frame of any two STAs adjacent to the transmission time of the I frame is not equal to the difference of the transmission period of the I frame of any two adjacent STAs, and any two adjacent ones
  • the initial transmission time interval of the I frames of the STAs is greater than zero.
  • Step 302 The AP sends an initial transmission time and a transmission period of the I frame to each STA.
  • Step 303 The AP allocates an I-frame service period, a P service period, and a channel competition period for each STA according to an initial transmission time and a transmission period of the I frame of each STA.
  • Step 304 The AP sends the service period of the I frame of each STA, the service period of the P frame, and the allocation result of the channel competition period to each STA.
  • step 301 and 302 For the specific implementation of the steps 301 and 302, reference may be made to the related description of the first embodiment, and details are not described herein again.
  • step 303 and step 304 For the specific implementation manner of step 303 and step 304, refer to the second embodiment. The relevant description is not repeated here.
  • Step 305 The AP sets a reference user priority for each STA according to the importance of each STA video surveillance area or monitoring content.
  • Step 306 The AP sends the reference user priority of each STA to each STA, so that each STA sets the channel contention access parameter of the channel contention period and the priority of the I frame and the P frame according to the respective reference user priorities.
  • Step 307 The AP detects whether the video surveillance content of each STA changes in motion.
  • step 308 is performed. If no, that is, no motion change occurs in the video monitoring content of each STA, then the process returns to step 307.
  • Step 308 The AP adjusts the service period of the I frame allocated by the STA and the service period of the P frame, and adjusts the reference user priority of the STA, and sends the adjustment result to the STA.
  • the service period of the I frame of the STA after the AP is adjusted is greater than the service period of the I frame before the adjustment, and the service period of the P frame of the STA after the AP adjustment is greater than the service period of the P frame before the adjustment, and the adjusted period is
  • the STA's baseline user priority is higher than the pre-adjusted baseline user priority.
  • Step 309 After the motion monitoring content of the STA does not change, the AP restores the service period of the I frame of the STA, the service period of the P frame, and the priority of the user of the user, and notifies the STA of the recovery result.
  • the service period of the I frame after the STA is restored is equal to the service period of the I frame before the adjustment
  • the service period of the P frame after the STA is restored is equal to the service period of the P frame before the adjustment
  • the reference user priority after the STA is restored. Equal to the baseline user priority before the adjustment.
  • the AP sets the reference user priority for each STA, so that each STA sets its own access parameters according to the respective reference user priorities, and contends the channel competition period according to the access parameters. Since the access parameters of users of different priorities are different, it is possible to reduce the collision probability when each STA competes for a channel competition period.
  • the AP also detects whether the video surveillance content of each STA changes in motion. When the motion monitoring content of a certain STA changes, the service period of the I frame of the STA and the service of the P frame are correspondingly increased. The priority of the STA is increased, so that the STA's delay QoS is preferentially guaranteed.
  • the method in this embodiment may be performed by the access point in the third embodiment.
  • the specific implementation is similar to the technical effect.
  • FIG. 13 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 9 of the present invention.
  • a method for transmitting a multiple video stream is described from the STA side.
  • the method in this embodiment may include the following steps:
  • Step 401 The STA receives an initial transmission time and a transmission period of an I frame sent by the AP.
  • the AP After the AP allocates the initial transmission time and the transmission period to the associated STAs, the AP sends the allocation result to each STA. Specifically, the STA receives the frame interval setting request of the first I frame sent by the AP, and the frame interval setting request of the first I frame includes the initial sending time of the STA. The STA receives the frame interval setting request of the second I frame sent by the AP, and the frame interval setting request of the second I frame includes the sending period of the I frame of the STA.
  • Step 402 The STA receives the service period of the I frame sent by the AP and the service period of the P frame, and the service period of the I frame and the service period of the P frame are the AP according to the initial sending time and the sending period of the STA in each BI. Assigned to the STA.
  • Step 403 The STA sends an I frame during the service period of the I frame according to the initial transmission time and the transmission period of the I frame, and sends the P frame during the service period of the P frame.
  • the STA exclusively enjoys the channel during the service period of the I frame and the service period of the P frame, and does not require a contention channel.
  • the STA sends an I frame during the service period of the P frame allocation period according to the initial transmission time and the transmission period of the I frame allocated by the AP, and the P frame is sent during the service period of the P frame.
  • the initial transmission time of each STA is staggered, so that each STA makes the network load balanced, and the delay QoS of each STA is guaranteed to meet the requirements.
  • the method of this embodiment can be performed by the site of the fourth embodiment.
  • the specific implementation is similar to the technical effect.
  • FIG. 14 is a flowchart of a method for transmitting a multiple video stream according to Embodiment 10 of the present invention. As shown in FIG. 14, the method provided in this embodiment may include the following steps:
  • Step 501 The STA receives an initial transmission time and a transmission period of an I frame sent by the AP.
  • Step 502 The STA receives the service period of the I frame and the service period of the P frame sent by the AP, and the service period of the I frame and the service period of the P frame are the APs according to the initial sending time and the sending period of the STA in each BI.
  • each BI also includes the channel competition period allocated by the AP.
  • the AP allocates a channel contention period to the associated STA in each BI.
  • the STA fails to send all the buffered data in the service period of the I frame and the service period of the P frame.
  • the STA transmits data using the channel contention period, and the channel contention period is shared by all STAs associated with the AP.
  • Step 503 The STA sends an I frame during the service period of the I frame according to the initial transmission time and the transmission period of the I frame, and sends the P frame during the service period of the P frame, if the STA is in the service period of the I frame and the service of the P frame.
  • the STA uses the channel to transmit data during the contention period.
  • the STA receives the contention period control signaling sent by the AP, where the contention period control signaling is used to prohibit the STA from accessing the channel during the channel competition period before the first service period in each BI, where the STA is first.
  • the service period is the service period of the I frame or the service period of the P frame.
  • Step 504 The STA receives the reference user priority sent by the AP, sets a channel contention access parameter of the channel competition period according to the reference user priority, and contends the channel according to the channel contention access parameter during the contention period, and preferentially according to the reference user.
  • the level sets the priority of the I frame and the priority of the P frame.
  • the priority of the P frame is the same as the priority of the reference user, the priority of the I frame is higher than the priority of the P frame, and the priority of the retransmission frame of the STA is higher than the priority of the non-retransmission frame.
  • Step 505 The STA receives the adjustment result sent by the AP, and the adjustment result is sent after the AP detects the motion monitoring content movement of the STA, and the adjustment result includes: the service period of the adjusted I frame of the STA, and the service of the adjusted P frame. Period and adjusted baseline user priority.
  • the service period of the adjusted I frame is greater than the service period of the I frame before the adjustment.
  • the service period of the P frame after the STA adjustment is greater than the service period of the P frame before the adjustment, and the priority of the adjusted user after the STA is higher than The baseline user priority before adjustment.
  • Step 506 The STA receives the recovery result sent by the AP, and the recovery result is sent after the AP detects that the video surveillance content of the STA does not change, and the recovery result includes: the service period of the I frame after the STA is restored, and the P frame after the restoration. Service period and baseline user priority after recovery.
  • the service period of the I frame after the STA is restored is equal to the service period of the I frame before the adjustment.
  • the service period of the P frame after the STA is restored is equal to the service period of the P frame before the adjustment, and the priority of the reference user after the STA is restored is equal to the adjustment. Previous base user priority.
  • the AP sets the reference user priority for each STA, so that each STA sets its own access parameters according to the respective reference user priorities, and contends the channel competition period according to the access parameters. Since the access parameters of users with different priorities are different, the STAs can be reduced. The probability of collision when competing for channel competition.
  • the AP also detects whether the video surveillance content of the STA changes in motion, correspondingly increases the service period of the I frame of the STA and the service period of the P frame, and raises the priority of the STA, thereby giving priority to Guarantee the STA's delay QoS.
  • the method of this embodiment can be performed by the site of the fifth embodiment.
  • the specific implementation is similar to the technical effect.
  • FIG. 15 is a schematic structural diagram of an access point according to Embodiment 11 of the present invention.
  • an access point 300 according to an embodiment of the present invention includes: a processor 31, a memory 32, a communication interface 33, and a system bus 34.
  • the memory 32 and the communication interface 33 are connected to the processor 31 via the system bus 34 and complete communication with each other; the memory 32 is configured to store a computer execution instruction; the communication interface 33 is used Communicating with other devices; the processor 31, configured to run the computer to execute instructions, to cause the access point 300 to perform the method as follows:
  • the interval of the initial transmission time of the frame is not equal to the difference of the transmission period of the intra prediction frame of any two adjacent stations, and the initial transmission time of the intra prediction frame of any two adjacent stations The interval is greater than 0;
  • T min and T max are calculated by the following formula:
  • T min min ⁇
  • T max max ⁇
  • N GOP (1) and N GOP (2) are respectively the length of the image group of any two adjacent stations, and F is the frame rate of any two adjacent stations, T 1 and T 2 The initial transmission time of the intra prediction frame of any two adjacent stations.
  • the initial transmission time of the intra prediction frames of the two adjacent stations is the same.
  • the initial transmission time interval of the intra prediction frames of the two adjacent stations is:
  • the processor 31 is further configured to: when detecting that an initial transmission time of an intra prediction frame of any two adjacent stations is equal to an interval of sending an intra prediction frame of any two adjacent stations And transmitting, by the interval request frame of the intra prediction frame, at least one of the two adjacent stations to adjust the transmission period of the own intra prediction frame, so as to make the adjacent arbitrary
  • the interval of the initial transmission time of the intra-predicted frame adjusted by the two stations is not equal to the difference of the transmission period of the intra-predicted frame of any two adjacent stations;
  • the processor 31 sends an initial transmission time and a transmission period of the intra prediction frame to the stations, specifically:
  • the station indicates that each station sets its own intra prediction according to the initial transmission time included in the frame interval setting request of the first intra prediction frame.
  • a frame interval setting request of the second intra prediction frame is sent to the stations, where the frame interval setting request of the second intra prediction frame includes the intra prediction frame of each station.
  • the transmission period is such that the stations adjust the transmission period of the respective intra prediction frame to the transmission period included in the frame interval setting request of the second intra prediction frame.
  • the processor 31 allocates the service period of the intra prediction frame and the service period of the forward prediction frame to the stations according to the initial transmission time and the transmission period of the intra prediction frame of each station, including:
  • Allocating intra-frames to the stations according to the service period of the intra-predicted frames of the stations and the service period of the forward-predicted frames, and the interval of the service period of the intra-predicted frames of any two adjacent stations The service period of the predicted frame and the service period of the forward predicted frame.
  • the processor 31 is further configured to: allocate, during the each beacon interval, a channel contention period for the stations, where the channel contention period is used when the stations predict the service period of the frame in its own frame and before When the entire data buffered cannot be transmitted to the predicted frame during the service period, the data is transmitted using the channel contention period, and the channel contention period is shared by the stations.
  • the processor 31 is further configured to: send, to the sites, contention control signaling, where the contention control signaling is used to prohibit some or all of the sites from being in the respective letters.
  • the channel is accessed during the channel competition period before the first service period within the standard interval, and the first service period of each station is the service period of the intra prediction frame or the service period of the forward prediction frame.
  • the service period of the intra prediction frame allocated by the access point to the each station is greater than the service period of the forward prediction frame allocated to the each station.
  • the processor 31 is further configured to: set a reference user priority for each site according to the importance of the video monitoring area of each site or the monitoring content; and send the reference user priority of each site to the Each station, such that each station sets a channel contention access parameter of the channel contention period according to a respective reference user priority, and a priority of the intra prediction frame and the forward prediction frame.
  • the processor 31 is further configured to: detect whether the video surveillance content of each site changes in motion; and if it detects that the video surveillance content of any one of the sites changes in motion, adjust to the site The service period of the allocated intra prediction frame and the service period of the forward predicted frame, and adjusting the reference user priority of the site, and notifying the site of the adjustment result.
  • the service period of the intra-predicted frame of the station is greater than the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-predicted frame of the station is greater than the service period of the forward-predicted frame before the adjustment.
  • the adjusted base user priority of the site is higher than the reference user priority before the adjustment.
  • the processor 31 is further configured to: restore a service period of the intra prediction frame of the station, a service period of the forward prediction frame, and a reference of the user after the motion monitoring content of the site does not undergo motion change. User priority and notify the site of the recovery result.
  • the service period of the intra-predicted frame after the station is restored is equal to the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-predicted frame after the station is restored is equal to the forward direction before the adjustment.
  • the service period of the predicted frame, the reference user priority after the site is restored is equal to the pre-adjusted reference user priority.
  • the application layer of the access point may be in the frame delivered to the media access control MAC layer. Carrying a frame type parameter in the predicted frame and the forward predicted frame, so that the MAC layer of the access point determines, according to the frame type parameter, that the received data frame is the intra predicted frame or the forward prediction frame.
  • the access point in this embodiment may be used to perform the methods in the sixth embodiment to the eighth embodiment.
  • the specific implementation manners and technical effects are similar, and details are not described herein again.
  • the site 400 provided by the embodiment of the present invention includes a processor 41, a memory 42, a communication interface 43, and a system bus 44.
  • the memory 42 and the communication interface 43 are connected to the processor 41 through the system bus 44 and are completed. Communication with each other; the memory 42 for storing computer execution instructions; the communication interface 43 for communicating with other devices; and the processor 41 for running the computer to execute instructions to make the site 400 performs the method described below:
  • a service period of the intra prediction frame and a service period of a forward prediction frame where a service period of the intra prediction frame and a service period of the forward prediction frame are Said access point is allocated for said station in each beacon interval according to an initial transmission time of said station and a transmission period of said intra prediction frame;
  • the forward predicted frame is transmitted during the period.
  • the processor 41 receives an initial transmission time of the intra prediction frame sent by the access point and a transmission period of the intra prediction frame, specifically, receiving a frame interval setting request of the first intra prediction frame sent by the access point. And the frame interval setting request of the first intra prediction frame includes an initial transmission time of the station. Receiving a frame interval setting request of the second intra prediction frame sent by the access point, where the frame interval setting request of the second intra prediction frame includes a transmission period of the intra prediction frame of the station.
  • the channel competition period allocated by the access point is further included in each beacon interval, when the station is in a service period of the intra prediction frame and a service period of the forward prediction frame Upon failing to transmit all of the buffered data, the station transmits data using the channel contention period, which is shared by all sites associated with the access point.
  • the processor 41 is further configured to: receive contention period control signaling sent by the access point, where the contention period control signaling is used to prohibit the first station in the each beacon interval.
  • the channel is accessed during the channel competition period before the service period, and the first service period of the station is the service period of the intra prediction frame or the service period of the forward prediction frame.
  • the processor 41 is further configured to: receive a user reference priority reference user priority sent by the access point; and set channel competition access of the channel competition period according to the user reference priority reference user priority. Parameters, and competing for access parameters according to the channel during the competition period a contention channel; and setting a priority of the intra prediction frame and a priority of the forward prediction frame according to the user reference priority reference user priority, wherein a priority of the forward prediction frame
  • the priority of the user reference priority reference is the same, the priority of the intra prediction frame is higher than the priority of the forward prediction frame, and the priority of the retransmission frame of the station is higher than the priority of the non-retransmission frame.
  • the processor 41 is further configured to: receive an adjustment result sent by the access point, where the adjustment result is sent after the access point detects a motion change of the video surveillance content of the site, where the adjustment is performed.
  • the result includes: a service period of the adjusted intra prediction frame of the station, a service period of the adjusted forward prediction frame, and an adjusted reference user priority, wherein the site-adjusted intra prediction frame is The service period is greater than the service period of the intra-predicted frame before the adjustment, the service period of the forward-adjusted frame of the station is greater than the service period of the forward-predicted frame before the adjustment, and the adjusted priority of the reference user is high.
  • the processor 41 is further configured to: receive a recovery result sent by the access point, where the recovery result is sent after the access point detects that the video surveillance content of the site does not move,
  • the recovery result includes: a service period of the intra predicted frame after the site is restored, a service period of the restored forward predicted frame, and a restored reference user priority, wherein the intra predicted frame after the station is restored
  • the service period is equal to the service period of the intra-predicted frame before the adjustment
  • the service period of the forward-predicted frame after the station is restored is equal to the service period of the forward-predicted frame before the adjustment, after the station is restored
  • the baseline user priority is equal to the baseline user priority before the adjustment.
  • the service period of the intra prediction frame allocated by the access point to the station is greater than the service period of the forward prediction frame.
  • the application layer of the station transmits the intra prediction frame to the medium access control MAC layer and the
  • the forward prediction frame carries a frame type parameter, so that the MAC of the station determines, according to the frame type parameter, that the received data frame is the intra predicted frame or the forward predicted frame.
  • the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

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Abstract

本发明实施例提供一种多视频流的传输方法和设备，AP设置关联的各STA的I帧的初始发送时间和发送周期，使I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I的发送周期的差值，并根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期和P帧的服务期，各STA在I帧的服务期和P帧的服务期内独享信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证每个STA的时延QoS满足要求。

Description

多视频流的传输方法和设备 技术领域
本发明涉及通信技术，尤其涉及一种多视频流的传输方法和设备。
背景技术
无线局域网(Wireless Local Area Networks，简称WLAN)具有成本低、部署便捷等优势，能满足无线视频监控网络的技术和成本要求。在无线视频监控中，人们对高清视频流的需求越来越大，而高清视频流的数据速率较高，导致多个视频监控终端并发传输高清视频流的网络负载较高。例如，720p编码格式的高清视频会议的典型数据速率为0.5Mbps-2.5Mbps，假设720p编码格式的高清视频流的平均速率约为1.5Mbps，15个视频监控终端的聚合数据速率将达到22.5Mbps。然而，根据802.11ah标准物理层的8MHz信道(Modulation and Coding Scheme，调制与编码策略，简称MCS)设计，即使15个站点(Station，简称STA)都能采用高阶的64-QAM(码率为2/3)，网络聚合吞吐量最大值也仅为23.4Mbps。因此，在中国分配的1GHz以下的频段779-787MHz上运行无线高清视频监控业务时，由于最大可用带宽有限，因此无线视频监控网络会常常运行在饱和状态。运行在饱和状态下的无线视频监控网络的负载变化范围不能过大，否则网络的峰值吞吐量会超过网络的负载容限。
在无线视频监控应用中，主流的视频编码标准采用H.264，其视频编码输出包括帧内预测帧(Intra frame，简称I帧)、前向预测帧(predictive frame，简称P帧)和双向预测内插编码帧(Bi-directional interpolated prediction frame，简称B帧)。由于I帧大小一般是P帧和B帧的8～10倍，因此，在均匀的图像帧间隔下，I帧的编码输出速率比P帧、B帧高得多。当多个STA同时或在相近的时间内都发送I帧时，会造成网络的负载峰值速率过高，超过网络负载容限，导致不能全部满足多个实时视频数据流的时延QoS要求。
发明内容
本发明实施例提供的多视频流的传输方法和设备，使得各STA的I帧的发送时间错开，使得网络负载均衡，保证每个STA的时延QoS满足要求。
本发明第一方面提供一种接入点，包括：
处理模块，用于为所述接入点关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0；
收发模块，用于向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期；
所述处理模块，还用于根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的；
所述收发模块，还用于向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
结合本发明第一方面，在本发明第一方面的第一种可能的实现方式中，Tmin和Tmax通过如下公式计算：
Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
其中，NGOP(1)和NGOP(2)分别为所述相邻的任意两个站点的图像组的长度，F为所述相邻的任意两个站点的帧率，T1和T2分别为所述相邻的任意两个站点的帧内预测帧的初始发送时间。
结合本发明第一方面以及本发明第一方面的第一种可能的实现方式，在本发明第一方面的第二种可能的实现方式中，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
结合本发明第一方面的第二种可能的实现方式，在本发明第一方面的第三种可能的实现方式中，所述任意相邻的两个站点的帧内预测帧的初始发 送时间的间隔为：
Figure PCTCN2014092577-appb-000001
其中，NGOP(i)为第i个站点的一个图像组的长度，i＝1，……K，K为站点的总数，F为所述各站点的帧率。
结合本发明第一方面的第二种和第三种可能的实现方式，在本发明第一方面的第四种可能的实现方式中，所述处理模块还用于：
当检测到所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值；
或者，当检测到所述相邻的任意两个站点的帧内预测帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的服务期的间隔的最小值不小于所述间隔门限。
结合本发明第一方面，以及本发明第一方面的第一种至第四种可能的实现方式，在本发明第一方面的第五种可能的实现方式中，所述收发模块具体用于：
向所述各站点分别发送第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述各站点的初始发送时间，以使所述各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间；
接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，所述第一帧内预测帧的帧间隔设置响应中包括所述各站点的帧内预测帧的初始发送时间的调整结果；
若所述各站点的帧内预测帧的初始发送时间的调整结果为表示所述各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时 间设置了自己的帧内预测帧的初始发送时间，则向所述各站点发送第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述各站点的帧内预测帧的发送周期，以使所述各站点将各自的帧内预测帧的发送周期调整为所述第二帧内预测帧的帧间隔设置请求中包括的发送周期。
结合本发明第一方面，以及本发明第一方面的第一种至第四种可能的实现方式，在本发明第一方面的第六种可能的实现方式中，所述处理模块具体用于：
获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率；
根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期；
根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔；
分配单元，用于根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
结合本发明第一方面，以及本发明第一方面的第一种至第六种可能的实现方式，在本发明第一方面的第七种可能的实现方式中，所述处理模块还用于：
在所述每个信标间隔内为所述各站点分配信道竞争期，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。
结合本发明第一方面的第七种可能的实现方式，在本发明第一方面的第八种可能的实现方式中，所述收发模块还用于：
向所述各站点发送竞争期控制信令，所述竞争期控制信令用于禁止所述各站点中的部分站点或者全部站点在各自的所述信标间隔内的第一个 服务期之前的信道竞争期内接入所述信道，所述各站点的第一个服务期为帧内预测帧的服务期或前向预测帧的服务期。
结合本发明第一方面的第一种至第八种可能的实现方式，在本发明第一方面的第九种可能的实现方式中，所述接入点为所述各站点分配的帧内预测帧的服务期大于为所述各站点分配的前向预测帧的服务期。
结合本发明第一方面的第七种或第八种可能的实现方式，在本发明第一方面的第十种可能的实现方式中，所述处理模块还用于：
根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级；
所述收发模块，还用于将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
结合本发明第一方面的第十种可能的实现方式，在本发明第一方面的第十一种可能的实现方式中，所述处理模块还用于：
检测所述各站点的视频监控内容是否发生运动变化；
若检测到所述各站点中的任意一个站点的视频监控内容发生运动变化，则调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级；
所述收发模块，还用于将所述处理模块的调整结果通知给所述站点；
结合本发明第一方面的第十一种可能的实现方式，在本发明第一方面的第十二种可能的实现方式中，所述处理模块还用于：
在所述站点的视频监控内容不发生运动变化后，恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
所述收发模块，还用于将所述处理模块的恢复结果通知给所述站点。
结合本发明第一方面，在本发明第一方面的第十三种可能的实现方式中，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述接入点的MAC层根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本发明第二方面提供一种站点，包括：
接收模块，用于接收接入点发送的帧内预测帧的初始发送时间和发送周期；
所述接收模块，还用于接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
发送模块，用于根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
结合本发明第二方面，在本发明第二方面的第一种可能的实现方式中，所述接收模块具体用于：
接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间；
接收所述接入点发送的第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
结合本发明第二方面，在本发明第二方面的第二种可能的实现方式中，所述每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
结合本发明第二方面的第二种可能的实现方式，在本发明第二方面的第三种可能的实现方式中，所述接收模块还用于：
接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁 止所述站点在所述每个信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
结合本发明第二方面的第二种或第三种可能的实现方式，在本发明第二方面的第四种可能的实现方式中，所述站点还包括：设置模块；
所述接收模块，还用于接收所述接入点发送的用户基准优先级基准用户优先级；
所述设置模块，用于根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期内竞争信道；
所述设置模块，还用于根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。
结合本发明第二方面的第四种可能的实现方式，在本发明第二方面的第五种可能的实现方式中，所述接收模块还用于：
接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
结合本发明第二方面的第五种可能的实现方式，在本发明第二方面的第六种可能的实现方式中，所述接收模块还用于：
接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等 于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
结合本发明第二方面以及第二方面的第一种或第六种可能的实现方式，在本发明第二方面的第七种可能的实现方式中，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
结合本发明第二方面，在本发明第二方面的第八种可能的实现方式中，当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本发明第三方面一种多视频流的传输方法，包括：
接入点为关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0；
所述接入点向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期；
所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的；
所述接入点向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
结合本发明第三方面，在本发明第三方面的第一种可能的实现方式中，Tmin和Tmax通过如下公式计算：
Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
其中，NGOP(1)和NGOP(2)分别为所述相邻的任意两个站点的图像组的长度，F为所述相邻的任意两个站点的帧率，T1和T2分别为所述相邻的任意两个站点的帧内预测帧的初始发送时间。
结合本发明第三方面以及本发明第三方面的第一种可能的实现方式，在本发明第三方面的第二种可能的实现方式中，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
结合本发明第三方面的第二种可能的实现方式，在本发明第三方面的第三种可能的实现方式中，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔为：
Figure PCTCN2014092577-appb-000002
其中，NGOP(i)为第i个站点的一个图像组的长度，i＝1，……K，K为站点的总数，F为所述各站点的帧率。
结合本发明第三方面的第二种和第三种可能的实现方式，在本发明第三方面的第四种可能的实现方式中，所述方法还包括：
当所述接入点检测到所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值时，所述接入点通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值；
或者，当所述接入点检测到所述相邻的任意两个站点的帧内预测帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，所述接入点通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的服务期的间隔的最小值不小于所述间隔门限。
结合本发明第三方面，以及本发明第三方面的第一种至第四种可能的实现方式，在本发明第三方面的第五种可能的实现方式中，所述接入点向所述各站点发送帧内预测帧的初始发送时间和发送周期，包括：
所述接入点向所述各站点分别发送第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述各站点的初始发送时间，以使所述各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间；
所述接入点接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，所述第一帧内预测帧的帧间隔设置响应中包括所述各站点的帧内预测帧的初始发送时间的调整结果；
若所述各站点的帧内预测帧的初始发送时间的调整结果为表示所述各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时间设置了自己的帧内预测帧的初始发送时间，则所述接入点向所述各站点发送第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述各站点的帧内预测帧的发送周期，以使所述各站点将各自的帧内预测帧的发送周期调整为所述第二帧内预测帧的帧间隔设置请求中包括的发送周期。
结合本发明第三方面，以及本发明第三方面的第一种至第四种可能的实现方式，在本发明第三方面的第六种可能的实现方式中，所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，包括：
所述接入点获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率；
所述接入点根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期；
所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔；
所述接入点根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
结合本发明第三方面，以及本发明第三方面的第一种至第六种可能的实 现方式，在本发明第三方面的第七种可能的实现方式中，所述方法还包括：
所述接入点在所述每个信标间隔内为所述各站点分配信道竞争期，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。
结合本发明第三方面的第七种可能的实现方式，在本发明第三方面的第八种可能的实现方式中，所述方法还包括：所述接入点向所述各站点发送竞争期控制信令，所述竞争期控制信令用于禁止所述各站点中的部分站点或者全部站点在各自的所述信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述各站点的第一个服务期为帧内预测帧的服务期或前向预测帧的服务期。
结合本发明第三方面的第一种至第八种可能的实现方式，在本发明第三方面的第九种可能的实现方式中，所述接入点为所述各站点分配的帧内预测帧的服务期大于为所述各站点分配的前向预测帧的服务期。
结合本发明第三方面的第七种或第八种可能的实现方式，在本发明第三方面的第十种可能的实现方式中，所述方法还包括：
所述接入点根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级；
所述接入点将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
结合本发明第三方面的第十种可能的实现方式，在本发明第三方面的第十一种可能的实现方式中，所述方法还包括：
所述接入点检测所述各站点的视频监控内容是否发生运动变化；
若所述接入点检测到所述各站点中的任意一个站点的视频监控内容发生运动变化，则所述接入点调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级；
所述接入点将调整结果通知给所述站点；
结合本发明第三方面的第十一种可能的实现方式，在本发明第三方面的第十二种可能的实现方式中，所述方法还包括：
在所述站点的视频监控内容不发生运动变化后，所述接入点恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
所述接入点将恢复结果通知给所述站点。
结合本发明第三方面，在本发明第三方面的第十三种可能的实现方式中，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述接入点的MAC层根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本发明第四方面提供一种多视频流的传输方法，包括：
站点接收接入点发送的帧内预测帧的初始发送时间和发送周期；
所述站点接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
所述站点根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
结合本发明第四方面，在本发明第四方面的第一种可能的实现方式中，所述站点接收接入点发送的帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，包括：
所述站点接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间；
所述站点接收所述接入点发送的第二帧内预测帧的帧间隔设置请求， 所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
结合本发明第四方面，在本发明第四方面的第二种可能的实现方式中，所述每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
结合本发明第四方面的第二种可能的实现方式，在本发明第四方面的第三种可能的实现方式中，所述方法还包括：
所述站点接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁止所述站点在所述每个信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
结合本发明第四方面的第二种或第三种可能的实现方式，在本发明第四方面的第四种可能的实现方式中，所述方法还包括：
所述站点接收所述接入点发送的用户基准优先级基准用户优先级；
所述站点根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期内竞争信道；
所述站点根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。
结合本发明第四方面的第四种可能的实现方式，在本发明第四方面的第五种可能的实现方式中，所述方法还包括：
所述站点接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服 务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
结合本发明第四方面的第五种可能的实现方式，在本发明第四方面的第六种可能的实现方式中，所述方法还包括：
所述站点接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
结合本发明第四方面以及第四方面的第一种或第六种可能的实现方式，在本发明第四方面的第七种可能的实现方式中，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
结合本发明第四方面，在本发明第四方面的第八种可能的实现方式中，所述方法还包括：
当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本发明实施例的多视频流的传输方法和设备，AP设置关联的至少两个个STA的I帧的初始发送时间和发送周期，使I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I的发送周期的差值，并根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期和P帧的服务期，各STA在I帧的服务期和P帧的服务期内独享信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证网络负载始终在网络负载容限之内，从而保证每个STA的时延满足QoS要求。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作一简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为无线信道划分的示意图；
图2为本发明实施例一提供的接入点的结构示意图；
图3为I帧间隔报告字段格式；
图4为VTSPEC元素的结构示意图；
图5为I帧的服务期和P帧的服务期的分配结果的示意图；
图6为STA的优先级分配元素的结构示意图；
图7为运动检测报告元素的结构示意图；
图8为本发明实施例四提供的站点的结构示意图；
图9为本发明实施例五提供的站点的结构示意图；
图10为本发明实施例六提供的多视频流的传输方法的流程图；
图11为本发明实施例七提供的多视频流的传输方法的流程图；
图12为本发明实施例八提供多视频流的传输方法的流程图；
图13为本发明实施例九提供的多视频流的传输方法的流程图；
图14为本发明实施例十提供的多视频流的传输方法的流程图；
图15为本发明实施例十一提供的接入点的结构示意图；
图16为本发明实施例十二提供的站点的结构示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明各实施例的方法应用在无线视频监控领域中，无线个域网 (Wireless Personal Area Network，简称WPAN)标准工作组已开始为无线视频监控等应用制定视频个域网(Vedio Personal Area Network，简称VPAN)标准。该标准聚焦室内和室外的无线高清视频监控应用，目标是为网络规模适中、支持多路高清视频流并发传输的无线视频监控网络制定国家标准。802.11ah将中国779-787MHz频段的信道划分为8个1MHz信道、4个2MHz、2个4MHz信道和1个8MHz信道，如图1所示，图1为无线信道划分的示意图。此外，802.11ah还将中国的755-779MHz频段划分为24个带宽为1MHz的信道。按照802.11ah的信道划分方法，中国用于各类控制设备的1GHz以下物联网频段最大信道带宽仅为8MHz(779-787MHz频段)。
由于VPAN的最大可用带宽有限(779-787MHz)，多个视频监控终端并发传输高清视频流很容易使网络达到饱和，在WLAN中，视频监控终端通常为站点STA。例如720p编码格式的高清视频会议的典型数据速率为0.5Mbps-2.5Mbps，假设720p编码格式的高清视频流的平均速率约为1.5Mbps，15个STA的聚合数据速率将达到22.5Mbps。然而，根据802.11ah物理层的8MHz带宽的MCS设计，即使15个STA都能采用高阶的64-QAM(码率为2/3)，网络聚合吞吐量最大值也仅23.4Mbps。所以，受限于带宽和高业务负载，VPAN网络会常常运行在饱和状态，此时网络负载变化过大很容易突破网络的负载容限。另外，高清视频流压缩编码分为固定比特率(Constant Bit Rate，简称CBR)和变比特率(Variable Bit Rate，简称VBR)两种编码格式，而CBR的视频压缩编码质量低于VBR的视频压缩编码质量。对于VBR的视频压缩编码，数据速率与监测内容的变化快慢密切相关，对于变化较快的监控画面，视频流速率将呈现出很大的变化范围。
H.264是业界广泛使用的主流视频编码标准，其视频编码输出包括帧内预测帧(Intra frame，简称I帧)、前向预测帧(predictive frame，简称P帧)和双向预测内插编码帧(Bi-directional interpolated prediction frame，简称B帧)，I帧作为参考帧，是P、B帧解码的基础，因此I帧的重要性超过P帧和B帧。根据经验值，I帧大小一般是P帧和B帧大小的8～10倍。因此，在均匀的帧间隔下，I帧的编码输出速率比P帧、B帧高得多。 而B帧作为双向预测帧，不适合实时性应用，一般不在视频监控应用的视频编码中使用。在无线视频监控网络中，如果不同STA的I帧同时或在相近的时间内发送，会造成网络负载峰值速率过高，超过网络负载容限，导致部分或全部STA的时延不能满足QoS要求。
为了解决现有技术的问题，本发明实施例一提供一种接入点，图2为本发明实施例一提供的接入点的结构示意图，如图2所示，本实施例提供的接入点包括：处理模块11和收发模块12。
其中，处理模块11，用于为所述接入点关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0。
接入点(Access Point，简称AP)是能够为站点(station，简称STA)提供无线信号收发服务的网络侧设备。每个AP提供的无线信号可覆盖一定的位置范围，覆盖范围内的STA通过该AP接入网络，AP和其连接的多个STA组成一个基本服务集(Basic Service Set，简称BSS)。本实施例中，AP关联的STA是指AP的BSS内的STA。
I帧是周期性发送的，本实施例中，各STA的I帧的初始发送时间是指各STA的I帧按照一个特定的发送周期进行工作时发送的第一个I帧的发送时间。AP通过为各STA的I帧的设置初始发送时间和发送周期，以使各STA的I帧的发送时间错开。本实施例中，各STA的I帧的初始发送时间需要满足以下条件：各STA中，I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值。本实施例中，相邻的任意两个STA都是指I帧的发送时间相邻的两个STA。
假设该任意两个STA为STA1和STA2，STA 1和STA 2的I帧的发送时间分别为t1和t2，且t1＝m NGOP(1)/F+T1，t2＝n NGOP(2)/F+T2，其中，m表示STA1的I帧发送周期的序号，m的取值为m＝0,1,2,…，n表示STA2的I帧发送周期的序号，n的取值为n＝0,1,2,…，NGOP(1)和NGOP(2)分别为STA1和STA2 的图像组(Group of Pictures，简称GOP)长度，GOP表示多少图像帧里面出现一次I帧的值，GOP的单位为个数，F为STA1和STA2的帧率，T1和T2分别为STA1和STA2的I帧的初始发送时间，则STA1和STA2的I帧的发送时间的间隔为：
t1-t2＝(mNGOP(1)/F+T1)-(nNGOP(2)/F+T2)
当m＝n±1时，得到STA1和STA2的I帧的发送时间的间隔的最小值为：
min(|t1-t2|)＝|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|
STA1和STA2的I帧的发送时间的间隔的最小值即为STA1和STA2的初始发送时间的间隔。
为了使min(|t1-t2|)>0，应当有|NGOP(1)-NGOP(2)|/F≠|T1-T2|，即STA1和STA2的I帧的初始发送时间的差值应当不等于STA1和STA2的I帧的发送周期的差值。
可选的，任意相邻的两个STA的帧内预测帧的初始发送时间的间隔相同，当然，任意相邻的两个STA的帧内预测帧的初始发送时间的间隔也可以不同。通过设置任意相邻的两个STA的帧内预测帧的初始发送时间的间隔相同，从而实现将各个STA的I帧发送时间均匀分布。
可选的，当各STA的I帧的GOP不相同时，任意相邻的两个STA的帧内预测帧的初始发送时间的间隔为：
Figure PCTCN2014092577-appb-000003
其中，GOP(i)为第i个STA的GOP的长度，i＝1，……K，K为STA的总数，F为各STA的帧率。当然，预设的帧间隔还可以通过其他方式确定，本实施例中只是举例说明，并不对此进行限制。
如果各STA的I帧的GOP相同时，任意相邻的两个STA的帧内预测帧的初始发送时间的间隔为：
Figure PCTCN2014092577-appb-000004
例如，假设各STA的帧率为30fps， 各STA的GOP值都为20，STA的个数为10个，则AP可以在每1/15秒的时间内为一个STA i分配服务期用于传输一个I帧。
收发模块12，用于向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期。
处理模块11在为各STA分配初始发送时间和发送周期之后，由收发模块12通知各STA，具体的，收发模块12用于：
首先，各STA分别发送第一I帧的帧间隔设置请求，第一I帧的帧间隔设置请求中包括各STA的初始发送时间，以使各STA根据各自的初始发送时间设置自己的I帧的初始发送时间。各STA在设置好自己的I帧的初始发送时间之后，会向AP返回第一I帧的帧间隔设置响应。
表1为第一I帧的帧间隔设置请求的帧格式的示意图，如图1所示，第一I帧的帧间隔设置请求包括4个字段，分别表示的信息为：类别、行动、会话令牌和新的I帧的生成间隔。类别用于表示第一I帧的帧间隔设置请求的类别，会话令牌字段设置为由发送这个帧的STA选择的一个值，以唯一的识别这项会话。新的I帧的间隔字段指示STA在收到帧间隔设置请求帧后，将当前视频压缩编码执行的I帧间隔立即调整为新的I帧的间隔字段的值。AP可根据I帧的帧间隔设置请求帧的发送时间与期望的STA的I帧初始发送时间的差值，设置新的I帧的间隔字段的值。
表1
次序 信息
1 类别
2 行动
3 会话令牌
4 新的I帧的间隔字段
然后，接收各STA返回的第一I帧的帧间隔设置响应，第一I帧的帧间隔设置响应中包括各STA的I帧的初始发送时间的调整结果。STA有可能按照AP的指示将初始发送时间设置成了第一I帧的帧间隔设置请求中包括的初始发送时间，也可能没有。
不论STA是否按照第一I帧的帧间隔设置请求中的初始发送时间设置 自己的I帧的初始发送时间，STA都会向AP返回第一I帧的帧间隔设置响应。表2为第一I帧的帧间隔设置响应的帧格式，如表2所示，第一I帧的帧间隔设置响应也包括四个字段：类别、行动、会话令牌和I帧的间隔报告。
表2
次序 信息
1 类别
2 行动
3 会话令牌
4 新的I帧的间隔报告
如图3所示，图3为I帧间隔报告字段格式，I帧的间隔报告字段包括三个字段：I帧间隔响应、未设置原因、期望的GOP值，I帧间隔响应字段占用1比特，当取值为1时表示STA已经按照第一I帧的帧间隔设置请求中的初始发送时间设置了自己的I帧的初始发送时间，同时未设置原因字段被保留。当I帧的间隔响应字段的取值不为1时，表示STA未按照第一I帧的帧间隔设置请求中的初始发送时间设置自己的I帧的初始发送时间，未设置的原因字段的值为STA未设置的原因，期望GOP值字段为STA期望的GOP值。
若各STA的I帧的初始发送时间的调整结果为表示各STA按照第一I帧的帧间隔设置请求中包括的初始发送时间设置了自己的I帧的初始发送时间，则收发模块12向各STA发送第二I帧的帧间隔设置请求，第二I帧的帧间隔设置请求中包括各STA的I帧的发送周期，以使各STA将各自的I帧的发送周期调整为第二I帧的帧间隔设置请求中包括的发送周期。
第二I帧的帧间隔设置请求的帧格式与第一I帧的帧间隔设置请求的帧格式相同，不同的是，第二I帧的帧间隔设置请求中的新的I帧的生成间隔字段的取值为STA的I帧的发送周期。
处理模块11，还用于根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足 如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的。
其中，相邻的任意两个STA的I帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为AP根据各STA的帧内预测帧的初始发送时间和发送周期确定的。
具体的，Tmin和Tmax通过如下公式计算：
Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，NGOP(1)和NGOP(2)分别为相邻的任意两个STA的GOP的长度，F为相邻的任意两个STA的帧率，T1和T2分别为相邻的任意两个STA的I帧的初始发送时间，一个STA的一个GOP内的各个数据帧的发送时间的总和等于该STA的发送周期的长度。
本实施例中，处理模块11根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期(Service Period，简称SP)和P帧的服务期，各STA的I帧的服务期在时间上不重叠，各STA的P帧的服务期在时间上也不重叠，各STA的I帧的服务期和P帧的服务期为免竞争时隙，各STA在I帧的服务期和P帧的服务期内独享信道。其中，各STA的I帧的服务期的大小和P帧的服务期的大小可以根据实际需要设置，通常一个STA的I帧的大小为P帧的8-10倍，因此，AP在设置时可以设置该STA的I帧的服务期大于P帧的服务期，当然，该STA的I帧的服务期也可以和P帧的服务期的大小相同，本发明并不对此进行限制。
本实施例中，处理模块11为各STA分配的I帧的服务期的间隔需要满足一定的条件：相邻的任意两个STA的I帧的间隔的最小取值为min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，相邻的任意两个STA的I帧的间隔的最大取值为：max(|t1-t2|)＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}。其中，|T1-T2|表示相邻的任意两个STA的I帧初始发送时间的间隔，|NGOP(1)-NGOP(2)|/F为相邻的任意两个STA的I帧的发送周期的差值。
所述收发模块12，还用于向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
处理模块11为各STA分配好I帧的服务期和P帧的服务期之后，收 发模块12将分配结果通知各STA，各STA根据在分配给自己的I帧的服务期内发送I帧，在分配给自己的P帧的服务期内发送P帧，不需要进行信道竞争。
本实施例的接入点，处理模块设置AP关联的各STA的I帧的初始发送时间和发送周期，使I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I的发送周期的差值，然后，并根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期和P帧的服务期，各STA在I帧的服务期和P帧的服务期内独享信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证每个STA的时延QoS满足要求。
本发明实施例二还提供的一种接入点，本实施例的接入点的结构可参照实施例一的接入点的结构示意图，本实施例提供的接入点在上述实施例一的接入点的基础上，处理模块11还用于：
获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率。
具体地，处理模块11接收各STA发送的视频业务规范(Video Traffic Specification，简称VTSPEC)元素，VTSPEC元素中包括对应的STA的I帧的标称长度、最大长度、P帧的标称长度、最大长度和平均发送速率。AP根据各STA的I帧的标称长度和最大长度，确定各STA的I帧的平均长度，根据各STA的P帧的标称长度和最大长度确定各STA的P帧的平均长度。
由于802.11标准中的业务规范(Traffic Specification，简称TSPEC)元素不能对视频流的I帧和P帧的特点进行区分，因此，本实施例中，对TSPEC元素进行了，修改后TSPEC元素即为VTSPEC元素，VTSPEC元素中携带的MAC服务数据单元(MAC Service Data Unit，简称MSDU)相关参数能够区分I帧和P帧。如图4所示，图4为VTSPEC元素的结构示意图，VTSPEC元素中依次包括以下字段：元素ID、长度、业务流信息、标称I帧MSDU长度、最大I帧MSDU长度、标称P帧MSDU长度、最大P帧MSDU长度、最小服务间隔、最大服务间隔、不活跃间隔、暂停间隔、服务起始时间、最小数据速率、平均数据速率、峰值数据速率、突发长度、时延界限、最小 的PHY速率、多余带宽容限、媒介时间。
其中，标称I帧MSDU长度字段包含一个无符号整数，用于规定属于该业务流的I帧的MSDU或者A-MSDU的标称大小，以八位位组为单位。最大I帧MSDU长度字段包含一个无符号整数，用于规定属于该业务流的I帧的MSDU或者A-MSDU的最大值，以八位位组为单位。类似地，标称P帧MSDU长度和最大P帧MSDU长度字段也分别包含一个无符号整数，用于规定属于该业务流的I帧的MSDU或者A-MSDU的标称大小或最大值，以八位位组为单位。
处理模块11，还用于根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期。
处理模块11可以根据以下公式计算I帧的服务期和P帧的服务：TI(i)＝DI(i)/R(i)，TP(i)＝DP(i)/R(i)，TI(i)为第i个STA的I帧的服务期的长度，DI(i)为第i个STA的I帧的平均长度，TP(i)为第i个STA的P帧的服务期的长度，DP(i)为第i个STA的P帧的平均长度，R(i)第i个STA的平均发送速率。
处理模块11，还用于根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔。
本实施例中，相邻的任意两个STA的I帧的服务期的间隔的最小值为min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，相邻的任意两个STA的I帧的服务期的间隔的最大值为max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}。相邻的任意两个STA的I帧的服务期的间隔只要大于等于该最小值小于等于该最大值即可。可选的，本实施例中，任意相邻的两个STA的I帧的服务期间隔相同，I帧的服务期的间隔的计算方式可参照实施例一中的相关描述，这里不再赘述。
处理模块11，还用于根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
进一步的，本实施例中，所述处理模块11还用于：在所述每个信标 间隔内为所述各站点分配信道竞争期，具体可有分配单元133分配，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。可选的，该信道竞争期可以为AP在BI内预先分配的，也可以是一些负载较轻的STA将剩余的I帧的服务期和/或P帧的服务期动态释放后的时间。
可选的，当处理模块11在BI内分配了信道竞争期，所述收发模块12还用于：还向各STA发送竞争期控制信令，该竞争期控制信令用于禁止各STA中的部分STA或者全部STA在各自的BI内的第一个服务期之前的信道竞争期内接入信道，各STA的第一个服务期为I帧的服务期或P帧的服务期。通过发送竞争期控制信令，可以避免大量STA都在同一个信道竞争期内发送数据造成碰撞。竞争期控制信令包含在AP为STA调度服务期时的调度元素的控制字段中，用1比特表示，当竞争期控制信令设置为1时，表示禁止该STA在自己的第一个服务期之前的信道竞争期接入信道，否则，允许该STA在自己的第一个服务期之前的信道竞争期接入信道。
本实施例中，处理模块11在每个BI内为各STA分配I帧和P帧的服务期时，应当满足：
Figure PCTCN2014092577-appb-000005
其中TBI为一个BI的长度，C是比例系数，TI(i)表示第i个STA的I帧的长度，TP(i)表示第i个STA的P帧的长度，i＝1,2……，K,C与STA的速率动态范围有关，STA的速率变化范围越大，则C越小，STA的速率变化范围越小，则C越大。
当C小于1时，BI内未被分配为服务期的剩余时间可用于分配为信道竞争期(competed period，简称CP)，即信道竞争期的长度为(1-C)·TBI，以满足部分速率变化范围较大的STA在I帧和P帧的服务期内不能满足发送需求时可以使用信道竞争期进行数据发送，信道竞争期为各STA共享，各STA通过在信道使用期竞争信道进行数据发送。当C等于1时，BI内所有时间都被分配为服务期，没有预留信道竞争期。
图5为I帧的服务期和P帧的服务期的分配结果的示意图，如图5所示，BTP为信标发送期(Beacon Transmission Period)，ATP表示通告发送期(Announce Transmission Period)，ATP在每个BI内可选出现，用于 AP与各个STA之间的轮询、命令帧和控制帧的交互，SP 1为STA1的P帧的服务期，SP 2为STA2的P帧的服务期，SP N为第N个P帧的STA的服务期，SP 3为STA3的I帧的服务期，CP 1和CP 2为信道竞争期。如图5中，STA 3、STA 4……STA N被禁止使用CP 1，但STA1和STA 2可以使用CP 1。
进一步地，处理模块11还用于：当检测到相邻的任意两个STA的I帧的初始发送时间的间隔等于该相邻的任意两个STA的I帧的发送周期的差值时，通过发送I帧的间隔请求帧来请求该相邻的任意两个STA中的至少一个STA调整自己的I帧的发送周期，以使该相邻的任意两个STA调整后的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值。
或者，当检测到相邻的任意两个STA的I帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，通过发送I帧的帧间隔请求来请求该相邻的任意两个STA中的至少一个STA调整自己的I帧的发送周期，以使该相邻的任意两个STA调整后的I帧的服务期的间隔的最小值不小于该间隔门限。
本实施例中，处理模块设置AP关联的各STA的I帧的初始发送时间和发送周期，处理模块根据各STA的I帧的初始发送时间和发送周期，为各STA在BI内分配I帧的服务期、P帧的服务期和信道竞争期，各STA在I帧的服务期和P帧的服务期内独享信道，各STA在信道竞争期内竞争信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证网络峰值负载不超过网络负载容限，进而保证每个STA的时延QoS满足要求，并通过为STA在BI内分配信道竞争期，使得SP时长不能满足发送需求的各STA能够按需地在信道竞争期内竞争接入信道，使缓存的剩余数据都能够被发送完毕。
当处理模块11为各STA分配信道竞争期之后，为了避免视频业务同质化带来的载波监听多路访问/冲突避免(Carrier Sense Multiple Access/Collision Avoidance，简称CSMA-CA)碰撞概率增大，AP应当首先从STA的重要性方面，对各STA设置一个基准用户优先级(User Priority，简称UP)，STA再依据自身的基准用户优先级设置视频流内不 同类型帧的优先级。无线视频监控网络中有两种类型的信道竞争期：一种是AP在BI中已经预先分配的信道竞争期时段，另一种是其它负载较轻的STA的剩余服务期释放为信道竞争期时段。为了解决该问题，本发明实施例三提供一种接入点，本发明实施例提供的接入点的结构可参照实施例一的接入点的结构示意图，本实施例的接入点在实施例二的接入点的基础上处理模块11还用于：根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级。
例如，本实施例可以采用4级用户优先级(UP)：紧级、高、中、低：
紧急(4级)：紧急信令/报告、数据
高(3级)：数据
中(2级)：数据
低(1级)：数据
相应的，收发模块12，还用于将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
收发模块12，可以将各STA的优先级携带在STA优先级分配元素中，STA优先级分配元素可以包含在信标帧内发送。如图6所示，图6为STA的优先级分配元素的结构示意图，该STA优先级分配元素包括：元素ID、长度、STA1的基准用户优先级、STA2的基准用户优先级、……STA N的基准用户优先级。各STA优先级字段的取值如下：设置为1时表示STA的基准用户优先级为1级，设置为2时表示STA的基准用户优先级为2级，设置为3时表示STA的基准用户优先级为3级，设置为4时表示STA的基准用户优先级为4级。
对于信道竞争期，如果各STA采用类似于802.11的增强型分布式信道访问(Enhanced Distributed Channel Access，简称EDCA)机制，则STA的接入参数包括：最小竞争窗口CWmin、最大竞争窗口CWmax、仲裁帧间间隔(Arbitration Interframe Space，简称AIFS)和发送机会(TXOP)。STA在设置这些信道竞争接入参数时既要考虑视频流业务的同质特性，即 各STA的参数值不能相差太大，同时又要在不同等级的优先级参数之间适当拉开差距，能够避免不同STA的竞争碰撞和有效降低高优先级视频业务的时延。如表3所示，表3为不同优先级的STA的信道竞争接入参数的示意图：
表4
  CWmin CWmax AIFS[i] TXOP
低(1级) 7 30 5 1.5毫秒
中(2级) 7 15 3 2毫秒
高(3级) 3 7 2 3毫秒
紧急(4级) 1 3 1 4毫秒
STA的用户优先级设置方法属于应用层，STA可以根据高层指令(SME发出包含优先级配置参数的原语)或接收AP指令(如STA优先级分配元素)的方式设定本地所有数据帧的用户优先级。本实施例中，STA的用户优先级分为内部数据帧优先级和STA之间的数据帧优先级。
对于STA的数据帧的发送顺序，同一视频流内部的各个数据帧(I帧或P帧)严格按进入缓存队列的时间上的先入先出顺序发送。这是因为对于同一个STA的I帧或者P帧，每个I帧或者P帧都分别对应视频的一幅图像，I帧和P帧具有相同的时延QoS要求，应当遵循视频编码的生成顺序进行先入先出缓存和发送。
STA需要对I帧和P帧分成两个队列分别进行缓存，其中I帧的优先级高于P帧的优先级。数据帧的优先级设置方法为：(1)STA的P帧的优先级与STA的基准用户优先级相同，I帧的优先级高于P的优先级，重传帧的优先级高于非重传帧的优先级；(2)检测到运动后，STA可以将所有数据帧的优先级提升相同级数；(3)重传数据帧应提升优先级。优先级对降低接入碰撞概率的作用就体现在不同STA的数据帧具有不同的优先级上。
进一步的，处理模块11还用于：检测所述各站点的视频监控内容是否发生运动变化。若检测到所述各站点中的任意一个站点的视频监控内容 发生运动变化，则调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
所述收发模块12，还用于将所述处理模块11的调整结果通知给所述站点。
静止图像中出现内容的运动变化是视频监控应用中的重要事件。例如用于安保的视频监控中的监控终端发现了静止的图像出现了人员运动，或者交通监控中的监控终端发现了静止的图像中出现了车辆运动，则该监控终端的重要性大大提高，导致其丢包率、时延等QoS要求也大大高于其它监控终端，因此，本实施例中，AP需要检测各STA的视频监控内容是否发生变化。
本实施例中，视屏监控内容的运动检测可以在STA或AP侧进行，当STA或AP检测到运动时具体可以通过运动检测报告元素把运动检测结果通知另一方。运动检测报告元素可以包含在通告帧或者信息响应帧内。图7为运动检测报告元素的结构示意图，如图7所示，本实施例提供的运动检测报告元素包括以下字段：元素ID、长度、检测到运动、服务期延迟请求和STA优先级。如果检测到STA的视频监控内容运动变化，则将运动字段设置为1，用来表示STA的视频监控内容发生了运动变化，否则，表示STA的视频监控内容没有发生运动变化。STA检测到视频监控内容发生运动变化时，将服务期延长请求字段设置为1，表示请求AP在后续的BI内临时延长STA的I帧的服务期和P帧的服务期；服务期延长请求字段设置为0时表示请求AP恢复到原来的I帧的服务期和P帧的服务期长度。STA优先级字段被AP用来指示STA在后续的BI内应设置的提高后的优先级等级，STA优先级字段被设置为0时，表示STA维持当前的优先级。
STA在收到AP发送的运动检测报告元素之后，按照STA之间的数据帧优先级规则，为检测到运动的STA的数据分配更多的调度时隙，即增加该STA的I帧的服务期长度和P帧的服务期长度，I帧的服务期增长的 幅度依赖于视频监控内容变化幅度，AP可根据不同STA监控速率的动态变化历史数据得出经验值，从而确定每个STA的视频监控内容运动变化后所需的I帧的服务期长度和所需的P帧的服务期长度。并且，AP提升该STA的基准用户优先级，相应的该STA的I帧的优先级和P帧的优先级都提高相同的等级，优先保障该STA的时延QoS。
所述处理模块11还用于：在所述站点的视频监控内容不发生运动变化后，恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
所述收发模块12，还用于将所述处理模块11的恢复结果通知给所述站点。
当AP检测到该STA的视频监控内容不运动之后，AP应该恢复该STA的I帧的服务期的长度以及P帧的服务期的长度，并恢复该STA的基准用户优先级，从而将该STA的所有数据帧的优先级恢复到提高之前。由于某些STA的视频监控内容运动变化导致这些STA的视频编码速率显著上升，进而导致时间资源不足，AP应通过设置STA的视频编码量化参数QP，降低部分优先级比较低的STA的编码速率、帧率，或者将编码方式设置为速率较低的CBR编码方式。
本实施例的接入点，处理模块通过为各STA设置基准用户优先级，使各STA根据各自的基准用户优先级设置自己的接入参数，根据该接入参数竞争信道竞争期。由于不同优先级的用户的接入参数不同，从而能够减小各STA竞争信道竞争期时的碰撞概率。同时，本实施例中，处理模块还检测各STA的视频监控内容是否发生运动变化，当某一STA的视频监控内容发生运动变化后，相应的增加该STA的I帧的服务期和P帧的服务期，并提升该STA的优先级，从而优先保障该STA的时延QoS。
本实施例中，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述接入点的MAC层根 据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
图8为本发明实施例四提供的站点的结构示意图，如图8所示，本实施例提供的站点包括：接收模块21和发送模块22。
其中，接收模块21，用于接收接入点发送的帧内预测帧的初始发送时间和发送周期。
所述接收模块21具体用于：接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间；接收所述接入点发送的第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
所述接收模块21，还用于接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
发送模块22，用于根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
本实施例的站点，发送模块根据AP分配的I帧的初始发送时间和发送周期，在AP分配I帧的服务期内发送I帧，在P帧的服务期内发送P帧，AP在分配时通过将各STA的初始发送时间错开，使得各STA的使得网络负载均衡，保证每个STA的时延QoS满足要求。
图9为本发明实施例五提供的站点的结构示意图，如图9所示，本实施例的站点在实施例四的站点的基础上，每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
相应的，所述接收模块21还用于：接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁止所述站点在所述每个信标间隔内的 第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
进一步的，所述站点还包括：设置模块23。所述接收模块21，还用于接收所述接入点发送的用户基准优先级基准用户优先级。所述设置模块23，用于根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期内竞争信道。所述设置模块23，还用于根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。本实施例中，设置模块23根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数的具体实现方式可参照实施例三的相关描述，这里不再赘述。
进一步的，所述接收模块21还用于：接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
进一步的，所述接收模块21还用于：接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
可选的，本实施例中，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
本实施例中，当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本实施例的站点，设置模块根据STA的基准用户优先级设置信道竞争期的接入参数，根据该接入参数竞争信道竞争期。由于不同优先级的用户的接入参数不同，从而能够减小各STA竞争信道竞争期时的碰撞概率。同时，本实施例中，AP还在检测到STA的视频监控内容是否发生运动变化，相应的增加该STA的I帧的服务期和P帧的服务期，并提升该STA的优先级，从而优先保障STA的时延QoS。
需要说明的是，在本发明各实施例中，STA的MAC层管理实体(MLME)与视频编码器之间的参数交互通过MLME_SAP(服务访问点)来传递的随包管理参数来实现。这是由于：I帧的初始发送时间和发送周期属于STA的视频编码器的输入参数，STA的MLME无权设置。但STA的MAC层在收到I帧的帧间隔设置请求帧以后，MLME可以将其中携带I帧的初始发送时间和发送周期通过MLME_SAP递交给STA管理实体(SME)，由SME调整设置视频编码器的输入参数。
为了使STA的MAC层能够区分I帧和P帧，STA必须为由高层传递给MAC层的MSDU中设置如下随包参数集：
MAC层与SME或者高层应用程序之间的随包原语参数集：TXLIST，RXLIST。其中，TXLIST包括：帧类型(FRAME_TYPE)，时延QoS(Latency_QoS)，设定的GOP值(GOP_SET)；RXLIST包括：检测到运动(Motion_Detected)，请求的GOP值(GOP_Requested)。通过携带帧类型参数的原语后，AP与STA发送数据帧时，将可以对同一个视频业务流的I帧和P帧进行区分，且AP和STA的MAC层将可以对I帧和P帧分别设置各自的缓存队列，并对不同的缓存队列应用不同的信道竞争接入参数。随包原语参数集中的其它控制参数将可以使AP和STA内部的MAC层与编码期或高层之间进行控制参数的交互。
图10为本发明实施例六提供的多视频流的传输方法的流程图，如图10所示，本实施例的方法可以包括以下步骤：
步骤101、AP为关联的至少两个STA分配I帧的初始发送时间和发送周期，其中，该至少两个STA中I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值，且该相邻的任意两个STA的I帧的初始发送时间的间隔大于0。
可选的，该任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
可选的，该任意相邻的两个站点的帧内预测帧的初始发送时间的间隔为：
Figure PCTCN2014092577-appb-000006
其中，NGOP(i)为第i个站点的一个图像组的长度，i＝1，……K，K为站点的总数，F为所述各站点的帧率。
步骤102、AP向该至少两个STA中的各STA发送I帧的初始发送时间和发送周期。
具体的，首先，接入点向各站点分别发送第一帧内预测帧的帧间隔设置请求，该第一帧内预测帧的帧间隔设置请求中包括各站点的初始发送时间，以使各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间。
然后，接入点接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，该第一帧内预测帧的帧间隔设置响应中包括各站点的帧内预测帧的初始发送时间的调整结果。
最后，若各站点的帧内预测帧的初始发送时间的调整结果为表示各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时间设置了自己的帧内预测帧的初始发送时间，则接入点向各站点发送第二帧内预测帧的帧间隔设置请求，该第二帧内预测帧的帧间隔设置请求中包括各站点的帧内预测帧的发送周期，以使各站点将各自的帧内预测帧的发送周期调整为该第二帧内预测帧的帧间隔设置请求中包括的发送周期。
步骤103、AP根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期和P帧的服务期，各STA在I帧的服务期和P帧的服务期内独享信道。
其中，该相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为接入点根据各站点的帧内预测帧的初始发送时间和发送周期确定的。
可选的，Tmin和Tmax通过如下公式计算：
Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
其中，NGOP(1)和NGOP(2)分别为该相邻的任意两个站点的图像组的长度，F为该相邻的任意两个站点的帧率，T1和T2分别为该相邻的任意两个站点的帧内预测帧的初始发送时间。
步骤104、AP向各STA发送各STA的I帧的服务期和P帧的服务期的分配结果。
AP为各STA分配好I帧的服务期和P帧的服务期之后，将分配结果通知各STA，各STA根据在分配给自己的I帧的服务期内发送I帧，在分配给自己的P帧的服务期内发送P帧，不需要进行信道竞争。
本实施例中，AP设置关联的各STA的I帧的初始发送时间和发送周期，使I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I的发送周期的差值，并根据各STA的I帧的初始发送时间和发送周期，为各STA分配I帧的服务期和P帧的服务期，各STA在I帧的服务期和P帧的服务期内独享信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证每个STA的时延QoS满足要求。
本实施例的方法可由实施例一提供的接入点执行，具体实现方式和原理相同，请参照实施例一的相关描述，这里不再赘述。
图11为本发明实施例七提供的多视频流的传输方法的流程图，本实施例中将详细的说明AP如何为各STA分配I帧和P帧的服务期，如图11所示，本实施例的方法可以包括以下步骤：
步骤201、AP为关联的各STA分配I帧的初始发送时间和发送周期，其中，I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值，且该相邻的任意两个STA的I帧的初始发送时间的间隔大于0。
步骤202、AP向各STA发送I帧的初始发送时间和发送周期。
步骤203、AP获取各STA的I帧的平均长度和P帧的平均长度，以及各STA的平均发送速率。
步骤204、AP根据各STA的I帧的平均长度和各STA的平均发送速率，分别计算各STA的I帧的服务期，以及根据各STA的P帧的平均长度和各STA的平均发送速率，分别计算各STA的P帧的服务期。
步骤205、AP根据各STA的I帧的初始发送时间和发送周期，确定相邻的任意两个STA的I帧的服务期的间隔。
步骤206、AP根据各STA的I帧的服务期和P帧的服务期，以及相邻的任意两个STA的I帧的服务期的间隔为各STA分配I帧的服务期和P帧的服务期，并在每个信标间隔内为各STA分配信道竞争期。
步骤207、AP向各STA发送各STA的I帧的服务期、P帧的服务期和信道竞争期的分配结果。
本实施例中，AP为各STA分配的I帧的服务期大于为各STA分配的P帧分配的服务期，并且预留了信道竞争期，信道竞争期用于当各STA在自己的I帧的服务期和P帧的服务期内未能将缓存的全部数据发送完毕时，使用信道竞争期发送数据，信道竞争期被各STA共享。可选的，该信道竞争期可以为AP在BI内预先分配的，也可以是一些负载较轻的STA将剩余的I帧的服务期和/或P帧的服务期动态释放后的时间。
可选的，当AP在BI内分配了信道竞争期，AP还向各STA发送竞争期控制信令，该竞争期控制信令用于禁止各STA中的部分STA或者全部STA在各自的BI内的第一个服务期之前的信道竞争期内接入信道，各STA的第一个服务期为I帧的服务期或P帧的服务期。通过发送竞争期控制信令，可以避免大量STA都在同一个信道竞争期内发送数据造成碰撞。
本实施例中，AP设置关联的各STA的I帧的初始发送时间和发送周期，并根据各STA的I帧的初始发送时间和发送周期，为各STA在BI内分配I帧的服务期、P帧的服务期和信道竞争期，各STA在I帧的服务期和P帧的服务期内独享信道，各STA在信道竞争期内竞争信道，从而使得各STA的I帧的发送时间错开，使得网络负载均衡，保证网络峰值负载不超过网络负载容限，进而保证每个STA的时延QoS满足要求，并通过 为STA在BI内分配信道竞争期，使得SP时长不能满足发送需求的各STA能够按需地在信道竞争期内竞争接入信道，使缓存的剩余数据都能够被发送完毕。
本实施例的方法，可以由实施例二中的接入点执行，具体实现方式和技术效果类似，请参照实施例二的描述，这里不再赘述。
进一步地，在实施例一和实施例二的基础上，实施例一和实施例二还可以包括以下步骤：当AP检测到相邻的任意两个STA的I帧的初始发送时间的间隔等于该相邻的任意两个STA的I帧的发送周期的差值时，AP通过发送I帧的间隔请求帧来请求该相邻的任意两个STA中的至少一个STA调整自己的I帧的发送周期，以使该相邻的任意两个STA调整后的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值。
或者，当AP在检测到相邻的任意两个STA的I帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，AP通过发送I帧的帧间隔请求来请求该相邻的任意两个STA中的至少一个STA调整自己的I帧的发送周期，以使该相邻的任意两个STA调整后的I帧的服务期的间隔的最小值不小于该间隔门限。
图12为本发明实施例八提供多视频流的传输方法的流程图，如图12所示，本实施例提供的方法可以包括以下步骤：
步骤301、AP为关联的各STA分配I帧的初始发送时间和发送周期。
其中，I帧的发送时间相邻的任意两个STA的I帧的初始发送时间的间隔不等于该相邻的任意两个STA的I帧的发送周期的差值，且该相邻的任意两个STA的I帧的初始发送时间的间隔大于0。
步骤302、AP向各STA发送I帧的初始发送时间和发送周期。
步骤303、AP根据各STA的I帧的初始发送时间和发送周期，在每个BI内为各STA分配I帧的服务期、P的服务期和信道竞争期。
步骤304、AP向各STA发送各STA的I帧的服务期、P帧的服务期和信道竞争期的分配结果。
对于步骤301和步骤302的具体实现方式可参照实施例一的相关描述，这里不再赘述。步骤303和步骤304的具体实现方式可参照实施例二 的相关描述，这里不再赘述。
步骤305、AP根据各STA视频监控区域或者监控内容的重要性为各STA设置基准用户优先级。
步骤306、AP将各STA的基准用户优先级发送给各STA，以使各STA根据各自的基准用户优先级设置信道竞争期的信道竞争接入参数，以及I帧和P帧的优先级。
步骤307、AP检测各STA的视频监控内容是否发生运动变化。
若是，即AP检测到各STA中的任意一个STA的视频监控内容发生运动变化，则执行步骤308，若否，即各STA的视频监控内容均未发生运动变化，则返回继续执行步骤307。
步骤308、AP调整为STA分配的I帧的服务期和P帧的服务期，以及调整STA的基准用户优先级，并将调整结果发送给STA。
其中，AP调整后的该STA的I帧的服务期大于调整前的I帧的服务期，AP调整后的该STA的P帧的服务期大于调整前的P帧的服务期，调整后的该STA的基准用户优先级高于调整前的基准用户优先级。
步骤309、在该STA的视频监控内容不发生运动变化后，AP恢复STA的I帧的服务期、P帧的服务期和用户的基准用户优先级，并将恢复结果通知给STA。
其中，STA恢复后的I帧的服务期等于所述调整前的I帧的服务期，STA恢复后的P帧的服务期等于调整前的P帧的服务期，STA恢复后的基准用户优先级等于调整前的基准用户优先级。
本实施例的方法，AP通过为各STA设置基准用户优先级，使各STA根据各自的基准用户优先级设置自己的接入参数，根据该接入参数竞争信道竞争期。由于不同优先级的用户的接入参数不同，从而能够减小各STA竞争信道竞争期时的碰撞概率。同时，本实施例中，AP还检测各STA的视频监控内容是否发生运动变化，当某一STA的视频监控内容发生运动变化后，相应的增加该STA的I帧的服务期和P帧的服务期，并提升该STA的优先级，从而优先保障该STA的时延QoS。
本实施例的方法，可以由实施例三的接入点执行，具体实现方式和技术效果类似，请参照实施例三，这里不再赘述。
图13为本发明实施例九提供的多视频流的传输方法的流程图，本实施例从STA侧描述多视频流的传输方法，如图13所示，本实施例的方法可以包括以下步骤：
步骤401、STA接收AP发送的I帧的初始发送时间和发送周期。
AP为关联的各STA分配好初始发送时间和发送周期之后，将分配结果发送给各STA。具体的，STA接收AP发送的第一I帧的帧间隔设置请求，第一I帧的帧间隔设置请求中包括STA的初始发送时间。STA接收AP发送的第二I帧的帧间隔设置请求，第二I帧的帧间隔设置请求中包括STA的I帧的发送周期。
步骤402、STA接收AP发送的I帧的服务期和P帧的服务期的分配结果，I帧的服务期和P帧的服务期是AP根据STA的初始发送时间和发送周期在每个BI内为STA分配的。
步骤403、STA根据I帧的初始发送时间和发送周期，在I帧的服务期内发送I帧，在P帧的服务期内发送P帧。
STA在I帧的服务期和P帧的服务期内独享信道，不需要竞争信道。
本实施例中，STA根据AP分配的I帧的初始发送时间和发送周期，在AP分配I帧的服务期内发送I帧，在P帧的服务期内发送P帧，AP在分配时通过将各STA的初始发送时间错开，使得各STA的使得网络负载均衡，保证每个STA的时延QoS满足要求。
本实施例的方法，可以由实施例四的站点执行，具体实现方式和技术效果类似，请参照实施例四的描述，这里不再赘述。
图14为本发明实施例十提供的多视频流的传输方法的流程图，如图14所示，本实施例提供的方法可以包括以下步骤：
步骤501、STA接收AP发送的I帧的初始发送时间和发送周期。
步骤502、STA接收AP发送的I帧的服务期和P帧的服务期的分配结果，I帧的服务期和P帧的服务期是AP根据STA的初始发送时间和发送周期在每个BI内为STA分配的，每个BI内还包括AP分配的信道竞争期。
本实施例中，AP在每个BI内还为关联的STA分配信道竞争期，当STA在I帧的服务期和P帧的服务期内未能将缓存的全部数据发送完毕 时，STA使用该信道竞争期发送数据，该信道竞争期被AP关联的所有STA共享。
步骤503、STA根据I帧的初始发送时间和发送周期，在I帧的服务期内发送I帧，在P帧的服务期内发送P帧，若STA在I帧的服务期和P帧的服务期内未能将缓存的全部数据发送完毕时，STA使用该信道竞争期发送数据。
可选的，STA接收AP发送的竞争期控制信令，该竞争期控制信令用于禁止STA在每个BI内的第一个服务期之前的信道竞争期内接入信道，STA的第一个服务期为I帧的服务期或P帧的服务期。
步骤504、STA接收AP发送的基准用户优先级，根据基准用户优先级设置该信道竞争期的信道竞争接入参数，并根据信道竞争接入参数在该竞争期内竞争信道，并根据基准用户优先级设置I帧的优先级和P帧的优先级。
其中，P帧的优先级与基准用户优先级相同，I帧的优先级高于P帧的优先级，STA的重传帧的优先级高于非重传帧的优先级。
步骤505、STA接收AP发送的调整结果，调整结果是AP检测到STA的视频监控内容运动变化后发送的，调整结果中包括：STA调整后的I帧的服务期、调整后的P帧的服务期和调整后的基准用户优先级。
其中，STA调整后的I帧的服务期大于调整前的I帧的服务期，STA调整后的P帧的服务期大于调整前的P帧的服务期，STA调整后的基准用户优先级高于调整前的基准用户优先级。
步骤506、STA接收AP发送的恢复结果，恢复结果是AP检测到STA的视频监控内容不运动变化后发送的，恢复结果中包括：STA恢复后的I帧的服务期、恢复后的P帧的服务期和恢复后的基准用户优先级。
其中，STA恢复后的I帧的服务期等于调整前的I帧的服务期，STA恢复后的P帧的服务期等于调整前的P帧的服务期，STA恢复后的基准用户优先级等于调整前的基准用户优先级。
本实施例的方法，AP通过为各STA设置基准用户优先级，使各STA根据各自的基准用户优先级设置自己的接入参数，根据该接入参数竞争信道竞争期。由于不同优先级的用户的接入参数不同，从而能够减小各STA 竞争信道竞争期时的碰撞概率。同时，本实施例中，AP还在检测到STA的视频监控内容是否发生运动变化，相应的增加该STA的I帧的服务期和P帧的服务期，并提升该STA的优先级，从而优先保障STA的时延QoS。
本实施例的方法，可以由实施例五的站点执行，具体实现方式和技术效果类似，请参照实施例五的描述，这里不再赘述。
图15为本发明实施例十一提供的接入点的结构示意图，如图15所示，本发明实施例提供的接入点300包括：处理器31、存储器32、通信接口33和系统总线34，所述存储器32和所述通信接口33通过所述系统总线34与所述处理器31连接并完成相互间的通信；所述存储器32，用于存储计算机执行指令；所述通信接口33，用于和其他设备进行通信；所述处理器31，用于运行所述计算机执行指令，使所述接入点300执行如下所述的方法：
为接入点关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0；
向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期；
根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的；
向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
可选的，Tmin和Tmax通过如下公式计算：
Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
其中，NGOP(1)和NGOP(2)分别为所述相邻的任意两个站点的图像组的长度，F为所述相邻的任意两个站点的帧率，T1和T2分别为所述相邻的任意两个站点的帧内预测帧的初始发送时间。
可选的，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
可选的，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔为：
Figure PCTCN2014092577-appb-000007
其中，NGOP(i)为第i个站点的一个图像组的长度，i＝1，……K，K为站点的总数，F为所述各站点的帧率。
进一步，处理器31还用于：当检测到所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值；
或者，当检测到所述相邻的任意两个站点的帧内预测帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的服务期的间隔的最小值不小于所述间隔门限。
处理器31向所述各站点发送帧内预测帧的初始发送时间和发送周期，具体为：
向所述各站点分别发送第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述各站点的初始发送时间，以使所述各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间。
接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，所述第一帧内预测帧的帧间隔设置响应中包括所述各站点的帧内预测帧的初始发 送时间的调整结果。
若所述各站点的帧内预测帧的初始发送时间的调整结果为表示所述各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时间设置了自己的帧内预测帧的初始发送时间，则向所述各站点发送第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述各站点的帧内预测帧的发送周期，以使所述各站点将各自的帧内预测帧的发送周期调整为所述第二帧内预测帧的帧间隔设置请求中包括的发送周期。
处理器31根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，包括：
获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率；
根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期；
根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔；
根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
处理器31还用于：在所述每个信标间隔内为所述各站点分配信道竞争期，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。
可选的，处理器31还用于：向所述各站点发送竞争期控制信令，所述竞争期控制信令用于禁止所述各站点中的部分站点或者全部站点在各自的所述信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述各站点的第一个服务期为帧内预测帧的服务期或前向预测帧的服务期。
可选的，所述接入点为所述各站点分配的帧内预测帧的服务期大于为所述各站点分配的前向预测帧的服务期。
进一步的，处理器31还用于：根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级；并将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
进一步的，处理器31还用于：检测所述各站点的视频监控内容是否发生运动变化；若检测到所述各站点中的任意一个站点的视频监控内容发生运动变化，则调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，并将调整结果通知给所述站点。所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
进一步的，处理器31还用于：在所述站点的视频监控内容不发生运动变化后，恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，并将恢复结果通知给所述站点。其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
本实施例中，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述接入点的MAC层根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本实施例的接入点，可用于执行实施例六至实施例八的方法，具体实现方式和技术效果类似，这里不再赘述。
图16为本发明实施例十二提供的站点的结构示意图，如图16所示， 本发明实施例提供的站点400包括：处理器41、存储器42、通信接口43和系统总线44，所述存储器42和所述通信接口43通过所述系统总线44与所述处理器41连接并完成相互间的通信；所述存储器42，用于存储计算机执行指令；所述通信接口43，用于和其他设备进行通信；所述处理器41，用于运行所述计算机执行指令，使所述站点400执行如下所述的方法：
接收接入点发送的帧内预测帧的初始发送时间和发送周期；
接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
处理器41接收接入点发送的帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，具体为：接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间。接收所述接入点发送的第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
可选的，所述每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
可选的，处理器41还用于：接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁止所述站点在所述每个信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
可选的，处理器41还用于：接收所述接入点发送的用户基准优先级基准用户优先级；根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期 内竞争信道；并根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。
可选的，处理器41还用于：接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
可选的，处理器41还用于：接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
可选的，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
本实施例中，当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
本实施例的站点，可用于执行实施例九和实施例十的方法，具体实现方式和技术效果类似，这里不再赘述。
本领域普通技术人员可以理解：实现上述方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成，前述的程序可以存储于一计算机可读 取存储介质中，该程序在执行时，执行包括上述方法实施例的步骤；而前述的存储介质包括：ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (46)

  1. 一种接入点，其特征在于，包括：
    处理模块，用于为所述接入点关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0；
    收发模块，用于向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期；
    所述处理模块，还用于根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的；
    所述收发模块，还用于向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
  2. 根据权利要求1所述的接入点，其特征在于，Tmin和Tmax通过如下公式计算：
    Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
    Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
    其中，NGOP(1)和NGOP(2)分别为所述相邻的任意两个站点的图像组的长度，F为所述相邻的任意两个站点的帧率，T1和T2分别为所述相邻的任意两个站点的帧内预测帧的初始发送时间。
  3. 根据权利要求1或2所述的接入点，其特征在于，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
  4. 根据权利要求3所述的接入点，其特征在于，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔为：
    Figure PCTCN2014092577-appb-100001
    其中，NGOP(i)为第i个站点的一个图像组的长度， i＝1，……K，K为站点的总数，F为所述各站点的帧率。
  5. 根据权利要求3或4所述的接入点，其特征在于，所述处理模块还用于：
    当检测到所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值；
    或者，当检测到所述相邻的任意两个站点的帧内预测帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的服务期的间隔的最小值不小于所述间隔门限。
  6. 根据权利要求1-5中任一项所述的接入点，其特征在于，所述收发模块具体用于：
    向所述各站点分别发送第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述各站点的初始发送时间，以使所述各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间；
    接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，所述第一帧内预测帧的帧间隔设置响应中包括所述各站点的帧内预测帧的初始发送时间的调整结果；
    若所述各站点的帧内预测帧的初始发送时间的调整结果为表示所述各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时间设置了自己的帧内预测帧的初始发送时间，则向所述各站点发送第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述各站点的帧内预测帧的发送周期，以使所述各站点将各自的帧内预测帧的发送周期调整为所述第二帧内预测帧的帧间隔设置请求中包括的 发送周期。
  7. 根据权利要求1-5中任一项所述的接入点，其特征在于，所述处理模块具体用于：
    获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率；
    根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期；
    根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔；
    根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
  8. 根据权利要求1-7中任一项所述的接入点，其特征在于，所述处理模块还用于：
    在所述每个信标间隔内为所述各站点分配信道竞争期，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。
  9. 根据权利要求8所述的接入点，其特征在于，所述收发模块还用于：
    向所述各站点发送竞争期控制信令，所述竞争期控制信令用于禁止所述各站点中的部分站点或者全部站点在各自的所述信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述各站点的第一个服务期为帧内预测帧的服务期或前向预测帧的服务期。
  10. 根据权利要求1-9中任一项所述的接入点，其特征在于，所述接入点为所述各站点分配的帧内预测帧的服务期大于为所述各站点分配的前向预测帧的服务期。
  11. 根据权利要求8或9所述的接入点，其特征在于，所述处理模块 还用于：
    根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级；
    所述收发模块，还用于将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
  12. 根据权利要求11所述的接入点，其特征在于，所述处理模块还用于：
    检测所述各站点的视频监控内容是否发生运动变化；
    若检测到所述各站点中的任意一个站点的视频监控内容发生运动变化，则调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级；
    所述收发模块，还用于将所述处理模块的调整结果通知给所述站点；
  13. 根据权利要求12所述的接入点，其特征在于，所述处理模块还用于：
    在所述站点的视频监控内容不发生运动变化后，恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
    所述收发模块，还用于将所述处理模块的恢复结果通知给所述站点。
  14. 根据权利要求1所述的接入点，其特征在于，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述接入点的MAC层根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
  15. 一种站点，其特征在于，包括：
    接收模块，用于接收接入点发送的帧内预测帧的初始发送时间和发送周期；
    所述接收模块，还用于接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
    发送模块，用于根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
  16. 根据权利要求15所述的站点，其特征在于，所述接收模块具体用于：
    接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间；
    接收所述接入点发送的第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
  17. 根据权利要求15所述的站点，其特征在于，所述每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
  18. 根据权利要求17所述的站点，其特征在于，所述接收模块还用于：
    接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁止所述站点在所述每个信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
  19. 根据权利要求17或18所述的站点，其特征在于，所述站点还包括：设置模块；
    所述接收模块，还用于接收所述接入点发送的用户基准优先级基准用 户优先级；
    所述设置模块，用于根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期内竞争信道；
    所述设置模块，还用于根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。
  20. 根据权利要求19所述的站点，其特征在于，所述接收模块还用于：
    接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
  21. 根据权利要求20所述的站点，其特征在于，所述接收模块还用于：
    接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
  22. 根据权利要求15-21中任一项所述的站点，其特征在于，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
  23. 根据权利要求15所述的站点，其特征在于，当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
  24. 一种多视频流的传输方法，其特征在于，包括：
    接入点为关联的至少两个站点分配帧内预测帧的初始发送时间和发送周期，其中，所述至少两个站点中帧内预测帧的发送时间相邻的任意两个站点的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值，且所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔大于0；
    所述接入点向所述至少两个站点中的各站点发送帧内预测帧的初始发送时间和发送周期；
    所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，所述各站点在帧内预测帧的服务期和前向预测帧的服务期内独享信道，其中，所述相邻的任意两个站点的帧内预测帧的服务期的间隔T满足如下条件：Tmin≤T≤Tmax，Tmin和Tmax为所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期确定的；
    所述接入点向所述各站点发送所述各站点的帧内预测帧的服务期和前向预测帧的服务期的分配结果。
  25. 根据权利要求24所述的方法，其特征在于，Tmin和Tmax通过如下公式计算：
    Tmin＝min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
    Tmax＝max{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}，
    其中，NGOP(1)和NGOP(2)分别为所述相邻的任意两个站点的图像组的长度，F为所述相邻的任意两个站点的帧率，T1和T2分别为所述相邻的任意两个站点的帧内预测帧的初始发送时间。
  26. 根据权利要求24或25所述的方法，其特征在于，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔相同。
  27. 根据权利要求26所述的方法，其特征在于，所述任意相邻的两个站点的帧内预测帧的初始发送时间的间隔为：
    Figure PCTCN2014092577-appb-100002
    其中，NGOP(i)为第i个站点的一个图像组的长度，i＝1，……K，K为站点的总数，F为所述各站点的帧率。
  28. 根据权利要求26或27所述的方法，其特征在于，所述方法还包括：
    当所述接入点检测到所述相邻的任意两个站点的帧内预测帧的初始发送时间的间隔等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值时，所述接入点通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的初始发送时间的间隔不等于所述相邻的任意两个站点的帧内预测帧的发送周期的差值；
    或者，当所述接入点检测到所述相邻的任意两个站点的帧内预测帧的服务期的间隔的最小值min{|(|NGOP(1)-NGOP(2)|/F-|T1-T2|)|,|T1-T2|}小于预设的间隔门限时，所述接入点通过发送帧内预测帧的间隔请求帧来请求所述相邻的任意两个站点中的至少一个站点调整自己的帧内预测帧的发送周期，以使所述相邻的任意两个站点调整后的帧内预测帧的服务期的间隔的最小值不小于所述间隔门限。
  29. 根据权利要求24-28中任一项所述的方法，其特征在于，所述接入点向所述各站点发送帧内预测帧的初始发送时间和发送周期，包括：
    所述接入点向所述各站点分别发送第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述各站点的初始发送时间，以使所述各站点根据各自的初始发送时间设置自己的帧内预测帧的初始发送时间；
    所述接入点接收所述各站点返回的第一帧内预测帧的帧间隔设置响应，所述第一帧内预测帧的帧间隔设置响应中包括所述各站点的帧内预测帧的初始发送时间的调整结果；
    若所述各站点的帧内预测帧的初始发送时间的调整结果为表示所述各站点按照所述第一帧内预测帧的帧间隔设置请求中包括的初始发送时 间设置了自己的帧内预测帧的初始发送时间，则所述接入点向所述各站点发送第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述各站点的帧内预测帧的发送周期，以使所述各站点将各自的帧内预测帧的发送周期调整为所述第二帧内预测帧的帧间隔设置请求中包括的发送周期。
  30. 根据权利要求24-28中任一项所述的方法，其特征在于，所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期，包括：
    所述接入点获取所述各站点的帧内预测帧的平均长度和前向预测帧的平均长度，以及所述各站点的平均发送速率；
    所述接入点根据所述各站点的帧内预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的帧内预测帧的服务期，以及根据所述各站点的前向预测帧的平均长度和所述各站点的平均发送速率，分别计算所述各站点的前向预测帧的服务期；
    所述接入点根据所述各站点的帧内预测帧的初始发送时间和发送周期，确定所述相邻的任意两个站点的帧内预测帧的服务期的间隔；
    所述接入点根据所述各站点的帧内预测帧的服务期和前向预测帧的服务期，以及所述相邻的任意两个站点的帧内预测帧的服务期的间隔为所述各站点分配帧内预测帧的服务期和前向预测帧的服务期。
  31. 根据权利要求24-30中任一项所述的方法，其特征在于，所述方法还包括：
    所述接入点在所述每个信标间隔内为所述各站点分配信道竞争期，所述信道竞争期用于当所述各站点在自己的帧内预测帧的服务期和前向预测帧的服务期内未能将缓存的全部数据发送完毕时，使用所述信道竞争期发送数据，所述信道竞争期被所述各站点共享。
  32. 根据权利要求31所述的方法，其特征在于，所述方法还包括：所述接入点向所述各站点发送竞争期控制信令，所述竞争期控制信令用于禁止所述各站点中的部分站点或者全部站点在各自的所述信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述各站点的第一个服务期为帧内预测帧的服务期或前向预测帧的服务期。
  33. 根据权利要求24-32中任一项所述的方法，其特征在于，所述接入点为所述各站点分配的帧内预测帧的服务期大于为所述各站点分配的前向预测帧的服务期。
  34. 根据权利要求31或32所述的方法，其特征在于，所述方法还包括：
    所述接入点根据所述各站点视频监控区域或者监控内容的重要性为所述各站点设置基准用户优先级；
    所述接入点将所述各站点的基准用户优先级发送给所述各站点，以使所述各站点根据各自的基准用户优先级设置所述信道竞争期的信道竞争接入参数，以及所述帧内预测帧和所述前向预测帧的优先级。
  35. 根据权利要求34所述的方法，其特征在于，所述方法还包括：
    所述接入点检测所述各站点的视频监控内容是否发生运动变化；
    若所述接入点检测到所述各站点中的任意一个站点的视频监控内容发生运动变化，则所述接入点调整为所述站点分配的帧内预测帧的服务期和前向预测帧的服务期，以及调整所述站点的基准用户优先级，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级；
    所述接入点将调整结果通知给所述站点；
  36. 根据权利要求35所述的方法，其特征在于，所述方法还包括：
    在所述站点的视频监控内容不发生运动变化后，所述接入点恢复所述站点的帧内预测帧的服务期、前向预测帧的服务期和所述用户的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
    所述接入点将恢复结果通知给所述站点。
  37. 根据权利要求24所述的方法，其特征在于，当所述接入点发送所述帧内预测帧或者所述前向预测帧时，所述接入点的应用层会在向媒体接入控制MAC层传递的所述帧内预测帧和所述前向预测帧中携带帧类型 参数，以使所述接入点的MAC层根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
  38. 一种多视频流的传输方法，其特征在于，包括：
    站点接收接入点发送的帧内预测帧的初始发送时间和发送周期；
    所述站点接收所述接入点发送的所述帧内预测帧的服务期和前向预测帧的服务期的分配结果，所述帧内预测帧的服务期和所述前向预测帧的服务期是所述接入点根据所述站点的初始发送时间和所述帧内预测帧的发送周期在每个信标间隔内为所述站点分配的；
    所述站点根据所述帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，在所述帧内预测帧的服务期内发送所述帧内预测帧，在所述前向预测帧的服务期内发送所述前向预测帧。
  39. 根据权利要求38所述的方法，其特征在于，所述站点接收接入点发送的帧内预测帧的初始发送时间和所述帧内预测帧的发送周期，包括：
    所述站点接收所述接入点发送的第一帧内预测帧的帧间隔设置请求，所述第一帧内预测帧的帧间隔设置请求中包括所述站点的初始发送时间；
    所述站点接收所述接入点发送的第二帧内预测帧的帧间隔设置请求，所述第二帧内预测帧的帧间隔设置请求中包括所述站点的帧内预测帧的发送周期。
  40. 根据权利要求38所述的方法，其特征在于，所述每个信标间隔内还包括所述接入点分配的信道竞争期，当所述站点在所述帧内预测帧的服务期和所述前向预测帧的服务期内未能将缓存的全部数据发送完毕时，所述站点使用所述信道竞争期发送数据，所述信道竞争期被所述接入点关联的所有站点共享。
  41. 根据权利要求40所述的方法，其特征在于，所述方法还包括：
    所述站点接收所述接入点发送的竞争期控制信令，所述竞争期控制信令用于禁止所述站点在所述每个信标间隔内的第一个服务期之前的信道竞争期内接入所述信道，所述站点的第一个服务期为所述帧内预测帧的服务期或所述前向预测帧的服务期。
  42. 根据权利要求40或41所述的方法，其特征在于，所述方法还包括：
    所述站点接收所述接入点发送的用户基准优先级基准用户优先级；
    所述站点根据所述用户基准优先级基准用户优先级设置所述信道竞争期的信道竞争接入参数，并根据所述信道竞争接入参数在所述竞争期内竞争信道；
    所述站点根据所述用户基准优先级基准用户优先级设置所述帧内预测帧的优先级和所述前向预测帧的优先级，其中，所述前向预测帧的优先级与所述用户基准优先级基准用户优先级相同，所述帧内预测帧的优先级高于前向预测帧的优先级，所述站点的重传帧的优先级高于非重传帧的优先级。
  43. 根据权利要求42所述的方法，其特征在于，所述方法还包括：
    所述站点接收所述接入点发送的调整结果，所述调整结果是所述接入点检测到所述站点的视频监控内容运动变化后发送的，所述调整结果中包括：所述站点调整后的帧内预测帧的服务期、调整后的前向预测帧的服务期和调整后的基准用户优先级，其中，所述站点调整后的帧内预测帧的服务期大于调整前的帧内预测帧的服务期，所述站点调整后的前向预测帧的服务期大于调整前的前向预测帧的服务期，所述站点调整后的基准用户优先级高于调整前的基准用户优先级。
  44. 根据权利要求43所述的方法，其特征在于，所述方法还包括：
    所述站点接收所述接入点发送的恢复结果，所述恢复结果是所述接入点检测到所述站点的视频监控内容不运动变化后发送的，所述恢复结果中包括：所述站点恢复后的帧内预测帧的服务期、恢复后的前向预测帧的服务期和恢复后的基准用户优先级，其中，所述站点恢复后的帧内预测帧的服务期等于所述调整前的帧内预测帧的服务期，所述站点恢复后的前向预测帧的服务期等于所述调整前的前向预测帧的服务期，所述站点恢复后的基准用户优先级等于所述调整前的基准用户优先级。
  45. 根据权利要求38-44中任一项所述的方法，其特征在于，所述接入点为所述站点分配的所述帧内预测帧的服务期大于所述前向预测帧的服务期。
  46. 根据权利要求38所述的方法，其特征在于，所述方法还包括：
    当所述站点发送所述帧内预测帧或者所述前向预测帧时，所述站点的 应用层会在向媒体接入控制MAC层传递所述帧内预测帧和所述前向预测帧中携带帧类型参数，以使所述站点的MAC根据所述帧类型参数确定接收到的数据帧为所述帧内预测帧或者所述前向预测帧。
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