CN105611537A - Unauthorized frequency band channel multiplexing method and device - Google Patents

Abstract

The embodiment of the present invention provides a channel multiplexing method and device for an unlicensed frequency band. The specific implementation of the method includes the steps: when there is data to be transmitted, the channel energy is detected in the detection frame of the transmission period; when the channel is detected to be idle, before the end of the countdown, when it is detected When participating in the request signaling for channel multiplexing and the first transmission start time, use the sending frame for data transmission at the first transmission start time; if no request signaling for participating in channel multiplexing sent by other LAA base stations is detected, then Send request signaling to other LAA base stations to obtain the backoff time of other LAA base stations; determine the LAA base stations currently participating in channel multiplexing and the second transmission start time, and use the sending frame to perform data transmission at the second transmission start time. By applying this embodiment, multiple LAA base stations of the same operator can realize channel multiplexing in an unlicensed frequency band.

Description

A channel multiplexing method and device for an unlicensed frequency band

technical field

The invention relates to the field of communication technology, in particular to a channel multiplexing method and device for an unlicensed frequency band.

Background technique

With the rapid growth of user service requirements, especially the rise of video services, the existing LTE system is difficult to meet user requirements, and new technologies must be sought. LTE's use of unlicensed frequency bands and coexistence with WiFi is currently a hot topic of discussion to solve the problem of spectrum shortage. The 3rd Generation Partnership Project 3GPP (the 3rd Generation Partnership Project) officially proposed LAA technology in the Realease-13 stage as LTE uses unlicensed frequency bands and coexists harmoniously with WiFi. main technology. After using the LAA system, the existing LTE base station can not only work normally in the licensed frequency band, but also offload some services to the LAA for transmission in the unlicensed frequency band.

The simple explanation of LAA is that it can compete fairly with other WiFi like a WiFi station, and can transmit data as efficiently as an LTE base station after occupying the channel.

In the prior art, in order to enable LAA base stations to compete like WiFi stations, the European Telecommunications Standards Institute (ETSI) proposed Listen Before Talk (LBT) as a key technology of LAA. After adopting LBT technology, the LAA system is divided into three links during data transmission: idle channel assessment CCA, channel occupancy time COT and idle period (IdlePeriod). When the LAA base station has data to access the channel, it first evaluates the CCA through the idle channel, and detects whether the channel energy exceeds the threshold through energy detection ED (Energy Detection) within the evaluation time. If it does not exceed the threshold, it is judged that the channel can be occupied, and the LAA base station starts Occupy the channel to transmit data; if the channel energy exceeds the threshold, the channel will not be occupied (there may be WiFi stations occupying the channel at this time), and data transmission will not start until it is detected that the channel energy does not exceed the threshold.

Furthermore, according to the different CCA stages of idle channel assessment, the above LBT techniques can be divided into four types, namely: Type 1, NOLBT; Type 2, LBT without random backoff; Type 3, with random backoff but fixed contention window Type 4, LBT with random backoff and changing competition window. Among them, CCA can be divided into ICCA stage and ECCA stage. The time length of ICCA is fixed, and the time length of ECCA is different according to the back-off value BO, and the back-off value BO is an integer, which takes a value between 0 and CW. The maximum value CW is the contention window. Type 1 means that there is no free channel assessment CCA, and the LAA base station directly accesses the channel when there is data to be transmitted; the length of the CCA of type 2 is fixed, that is, after the idle channel assessment is completed, the LAA base station accesses the channel; the length of the CCA of types 3 and 4 varies , that is, the length of the CCA can vary according to the BO value and the CW value, and the LAA base station accesses the channel after the idle channel evaluation is completed.

Although the LAA technology can improve the transmission rate of the existing LTE system, it still has some shortcomings. For example, when an LAA base station accesses a channel, other nearby LAA base stations of the same operator may detect that the channel is busy, so they freeze the detection and wait for the channel to be free. In fact, multiple nearby LAA base stations of the same operator can occupy the same channel at the same time for channel multiplexing. That is to say, the existing method for channel multiplexing of LAA base stations cannot realize simultaneous multiplexing of channels by multiple LAA base stations of the same operator, and the efficiency of channel multiplexing is not high.

This application designs a channel multiplexing method among multiple LAA base stations of the same operator based on type 4.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a method and device for channel multiplexing in an unlicensed frequency band, which can realize channel multiplexing in an unlicensed frequency band by multiple LAA base stations of the same operator.

In order to achieve the above object, the present invention discloses a channel multiplexing method of an unlicensed frequency band, which is applied to authorized and assisted access to LAA base stations, including:

When there is data to be transmitted, the channel energy is detected in the detection frame of the sending cycle; wherein, the sending cycle includes a detection frame, a sending frame and a blank frame;

When detecting that the channel is idle, determining a backoff time, and starting a data transmission countdown based on the backoff time;

Before the end of the countdown, if a request signaling for acquiring the backoff time is received, sending the backoff time;

When detecting the request signaling to participate in channel multiplexing sent by other LAA base stations and the first transmission start time, using the sending frame to perform data transmission at the first transmission start time;

If the request signaling for obtaining the backoff time is not received or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected, when the countdown ends, send to other LAA base stations to obtain the backoff of other LAA base stations Time request signaling;

According to the back-off time returned by other LAA base stations, according to the preset rules, determine the LAA base stations currently participating in channel multiplexing and the second transmission start time, and send channel multiplexing request signaling and the second transmission start time to each LAA base station participating in channel multiplexing 2. Transmission start time: at the second transmission start time, data transmission is performed by using a sending frame.

Preferably, the method also includes:

If it is detected that the channel is busy before the countdown ends, the countdown is frozen, and when the channel is detected to be idle again, the countdown is unfrozen.

Preferably, the method also includes:

After the countdown ends, but before the first transmission start time or the second transmission start time, if it is detected that the channel is busy, the channel multiplexing process at the first transmission start time or the second transmission start time is ended, and the transmission period is repeated The step of detecting the channel energy in the detection frame.

Preferably, the method also includes:

According to the length of the contention window in the previous sending cycle, the number of confirmation messages obtained after data transmission and ${\mathrm{CW}}_{i+1}=\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array},$ Determine the duration of the contention window in the current sending cycle, where CW _i is the duration of the contention window in the previous sending cycle, CW _i+1 is the duration of the contention window in the current sending cycle, and α is the intra-frame data transmission in the previous sending cycle The ratio of the number of acknowledgment messages obtained later to the number of subframes in the sending frame in the sending cycle.

Preferably, the LAA base station currently participating in channel multiplexing is determined according to the backoff time returned by other LAA base stations according to preset rules, including:

identifying the median of the backoff times of the other LAA base stations according to the backoff times returned by the other LAA base stations;

Other LAA base stations whose backoff time is smaller than the median are determined as LAA base stations currently participating in channel multiplexing.

Preferably, the method also includes:

The duration of the blank frame for data transmission by the WiFi station in the sending cycle is not less than 5% of the sending frame duration, and the sending frame duration is between 1ms and 10ms.

In order to achieve the above purpose, the present invention discloses a channel multiplexing device in an unlicensed frequency band, which is applied to authorized and assisted access to LAA base stations, including:

The channel detection module is used to detect the channel energy in the detection frame of the sending cycle when there is data to be transmitted; wherein, the sending cycle includes a detection frame, a sending frame and a blank frame;

A countdown module, configured to determine a backoff time when the channel is detected to be idle, and start a data transmission countdown based on the backoff time;

A backoff time sending module, configured to send the backoff time if a request signaling for acquiring the backoff time is received before the countdown ends;

The first transmission module is configured to use a sending frame to perform data transmission at the first transmission start time when detecting the request signaling and the first transmission start time sent by other LAA base stations to participate in channel multiplexing;

A backoff time requesting module, configured to send a request to other LAA base stations at the end of the countdown if the request signaling for obtaining the backoff time is not received or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected. Sending request signaling for obtaining the backoff time of other LAA base stations;

The second transmission module is used to determine the LAA base station currently participating in channel multiplexing and the second transmission start time according to the backoff time returned by other LAA base stations according to preset rules, and send the channel to each LAA base station participating in channel multiplexing Multiplexing the request signaling and the second transmission start time; using the sending frame to perform data transmission at the second transmission start time.

Preferably, the device also includes a countdown freezing module;

The countdown freezing module is configured to freeze the countdown if it is detected that the channel is busy before the countdown ends, and unfreeze the countdown when the channel is detected to be idle again.

Preferably, the device further includes a contention window determination module;

The contention window determination module is used to determine the number of confirmation messages obtained after data transmission and ${\mathrm{CW}}_{i+1}=\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array},$ Determine the duration of the contention window in the current sending cycle, where CW _i is the duration of the contention window in the previous sending cycle, CW _i+1 is the duration of the contention window in the current sending cycle, and α is the intra-frame data transmission in the previous sending cycle The ratio of the number of acknowledgment messages obtained later to the number of subframes in the sending frame in the sending cycle.

Preferably, the second transmission module includes;

The identification submodule is used to identify the median of the backoff time of the other LAA base stations according to the backoff time returned by other LAA base stations;

The determining submodule is configured to determine other LAA base stations whose backoff time is smaller than the median as LAA base stations currently participating in channel multiplexing.

It can be seen from the above technical solution that in the embodiment of the present invention, when the channel is detected to be idle, before the end of the countdown, when the LAA base station detects the request signaling for participation in channel multiplexing and the first transmission start time sent by other LAA base stations, Data transmission is performed at the first transmission start time; when the request signaling for obtaining backoff time is not received or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected, at the end of the countdown, send to other LAA base stations Obtaining the request signaling of the backoff time of other LAA base stations and performing data transmission at the second transmission start time can realize channel multiplexing of multiple LAA base stations of the same operator in the unlicensed frequency band, thereby improving channel multiplexing efficiency.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings that are required in the description of the embodiments or the prior art. Apparently, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

FIG. 1 is a schematic flow diagram of a channel multiplexing method in an unlicensed frequency band provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a sending cycle in an embodiment of the present invention;

FIG. 3 is a schematic diagram of different determination schemes for transmission start time during channel multiplexing provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of the countdown of freezing and thawing during the detection process provided by the embodiment of the present invention;

FIG. 5 is another schematic flowchart of step S106 in FIG. 1 provided by an embodiment of the present invention;

FIG. 6a is a schematic flowchart of another channel multiplexing method in an unlicensed frequency band provided by an embodiment of the present invention;

FIG. 6b is a schematic diagram of the process of an example of multiplexing channels at an LAA site provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a channel multiplexing device in an unlicensed frequency band provided by an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of another device for channel multiplexing in an unlicensed frequency band according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiments of the present invention provide a channel multiplexing method and device for an unlicensed frequency band, which can realize channel multiplexing of multiple LAA base stations of the same operator in the unlicensed frequency band.

The present invention will be described in detail below through specific examples.

Referring to Fig. 1, this figure is a schematic flow diagram of a channel multiplexing method in an unlicensed frequency band provided by an embodiment of the present invention, including the following steps:

Step S101: When there is data to be transmitted, the channel energy is detected in the detection frame of the sending cycle.

Wherein, the sending cycle includes a detection frame, a sending frame and a blank frame, as shown in FIG. 2 . The WiFi station can use the blank frame in the sending cycle for data transmission. In practical applications, the duration of the blank frame is not less than 5% of the sending frame duration, and the sending frame duration is between 1ms and 10ms.

Step S102: When it is detected that the channel is idle, determine a backoff time, and start a data transmission countdown based on the backoff time.

Specifically, when WiFi occupies a channel, the channel energy will increase. If it is detected that the channel energy is not greater than a certain threshold, it may be determined that the channel is idle. When detecting that the channel is idle, the LAA base station obtains a value from 0 to the contention window, and determines the backoff time of the LAA base station according to the value. Assuming that the contention window is 50, and a value 17 is randomly obtained from 0 to 50, then the backoff time of the LAA base station can be determined to be 170 μs according to the value 17, and the countdown starts from the 170 μs.

Step S103: before the end of the countdown, if a request signaling for obtaining the backoff time is received, the backoff time is sent.

In practical applications, communication between different LAA base stations of the same operator is performed through the X2 interface. If the request signaling for acquiring the backoff time is received through the X2 interface, it means that other LAA base stations initiate channel multiplexing.

Step S104: When detecting the request signaling to participate in channel multiplexing sent by other LAA base stations and the first transmission start time, use the sending frame to perform data transmission at the first transmission start time.

Step S105: If the request signaling for obtaining the backoff time is not received or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected, at the end of the countdown, send to other LAA base stations to obtain other LAA base stations The request signaling of the backoff time of the base station.

Step S106: According to the back-off time returned by other LAA base stations, according to the preset rules, determine the LAA base stations currently participating in channel multiplexing and the second transmission start time, and send a channel multiplexing request message to each LAA base station participating in channel multiplexing and a second transmission start time; at the second transmission start time, a sending frame is used for data transmission.

Specifically, if the request signaling for obtaining the backoff time is not received, it means that the countdown end time of the LAA base station is earlier than the countdown end time of other LAA base stations in the same group; request signaling, it indicates that the LAA base station does not participate in channel multiplexing initiated by other LAA base stations. Both cases are judged before the countdown ends. Therefore, when two conditions are satisfied that the LAA base station does not participate in the channel multiplexing initiated by other base stations, and the countdown of the LAA base station ends first, when the countdown ends, the LAA base station sends to other LAA base stations a request to obtain the backoff time of other LAA base stations. request signaling.

After obtaining the backoff time of other LAA base stations, the LAA base station will determine which LAA base stations participate in channel multiplexing according to certain rules. It is determined as an object to participate in channel multiplexing, or all LAA base stations that return the backoff time are determined as objects to participate in channel multiplexing.

In order to ensure that the LAA base station can access the channel in a timely manner, in another embodiment of the present invention, corresponding to step S106 in the method embodiment shown in Figure 1, according to the backoff time returned by other LAA base stations, according to the preset rules, Determining the LAA base stations currently participating in channel multiplexing can be performed according to the flow shown in Figure 5, and the specific process includes the following steps:

Step S501: According to the backoff times returned by other LAA base stations, identify the median of the backoff times of the other LAA base stations;

Step S502: Determine other LAA base stations whose backoff times are smaller than the median as LAA base stations currently participating in channel multiplexing.

In this embodiment, as a preferred manner, the LAA base stations participating in channel multiplexing should meet certain conditions, that is, their backoff time should be relatively small. This reduces waiting time and speeds up the data transfer process.

After the object participating in channel multiplexing is determined, the second transmission start time needs to be determined according to the backoff time of the object participating in channel multiplexing. The determination of the second transmission start time will affect the fairness of channel occupation between the LAA base station and the WiFi station.

Assume that the countdown end time of the LAA base station that initiates multiplexing is determined as the transmission start time, and other LAA base stations that participate in multiplexing all transmit data "in advance", as shown in Figure 3 . In this way, the waiting time of the LAA base station is relatively short. As shown in Figure 3, it can be seen that the LAA base station has almost no waiting time. After the channel detection is completed, the data transmission will be carried out, and the chance of WiFi accessing the channel will be reduced. For WiFi unfair. The channel detection process shown in FIG. 3 includes the process of performing channel energy detection and the process of counting down according to the backoff time.

Assume that among the LAA base stations participating in channel multiplexing, the countdown end time of the LAA base station with the longest backoff time (LAA2 base station as shown in Figure 3) is determined as the transmission start time, and other LAA base stations need to wait for the countdown end time of the LAA2 base station. arrival, thereby "delaying" the transmission of data, as shown in Figure 3. In this way, the chance of WiFi accessing the channel will increase, and the fairness to WiFi will be considered more, but the possibility of LAA accessing the channel will be reduced.

Therefore, in order to take into account the fairness of channel occupancy by LAA base stations and WiFi stations, a "compromise" method can be used when determining the transmission start time, that is, the average value of the backoff time of the LAA base stations that will participate in channel multiplexing, or the median number, or the smaller of the mean and median as the transmission start time.

As can be seen from the above-mentioned embodiments, in the embodiment of the present invention, when an LAA base station detects that the channel is idle and the countdown ends, it sends a channel multiplexing request to other LAAs, and then determines the LAA base stations participating in channel multiplexing according to the backoff time of other LAAs. Transmission start time. The LAA base station and other LAA base stations perform data transmission simultaneously at the determined transmission start time, realizing channel multiplexing of multiple LAA base stations of the same operator in an unlicensed frequency band, and improving channel multiplexing efficiency.

In another embodiment of the present invention, the method embodiment shown in FIG. 1 also includes, if it is detected that the channel is busy before the end of the countdown, freezing the countdown, and unfreezing the countdown when the channel is detected to be idle again. countdown. In the schematic diagram shown in Figure 4, during the countdown process of the LAA base station, if the WiFi is performing data transmission or the LAA base station of other operators is performing data transmission, the LAA base station detects that the channel is busy. At this time, the LAA base station freezes the countdown. When the WiFi station When the channel is idle after completing the data transmission with the LAA base station of other operators, the LAA base station detects that the channel is idle, and it will unfreeze the countdown. It can be seen that the backoff mechanism of the LAA base station can avoid causing greater interference to the WiFi site, and is more fair to the WiFi site.

In another embodiment of the present invention, the method embodiment shown in FIG. 1 also includes, after the countdown ends, before the first transmission start time or the second transmission start time, if it is detected that the channel is busy, then end at The channel multiplexing process at the first transmission start time or the second transmission start time repeats the step of detecting channel energy in the detection frame of the sending cycle. After the countdown ends and before the transmission start time, if the channel is detected to be busy, then the channel multiplexing process will not be participated in, and the multiplexing process will end, and step S101 will be continued, that is, the channel energy will be detected. When the channel is detected to be free, the backoff time is determined. It can be seen from the above that when the transmission start time is determined, after the countdown ends, when the LAA base station does not occupy the channel, if it detects that the channel is busy, it will not participate in the channel multiplexing process, which avoids causing interference to WiFi stations and enables multiplexing. The process is friendlier and fairer.

In another embodiment of the present invention, the method embodiment shown in FIG. 1 also includes, according to the duration of the contention window in the last sending cycle, the number of confirmation messages obtained after data transmission and ${\mathrm{CW}}_{i+1}=\left\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array}\right.,$ Determine the duration of the contention window in the current sending cycle, where CW _i is the duration of the contention window in the previous sending cycle, CW _i+1 is the duration of the contention window in the current sending cycle, and α is the intra-frame data transmission in the previous sending cycle The ratio of the number of acknowledgment messages obtained later to the number of subframes in the sending frame in the sending cycle. The contention window is an integer between 16 and 1024. In practical applications, when the LAA access channel performs data transmission, in order to further ensure the fairness of the WiFi access channel, in the embodiment of the present invention, the size of the contention window is adjusted according to the number of confirmation messages obtained in the previous cycle , and then randomly select a value from 0 to the contention window, and determine the backoff time according to this value. Therefore, changing the value of the contention window can adjust the value range of the backoff time.

In this embodiment, the number of acknowledgment messages obtained after data transmission in the last sending cycle can reflect the user's data reception situation and channel quality. When 0 ≤ α < 0.6, it means that the number of confirmation messages obtained after data transmission in the last sending cycle is small, and there are WiFi or LAA base stations of other operators in the data transmission channel of the LAA base station, and the channel quality is relatively low. Poor, the contention window of the LAA base station should be doubled so that the backoff time will be extended to delay the access channel of the LAA base station; If there is no WiFi or LAA base station of other operators occupying the channel for data transmission, or the time for WiFi or LAA base station of other operators to occupy the channel for LAA base station data transmission is relatively short, the channel quality is good, and the competition window should be The backoff time will be shortened by halving to speed up the access channel of the LAA base station. In this way, the data transmission efficiency of the LAA site can be improved, the service quality can be improved, and the fairness in the process of coexistence with the WiFi site can be taken into consideration.

Referring to FIG. 6a, this figure is a schematic flow diagram of another channel multiplexing method in an unlicensed frequency band provided by an embodiment of the present invention, which specifically includes the following steps:

Step S601: When there is data to be transmitted, the channel energy is detected in the detection frame of the sending cycle. Wherein, the sending period includes a detection frame, a sending frame and a blank frame.

Step S602: When it is detected that the channel is idle, determine a backoff time, and start a data transmission countdown based on the backoff time.

Step S603: before the end of the countdown, if it is detected that the channel is busy, then freeze the countdown, and when it is detected that the channel is idle again, unfreeze the countdown.

Step S604: before the end of the countdown, if a request signaling for acquiring the backoff time is received, the backoff time is sent, and step S605 is executed.

Step S605: When the request signaling to participate in channel multiplexing and the first transmission start time sent by other LAA base stations are detected, step S606 is executed.

Step S606: After the countdown ends and before the first transmission start time, check whether the channel is busy, if it is detected that the channel is busy, then perform step S601; if it is not detected that the channel is busy, then perform step S607.

Step S607: Perform data transmission by using the sending frame at the first transmission start time, and execute step S612.

Step S608: Before the end of the countdown, if the request signaling for obtaining the backoff time is not received, or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected, then when the countdown ends, send to other The LAA base station sends a request signaling for obtaining the backoff time of other LAA base stations, and step S609 is executed.

Step S609: According to the back-off time returned by other LAA base stations, according to the preset rules, determine the LAA base stations currently participating in channel multiplexing and the second transmission start time, and send a channel multiplexing request message to each LAA base station participating in channel multiplexing and the second transmission start time, step S610 is executed.

Step S610: After the countdown ends and before the second transmission start time, check whether the channel is busy, if it is detected that the channel is busy, then perform step S601; if it is not detected that the channel is busy, then perform step S611.

Step S611: Perform data transmission by using the sending frame at the second transmission start time, and execute step S612.

Step S612: According to the length of the contention window in the sending cycle, the number of confirmation messages obtained after data transmission and the preset formula ${\mathrm{CW}}_{i+1}=\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array},$ Determine the duration of the contention window in the next sending cycle. Among them, CW _i+1 is the duration of the contention window in the next sending cycle, CW _i is the duration of the contention window in the current sending cycle, and α is the number of confirmation messages obtained after sending intra-frame data transmission in the current sending cycle and the number of confirmation messages in the sending cycle The ratio of the number of subframes within a transmit frame. The contention window is an integer between 16 and 1024.

It can be seen from the above that when an LAA base station detects that the channel is idle and the countdown ends, it will multiplex the channel with other LAAs at the determined transmission start time, realizing the multiplexing among multiple LAAs of the same operator, and improving the channel efficiency. reuse efficiency. At the same time, the channel detection process and backoff mechanism of the LAA base station and the adjustment process of the contention window effectively avoid interference to WiFi, making the LAA base station more efficient and friendly when using unlicensed frequency bands to transmit data.

Hereinafter, an example is used to describe the present invention in detail, and the specific process is shown in FIG. 6b.

Assume that there are data to be transmitted in the three LAA base stations, and the three LAA base stations are respectively represented by LAA1, LAA2, and LAA3, and the initial contention windows of the three LAA base stations are all 32. The duration of the sending frame is 10ms, and the duration of the blank frame is 1ms.

Phase 1: LAA1, LAA2, and LAA3 all detect channels, and WiFi is also detecting channels. At this time, the three LAA base stations detect that the channel is idle, and the backoff times determined according to the contention window are 100 μs, 180 μs, and 280 μs respectively, and the countdown starts based on the backoff time.

LAA1 ends the countdown first, so LAA1 sends a request signaling to LAA2 and LAA3 through the X2 interface to obtain the current backoff time; the two backoff times obtained by LAA1 and returned by LAA2 and LAA3 are 80 μs and 180 μs respectively, and LAA2 is found according to the preset rules , the median of the backoff time of LAA3, in this example, there are two medians, and the average value can be taken as the final median, that is, (80+180)/2=130 μs. Determine LAA2 whose backoff time is less than the median of 130μs as the LAA base station currently participating in channel multiplexing, and send channel multiplexing request signaling and transmission start time T to LAA2, where T is the backoff time of all LAAs currently participating in channel multiplexing The average value of , that is (0+80)/2=40μs, start to transmit data.

LAA1 waits, LAA2 and LAA3 continue to count down, when time T is reached, LAA1 transmits data, and LAA2 counts down to zero directly and transmits data, and starts multiplexing channels. LAA3 does not participate in channel multiplexing, and continues to detect channels. When LAA1 and LAA2 multiplex channels, LAA3 detects that the channel is busy, so it freezes the countdown.

WiFi detects that the channel is busy and does not transmit data.

Phase 2: When LAA1 and LAA2 end multiplexing the channel, LAA3 detects that the channel is idle, and counts down to unfreeze. After LAA1 and LAA2 have finished transmitting data, they enter the blank frame stage. During this time, WiFi detects that the channel is idle and transmits data. When the WiFi transmits data, LAA3 detects that the channel is busy, and freezes the countdown.

Since LAA1 and LAA2 multiplex channels, their data transmission processes affect each other. The ratio of the number of confirmation messages received by LAA1 to the number of subframes in the sending frame is 0.8, and the ratio of the number of confirmation messages received by LAA2 to the number of subframes in the sending frame is 0.5, then in the next sending cycle of LAA1 and LAA2 Among them, the competition window of LAA1 remains unchanged at 32, and the competition window of LAA2 is adjusted from 32 to 64.

Phase 3: WiFi transmission data ends. LAA3 detects that the channel is idle, and counts down to unfreeze. At this time, the backoff time of LAA3 is 60 μs. At the same time, LAA1 and LAA2 detect that the channel is idle in the new sending period, and determine the backoff time to be 120 μs and 440 μs respectively based on their respective contention windows 32 and 64 .

LAA3 ends the countdown first, and sends a request signaling to LAA1 and LAA2 to obtain the current backoff time through the X2 interface; the two backoff times obtained by LAA1 and LAA2 returned by LAA3 are 60μs and 380μs respectively. According to the preset rules, find out LAA1, The median of the back-off time of LAA2 has a two-digit median here, and its average value can be taken as the final median, that is, (60+380)/2=220 μs. Determine LAA1 whose backoff time is less than the median of 220μs as the LAA base station currently participating in channel multiplexing, and send channel multiplexing request signaling and transmission start time T' to LAA1, T' is taken from all LAAs currently participating in channel multiplexing The average value of the back-off time, that is, (0+60)/2=30μs, starts to transmit data.

LAA3 waits, LAA1 and LAA2 continue to count down, when reaching T', LAA3 transmits data, LAA1 counts down directly to zero and transmits data, and starts multiplexing channels. LAA2 does not participate in channel multiplexing, and continues to detect channels. When LAA3 and LAA1 multiplex channels, LAA2 detects that the channel is busy, so it freezes the countdown.

Since LAA3 and LAA1 multiplex channels, their data transmission processes affect each other. The ratio of the number of confirmation messages received by LAA1 to the number of subframes in the sending frame is 0.9, and the ratio of the number of confirmation messages received by LAA3 to the number of subframes in the sending frame is 1. According to these values, the contention windows of LAA3 and LAA1 in the next sending cycle are both halved, that is, the contention windows of LAA3 and LAA1 are both adjusted from 32 to 16. The subsequent data transmission process is the same as the above description, and will not be repeated here.

It can be understood that in Figure 6b, for LAA1 and LAA2, phase 1 and phase 2 constitute a transmission cycle, wherein phase 1 corresponds to the detection frame and transmission frame of LAA1 and LAA2, and phase 2 corresponds to LAA1 and LAA2 blank frames. For LAA3, Phase 1, Phase 2 and Phase 3 correspond to detection frames and transmission frames in one transmission cycle.

It can be seen from the above that when an LAA base station detects that the channel is idle and the countdown ends, it sends a channel multiplexing request to other LAA base stations, and then determines the LAA base stations participating in channel multiplexing and the transmission start time according to the backoff time of other LAA base stations. The LAA base station and other LAA base stations perform data transmission at the determined transmission start time at the same time, realizing channel multiplexing of multiple LAA base stations of the same operator in an unlicensed frequency band. At the same time, in this embodiment, the LAA base stations with smaller back-off times are determined as the LAAs participating in channel multiplexing, and the average value of the back-off times of the LAA base stations participating in channel multiplexing is used as the transmission start time, which reduces the waiting time and improves the efficiency. Efficiency of data transfer.

Referring to FIG. 7, this figure is a schematic structural diagram of a channel multiplexing device in an unlicensed frequency band provided by an embodiment of the present invention, corresponding to the method embodiment shown in FIG. 1, and the device includes:

The channel detection module 701 is configured to detect channel energy in a detection frame of a sending cycle when there is data to be transmitted.

Wherein, the sending period includes a detection frame, a sending frame and a blank frame.

Specifically, the duration of the blank frame for data transmission by the WiFi station within the sending period is not less than 5% of the duration of the sending frame, and the duration of the sending frame is between 1 ms and 10 ms.

The countdown module 702 is configured to determine a backoff time when the channel is detected to be idle, and start a data transmission countdown based on the backoff time.

The backoff time sending module 703 is configured to send the backoff time if a request signaling for acquiring the backoff time is received before the countdown ends.

The first transmission module 704 is configured to use a sending frame to perform data transmission at the first transmission start time when the request signaling to participate in channel multiplexing and the first transmission start time sent by other LAA base stations are detected.

The backoff time requesting module 705 is configured to, if the request signaling for obtaining the backoff time is not received or the request signaling for participating in channel multiplexing sent by other LAA base stations is not detected, when the countdown ends, send a request to other LAA The base station sends request signaling for obtaining the backoff time of other LAA base stations.

The second transmission module 706 is configured to determine the LAA base station currently participating in channel multiplexing and the second transmission start time according to the backoff time returned by other LAA base stations according to preset rules, and send the second transmission start time to each LAA base station participating in channel multiplexing Channel multiplexing request signaling and a second transmission start time; at the second transmission start time, a sending frame is used for data transmission.

In another embodiment of the present invention, the device embodiment shown in FIG. 7 also includes a countdown freezing module (not shown in the figure).

The countdown freezing module is configured to freeze the countdown if it is detected that the channel is busy before the countdown ends, and unfreeze the countdown when the channel is detected to be idle again.

In another embodiment of the present invention, the device embodiment shown in FIG. 7 also includes a multiplexing end module (not shown in the figure).

The multiplexing end module is configured to end the time at the first transmission start time or the second transmission start time if it is detected that the channel is busy after the countdown ends and before the first transmission start time or the second transmission start time In the process of channel multiplexing, the step of detecting channel energy in the detection frame of the sending cycle is repeated.

In another embodiment of the present invention, the device embodiment shown in FIG. 7 further includes a contention window determination module (not shown in the figure).

The contention window determination module is used to determine the number of confirmation messages obtained after data transmission and ${\mathrm{CW}}_{i+1}=\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array},$ Determine the duration of the contention window in the current sending cycle, where CW _i is the duration of the contention window in the previous sending cycle, CW _i+1 is the duration of the contention window in the current sending cycle, and α is the intra-frame data transmission in the previous sending cycle The ratio of the number of acknowledgment messages obtained later to the number of subframes in the sending frame in the sending cycle.

Referring to FIG. 8, this figure is a schematic structural diagram of another unlicensed frequency band channel multiplexing device provided by an embodiment of the present invention. In this device, a channel detection module 801, a countdown module 802, a backoff time sending module 803, a first transmission The module 804 and the backoff time requesting module 805 are the same as the channel detection module 701, the countdown module 702, the backoff time sending module 703, the first transmission module 704, and the backoff time requesting module 705 in FIG. The second transmission module 806 may specifically include:

The identifying submodule 8061 is configured to identify the median of the backoff times of other LAA base stations according to the backoff times returned by other LAA base stations;

The determining submodule 8062 is configured to determine other LAA base stations whose backoff time is less than the median as the LAA base stations currently participating in channel multiplexing.

Since the above device embodiment is obtained based on the method embodiment of channel occupancy in the unlicensed frequency band, and has the same technical effect as the method, the technical effect of the device embodiment will not be repeated here.

As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the part of the description of the method embodiment.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprising", or any other variation is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also items not expressly listed. other elements, or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Those skilled in the art can understand that all or part of the steps in the above embodiments can be implemented by program instructions related hardware, and the program can be stored in a computer-readable storage medium. The storage medium referred to here refers to ROM/RAM, magnetic disk, optical disk, and the like.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims (10)

1. a channel multiplexing method for unauthorized frequency range, is characterized in that, is applied to authorize to assist access LAA base station, comprising:

In the time there is data to be transmitted, in the detection frame in the cycle of transmission, channel energy is detected; Wherein, send periodic packetsDraw together one and detect frame, a transmission frame and a blank frame;

In the time channel idle being detected, determine back off time, and start transfer of data countdown based on described back off time;

Before described countdown finishes, obtain the demand signalling of described back off time if receive, while keeping out of the way described in sendingBetween;

In the time detecting that the demand signalling and first of the participation channel multiplexing that other LAA base stations send transmits the time started, in instituteState the first transmission time started employing transmission frame and carry out transfer of data;

Obtain the demand signalling of described back off time if do not receive or the participation channel that other LAA base stations send do not detectedMultiplexing demand signalling, in the time that described countdown finishes, while obtaining keeping out of the way of other LAA base stations to other LAA base stations transmissionsBetween demand signalling;

The back off time returning according to other LAA base stations, according to preset rules, determines the LAA base station of current participation channel multiplexingAnd second transmission the time started, and to participate in channel multiplexing the multiplexing demand signalling of each LAA base station transmitting channel and second passThe defeated time started; Adopt transmission frame to carry out transfer of data in described the second transmission time started.

2. method according to claim 1, is characterized in that, described method also comprises:

If channel busy detected before countdown finishes, freeze described countdown, when channel idle again being detectedTime, the described countdown of thawing.

3. method according to claim 2, is characterized in that, described method also comprises:

After countdown finishes, before the first transmission time started or the second transmission time started, if channel busy detected,Finish the channel multiplexing process in described the first transmission time started or the second transmission time started, repeat in the cycle of transmissionDetect the step in frame, channel energy being detected.

4. according to the method described in claim 1 or 2 or 3, it is characterized in that, described method also comprises:

According to the duration of contention window in the upper transmission cycle, the confirmation message number obtaining after transfer of data and ${\mathrm{CW}}_{i+1}=\left\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array}\right.,$ Determine the duration of contention window in the current transmission cycle, wherein CW_iForThe duration of contention window in the upper transmission cycle, CW_i+1For the duration of contention window in the current transmission cycle, α is upper one and sends weekIn the confirmation message number obtaining after the transmission of interim transmission intraframe data and this transmission cycle, send the ratio of the sub-frame number in frameValue.

5. method according to claim 1, is characterized in that, the described back off time returning according to other LAA base stations, pressesAccording to preset rules, determine the LAA base station of current participation channel multiplexing, comprising:

The back off time returning according to other LAA base stations, the median of described other LAA base station back off times of identification;

Back off time is less than to other LAA base stations of described median, is defined as the LAA base station of current participation channel multiplexing.

6. method according to claim 1, is characterized in that, described method also comprises:

The duration that interior WiFi website of transmission cycle carries out the blank frame of transfer of data is not less than 5% of transmission frame duration, sends frameDuration is between 1ms～10ms.

7. a channel multiplexing device for unauthorized frequency range, is characterized in that, is applied to authorize to assist access LAA base station, comprising:

Channel Detection module in the time there is data to be transmitted, is examined channel energy in the detection frame in the cycle of transmissionSurvey; Wherein, the transmission cycle comprises that one is detected frame, a transmission frame and a blank frame;

Countdown module, in the time channel idle being detected, determines back off time, and starts data based on described back off timeTransmission countdown;

Back off time sending module, before finishing in described countdown, the request of obtaining described back off time if receiveSignaling, sends described back off time;

The first transport module, for passing when the demand signalling and first that the participation channel multiplexing that other LAA base stations send detectedWhen the defeated time started, adopt transmission frame to carry out transfer of data in described the first transmission time started;

Back off time is asked for module, if obtain the demand signalling of described back off time or do not detect other for not receivingThe demand signalling of the participation channel multiplexing that LAA base station sends,, in the time that described countdown finishes, sends and obtains to other LAA base stationsGet the demand signalling of the back off time of other LAA base stations;

The second transport module, for the back off time returning according to other LAA base stations, according to preset rules, determines current participationThe LAA base station of channel multiplexing and the second transmission time started, and multiplexing to each LAA base station transmitting channel of participating in channel multiplexingDemand signalling and the second transmission time started; Adopt transmission frame to carry out transfer of data in described the second transmission time started.

8. device according to claim 7, is characterized in that, described device also comprises that countdown freezes module;

Module is freezed in described countdown, if channel busy detected before finishing in countdown, freezes described meterTime, in the time again channel idle being detected, the described countdown of thawing.

9. according to the device described in claim 7 or 8, it is characterized in that, described device also comprises contention window determination module;

Described contention window determination module, for according to the duration of a upper transmission cycle contention window, obtains after transfer of dataConfirmation message quantity and ${\mathrm{CW}}_{i+1}=\left\{\begin{array}{cc}{\mathrm{CW}}_i\&times;2,& 0\&le;\mathrm{\&alpha;}<0.6\\ {\mathrm{CW}}_i,& 0.6\&le;\mathrm{\&alpha;}<0.9\\ {\mathrm{CW}}_i/2,& 0.9\&le;\mathrm{\&alpha;}\&le;1\end{array}\right.,$ Determine contention window in the current transmission cycleDuration, wherein CW_iFor the duration of contention window in the upper transmission cycle, CW_i+1For contention window in the current transmission cycle timeLong, α sent the confirmation message number obtaining after intraframe data transmission and sends in this transmission cycle in the upper transmission cycleThe ratio of the sub-frame number in frame.

10. device according to claim 7, is characterized in that, described the second transport module comprises;

Recognin module, for the back off time returning according to other LAA base stations, described other LAA base station back off times of identificationMedian;

Determine submodule, for back off time being less than to other LAA base stations of described median, be defined as current participation channel multipleWith LAA base station.