KR20100023616A - Wireless network system of multi tier and communication method and apparatus thereof - Google Patents

Abstract

PURPOSE: A wireless network system of multi-layered structure, a communication method thereof, and an apparatus thereof are provided to differentiate QoS according to priority of users by introduction of multi-band method and multi-layered network structure. CONSTITUTION: Users(102,104) of a primary user layer(100) have a priority higher than that of users(202,204) of a secondary user layer(200). A wireless network system of multi-layered structure includes the primary user layer, and the secondary user layer, and an access point(300). In the primary user layer, QoS(Quality of Service) condition is absolutely satisfied. In the secondary user layer, QoS condition can be satisfied in best effort type. The access point operates allocation of a medium access type and access parameter depending on access sensing of a user terminal, joining decision of a user, and a priority of each user.

Description

Wireless network system, wireless network communication method and wireless network communication device {Wireless Network System of Multi tier and Communication Method and Apparatus}

The present invention relates to a wireless network system, a wireless network communication method, and a wireless network communication device, wherein a wireless network system, a wireless network communication method, and communication in which QoS of each user is differently set according to priorities in a wireless network composed of multiple layers of users. For the device.

Conventionally, communication between users is generally performed using a wired network, but in recent years, wireless communication has been widely used to develop wireless communication technology and improve user convenience.

Unlike wired communication, since the same channel is more likely to be used by other users at the same time, the probability of collision between users is relatively higher, and the retransmission of data frequently occurs due to the collision. There is a problem that it is difficult to ensure reliable traffic transmission.

The conventional wireless communication method of medium access control (MAC) of IEEE 802.11 has many problems in support of WLAN quality of service (QoS), which is a distributed coordination function (DCF) of 802.11, in which all data traffic arrives in the transmission queue. There is a problem in that it does not provide any function for supporting QoS according to priority in a best effort manner in which a service is provided.

For the conventional 802.11 MAC, Korean Institute of Communication Sciences 07-5 Vol. 32 In No. 5, “Repetitive Tone-based Competition Techniques in Competitive-based MAC,” introduced a new competitive technique, TAR (Tone-based Access Scheme with Repetitive Contention), in parallel with the data transmission channel to reduce the probability of collision in the conventional DCF. Although a technique for reducing collision probability is introduced by introducing a competitive channel, which is handled by a network, this technique also has a problem in that it does not provide any function for supporting QoS according to priority.

In order to improve the above problems in 802.11 MAC, 802.11e provides a new wireless LAN MAC protocol that can transmit sensitive traffic in addition to the best transmission service based on the DCF transmission method of MAC. As a result, there is a problem in that QoS cannot be guaranteed according to priority among users.

The present invention is to solve the above problems by setting the medium access method and the access parameters according to the user's priority so that the degree of guarantee of QoS can be changed according to the user's priority, A wireless network system, a wireless network communication method, and a wireless network communication device operating according to the present invention are provided.

In order to achieve the above object, in the wireless network system of the present invention, a wireless terminal composed of multiple layers of users includes a user terminal consisting of n layers having different priorities for communication resources, and a subscription of the user terminals of each layer. It includes an access point for determining whether or not to assign a medium access method and access parameters set according to the priority of each layer.

In addition, in order to achieve the above object, the wireless network communication method of the present invention is a communication method of a wireless network composed of users having a multi-layer having different priorities, in which a user terminal constituting the wireless network attempts to subscribe. Determining whether or not; Allocating a medium access method and a access parameter set according to the priority of the user terminal allowed to subscribe; Communicating with another user terminal based on the assigned medium access method and access parameter.

In addition, in order to achieve the above object, the wireless network communication apparatus of the present invention is a multi-layer wireless communication system having different priorities using the MAC protocol in the data link layer, and the MAC protocol is applied according to data transmission requirements of higher layers. A data analysis generator for generating a frame by analyzing data to be transmitted through the data; and searching for a band to be used for communication among available communication resources based on a medium access method and a connection parameter allocated according to priority for transmitting the generated frame. It includes a resource management unit for determining, and a data transceiver for transmitting and receiving the frame generated through the determined band provided for the transmission and reception of data, or a frame transmitted by another user.

The present invention having the above configuration has the effect of communicating by varying the QoS according to the priority of the user by introducing a multi-band hopping method and a multi-layered network structure.

In addition, by differently assigning the media access method and access parameters according to the priority, it is possible to implement the communication of the trust transmission method to the users of the highest priority and to provide the best effort service to other users. .

In addition, by properly setting the hopping period can ensure the priority of the user of the highest priority while allowing other users to use the appropriate channel has the effect of enabling efficient wireless communication.

Hereinafter, a wireless network system, a wireless network communication method, and a communication apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating an example of a multi-layered wireless network system, in which a priority classification concept of a user is added to a general cellular, WLAN, and WPAN configuration, and is referred to as a user of a primary user layer 100 (hereinafter, referred to as a “primary user”). 102, 104 have a higher priority than users of the secondary user hierarchy 200 (hereinafter referred to as " secondary users ") 202,204. Although only two layers of users are shown in FIG. 1, two or more layers may exist with different priorities. In addition, although FIG. 1 shows users of the same priority grouped together for convenience of description, each user may be mixed and arranged on a wireless network with different priorities.

The wireless network system of the multilayer structure shown in FIG. 1 includes a primary user layer 100, a secondary user layer 200, and an access point (AP) 300. The primary user layer 100 has absolutely satisfied QoS conditions. The group of users that should be identifiable is a user with priority characteristics, such as a regular member or a user who has paid a high price.

Secondary user layer (200) is a group of users who want to satisfy the best-effort QoS conditions. For example, a non-priority guest or non-priority user who does not belong to a group or a low-paying user. Users.

The access point 300 detects a connection of a user terminal and determines a user's subscription or allocates a media access method and a connection parameter according to the priority of each user.

2 is a block diagram schematically illustrating an access point and includes a user subscription determiner 310 and a resource allocator 320.

The user subscription determiner 310 classifies users who attempt to access a subscription according to a predetermined criterion in the hierarchy. In the case of FIG. 1, the users are classified into two hierarchies according to priorities.

Regarding the operation of the user subscription determining unit 310, the method of determining whether to subscribe according to the priority of each user may be different. For example, in a situation where the number of primary users is equal to the number of orthogonal resources, If the primary user wants to subscribe, the user subscription determination unit 310 may not allow the subscription or allow the subscription as a secondary user having a lower priority. This is a matter of network operation and is a network operator's option. However, in the former case, the QoS of the existing primary user can be absolutely guaranteed, but in the latter case, the QoS guarantee of the primary user to be accessed later is lowered. That is, in the former case, the primary user occupies and uses the multi-band communication resources with the highest priority. When there are more primary users than the communication resources, the primary user's QoS can be absolutely guaranteed. It does not allow additional subscriptions.

The user subscription determiner 310 also limits the number of secondary users only to the extent that the performance indicator value does not fall below a specific threshold value N. FIG. The specific threshold value (N) indicates the occupancy state of the multiband considering the number of primary users, that is, the channel utilization indicating the available communication resources composed of the multibands and the state occupied by the primary user. Set considering channel utilization. This is because when there are too many users, the possibility of collision between secondary users increases and throughput decreases due to frequent retransmissions.

In the following, with reference to FIG. 3, a new user will be described in more detail.

Primary and secondary users go through the same process when joining the network. 3 is a message flow chart sequentially showing a user's network subscription procedure. The user first goes through the authentication process on the network. Use open system authentication as authentication on networks that do not specifically care about security, and use shared key authentication on networks that require security. If the user succeeds in the authentication process from the access point 300, the user requests association from the access point 300. After the user is associated with the access point 300, the user may send data messages through the access point 300.

 According to an embodiment of the present invention, the user may represent a layer to which the user belongs and the amount of power remaining by using some of the 11 reserved bits of the capability information field of the association request frame sent to the access point 300. When 300 receives it, it transmits it to the user subscription determination unit 310 in the access point 300.

When the user requesting the subscription is a primary user, the user subscription determination unit 310 may determine whether there is an orthogonal resource that can be allocated to the primary user, and allow the subscription only when the resource exists. That is, if the number of primary users subscribed to the access point 300 at the time t is N1 and the orthogonal resource is Nr, the user subscription determiner 310 checks whether N1 + 1 ≦ Nr, and is true. If it is allowed to join. However, when N1 + 1> Nr, in order to maintain the orthogonality of the primary user, that is, the QoS of the primary user, the user is allowed to join or allow the user to join as a low priority user, that is, a secondary user. Then, the information on whether to allow the subscription is transmitted to the resource allocation unit 320.

If the user requesting a subscription is a secondary user, as mentioned above, the user subscription determination unit 310 requests a new subscription when the number of secondary users (T) already subscribed is smaller than a specific threshold value (N). Join the secondary user. In this case, N is determined in consideration of channel utilization, which is the primary user's communication resource occupancy state and secondary user's communication resource, the occupancy state channel utilization. Of course, even if it is smaller than the threshold value (N) it can be allowed to subscribe to a lower priority user.

The resource allocator 320 allocates a medium access method and a connection parameter according to the priority of the user when the user is allowed to subscribe.

The medium access method determines which MAC-based protocol the user will use or how the user communicates in a particular MAC protocol, for example whether the user will communicate in TDMA or CSMA / CA. This includes whether to use frequency-based or cognitive communication in CSMA / CA. For example, the frequency-based communication method is assigned to the primary user. Each primary user occupies a specific frequency and uses the access method to allocate to the user whose QoS must be absolutely guaranteed. It is a method of sensing a channel according to the index order by assigning an index group of a channel, and communicating using the channel when an idle channel is detected.

The access parameter may be a parameter required for communication, and may include, for example, a hopping sequence and an index group allocated through a contention window, AIFS, Latin square, and the like. This connection parameter can of course be added depending on the protocol used.

When the user requesting to join is a primary user, the resource allocator 320 may use Latin square or manhattan square when the information received from the user subscription decision unit 310 on whether to allow the user to join is notified of the subscription. Allocates unused sequences to primary users. The access point 300 includes the periodically repeated sequence allocated by the resource allocator 320 in the reserved bit of the capability information field of the association response frame and requests the association, that is, transmits the association request frame to the primary user. . In the capability information field of a frame, AIFS (Arbitration Inter Frame Space) length and contention window (CW) value to be set by the primary user, which is a connection parameter, are transmitted together.

 When the user requesting the subscription is the secondary user, the resource allocator 320 allocates the index group of the band to be sensed to the secondary user in consideration of the remaining power amount of the secondary user received from the user subscription determiner 310. This allows the efficient use of available communication resources. In addition, the size of the sensing band index group may be determined in proportion to the remaining power of the secondary user, thereby enabling communication suitable for the situation of the secondary user. For example, if there is enough remaining power, the secondary user may sense enough bandwidth to avoid the situation where the primary user may be delayed by delaying the transmission, thereby increasing the QoS of the secondary user. Allocate the index group large enough.

In addition, the resource allocator 320 should consider how the band index group is allocated to the existing secondary users in allocating the sensing band index group to the secondary user requesting a new subscription. For example, if a specific band is concentrated and allocated to secondary users who are already subscribed and communicating, new secondary users are allocated to secondary users with a similar activity as the channel activity of the primary user of the band. You must assign a band that is not available. In the present invention, in the resource allocation unit 320 allocates the sensing band index group, as described above, the sequence and channel activity assigned to existing primary users, the band index group and channel activity assigned to existing secondary users, Then, the sensing band index group is allocated in consideration of the remaining power amount of the terminal of the secondary user who newly requests a subscription.

The users who are classified as described above and succeed in joining are assigned to the medium access method and access parameters through the resource allocating unit 320 of the access point 300 to access the medium.

Users receive a media access method and access parameters from the access point 300 through a broadcasting channel. Frames broadcast periodically through a broadcasting channel need to be the same as beacons or some fields added to the beacons.

The primary user of the present invention receives the sequence generation index and transmits data to CSMA / CA while hopping orthogonally hopping a multiband channel when data is generated. The secondary user is allocated an index group of the band to be sensed and senses the entire band or some bands of the index group when data is generated and transmits data to the CSMA / CA among the band groups.

 To minimize delays when the primary user hopping bands orthogonally, the hopping unit is set to the shortest expected length of the frame to reduce unnecessary resource waste while reducing latency. That is, primary users hop in orthogonality while keeping frequency bands synchronized to ensure QoS. In the present invention, a hop period is set to the shortest frame length among primary users who want to transmit data. Primary users use this leap cycle in equal synchronization. 4 is a diagram illustrating a communication state when the hopping period is set longer than the length of the shortest data frame among the primary users. A, B, C, and D sections represent idle states of the band, and communication resources are wasted. Indicates. As such, when the hopping period is set longer than the length of the shortest data frame among the primary users, communication resources are not used efficiently. This is because when the hopping period is set longer than the length of the shortest frame, the frames with short frames cannot use the corresponding frequency band resource until the hopping period ends.

The period in which the secondary user senses the band is set to a unit that is equal to or shorter than the hopping unit of the primary user to synchronize with the primary user, and at the same time, the primary user transmits data through the band sensed by the secondary user. To support AIFS length-based algorithms that always give priority to primary users. 5 is a diagram illustrating a situation that occurs when the length of the secondary user slot is longer than the length of the primary user slot, and FIG. 6 is a diagram illustrating a communication state when AIFS is set differently according to priority.

First, the contention window (hereinafter referred to as CW) is set to 0 in order to efficiently use the orthogonal band allocated by primary users as shown in FIG. 5, and is caused by a user other than the primary user. To avoid congestion, set the length of the primary user's AIFS to a length shorter than that of the non-primary user. Since the secondary AIFS is longer than the primary user's AIFS, when the primary user preoccupies the band, the secondary user senses that the channel is occupied and sends no data and freezes the backoff counter. In FIG. 5, the AIFS of the primary user and the secondary user is indicated as AIFS (1) and AIFS (2), respectively. In the following, when the AIFS (1) <AIFS (2) is set, the primary user's priority is guaranteed. This will be explained in detail. In Slot 1, if the primary user has no data to send and the secondary user has data to send, the secondary user will not be able to send data in that slot, so the channel will be idle until AIFS (2), so the secondary user will send data to AIFS (2). Start sending. In this way, the secondary user uses an unused frequency resource because the primary user is assigned but has no data to send. In Slot 3, both primary and secondary users want to send frames. The channel is idle until AIFS (3), but since the traffic of primary user is transmitted through the channel between AIFS (3) and AIFS (4), the secondary user freezes the backoff counter value after sensing that the channel is not idle. Thus, in slot 3, the primary user has priority and transmits data when there is a conflict between the primary user and the secondary user.

As shown in FIG. 6, when the length of the secondary user slot is longer than the length of the primary user slot, the secondary user starts transmitting the frame without collision in slot 1 because there is no data to be sent by the primary user. When the frame to be transmitted to the primary user arrives at the beginning of slot 2, the primary user senses the channel for the length of AIFS as shown in FIG. While freezing, the secondary user waits until the start of slot 3, which sends out the frame. This causes delays in the frame transmission of primary users, making it difficult to guarantee QoS. Accordingly, the frame transmission unit of the secondary user can be made smaller than the leap unit length of the primary user, and the QoS of the primary user can be guaranteed by synchronizing with the leap unit of the primary user.

FIG. 7 is a view illustrating a state in which communication is performed between users by a wireless network communication method according to the present invention. The frame lengths of the primary users # 1, # 2, and # 3 are the same as 3 slots, and the primary user # 1 is 1, 3, 1 order, # 2 is 2, 2, 3 order, # 3 is 3, 1, 2 band hopping and packet is transmitted. However, due to burstiness of user traffic, primary users may not use all slots 1-9. As shown in the drawing, only primary user # 3 uses all slots 1 to 9, # 1 uses only slots 1 to 3, and # 2 uses only 7 to 9 slots. The unused slot transmits data through the slot when the secondary user senses the channel according to the index group granted when the secondary user is not used.

In addition, the secondary user may determine the data transmission band based on the sensed results for each band when determining the bands to be sensed in the next data transmission by storing the data transmission success in the sensed channel to increase the throughput. In this case, the transmission efficiency is increased.

8 is a flowchart illustrating a wireless network communication method according to the present invention, and descriptions of parts overlapping with those described above will be omitted. First, when a signal according to a subscription is transmitted to a newly approaching access point 300, as described above, the network first undergoes an authentication procedure. If the user succeeds in obtaining authentication from the access point 300, the user requests an association from the access point 300, and the user subscription determining unit 310 displays communication resources, the number of primary users, the number of secondary users, and the like. In this case, the user subscription determination unit 310 may approve the subscription in consideration of efficiency or may allow the subscription at a low priority. If the subscription is approved, the media access method and the access parameters are allocated from the resource allocator 320 to communicate based on this. (Steps S120 and S130)

9 is a block diagram schematically illustrating a wireless network communication device according to the present invention. As shown in FIG. 9, the communication device 120 generates a frame by analyzing data such as characteristics, priority, and access parameters of data to be transmitted according to a data transmission request in a higher layer. When the frame is generated, the resource manager 124 senses a band to be used for communication based on a medium access method and a connection parameter granted by the resource allocator 320 and determines a slot of an appropriate band. When the band and the slot is determined, the data is transmitted and received through the data transceiver 126.

As described above, the resource management unit 124 senses the band in consideration of the priority of the user and sets an appropriate slot. For example, the secondary user is given an index group in consideration of the remaining power and the channel in each index group. In this case, the communication resource is set to transmit data when there is an empty slot. In case of the primary user, the unused sequence among the generated Latin square or manhattan square is used, so hopping each band according to the sequence.

1 is a diagram illustrating a wireless network system having a multilayer structure.

2 is a block diagram schematically showing an access point in a wireless network system according to the present invention;

3 is a view showing a fixed that the transmission and reception of data is allowed when the user terminal attempts to access,

4 is a diagram illustrating a communication state when the hopping period is set longer than the length of the shortest data frame among the primary users.

5 is a diagram illustrating a communication state when the length and sync of a frame of a secondary user do not match;

6 is a diagram illustrating a communication state when AIFS is set differently according to priority;

7 is a diagram illustrating a state in which communication is performed between users by a wireless network communication method according to the present invention;

8 is a flowchart illustrating a wireless network communication method according to the present invention;

9 is a block diagram schematically illustrating a wireless network communication device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

primary user hierarchy: 100 secondary user hierarchy: 200

Access Point: 300

User Subscription Determination Unit: 310 Resource Allocation Unit: 320

Claims (27)

In a wireless network consisting of multiple layers of users, A user terminal in n layers having different priorities for communication resources, And an access point for determining whether to subscribe the user terminal of each layer and assigning a media access method and access parameters set according to the priority of each layer. In claim 1, Communication between the user terminal constituting the wireless network is a wireless network system, characterized in that via a communication resource consisting of a multi-band of the hopping method. In claim 2, The communication resource consisting of the multi-band of the hopping method is made of a slot method, The hopping period of the communication resource is set to the shortest frame length among frames to be transmitted by a user terminal (hereinafter, referred to as a "primary user") belonging to a layer having the highest priority. In claim 3, And a length of a transmission frame of a user terminal of a layer having a lower priority as the highest priority is set equal to or smaller than the hopping period. In claim 1, The medium access method of each user terminal is applied differently according to each layer classified according to priority. The medium access method includes a reliable transmission method and a best effort method according to a quality of service (QoS) condition required for each user terminal. In claim 1, The access point includes a user subscription determining unit that determines whether to join the wireless network of the user terminal included in each layer; And a resource allocating unit for allocating a medium access method and a connection parameter set according to a priority of a layer to which a user terminal subscribed to the wireless network belongs through the user subscription determining unit. In claim 6, And the user subscription determining unit determines whether to subscribe to a user terminal which attempts to access after preparing the available communication resources and a primary user. In claim 7, The user subscription determining unit, when all available communication resources are allocated to the primary user, Wireless network system, characterized in that does not allow the subscription of the user terminal attempting to access or to subscribe at a lower priority than the priorities. In claim 7, If the user terminal attempting the connection is not the primary user, The user subscription determining unit performs a subscription when the number of non-primary users who are currently subscribed is smaller than the threshold value N set in consideration of the communication resource occupation state of the primary user and the communication resource occupation state of the non-primary user. Wireless network system, characterized in that allowed. In claim 6, The access parameter includes a length of a contention window and an arbitration inter frame space (AIFS). The resource allocator sets the length of the contention window of the primary user to zero. In claim 10, The resource allocator sets the length of the AIFS shorter as the priority of the user terminal is higher. In a communication method of a wireless network composed of users of multiple layers having different priorities, Determining whether to subscribe when a user terminal forming the wireless network attempts to subscribe; Allocating a medium access method and a access parameter set according to the priority of the user terminal allowed to subscribe; Communicating with another user terminal based on the assigned medium access method and access parameter. The method of claim 12, In the step of determining whether to subscribe, the connection of the user terminal attempting to subscribe is a user terminal belonging to a layer having the highest priority and communication resources composed of multi-bands of the wireless network (hereinafter referred to as a "primary user"). Comparing and determining the communication method of the wireless network. The method of claim 13, As a result of comparing the primary user and the available communication resources, if all the multi-bands are allocated, the user is not allowed to join or the subscription is allowed at a lower priority than the priority of the user terminal attempting to join. A communication method of a wireless network. The method of claim 12, In the step of assigning the medium access method and access parameters, The access parameter includes the length of the contention window and the AIFS, and assigns a length of the contention window of the primary user to 0. The method of claim 15, The AIFS is a communication method of a wireless network, characterized in that the higher the priority of the user terminal is assigned a shorter length. The method of claim 15, The medium access method is applied differently according to the priority of the user terminal, The medium access method includes a reliable transmission method and an optimal transmission method according to QoS conditions required for each user terminal. The method of claim 12, In the communicating step, Communication between the user terminal is a communication method of a wireless network, characterized in that the multi-band orthogonal hopping method. The method of claim 17, The hopping communication is performed based on a time slot. The hopping period of the hopping scheme is set to the frame length of the smallest length of the frame to be transmitted by the primary user. The method of claim 18, And a length of a transmission frame of a user terminal other than the primary user is set equal to or smaller than the hopping period. A computer-readable recording medium having recorded thereon program code for executing a communication method according to any one of claims 12 to 20. In a wireless communication system having a multi-layered priority using the MAC protocol at the data link layer, A data analysis generator for generating a frame by analyzing data to be transmitted through a MAC protocol according to a data transmission request of an upper layer; A resource management unit for searching and determining a band to be used for communication among communication resources available based on a media access method and a connection parameter allocated according to priority for transmitting the generated frame; And a data transmitting / receiving unit provided for transmitting and receiving data and transmitting a frame generated through the determined band or receiving a frame transmitted by another user. The method of claim 22, The communication resource is made of a multi-band, And transmitting and receiving the data is performed in a manner of randomly hopping the multi bands. The method of claim 22, The connection parameter includes a length of a contention window. The length of the contention window of the primary user is zero. The method of claim 22, The access parameter includes an arbitration inter frame space (AIFS), Wireless network communication device characterized in that the higher the priority, the shorter the length of AIFS. The method of claim 22, In the case of a user other than the primary user, the frame generated by the data analysis generator includes data on the amount of power remaining in the user terminal. The larger the amount of power remaining, the larger the size of the index group to sense whether the idle idle of the communication resources. The method of claim 26, The size of the index group to be sensed is set in consideration of the band activity of the primary user and the size of the index group assigned to the previous user, The greater the band activity and the size of the index group of the previous user, the smaller the size of the index group to be sensed.

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