WO2006063499A1

WO2006063499A1 - A METHOD FOR GROUP POLLING IN WLAN BASED ON ADAPTIVE QoS ASSURANCE

Info

Publication number: WO2006063499A1
Application number: PCT/CN2005/001606
Authority: WO
Inventors: Feng Li; Gonghang Sun; Fengguo Ma; Bo Sun; Wei Cheng
Original assignee: Zte Corporation
Priority date: 2004-12-17
Filing date: 2005-09-29
Publication date: 2006-06-22
Also published as: CN1791046A; CN100401708C

Abstract

A method for group polling WLAN based on adaptive QoS assurance, includes: adjusting the group polling policy according to the priority of service type and the variety of transmission data service type of site in the network and the current state, polling cyclically the groups that may have service to transmit, the polling content of said cyclic polling can be different; the site responds group polling according to the priority of data service type it will transmit; the site complied with the polling condition transmits data to the destination site, the destination site receives and responds. The frame time interval of different priority service type in the invention could set to be same or different, shorten the frame time interval adaptively, it doesn’t make transmission time delay, it increases the network throughput and enhances network performance.

Description

Wireless local area network grouping polling method based on adaptive service quality assurance

Technical field

The present invention relates to wireless communication technologies, and more particularly to a wireless local area network grouping polling method based on quality of service guarantee.

Background technique

The WLAN is usually based on the Carrier Sense Multiple Access Protocol (CSMA). The improvements are as follows: split-channel reservation multiple access (SRMA), collision avoidance multiple access protocol (MACA) (multiple access with Collision avoidance), improved collision avoidance multiple access protocol MACAW, floor acquisition multiple access (FAMA) and 802.11 protocols, etc., the wireless local area network referred to in the present invention is generally based on the CSMA protocol.

There is a need to establish a Quality of Service (QoS) guarantee mechanism in a wireless local area network. Currently, there are two typical methods: IEEE802. il standard and IEEE802. lie draft standard. Among them, there are IEEE802.11, which specifies the Distributed Coordination Function (DCF) and Point Coordination (PCF) functions, which can implement two simple QoS guarantee mechanisms with different priorities. In 802.11, the PCF uses the polling method to transmit the delay-sensitive traffic category, the inter-frame interval is short, and the priority is high. The service class transmitted by the DCF mode must be competing for access, and the inter-frame spacing. Relatively long, low priority. The definition of the service category means that one service category is a set of medium access control (MAC) layer service data units (MSDUs), and the MSDUs of the same service category have specific priority requirements compared to other service categories MSDU. IEEE 802.11 cannot adapt to the transmission requirements of multimedia services with higher priority. To overcome this shortcoming, the IEEE 802.11e draft standard adds Enhanced Distributed Coordination (EDCF) and Hybrid Coordination (HCF). The EDCF assigns different inter-frame spaces to different priority service classes. The service class access probability with a long inter-frame interval is lower than the service class with a short inter-frame interval. The EDCF can be mixed with the polling method as HCF to implement more complex QoS. Guarantee mechanism. The disadvantage is that when there are many service categories specified in the network, the inter-frame spacing of data transmission of each service category is relatively large, and the lower priority service category has a longer interframe space, which is not required by the service transmission itself, but Due to the fact that multiple services with different priorities are simultaneously competing for media, through different service categories Different interframe spaces are set to have different access probabilities to achieve QoS guarantee. The inter-frame spacing of the low-priority service class transmission is large, especially when there is no high-priority service class transmission, the low-priority service class cannot shorten the interframe space, causing unnecessary transmission delay, reducing network throughput, and network performance. Getting worse. Summary of the invention

The technical problem to be solved by the present invention is to provide a wireless local area network grouping and polling method based on adaptive quality of service guarantee, which solves the problem that the prior art has a large difference in the inter-frame spacing of data transmission in each service category when the service category is large, and the low priority The level of service class cannot adaptively shorten the interframe space, which will cause unnecessary transmission delay and reduce the technical problem of network throughput.

In order to achieve the above object, the present invention provides a wireless local area network grouping polling method based on adaptive quality of service guarantee, which is characterized in that it includes step one, service class priority and network traffic type of network service in the network. The state adaptively adjusts the grouping and polling policy, and performs cyclically repeated polling for the group that may have service transmission, and the round robin polling may have different polling contents; Step 2: The station needs to transmit data according to itself The priority of the category responds to the group polling; Step 3: The station that meets the polling condition sends data to the destination station.

The foregoing method is characterized in that: the step 1 further comprises: the grouping and the polling coordination point grouping the service category according to the priority, the correspondence between the service class priority and the grouping number is determined by the site or is polled by the group. After the coordination point is determined, the site is notified, and the cluster-based polling coordination point adaptively adjusts the group-based polling strategy according to the change of the data transmission type of the station in the network, and performs round-robin polling for the group that may have the service category transmission, and achieves high During the transmission of the priority service class, there is a certain proportion of the transmission of the low priority service class, or the transmission of the low priority service class is prohibited before the transmission of the high priority service class in the network is completed within a certain time interval.

The above method is characterized in that: the step 2 further comprises: step of setting the interframe space and the backoff window when the different priority service classes are transmitted to be the same or different, and the step that one station can respond to the polling of the plurality of groups .

The above method is characterized in that, in the step (3), the station that meets the polling condition transmits data to the destination station based on a carrier sense multiple access protocol.

The foregoing method is characterized in that, in the step 1, the adaptively adjusting the grouping and polling policy comprises: the station sending the capability information to the grouping and polling coordination point in the process of establishing the connection, The capability information contains which priority class of service the site may send or the highest priority of the class that can be sent, and the cluster polling coordination point initializes or updates the polling policy based on the capability information.

The above method is characterized in that the polling policy includes all or part of the following parameters: a maximum time interval of each round of group polling, a maximum time interval of each group polling in each round of group polling, and a group polling The order, the interframe space, whether a high priority traffic class is allowed to transmit during a specified period of time has a certain proportion of low priority traffic classes.

The above method is characterized in that: the update polling policy comprises: the group polling coordination point polls the group according to the polling order according to the priority level, and transmits the group to the station during the group polling period, including the grouping The group number and the policy information of the grouping number corresponding to the highest priority service category in the polling policy, the site receives and records the policy information, and if the site sends a service category data other than the polling policy, Notify the group polling association ^..,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, The process before the start of the next highest priority group polling in the next policy information is a round of group polling.

The above method is characterized in that the update polling policy further comprises: during the transmission process, the group polling coordination point establishes an observation window having a window range represented by a parameter, 'if within the window range , there is no data transmission for a service category in the polling policy, and the cluster polling coordination point will remove the polling for the service category from the polling policy.

The above method is characterized in that the parameter characterizing the window range is time or statistical number. The foregoing method is characterized in that, in the step 1, the group polling coordination point groups the service categories according to the priorities, and includes: dividing the service categories into P groups from S1 to SP according to different priorities. The S1 group has the highest priority, the priority is decremented, and the SP group has the lowest priority. There are actually N types of transmission services with different priorities in the network. NP, the group polling coordination point is based on the N types of different transmission service categories. N groups are established, and different group numbers of the N groups are assigned according to priorities, and the group number and the priority are in one-to-one correspondence.

The above method is characterized in that the station in the second step responds to the group polling according to the priority of the data service category to be transmitted, including: the station identifies the grouping number of the polled group, and numbers the group and the group. Priority comparison of the service category data to be sent, if there is pending data corresponding to the group number priority service class in the station, participate in the transmission during the group polling period, based on carrier sensing during the group polling The multiple access protocol sends the corresponding pending data. The above method is characterized in that the priority of the corresponding data to be sent is consistent with the priority corresponding to the group number, or the priority of the corresponding data to be sent is not lower than the priority corresponding to the group number.

The foregoing method is characterized in that, in the step 1, the transmitting in the high priority service class transmission process has a certain proportion of low priority service class, including: during the group polling, the group polling coordination point Different clustering polling maximum intervals are assigned to different priority groups. During the group polling, when the media is idle, the cluster polling coordination point determines whether there is no corresponding service category data transmission during the current group polling period. The cluster polling coordination point polls the next cluster, otherwise it continues to poll the current cluster poll until the polling interval reaches the maximum interval of the cluster poll.

The above method is characterized in that, the method further includes: the group polling coordination point sets a maximum duration of the current round of group polling, and if the polling interval of the round group polling reaches the maximum duration, the group polling coordination point Conduct the next round of group polling.

The foregoing method is characterized in that, in the step 1, the implementation prohibits transmission of the low priority service category before the high priority service category in the network is completed in a certain time interval, including: determining each round of group polling The maximum duration, during the group polling, whenever the media is idle, the cluster polling coordination point will judge whether there is no corresponding category of service data transmission during the current group polling, and the cluster polling coordination point will poll the next group. Otherwise, the current cluster polling will continue to be polled until the current round of cluster polling reaches its corresponding maximum duration.

The foregoing method is characterized in that: in the first step, cyclically repeating polling for a group that may have service transmission, further comprising: the group polling coordination point sequentially from a service class with a high priority to a service class with a low priority Polling, during the current group polling, set the M interframe spacing from QIFS1 to QIFSM. The QIFS1 duration is the shortest, and the QIFSM duration is the longest. The priority service category strictly corresponding to the current polling number is QIFSI. ( KI^M) Inter-frame interval transmission, the current group group number transmitted by the station according to the group polling coordination point, the group number corresponding to the highest priority service category in the polling list, and the grouping recorded from the beginning of the polling process to the current time period The group number, determining whether the site itself has a service class other than the polling list of the current cluster group number, and transmitting the service class priority information at other interframe intervals shorter than the QIFSI or directly transmitting the priority Service category, the group polling coordination point transmits data according to a specific transmission service class priority information frame or by parsing The priority service class in the frame learns the new service class to update the polling list. The technical effects of the present invention are:

According to the present invention, the group polling coordination point groups the service categories of different priorities according to the correspondence between the service class priority and the group number, which are well-known by the site, and adaptively adjusts the grouping polling strategy, and the station transmits according to itself. The priority of the data service category responds to the group polling, so that the interframe space and the backoff window when different priority service classes are transmitted may be the same or different, thereby avoiding the prior art because different inter-frames are set by different service categories. Interval to achieve technical issues caused by QoS guarantees. The inter-frame spacing of the high- and low-priority service class transmissions of the present invention may be set to be the same or different, and the inter-frame spacing of the low-priority service class transmission is not large, and when there is no high-priority service class transmission, the low-priority service Classes can adaptively reduce interframe spacing without causing unnecessary transmission delays, increasing network throughput and enhancing network performance.

BRIEF abstract

1 is a flow chart showing polling of QoS-based clustering in a wireless local area network in accordance with an embodiment of the present invention;

Figure 2 is a flow chart of the steps of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

2 is a flow chart of the steps of the present invention. The present invention provides a wireless local area network grouping polling method based on service quality assurance, including:

Step 210: The initiation and control of the group polling is completed by the group polling coordination point, the group polling coordination point may reside in the access point (AP), and the group polling coordination point groups the service categories according to the priority, the service category The correspondence between the priority and the group number may be determined by the station (STA), or may be determined and notified by the group polling coordination point, and the group polling coordination point polls the group that may have the service category transmission; The coordination point can adaptively adjust the clustering polling strategy according to the actual situation and changes of the data transmission service category in the network, and the polling is cyclically repeated; the clustering polling coordination point can be implemented in the high priority service category transmission process. The transmission of a certain proportion of low priority service classes, or guarantees that the transmission of low priority service classes is prohibited before the transmission of high priority service classes in the network is completed within a certain time interval;

Step 220: The STA responds to the group poll according to the service class priority level of the data to be transmitted. A site can respond to multiple clusters of polls;

Step 230: During the group polling, the STA that meets the polling condition sends data based on the Carrier Sense Multiple Access Protocol (CSMA), and the receiving station responds whether it is polled or whether it can be polled, different priority services. The interframe space and the backoff window at the time of class transmission may be the same or different.

1 is a flow chart showing a method of transmitting data in a wireless local area network in accordance with one embodiment of the present invention.

As shown in FIG. 1, in the method for transmitting data in the wireless local area network of this embodiment, first, in step 101, a polling policy is determined according to the grouping polling request, and the grouping polling linked list is initialized. Specifically, in the present application, the service category is divided into P group numbers S1 to SP by category, and the service category category corresponding to the SI has the highest priority, and the priority level is successively decreased, and the SP priority level is the lowest, and the corresponding relationship may be STA. Known, it can also be determined by the cluster polling coordination point. When there are STAs in the network that want to target different service categories, the network can provide personalized services, and a group polling request will be sent. As is known to those skilled in the art, the cluster polling request may pass the capability information field with an associated frame or a re-association frame, where the capability information field in the present application contains which priority class of service the STA may send or the class of service that can be sent. The highest priority. The cluster polling coordination point determines the polling policy according to the capability information field of the group polling request, the polling policy includes the time parameter of the group polling, the maximum interval of the group polling loop repetition, whether it is allowed during each round of group polling, During the transmission of the priority service class, there is a certain proportion of transmission of the low priority service class. The polling policy specifies the order of the group polling. The priority level is higher, and the group polling coordination point polls repeatedly according to the order. Cluster polling does not include priority service categories that are not reflected in the capability information. If the correspondence between the grouping and the service class priority is determined by the grouping polling coordination point, the grouping polling coordination point may return the grouping information through the association response or the re-association response, and if the corresponding relationship is determined by the STA, it is not necessary to return the Grouping information. In step 101, it is also determined that the M types of interframe spacing, QIFS1~QIFSM, M can be less than P, and the QIFS1 duration is the shortest, and the QIFSM is incremented by the longest.

Next, in step 105, the first round of grouping polling is started. Specifically, the first round of grouping polling starts with the transmission of a beacon frame, and the beacon frame includes the maximum duration and remaining duration of the rounding group polling period. In addition to all STAs outside the STA where the clustering coordination coordination point is located, the network allocation is appropriate based on these parameters, and the cluster polling coordination point will initially establish a service counter for each cluster.

Next, in step 110, the first grouping grouping polling is started. Specifically, the grouping polling coordination point broadcasts the grouping polling start information, where the clustering group number and the polling policy of the current grouping polling are included. The grouping number corresponding to the highest priority service class, and the startup service timeout timer and the grouping polling timeout timer are set, or only the startup service timeout timer is set. The beacon frame sent during the current group query carries the group information of the currently polled group.

Next, in step 115, the current grouping polling transmission, specifically, the STA can identify the grouping number and the grouping number corresponding to the highest priority service category in the polling policy, record the information, and record the current history of the records. And the current information is compared with the priority of the service category to be sent. If the STA has the service category data corresponding to the current polling number, the STA participates in the cluster polling, and sends corresponding data at the corresponding interframe interval, when the STA finds A new pending service category that is not in the polling policy needs to be notified with the cluster polling coordination point. The notification method may be to send a specific frame or directly send the new service category data. The STA finds that there is a new pending service category that is not in the polling policy: the priority of the pending service category is compared with the history of the current round of clustering polled grouped and current polling grouping numbers. A service class that has a higher priority than the current polling number outside the record is a service class other than the polling policy.

The priority service class that is consistent with the current polling number is transmitted at the QIFSI interframe interval. The specific frame used by the STA to exchange the service class priority and the service class priority change information with the group polling coordination point is shorter than the QIFSI. The interframe spacing is transmitted. In addition, if traffic class data with higher priority than the current polling number is allowed to be transmitted during the current cluster polling, these data frames are also transmitted at a shorter interframe space than QIFSI. STAs that do not participate in this group polling cannot send data. The STA participating in the group polling sends data according to the CSMA protocol.

The receiving STA responds regardless of whether it is polled or whether it can be polled. The interframe space and the backoff window when different priority service classes are transmitted may be the same or different.

In step 115, the cluster polling coordination point further updates the cluster polling policy according to the service class priority or service class priority change information delivered by the STA in the current polling group, and the group polling policy can be polled in the next round. Effective at the beginning, it can also take effect immediately.

Next, at step 120, it is determined whether the current cluster polling is over. Specifically, during each group polling, the method for the group polling coordination point to determine whether there is still data transmission during the current group polling is that, once the media is idle, the group polling coordination point sets a start service timeout timer, if If the timer is not polled before being sent to the group service category, the group polling coordination point considers that there is no data for the service category to be transmitted. The group polling ends, and the group polling coordination point polls according to the polling policy. One group, otherwise the timer is turned off, until the next time the media is idle, reset Set the start service timeout timer. The group polling timeout timer specifies the maximum time interval for each group polling. If the service timeout timer does not time out during the current group polling period, the grouping polling timeout or the current round of grouping polling interval has been When the maximum interval of the round group is reached, the current cluster polling ends, and the cluster polling coordination point will detect whether the media is idle. If the idle cluster polling coordination point will immediately poll the next group, if the media is busy, once the media turns to Idle, the cluster polling coordination point will poll the next group. If the service category that is consistent with the current cluster number is not sent in the current cluster polling, the service counter in the cluster polling coordination point is decremented by one, and when the service counter is reduced to zero, the cluster polling coordination point classifies the service. The category is deleted from the group polling policy. The new policy can take effect at the beginning of the next round of group polling. It can also take effect immediately. Otherwise, the service counter returns to the initial value. If the current group polling ends, proceed to step 125. Otherwise, continue. Current cluster polling transmission.

Next, in step 125, it is determined whether it is the last group polling of the round. Specifically, if it is determined in step 120 that the current grouping polling ends, the group polling coordination point determines the ending current group polling according to the polling policy. Whether it is the last group of this round of polling, if not, proceed to step 130; if yes, determine whether the maximum duration of the round-robin polling period is reached, and if yes, proceed to step 135; if not, advance After the round-trip grouping polling is performed, step 135 is performed, and all STAs may be used to compete for media transmission by using the CSMA protocol or transmit data by using other transmission methods, and step 135 is performed when the maximum duration of the round-robin polling period is reached.

Next, in step 130, the next grouping grouping polling is started. Specifically, the grouping polling coordination point broadcasts the grouping polling start information, where the grouping group number of the current grouping polling and the highest priority service category in the polling policy are corresponding. The grouping number is set, and the startup service timeout timer and the grouping polling timeout timer are set, or only the startup service timeout timer is set, and the beacon frame sent during the current grouping inquiry carries the grouping information of the currently polled group.

Next, in step 135, the next round of grouping polling is started. Specifically, the grouping polling starts with the transmission of a beacon frame containing the maximum duration and remaining duration of the round-robin polling period. All STAs except the STA where the clustering coordination coordination point is located are allocated and updated according to these parameters.

Further, according to a modification of the present invention, in step 110 and step 130, the cluster polling coordination point broadcasts the group polling start information while setting only the start service timeout timer. In step 120, the group polling coordination point needs to judge whether there is still data transmission during the current group polling period, and also judge this If the current round-robin polling interval has reached the maximum duration of the round-robin polling period, if the current cluster-based polling has no corresponding category of service transmission, or the current group-based polling interval has reached the maximum duration of the round-robin polling period, then the steps are performed. 125. In step 125, if the current group polling has no corresponding category service transmission and the process proceeds from step 120 to step 125, the group polling coordination point determines whether it is the last group. If not, proceed to step 130, and if yes, proceed to step 135. If, at step 125, the maximum duration of the round-robin polling cycle is reached from step 120 to step 125, then step 135 is performed. In this variant, the cluster polling coordination point does not guarantee that all traffic classes can be polled during each round of polling.

Although the method for transmitting data in the wireless local area network of the present invention has been described in detail through some exemplary embodiments, the above embodiments are not exhaustive, and those skilled in the art can implement the spirit and scope of the present invention. Various changes and modifications. Therefore, the invention is not to be construed as being limited by the scope of the appended claims.

Claims

A method for wireless local area network grouping and polling based on adaptive service quality assurance, comprising: step-step 1, adaptively adjusting grouping according to service class priority and change of network transmission data service category in the network and current state a polling strategy, which performs round-robin polling on a group that may have a service transmission, and each round of round-robin polling may have different polling contents;

Right

Step 2: The station responds to the group poll according to the priority of the data service category to be transmitted. Step 3: The station that meets the polling condition sends data to the destination station.

The method according to claim 1, wherein the step 1 further comprises: grouping the coordination points according to the priority by the grouping polling coordination point, and the correspondence between the service class priority and the grouping number is the site determining Or the site is notified by the group polling coordination point, the group polling book

The coordination point adaptively adjusts the grouping and polling strategy according to the change of the data transmission service type of the station in the network, and performs cyclically repeated polling for the group that may have the service category transmission, and achieves a certain proportion in the transmission process of the high priority service category. The transmission of the low priority service class, or the transmission of the low priority service class is prohibited before the transmission of the high priority service class in the network is completed within a certain time interval.

The method according to claim 1, wherein the step 2 further comprises: setting an interframe space and a backoff window when different priority service classes are transmitted to be the same or different, and one station can respond more The steps of grouping polling.

The method according to claim 1, wherein in the step 3, the station that meets the polling condition transmits data to the destination station based on a carrier sense multiple access protocol. '

The method according to claim 1, 2, 3 or 4, wherein in the step 1, the adaptively adjusting the grouping polling strategy comprises: the group is grouped in the process of establishing a connection The polling coordination point sends capability information, the capability information includes which priority class of traffic classes the site may send or the highest priority of the transmittable traffic class, and the cluster polling coordination point initializes or updates the polling policy according to the capability information.

The method according to claim 5, wherein the polling policy includes all or part of the following parameters: a maximum time interval of each round of group polling, and a maximum of each group polling in each round of group polling. Time interval, order of each group polling, interframe space, whether allowed within the specified time There is a certain percentage of low priority service class transmissions during the transmission of high priority service classes.

7. The method according to claim 5, wherein the update polling policy comprises: a group polling coordination point polling the group according to a polling order according to a priority, and polling the group in a polling order During the period, the policy information including the grouping number and the grouping number corresponding to the highest priority service category in the polling policy is transmitted to the site, and the site receives and records the policy information, if the site finds that it has a pending service category other than the polling policy. Data, the cluster polling coordination point is notified in time, and the cluster polling coordination point will update the polling policy according to the site situation, including the pending service category of the site in the polling policy; the highest priority clustering polling in the policy information The process before the start of the next highest priority group polling in the next policy information is a round of group polling.

The method according to claim 7, wherein the updating the polling policy further comprises: during the transmitting process, the group polling coordination point establishes an observation window having a window range represented by a parameter, If there is no data transmission for a service category in the polling policy within the window, the cluster polling coordination point will remove the poll for that service category from the polling policy.

9. Method according to claim 8, characterized in that the parameters characterizing the window range are time or statistical times.

The method according to claim 6, 7, 8, or 9, wherein in the step 1, the group polling coordination point groups the service categories by priority, including: The priority is divided into P groups from S1 to SP. The S1 group has the highest priority, the priority is decremented, and the SP group has the lowest priority. There are actually N different types of transmission services in the network, N^P, grouping. The polling coordination point establishes N groups according to the N types of transmission service categories with different priorities, and assigns different group numbers to the N groups according to priorities, and the group number and the priority are in one-to-one correspondence.

The method according to claim 10, wherein the station in the second step responds to the group poll according to the priority of the data service class to be transmitted, including: the site identification group number of the polled group, And comparing the priority of the grouping number with the priority of the service category data to be sent, if the station has the pending data corresponding to the grouping priority service category, participating in the transmission during the grouping polling period, in the grouping The corresponding pending data is transmitted based on a carrier sense multiple access protocol during polling.

The method according to claim 11, wherein the priority of the corresponding data to be sent and the priority corresponding to the group number are the same, or the priority of the corresponding data to be sent is Not lower than the priority corresponding to the cluster number.

The method according to claim 10, wherein in the step 1, the transmitting in the high priority service class transmission process has a certain proportion of low priority service classes, including: in the group polling During the period, the grouping and polling coordination point assigns different grouping polling maximum intervals to different groups of priorities. During the group polling, when the media is idle, the group polling coordination point determines whether there is no corresponding period during the current group polling period. If the service category data is sent, the group polling coordination point polls the next group, otherwise it continues to poll the current group poll until the polling interval reaches the maximum interval of the group poll.

14. The method according to claim 13, further comprising: the group polling coordination point sets a maximum duration of the current round of group polling, if the polling interval of the round group polling reaches the maximum duration , the cluster polling coordination point will conduct the next round of group polling.

The method according to claim 10, wherein, in the step 1, the implementing prohibits transmission of a low priority service class before the transmission of the high priority service class in the network is completed within a certain time interval, including : Determine the maximum duration of each round of group polling. During the group polling, whenever the media is idle, the cluster polling coordination point will judge whether there is no corresponding category of service data transmission during the current group polling period, and then the group polling coordination The point will poll the next group, otherwise it will continue to poll the current group poll until the current round of group polling reaches its corresponding maximum duration.

The method according to claim 10, wherein the step 1 performs round-robin polling for a group that may have a service transmission, and further includes: the group polling coordination point sequentially selects a service class with a higher priority Polling the service class with low priority. During the current group polling, set the M interframe space from QIFS1 to QIFSM. The QIFS1 duration is the shortest. The QIFSM duration is the longest. The strict match with the current polling number. The priority service categories are transmitted at QIFSI interframe intervals, where 1<IM, the current cluster group number transmitted by the station according to the cluster polling coordination point, the group number corresponding to the highest priority service category in the polling list, and the polling process begins. The group number recorded in the current time period, determining whether the station itself has a service class other than the polling list of the current cluster group number, and the service class priority is transmitted at other interframe intervals shorter than the QIFSI. Information or directly pass the priority service category, the cluster polling coordination point is based on a specific transmission service category The polling list is updated by the frame of the priority information or by parsing the priority service class in the transmitted data frame to know the new service class.