WO2006063500A1

WO2006063500A1 - A grouped polling method based on guarantee strategy of fixed quality of service (qos) in the wireless local area network

Info

Publication number: WO2006063500A1
Application number: PCT/CN2005/001616
Authority: WO
Inventors: Feng Li; Gonghang Sun; Fengguo Ma; Bo Sun; Dengfang Lu
Original assignee: Zte Corporation
Priority date: 2004-12-17
Filing date: 2005-09-29
Publication date: 2006-06-22
Also published as: CN1791047A; CN100401709C

Abstract

A grouped polling method based on guarantee strategy of fixed quality of service (QoS) in the wireless local area network includes: determine the grouped polling strategy according to the priority of the traffic type and perform the circular polling to the groups according to said strategy, one grouped polling of said circular polling is for all the groups or part of the groups, the content of the each grouped polling can be different, the stations respond the grouped polling according to the priority of the data traffic type to be transmitted, the stations that comply with the polling terms transmit the data to the destination station and the destination station receives the response. The invention enables the interval between frames when transmitting the traffic type with different priority and the retreating window to be set as same or different. The interval between frames when transmitting the traffic type with low priority is not very large. The invention doesn’t have the unnecessary transmission delay, increases the network throughput and enhances the network performance.

Description

Wireless local area network group polling method based on fixed service quality assurance strategy

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), multiple access with collision avoidance (MACA) (multiple access with collision avoidance) The improved collision avoidance multiple access protocol (MACAW), BAMA (floor acquisition multiple acess) and 802.11 protocols, etc., are generally based on the CSM 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. Commercially available is IEEE 802. il, which specifies Distributed Coordination Function (DCF) and Point Coordination (PCF) functions to implement two simple QoS guarantee mechanisms of different priorities. In IEEE 802.11, the PCF adopts a polling method, which is suitable for transmitting a delay-sensitive traffic category, with a short interframe interval and a high priority. The service class transmitted by the DCF method requires contention access and interframe space. Relatively long, low priority. The definition of a service class means that one service class is a set of Media Access Control (MAC) layer Service Data Units (MSDUs), and the MSDUs of the same service class have specific priority requirements compared to other service classes MSDU. IEEE 802.11 cannot accommodate the multimedia service transmission requirements with a higher priority.

To overcome this shortcoming, the IEEE 802.11e draft standard adds enhanced distributed coordination capabilities.

(EDCF) and Hybrid Coordination Function (HCF). The EDCF assigns different inter-frame spaces to different priority service classes. The service access probability with a long inter-frame interval is lower than the short inter-frame interval. The EDCF can be mixed with the polling method as HCF, which can implement a 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 multiple advantages Different service categories of the predecessors are caused by competing media at the same time. By setting different interframe spaces for different service classes, they 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 a fixed service quality assurance policy, which solves the problem that the prior art has a large difference in frame spacing between different classified service data transmissions when the service category is large. The priority service class has a longer interframe space, which causes unnecessary transmission delay and reduces the technical problem of network throughput.

To achieve the above objective, the present invention provides a wireless local area network grouping and polling method based on a fixed service quality assurance policy, which is characterized by the following steps: Step 1: Determine a group polling strategy according to a service category priority and The cluster performs cyclically repeated polling, and the round-robin polling of the round-robin polling polls all clusters or polling partial clusters, and the round-robin polling content of each round may be different; Step 2: The site according to itself The priority response group polling of the data service category is to be transmitted; Step 3: The station that meets the polling condition sends data to the destination station.

The above method is characterized in that: the step 1 further comprises: grouping, by the grouping and polling coordination point, grouping service categories of different priorities according to the correspondence between the service class priority and the grouping number known by the station, and determining the grouping Polling the policy and performing round-robin polling for each group according to the policy, achieving a certain proportion of low-priority service class transmission in the high-priority service class transmission process, or achieving high priority in the network within a certain time interval The transmission of low priority service classes is prohibited before the service class is transmitted. The initiation and control of the group polling is completed by the group polling coordination point.

The foregoing method is characterized in that, in the step 2, the inter-frame interval and the backoff window when different priority service classes are transmitted may be set to be the same or different, and one station may respond to the polling of multiple groups. step.

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 above method is characterized in that, in the step 1, the corresponding relationship is: The category category is divided into P priorities from SI to SP, S1 has the highest priority, the priority is decremented, the SP priority is the lowest, and the site knows the correspondence.

The above method is characterized in that, in the step 1, the group polling strategy is:

S1 polls the SPs sequentially and cyclically, and the process from the start of the SI group polling to the start of the next S1 group polling is the round polling of the rounds. All clusters or partial clusters are polled. During each cluster polling period, the periodic polling parameters are sent periodically or only at the beginning of the cluster polling. This parameter contains the number of the polled cluster.

The above method is characterized in that: the step 2 further comprises: the station identifying the grouping polling parameter and comparing the grouping number in the parameter with the to-be-sent service category of the station itself, determining the service category to be sent and Whether the service category corresponding to the group number is consistent, if the station participates in the current group polling and transmits the service category data of the corresponding category, otherwise the station stops transmitting data during the current group polling; if there are multiple to be transmitted in the station The service category data, the station can respond to multiple clusters of polls according to the above rules during each round of group polling.

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 foregoing 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 The point will poll 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. If the SP cluster polling ends before the specified maximum time of the current round of cluster polling arrives, the cluster polling coordination point ends the round polling of the round. The next round of group polling, otherwise until the current round of group polling reaches its corresponding maximum duration, the cluster polling coordination point ends the round of the group Inquire, start the next round of group polling.

The above method is characterized in that the group polling coordination point resides in an access point.

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 known by the site, and the station responds to the group poll according to the priority of the data service class to be transmitted. Therefore, the interframe space and the backoff window when different priority service classes are transmitted may be the same or different, thereby avoiding the technology of the prior art because QoS guarantee is implemented by setting different interframe spaces for different service classes. problem. 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 transmissions will not increase due to the increase in the number of high-priority service classes, when there is no high priority When the service class is transmitted, the polling of the low priority service class can be initiated in advance, the unnecessary transmission delay is reduced, the network throughput is increased, and the network performance is enhanced.

BRIEF abstract

1 is a polling flow chart of QoS-based group polling in a wireless local area network according to 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

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a flow chart of the steps of the present invention, and the method for grouping and polling the wireless local area network based on the service quality assurance provided by the present invention includes:

Step 210: The initiation and control of the group polling is completed by the group polling coordination point, and the group polling coordination point may reside in the access point (AP), and the service category is grouped according to the service category priority, and the service class priority is The correspondence between the group and the group number is known to the station (STA). The group polling coordination point determines the group polling strategy and polls each group according to the policy. The polling is cyclically repeated. Step 220: The STA transmits according to itself. The service category priority of the data is responded to the group polling, and one station can respond to the polling of multiple groups; the group polling coordination point can realize the transmission of a certain proportion of low priority service categories in the transmission process of the high priority service category, or Guaranteed for a certain period of time In the interval, the transmission of the low priority service class is prohibited before the transmission of the high priority service class in the network is completed;

Step 230 During the group polling, the STA that meets the polling condition transmits data based on the carrier sense multiple access protocol CSMA, and the receiving STA responds whether it is polled or whether it can be polled. When different priority service classes are transmitted, The interframe space and the backoff window may be the same or different.

Preferably, the foregoing is a group of service categories grouped according to different service category priorities, and the correspondence between the service category and the group number is known by the station (STA), and the group polling coordination point determines the group polling strategy and performs rounds for each group according to the policy. The polling is a cyclically repeated step, including: dividing the service class into P priorities, that is, S1 to SP, the SI priority is the highest, the priority is decreased in descending, and the SP priority is the lowest, and the STA knows the corresponding relationship. The group polling coordination point determines the group polling strategy according to the actual situation. Usually, the group polling strategy is polled sequentially from S1 to SP, and the loop is repeated after polling the last group, and is sent periodically during each group polling period. The cluster polling parameter is sent at the beginning of the group polling, and the parameter contains the number of the polled group (such as S3).

Preferably, the STA responds to the group polling according to the service class for which the data is to be transmitted, and the step that one station can respond to the plurality of grouped polls includes: the STA can identify the group polling parameter and group the group in the parameter If the service class to be sent in the STA is the same as the service class corresponding to the group number, the STA participates in the current group polling and transmits the service data of the corresponding category. Otherwise, during the current group polling period, The STA will stop sending data. If there are multiple service category data in the STA, the site can respond to multiple grouped polls according to the above rules.

Preferably, the foregoing grouping and polling coordination point may implement a transmission step of a certain proportion of low priority service classes in the high priority service class transmission process, including: during the grouping polling, the grouping polling coordination point is a group with different priorities The maximum interval for grouping polling is assigned. The group polling coordination point can set the maximum interval of the current round of group polling, or can not set this parameter. During the group polling, when the media is idle, the group polling The coordination point will judge whether there is still data transmission during the current cluster polling. If the cluster polling coordination point believes that there is no corresponding service category data transmission during the current cluster polling period, the cluster polling coordination point will poll the next cluster, and vice versa. Continue to poll the current cluster poll until the polling interval reaches the maximum interval for the cluster poll or the maximum duration of the current round poll.

Preferably, the high-priority service category in the network is transmitted within a certain time interval. The transmission steps of the low priority service class are prohibited before, including: determining the maximum duration of each round of group polling. During the group polling, whenever the media is idle, the cluster polling coordination point will determine whether there is still a current group polling period. Data transmission, if the group polling coordination point believes that there is no corresponding service category data transmission during the current group polling period, the cluster polling coordination point will poll the next group, and vice versa, will continue to poll the current group poll until the current one The round polling of the round reaches its maximum polling duration. Cluster polling does not guarantee that all service categories can be polled during each round of polling.

1 is a flow chart of a method of transmitting data in a wireless local area network, in accordance with an embodiment of the present invention. As shown in FIG. 1 , in the method for transmitting data in the WLAN of the embodiment, first, in step 101, the polling policy is determined according to the priority of the service category, and specifically, the group polling coordination point divides the service category into categories according to the category. For the P group numbers S1 to SP, the service category corresponding to the SI has the highest priority, and the priority level is decremented, and the SP priority level is the lowest. The STA knows the corresponding relationship. The group polling coordination point determines the group polling strategy, including: time parameter of the group polling, whether to allow a certain proportion of low priority service class transmission during the high priority service class transmission during each round of group polling, The inquiry policy specifies the order of group polling, and the priority level is higher, and the group polling coordination point polls repeatedly according to the order.

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. All STAs except the STA where the clustering coordination coordination point is located are allocated and updated according to these parameters.

Next, in step 110, the first grouping grouping polling is started. Specifically, the grouping polling coordination point broadcasts the grouping polling start information, which includes the grouping group number of the current grouping polling, and sets the startup service timeout timer and the grouping. The polling timeout timer, or only the start service timeout timer is set, and the beacon frame sent during the current packet query carries the group information of the currently polled group.

Next, in step 115, the current group polling transmission, specifically, the STA can identify the grouping group number, and compare the priority of the service category to be sent and the group group number, if the STA has a service that is consistent with the current polling number. The category data participates in the cluster polling, and sends corresponding data at certain interframe intervals according to the CSMA protocol. STAs that do not participate in this group polling cannot send data. 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.

Next, at step 120, it is determined whether the current cluster polling is over. Specifically, in each group During the polling period, the group polling coordination point determines whether there is still data transmission during the current group polling. Once the media is idle, the cluster polling coordination point sets the start service timeout timer, if at this timing. If the packet is not polled before being timed out, the cluster polling coordination point considers that there is no traffic class data to be transmitted. The cluster polling ends, and the cluster polling coordination point polls the next poll according to the polling policy. Grouping, otherwise, the timer is turned off, and the startup service timeout timer is reset until the next time the media is idle. 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 current cluster polling is over, proceed to step 125, otherwise continue the 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, which includes the grouping group number of the current grouping polling, and sets the startup service timeout timer and the grouping wheel. The timeout timer is set, or only the start service timeout timer is set, and the beacon frame sent during the current group query carries the group 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.

In addition, according to a variant of the present invention, in step 110 and step 130, the group polling coordination point broadcasts the group polling start information, which includes the cluster group number of the current group polling, and only sets the start service timeout timer. In step 120, the group polling coordination point needs to determine the current group polling period. PT/CN2005/001616 Is there any data transmission, and it is also judged whether the current round-robin polling interval has reached the maximum duration of the round-robin polling period, if there is no corresponding category service transmission in the current cluster polling, or the current group polling interval If the maximum duration of the round-robin polling period has been reached, then step 125 is performed. In step 125, if the current group polling does not have the corresponding category service transmission ends, the step 120 proceeds to step 125, and the cluster polling coordination point determines whether it is the last group. If not, proceed to step 130, and if yes, proceed 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 group polling coordination point does not guarantee that all service categories can be polled during each round of polling, and the SP group polling ends, and the group polling coordination point ends the round polling of the round. Start the next round of group polling.

As can be seen from the above, the present invention is configured by the group polling coordination point according to the correspondence between the service class priority and the group number known by the site, and the station responds to the group poll according to the priority of the data service class to be transmitted, thereby making different priorities. The inter-frame spacing and the back-off window of the service class transmission may be the same or different, and the inter-frame spacing of the low-priority service class transmission is not large. When there is no high-priority service class transmission, the low-priority service class can adaptively Shortening the interframe space does not cause unnecessary transmission delays, increases network throughput, and enhances network performance.

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 limited to the embodiments, and the scope of the invention is only limited by the appended claims.

Claims

Claim

1. A wireless local area network group polling method based on a fixed service quality assurance policy, which is characterized in that:

Step 1: Determine a group polling strategy according to the priority of the service category, and perform round-robin polling for each group according to the policy, and the round-robin polling of the round-robin polling, polling all the grouping or polling part grouping, The polling content of each round of group polling may be different;

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: the grouping and the polling coordination point according to the correspondence between the service class priority and the grouping number known by the station, and the different priorities The service category is grouped, the clustering polling strategy is determined, and the round-robin polling is performed for each group according to the policy, so that a certain proportion of low-priority service categories are transmitted during the transmission of the high-priority service class, or implemented at a certain time. During the interval, the transmission of the low priority service class is prohibited before the transmission of the high priority service class in the network is completed. The initiation and control of the group polling is completed by the group polling coordination point.

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 may The step of responding to multiple clusters of polls.

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 correspondence is: dividing the service category into P priorities from S1 to SP, S1 has the highest priority, the priority is decremented, the SP priority is the lowest, and the site knows the correspondence.

The method according to claim 5, wherein, in the step 1, the grouping polling strategy is: polling each group in turn from S1 to SP in sequence, by the SI grouping wheel The process from the start of the inquiry to the start of the next S1 group polling is the round-robin polling described, and the round-robin polling polls all clusters or partial clusters during each cluster polling period. The periodic polling parameter is sent periodically or only at the beginning of the cluster polling, and the parameter contains the number of the polled cluster.

The method according to claim 6, wherein the step 2 further comprises: the station identifying the grouping polling parameter and comparing the grouping number in the parameter with the to-be-sent service category of the station itself, and determining Whether the service category to be sent and the service category corresponding to the group number are consistent, if the station participates in the current group polling, and transmits the service category data of the corresponding category, otherwise the station stops sending data during the current group polling; If there are multiple service category data to be transmitted in the station, the station can respond to multiple group polls according to the above rules during each round of group polling.

The method according to claim 7, wherein in the step 1, the transmitting in the high priority service class transmission process has a certain proportion of low priority service class, 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.

The method according to claim 8, 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 then poll the next round of group polling.

The method according to claim 8, wherein in the step 1, the implementing prohibits transmission of the low priority service category before the transmission of the high priority service category 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 polling. If the SP group polling ends before the specified maximum time of the current round of group polling arrives, the group polling coordination point ends. The round polling of the round starts the next round of group polling, otherwise until the current round of group polling reaches its corresponding maximum duration, the group polling coordination point ends the round polling of the round, and starts the next round of group polling. .

The method of claim 8, wherein the grouping polling coordination point resides in an access point.