WO2016172942A1 - Method for determining initial competition window parameter, site and access point - Google Patents

Abstract

Embodiments of the present invention provide a method for determining an initial competition window parameter, a site and an access point. The method for determining an initial competition window parameter comprises: receiving a notification frame broadcast by at least one access point, wherein the notification frame broadcast by each access point carries the number of active sites associated with the access point; and calculating, according to the number of the active sites associated with each access point, an initial competition window parameter. In accordance with the technical solutions provided by the embodiments of the present invention, a site determines, according to the number of surrounding active sites, an initial competition window parameter, such that the determined initial competition window parameter can change along with the change of the number of the active sites. Thus, the probability of selecting the same backoff duration by different sites is reduced, and therefore the probability of sending failure caused by selection of the same backoff duration can be significantly reduced.

Description

Method, site and access point for determining initial contention window parameters Technical field

The present invention relates to wireless local area network technology and, more particularly, to a method, station and access point for determining initial contention window parameters.

Background technique

In order to achieve wireless LAN communication, the Institute of Electrical and Electronics Engineers (IEEE) has developed the 802.11 series of standards. After continuous evolution, this series of standards has developed into the mainstream standard for wireless LAN communication.

In the 802.11 family of standards, the most basic media access rule is called Distributed Coordination Function (DCF). The DCF allows 802.11 devices to implement media sharing by using a Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) mechanism and a backoff mechanism. Specifically, before transmitting data, the 802.11 device first detects the media status through the CSMA/CA mechanism. When it is detected that the medium is in an idle state, the 802.11 device starts to perform the backoff operation specified by the backoff mechanism, and starts transmitting data when the backoff operation ends.

The above backoff operation mainly refers to the 802.11 device waiting for a period of backoff before starting to send data. By selecting different backoff durations, different 802.11 devices can start transmitting data at different times, thereby reducing the probability of collisions caused by different 802.11 devices transmitting data simultaneously. However, even after waiting for a period of backoff to start sending data, it is still possible to send a failure. This is because the above-mentioned backoff duration is usually randomly selected by the 802.11 device, and there may be cases where multiple 802.11 devices select the same backoff duration. As a result, the backoff operation of these devices may end at the same time, so that multiple 802.11 devices start transmitting data at the same time. This situation will cause the transmission to fail. The transmission failure is directly reflected by the sending device not receiving the response frame returned by the receiving device for the transmitted data. If the transmission fails, the sending device needs to To re-execute the back-off operation and re-attempt to send data at the end of the back-off operation, perform retransmission.

The backoff duration involved in the backoff operation generally includes a plurality of time slots, and the number of time slots is generally randomly selected by the transmitting device in a numerical interval, and the value interval can be uniformly expressed as [0, 2 ^j × (CW _min +1)- 1], where CW refers to the Contention Window, ie, the contention window, CW _min is the minimum value of the contention window, j is the number of retransmissions, the minimum value of j is 0, and the maximum value of j depends on CW _max . When performing the initial retraction operation, the initial value of the transmission device in the interval [0, CW _min] (i.e., j = 0) the number of long randomly selected backoff slots contained within. When the transmission fails, the transmitting device needs to perform the first retransmission, so the number of slots included in the backoff duration is randomly selected in the next value interval [0, 2 × (CW _min +1) - 1]. If the transmission fails again and the second retransmission is required, the sender needs to randomly select the number of slots included in the backoff duration in [0, ^{2 2} × (CW _min +1)-1]. When 2 ^j ×(CW _min +1)-1 reaches CW _max , if the transmission failure occurs again, the value of j will return to the initial value of 0, and then the previous process is repeated. On the other hand, once the transmission is successful, the transmitting device still randomly selects the number of slots included in the backoff duration from the initial value interval, ie [0, CW _min ], when transmitting subsequent data. In other words, as long as the transmission is successful, or 2 ^j ×(CW _min +1)-1 reaches CW _max , then the value of j is the next time the transmitting device performs the next data transmission (whether it is a new data transmission or a retransmission). Will return to the initial value of 0. For details on the CSMA/CA mechanism and backoff mechanism, refer to the 802.11 series of standards.

According to the existing 802.11 standard, the value of CW _min is usually a fixed value. At the same time, the values of CW _min involved in different stages of the transmission process are different. Further, the maximum value among these different CW _min values is 31. In other words, when the CW _min value takes the maximum value 31, the above initial numerical interval is [0, 31]. In the scenario where the number of 802.11 devices is small, the above initial numerical interval can function normally. However, in dense scenes (ie, the number of 802.11 devices is large, such as the number of devices in a cinema auditorium can reach several hundred), the number of optional values in the initial numerical interval is limited (ie, the number of devices is much larger than CW). _Min value), it is very possible that multiple devices select the same value. In this way, multiple devices that select the same value will almost always encounter a transmission failure at the end of the backoff operation. It can be seen that the value of CW _min specified in the existing 802.11 standard is not flexible enough to meet the needs of dense scenes.

Summary of the invention

In view of this, it is necessary to provide a method for determining the initial contention window parameters in order to flexibly determine CW _min .

At the same time, it is necessary to provide a site to flexibly determine CW _min .

At the same time, it is necessary to provide an access point to flexibly determine CW _min .

According to a first aspect of the embodiments of the present invention, a method for determining an initial contention window parameter includes:

Receiving, by the at least one access point, a notification frame, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point;

The initial contention window parameters are calculated based on the number of active sites associated with each access point.

According to a second aspect of the embodiments of the present invention, a method for determining an initial contention window parameter includes:

Determine the number of active sites associated with;

Broadcasting a notification frame, wherein the notification frame carries the number of associated active sites.

According to a third aspect of the embodiments of the present invention, a site is provided, including:

a receiving module, configured to receive a notification frame broadcast by the at least one access point, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point;

And a processing module, configured to calculate an initial contention window parameter according to the number of active sites associated with each access point.

According to a fourth aspect of the embodiments of the present invention, an access point is provided, including:

a processing module for determining the number of associated active sites;

And a transmitting module, configured to broadcast a notification frame, where the notification frame carries the number of the associated active sites.

According to a fifth aspect of the embodiments of the present invention, a method for determining an initial contention window parameter includes:

Sending a query frame to at least one access point;

Receiving a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point;

The parameters of the contention window are calculated according to the number of active sites associated with each access point.

According to a sixth aspect of the embodiments of the present invention, a method for determining an initial contention window parameter includes:

Receiving a query frame from the site;

Determine the number of active sites associated with;

An acknowledgment frame is returned to the site, wherein the acknowledgment frame carries the number of associated active sites.

According to a seventh aspect of the embodiments of the present invention, a site is provided, including:

a transmitting module, configured to send a query frame to at least one access point;

a receiving module, configured to receive a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point;

The processing module is configured to calculate a parameter of the contention window according to the number of active sites associated with each access point.

According to an eighth aspect of the embodiments of the present invention, an access point is provided, including:

a receiving module, configured to receive a query frame from the site;

a processing module for determining the number of associated active sites;

And a transmitting module, configured to return a response frame to the site, where the response frame carries the number of the associated active sites.

According to the technical solution provided by the embodiment of the present invention, the station determines an initial contention window parameter according to the number of active sites around, so that the determined initial contention window parameter may change according to the number of active sites. In this way, the probability of selecting the same backoff duration for different sites is reduced, thereby significantly reducing the probability of a transmission failure due to the selection of the same backoff duration.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

1 is an exemplary flow chart of a method of determining initial contention window parameters in accordance with an embodiment of the present invention;

2 is an exemplary flow chart of a method of determining initial contention window parameters in accordance with an embodiment of the present invention;

3 is a schematic structural diagram of a station in accordance with an embodiment of the present invention;

4 is a schematic structural diagram of an access point according to an embodiment of the present invention;

5 is an exemplary flow chart of a method of determining initial contention window parameters in accordance with an embodiment of the present invention;

6 is an exemplary flow chart of a method of determining initial contention window parameters in accordance with an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a station according to an embodiment of the present invention; FIG.

FIG. 8 is a schematic diagram of an exemplary structure of an access point according to an embodiment of the invention.

detailed description

1 is an exemplary flow diagram of a method 100 of determining initial contention window parameters in accordance with an embodiment of the present invention. In a particular implementation, method 100 can be performed by, for example, but not limited to, a station (sta).

Step 102: Receive a notification frame broadcast by at least one access point, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point.

Step 104: Calculate an initial contention window parameter according to the number of active sites associated with each access point.

It is not difficult to understand that the at least one access point is an access point around the station, that is, the station is located within the coverage of each of the at least one access point. The active site associated with each access point may be a site that is transmitting data or a site that requests data transmission. The active site does not include sites that are associated with the access point but do not perform data transmission, and sites that are not requested for data transmission even if associated with the access point, such as active sites that do not include the Power-saving mode. Site. In fact, the active sites associated with each of the above access points can be considered active sites around the site.

In a specific implementation process, the number of active sites associated with the access point may also be replaced by the number of sites associated with the access point, or the load condition of the access point.

In a specific implementation process, the foregoing notification frame may be, for example, but not limited to, a Management frame, a Control frame, or a Data frame. Further, if the notification frame is a management frame, the management frame may be, for example, but not limited to, a beacon frame, or may be other types of management frames. The above initial contention window parameters may be, for example but not limited to, CW _min or CW _max . For ease of description, CW _min can be recorded as the minimum value of the contention window, and CW _{max is} recorded as the maximum value of the contention window.

In addition, the step 104 may include: calculating an activity index according to the number of active sites associated with each access point and a preset weight of each access point; and calculating an initial contention window parameter according to the activity index.

Specifically, the above active index A may be a weighted average of active sites, namely:

Where N _sta is the weighted average of the active sites, N _AP is the number of access points, W _i is the weight of access point i, and N _i is the number of active sites associated with access point i.

If the initial contention window parameter CW _min, CW _min may be calculated according to the following manner:

If the initial contention window parameter CW _max, CW _max can be calculated according to the following manner:

The parameter A is an active index, and the parameter j is a preset maximum number of retransmissions, for example, an access point (AP) is notified to the site in advance, or preset in the access point and the site. In addition, [log ₂ N _sta ] represents rounding up to log ₂ N _sta . Furthermore, the active index A can be the weighted average N _sta of the active site.

It should be noted that the weights of the foregoing access points may be set according to multiple standards, such as, but not limited to, the current load of each access point, and the probability of occurrence of collisions counted by each access point. In addition, the weight may also be set according to whether the site is associated with the access point, that is, the weight of the access point associated with the site is different from the weight of the access point that is not associated with the site.

After determining the initial contention window parameter, the number of time slots included in the backoff duration may be determined based on the initial contention window parameter each time a backoff operation needs to be performed. For the specific determination method of the number of time slots included in the backoff duration, reference may be made to the provisions of the 802.11 standard. In this case, the backoff duration can be expressed as the product of the number of slots included and the length of the slot.

It should be noted that, in addition to expressing the backoff duration as the product of the number of slots included and the slot length, the backoff duration may also be expressed as the number of resource units included and the size of the resource unit. A product, where the resource unit refers to a basic unit of resources under an OFDMA (Orthogonal Frequency Division Multiple Access) mechanism. In this way, after determining the initial contention window parameter, the number of resource blocks included in the backoff duration can be determined based on the initial contention window parameter each time the backoff operation needs to be performed. The number of resource blocks included in the backoff duration may be determined by referring to the method of determining the number of time slots included in the backoff duration specified in the 802.11 standard.

In addition, the at least one access point refers to one or more access points.

It should be noted that the above calculation steps, calculation formulas, and technical features are applicable to various embodiments of the present invention.

According to the technical solution provided by the embodiment of the present invention, the station determines an initial contention window parameter according to the number of active sites around, so that the determined initial contention window parameter can be related to the number of active sites. The change has changed. In this way, the probability of selecting the same backoff duration for different sites is reduced, thereby significantly reducing the probability of a transmission failure due to the selection of the same backoff duration.

In order to make the station know the number of active sites around, it is necessary to adapt the access point. The specific operation of the access point side will be described in detail below with reference to FIG. 2 .

2 is an exemplary flow diagram of a method 200 of determining initial contention window parameters in accordance with an embodiment of the present invention. In a particular implementation, method 200 can be performed by, for example, but not limited to, an Access Point.

Step 202, determining the number of associated active sites.

Step 204: Broadcast a notification frame, where the notification frame carries the number of the associated active sites.

A number of technical features involved in method 200 have been described in detail in method 100 and therefore will not be described again herein.

In a specific implementation process, an active site number field may be set in the foregoing notification frame to carry the number of active sites associated with the foregoing. It is not difficult to understand that the field can be a newly added field, or the function of an original field in the notification frame can be changed to carry the number of active sites associated with the above.

FIG. 3 is a schematic block diagram of a station 300 in accordance with an embodiment of the present invention. As shown in FIG. 3, the station 300 includes a receiving module 302 and a processing module 304.

The receiving module 302 is configured to receive a notification frame broadcast by the at least one access point, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point;

The processing module 304 is configured to calculate an initial contention window parameter according to the number of active sites associated with each access point.

In a specific implementation process, the processing module 304 is specifically configured to:

Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point;

An initial contention window parameter is calculated based on the activity index.

A number of technical features involved in the site 300 have been described in detail in the method 100 and therefore will not be described again herein.

4 is a schematic block diagram of an access point 400 in accordance with an embodiment of the present invention. As shown in FIG. 4, access point 400 includes a processing module 402 and a transmitting module 404.

The processing module 402 is configured to determine the number of associated active sites;

The transmitting module 404 is configured to broadcast a notification frame, wherein the notification frame carries the number of the associated active sites.

A number of technical features involved in the access point 400 have been described in detail in the method 100 and therefore will not be described again herein.

FIG. 5 is an exemplary flow diagram of a method 500 of determining initial contention window parameters in accordance with an embodiment of the present invention. In a particular implementation, method 500 can be performed by, for example, but not limited to, a station (sta).

Step 502: Send a query frame to at least one access point.

Step 504: Receive a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point;

Step 506: Calculate parameters of the contention window according to the number of active sites associated with each access point.

In a specific implementation process, the foregoing query frame may be, for example, but not limited to, a probe request, and the response frame may be, for example, but not limited to, a probe response.

Other technical features involved in method 500 have been described in detail in method 100 and will not be described again herein.

FIG. 6 is an exemplary flow diagram of a method 600 of determining initial contention window parameters in accordance with an embodiment of the present invention. In a particular implementation, method 600 can be performed by, for example, but not limited to, an Access Point.

Step 602: Receive a query frame from a site.

Step 604, determining the number of associated active sites;

Step 606: Return a response frame to the site, where the response frame carries the associated active The number of sites.

In a specific implementation process, an active site number indication may be set in the query frame to indicate that the site carries the number of the associated active sites in the response frame. It is not difficult to understand that the indication may be a newly added field or a function of changing an original field in the query frame to indicate that the station carries the number of active sites associated with the above in the response frame.

Correspondingly, an active station number field may be set in the response frame to carry the number of active sites associated with the foregoing. It is not difficult to understand that the field may be a newly added field, or the function of an original field in the response frame may be changed to carry the number of active sites associated with the above.

A number of technical features involved in method 600 have been described in detail in method 100 and method 500, and thus are not described herein.

FIG. 7 is a schematic diagram of an exemplary structure of a station 700 in accordance with an embodiment of the present invention. As shown in FIG. 7, the station 700 includes a receiving module 702, a receiving module 704, and a processing module 706.

The transmitting module 702 is configured to send a query frame to the at least one access point;

The receiving module 704 is configured to receive a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point;

The processing module 706 is configured to calculate a parameter of the contention window according to the number of active sites associated with each access point.

In a specific implementation process, the processing module 706 is specifically configured to:

Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point;

An initial contention window parameter is calculated based on the activity index.

A number of technical features involved in the site 700 have been described in detail in the methods 100 and 500, and thus are not described herein.

FIG. 8 is a schematic diagram showing an exemplary structure of an access point 800 in accordance with an embodiment of the present invention. As shown in FIG. 8, access point 800 includes a processing module 802, a processing module 804, and a transmitting module 806.

The receiving module 802 is configured to receive a query frame from the site;

The processing module 804 is configured to determine the number of associated active sites;

The transmitting module 806 is configured to return a response frame to the site, where the response frame carries the number of the associated active sites.

A number of technical features involved in access point 800 have been described in detail in methods 100 and 500, and thus are not described herein.

It should be noted that the receiving module mentioned in the embodiments of the present invention may be a receiver, a receiving circuit, etc., the transmitting module may be a transmitter, a transmitting circuit, etc., and the processing module may be a processor, a processing circuit, a processing integrated circuit. , processing chips, etc.

A person skilled in the art may know that all or part of the above steps may be completed by hardware related to program instructions, and the program may be stored in a computer readable storage medium such as a ROM, a RAM, an optical disc, or the like. .

In conclusion, the above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims (26)

A method for determining an initial contention window parameter, comprising: Receiving, by the at least one access point, a notification frame, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point; The initial contention window parameters are calculated based on the number of active sites associated with each access point. The method according to claim 1, wherein the calculating the parameters of the contention window according to the number of active sites associated with each access point comprises: Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point; An initial contention window parameter is calculated based on the activity index. The method according to claim 1 or 2, wherein said activity index A is calculated according to the following formula:

The N _AP is the number of access points, W _i is the weight of the access point i, and N _i is the number of active sites associated with the access point i. A method to any one of claims 1 to 3 as claimed in claim, wherein the contention window parameter is a contention window minimum contention window CW _min or maximum value CW _max. The method of any one 1 to 4 as claimed in claim, wherein, when the contention window parameter is the minimum contention window CW _min,

When the contention window parameter is the contention window maximum value CW _max ,

Where A is the active index and j is the preset maximum number of retransmissions. A method for determining an initial contention window parameter, comprising: Determine the number of active sites associated with; Broadcasting a notification frame, wherein the notification frame carries the number of associated active sites. The method of claim 6 wherein said notification frame is a management frame, said tube The frame is a beacon frame. A site characterized by comprising: a receiving module, configured to receive a notification frame broadcast by the at least one access point, where the notification frame broadcasted by each access point carries the number of active sites associated with the access point; And a processing module, configured to calculate an initial contention window parameter according to the number of active sites associated with each access point. The station according to claim 8, wherein the processing module is specifically configured to: Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point; An initial contention window parameter is calculated based on the activity index. A station according to claim 8 or 9, wherein said activity index A is calculated according to the following formula:

The N _AP is the number of access points, W _i is the weight of the access point i, and N _i is the number of active sites associated with the access point i. Site 8 to 10 as one of the preceding claims, characterized in that the initial contention window parameter is a contention window minimum contention window CW _min or maximum value CW _max. Site 8 to 11 as claimed in any one of the claims, characterized in that, when the contention window parameter is the minimum contention window CW _min,

When the contention window parameter is the contention window maximum value CW _max ,

Where A is the active index and j is the preset maximum number of retransmissions. An access point, comprising: a processing module for determining the number of associated active sites; And a transmitting module, configured to broadcast a notification frame, where the notification frame carries the number of the associated active sites. The access point of claim 13 wherein said notification frame is a management frame and said management frame is a beacon frame. A method for determining an initial contention window parameter, comprising: Sending a query frame to at least one access point; Receiving a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point; The parameters of the contention window are calculated according to the number of active sites associated with each access point. The method of claim 15, wherein the calculating the parameters of the contention window according to the number of active sites associated with each access point comprises: Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point; An initial contention window parameter is calculated based on the activity index. The method according to claim 15 or 16, wherein said activity index A is calculated according to the following formula:

The N _AP is the number of access points, W _i is the weight of the access point i, and N _i is the number of active sites associated with the access point i. A method according to any one of claims 15 to 17, wherein the contention window parameter is a contention window minimum contention window CW _min or maximum value CW _max. The method of any one of 15 to 18 as claimed in claim, wherein, when the contention window parameter is the minimum contention window CW _min,

When the contention window parameter is the contention window maximum value CW _max ,

Where A is the active index and j is the preset maximum number of retransmissions. A method for determining an initial contention window parameter, comprising: Receiving a query frame from the site; Determine the number of active sites associated with; An acknowledgment frame is returned to the site, wherein the acknowledgment frame carries the number of associated active sites. A site characterized by comprising: a transmitting module, configured to send a query frame to at least one access point; a receiving module, configured to receive a response frame from the at least one access point, where the response frame returned by each access point carries the number of active sites associated with the access point; The processing module is configured to calculate a parameter of the contention window according to the number of active sites associated with each access point. The site of claim 21, wherein the processing module is specifically configured to: Calculating an activity index according to the number of active sites associated with each access point and the weight of each preset access point; An initial contention window parameter is calculated based on the activity index. A station according to claim 21 or 22, wherein said activity index A is calculated according to the following formula:

The N _AP is the number of access points, W _i is the weight of the access point i, and N _i is the number of active sites associated with the access point i. Site 21 to 23 as claimed in any one of claims, wherein the contention window parameter is a contention window minimum contention window CW _min or maximum value CW _max. 21 to 24 according to any one of the station as claimed in claim, wherein, when the contention window parameter is the minimum contention window CW _min,

When the contention window parameter is the contention window maximum value CW _max ,

Where A is the active index and j is the preset maximum number of retransmissions. An access point, comprising: a receiving module, configured to receive a query frame from the site; a processing module for determining the number of associated active sites; And a transmitting module, configured to return a response frame to the site, where the response frame carries the number of the associated active sites.

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