Ofdma contention method and access point

Abstract

Embodiments of the invention provide an OFDMA contention method and an access point. The OFDMA contention method includes: receiving, by an access point, a contention request frame transmitted by a station over a subchannel, and judging whether a sum of a number of stations succeeding in a contention in a current channel contention period and a number of stations succeeding in a historic contention is minor than a preset threshold; if yes, triggering the station to enter a next channel contention period, and repeatedly executing the steps of the receiving and the judging, until a number of stations succeeding in contentions is greater than or equal to the preset threshold. The OFDMA contention method and the access point can increase the number of the stations succeeding in contentions, thereby improving the throughput of an OFDMA system.

What is claimed is: 
     
         1 . An orthogonal frequency division multiplexing access (OFDMA) contention method, comprising:
 receiving, by an access point, a contention request frame transmitted by a station over a subchannel; and   judging whether a sum of a number of stations succeeding in a contention in a current channel contention period and a number of stations succeeding in a historic contention is minor than a preset threshold,   if yes, triggering the station to enter a next channel contention period, and repeatedly executing the steps of the receiving, by the access point, the contention request frame transmitted by the station over the subchannel, and the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, until a number of stations succeeding in contentions is greater than or equal to the preset threshold.   
     
     
         2 . The OFDMA contention method according to  claim 1 , wherein the triggering the station to enter the next channel contention period comprises:
 transmitting, by the access point, a first request response frame in a broadcast mode, to acknowledge a success of contention to a station succeeding in the contention in the current channel contention period, and triggering the station to enter the next channel contention period; and   the repeatedly executing the steps of the receiving, by the access point, the contention request frame transmitted by the station over the subchannel, and the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, until the number of stations succeeding in contentions is greater than or equal to the preset threshold, comprises:   repeatedly executing the steps of the receiving, by the access point, the contention request frame transmitted by the station over the subchannel, and the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, until the number of stations succeeding in contentions is greater than or equal to the preset threshold; otherwise, transmitting, by the access point, a second request response frame in the broadcast mode, to acknowledge a success of contention to a station succeeding in a contention in the last channel contention period, and terminating procedure.   
     
     
         3 . The OFDMA contention method according to  claim 2 , further comprising:
 judging whether a number of channel contention periods reaches a preset period threshold, if yes, performing the step of transmitting, by the access point, the second request response frame in the broadcast mode, to acknowledge a success of contention to the station succeeding in the contention in the current channel contention period; otherwise,   performing the judging whether the sum of the number of stations succeeding in contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold.   
     
     
         4 . The OFDMA contention method according to  claim 2 , further comprising:
 monitoring whether channel contention time reaches a preset time threshold, if yes, transmitting, by the access point, a contention termination frame in the broadcast mode, to notify the station that a channel contention is terminated.   
     
     
         5 . The OFDMA contention method according to  claim 2 , wherein:
 when transmitting, by the access point, the first request response frame in the broadcast mode, the first request response frame is further used to allocate a resource to the station succeeding in the contention in the current channel contention period; and   when transmitting, by the access point, the second request response frame in the broadcast mode, the second request response frame is further used to allocate a resource to the station succeeding in the contention in the last channel contention period.   
     
     
         6 . The OFDMA contention method according to  claim 2 , wherein:
 when transmitting, by the access point, the second request response frame in the broadcast mode, the second request response frame is further used to allocate a resource to both the station succeeding in the contention in the last channel contention period and the station succeeding in the historic contention.   
     
     
         7 . The OFDMA contention method according to  claim 2 , wherein after the transmitting, by the access point, the second request response frame in the broadcast mode, to acknowledge the success of contention to the station succeeding in the contention in the last channel contention period, further comprising:
 performing, by the access point, an acknowledgment response after the stations succeeding in contentions finish data transmitting.   
     
     
         8 . The OFDMA contention method according to  claim 1 , wherein the triggering the station to enter the next channel contention period, comprises:
 waiting, by the access point, for a first preset time without response, to trigger the station to enter the next channel contention period; and   the repeatedly executing the steps of the receiving, by the access point, the contention request frame transmitted by the station over the subchannel, and the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, until the number of stations succeeding in contentions is greater than or equal to the preset threshold, comprises:   repeatedly executing the steps of the receiving, by the access point, the contention request frame transmitted by the station over the subchannel, and the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, until the number of stations succeeding in contentions is greater than or equal to the preset threshold; otherwise, transmitting, by the access point, a third request response frame in the broadcast mode after waiting for a second preset time, to acknowledge a success of contention to all stations succeeding in contentions;   wherein length of the first preset time is longer than that of the second preset time.   
     
     
         9 . The OFDMA contention method according to  claim 8 , wherein before the judging whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, further comprising:
 judging whether a number of channel contention periods reaches a preset period threshold, if yes, performing directly the step of transmitting, by the access point, the third request response frame in the broadcast mode after waiting for the second preset time, to acknowledge the success of contention to all stations succeeding in contentions; otherwise,   performing the judging whether the sum of the number of stations succeeding in contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold.   
     
     
         10 . The OFDMA contention method according to  claim 8 , further comprising:
 monitoring whether channel contention time reaches a preset time threshold, if yes, performing directly the step of transmitting, by the access point, the third request response frame in the broadcast mode after waiting for the second preset time, to acknowledge the success of contention to all stations succeeding in contentions.   
     
     
         11 . The OFDMA contention method according to  claim 8 , wherein:
 when transmitting, by the access point, the third request response frame in the broadcast mode after waiting for the second preset time, the third request response frame is further used to allocate a resource to all stations succeeding in contentions.   
     
     
         12 . The OFDMA contention method according to  claim 8 , wherein after the transmitting, by the access point, the third request response frame in the broadcast mode after waiting for the second preset time, to acknowledge the success of contention to all stations succeeding in contentions, further comprising:
 performing, by the access point, an acknowledgment response, after the stations succeeding in contentions finish data transmitting.   
     
     
         13 . An access point, comprising:
 a request receiving unit, configured to receive a contention request frame transmitted by a station over a subchannel; and   a request processing unit, configured to judge whether a sum of a number of stations succeeding in a contention in a current channel contention period and a number of stations succeeding in a historic contention is minor than a preset threshold, if yes, trigger the station to enter a next channel contention period, until a number of stations succeeding in contentions is greater than or equal to the preset threshold.   
     
     
         14 . The access point according to  claim 13 , wherein the request processing unit comprises:
 a first threshold judging module, configured to judge whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, if yes, transmit a first notification message to a first response module; otherwise, transmit a second notification message to a second response module;   the first response module, configured to transmit a first request response frame in a broadcast mode according to the first notification message, to acknowledge a success of contention to a station succeeding in the contention in the current channel contention period, and trigger the station to enter the next channel contention period; and   the second response module, configured to transmit a second request response frame in the broadcast mode according to the second notification message, to acknowledge a success of contention to a station succeeding in a contention in the last channel contention period.   
     
     
         15 . The access point according to  claim 14 , wherein the request processing unit further comprises:
 a first number judging module, configured to judge whether the number of channel contention periods reaches a preset period threshold, if yes, transmit the second notification message to the second response module; otherwise, transmit a first threshold judging message to the first threshold judging module.   
     
     
         16 . The access point according to  claim 14 , wherein the request processing unit further comprises:
 a first time monitoring module, configured to monitor whether channel contention time reaches a preset time threshold, if yes, transmit a contention termination frame in the broadcast mode, to notify the station that a channel contention is terminated.   
     
     
         17 . The access point according to  claim 14 , wherein:
 the first response module is further configured to allocate a resource to the station succeeding in the contention in the current channel contention period through the first request response frame; and   the second response module is further configured to allocate a resource to the station succeeding in the contention in the last channel contention period through the second request response frame.   
     
     
         18 . The access point according to  claim 14 , wherein the second response module is further configured to allocate a resource to both the station succeeding in the contention in the last channel contention period and the station succeeding in the historic contention through the second request response frame. 
     
     
         19 . The access point according to  claim 13 , further comprising:
 an acknowledgement response module, configured to perform an acknowledgment response, after the stations succeeding in contentions finish data transmitting.   
     
     
         20 . The access point according to  claim 13 , wherein the request processing unit comprises:
 a second threshold judging module, configured to judge whether the sum of the number of stations succeeding in the contention in the current channel contention period and the number of stations succeeding in the historic contention is minor than the preset threshold, if yes, the access point waits for a first preset time without response, to trigger the station to enter the next channel contention period; otherwise, transmit a third notification message to a third response module; and   the third response module, configured to transmit a third request response frame in the broadcast mode after waiting for a second preset time according to the third notification message, to acknowledge a success of contention to all stations succeeding in contentions;   wherein length of the first preset time is longer than that of the second preset time.   
     
     
         21 . The access point according to  claim 20 , wherein the request processing unit further comprises:
 a second number judging module, configured to judge whether the number of channel contention periods reaches a preset period threshold, if yes, transmit the third notification message to the third response module; otherwise, transmit a second threshold judging message to the second threshold judging module.   
     
     
         22 . The access point according to  claim 20 , wherein the request processing unit, further comprises:
 a second time monitoring module, configured to monitor whether channel contention time reaches a preset time threshold, if yes, transmit the third notification message to the third response module.   
     
     
         23 . The access point according to  claim 20 , wherein the third response module is further configured to allocate a resource to all stations succeeding in contentions through the third request response frame.