Dynamic tuning of contention windows in computer networks

Abstract

Techniques for avoiding packet collision in wireless communications networks include initializing a first data indicating a plurality of fixed delay values in a range from a minimum delay to a maximum delay and indicating a corresponding plurality of adjustable weights. A first applied delay for a first packet is determined based on the first data. The first packet if transmitted at a time based on the first applied delay. Based on whether transmission of the first packet was successful the first data is adjusted by reducing a first weight of the plurality of adjustable weights for a corresponding first fixed delay value greater than the first applied delay, or by increasing a second weight of the plurality of adjustable weights for a corresponding second fixed delay value smaller than the first applied delay, or both.

1 . A method for avoiding packet collisions in a communications network,
 the method comprising:   initializing first data indicating a plurality of fixed delay values in a range from a minimum delay to a maximum delay;   determining a first applied delay for a first packet based on the first data;   transmitting the first packet at a time based on the first applied delay; and   adjusting the first data based on whether transmission of the first packet was successful.   
     
     
         2 . The method as recited in  claim 1 , further comprising:
 determining a second applied delay for a second packet based on the adjusted first data; and   transmitting the second packet at a time based on the second applied delay.   
     
     
         3 . The method as recited in  claim 1 , said adjusting the first data further comprises adjusting the first data to incrementally promote shorter delay times when transmission of the first packet is successful or incrementally promote longer delay times when transmission of the first packet is not successful or both, whereby recent past transmission performance influences an applied delay. 
     
     
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         11 . The method as recited in  claim 1 , wherein, the plurality of fixed values forms a geometric sequence. 
     
     
         12 . The method as recited in  claim 11 , wherein the geometric sequence is incremented by a factor of 1.5. 
     
     
         13 . The method as recited in  claim 1 , wherein the plurality of fixed delay values indicate slots for a Distributed Coordination Function used by an IEEE 802.11 (WiFi) standard and the minimum delay is a minimum applied delay and the maximum delay is a maximum applied delay. 
     
     
         14 . A non-transitory computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:
 initialize first data indicating a plurality of fixed delay values in a range from a minimum delay to a maximum delay;   determine a first applied delay for a first packet based on the first data;   transmit the first packet at a time based on the first applied delay; and   adjust the first data data based on whether transmission of the first packet was successful.   
     
     
         15 . The non-transitory computer-readable medium as recited in  claim 14 , wherein execution of the one or more sequences of instructions further causes the one or more processors to perform the steps of:
 determining a second applied delay for a second packet based on the adjusted first data; and   transmitting the second packet at a time based on the second applied delay.   
     
     
         16 . The non-transitory computer-readable medium as recited in  claim 14 , said adjusting the first data further comprises adjusting the first data to incrementally promote shorter delay times when transmission of the first packet is successful or incrementally promote longer delay times when transmission of the first packet is not successful or both, whereby recent past transmission performance influences an applied delay. 
     
     
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         22 . The non-transitory computer-readable medium as recited in  claim 14 , wherein, the plurality of fixed values forms a geometric sequence. 
     
     
         23 . An apparatus comprising:
 at least one processor; and   at least one memory including one or more sequences of instructions,   the at least one memory and the one or more sequences of instructions configured to, with the at least one processor, cause the apparatus to perform at least the following,
 initialize first data indicating a plurality of fixed delay values in a range from a minimum delay to a maximum; 
 determine a first applied delay for a first packet based on the first data; 
 transmit the first packet at a time based on the first applied delay; and 
 adjust the first data based on whether transmission of the first packet was successful. 
   
     
     
         24 . The apparatus as recited in  claim 23 , wherein the one or more sequences of instructions are further configured to cause the apparatus to perform the steps of:
 determining a second applied delay for a second packet based on the adjusted first data; and   transmitting the second packet at a time based on the second applied delay.   
     
     
         25 . The apparatus as recited in  claim 23 , said adjusting the first data further comprises adjusting the first data to incrementally promote shorter delay times when transmission of the first packet is successful or incrementally promote longer delay times when transmission of the first packet is not successful or both, whereby recent past transmission performance influences an applied delay. 
     
     
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         31 . The apparatus as recited in  claim 23 , wherein, the plurality of fixed values forms a geometric sequence. 
     
     
         32 . The apparatus as recited in  claim 31 , wherein the geometric sequence is incremented by a factor of 1.5. 
     
     
         33 . The apparatus as recited in  claim 23 , wherein the plurality of fixed delay values indicate slots for a Distributed Coordination Function used by an IEEE 802.11 (WiFi) standard and the minimum delay is a minimum applied delay and the maximum delay is a maximum applied delay. 
     
     
         34 . The non-transitory computer-readable medium as recited in  claim 22 , wherein the geometric sequence is incremented by a factor of 1.5. 
     
     
         35 . The non-transitory computer-readable medium as recited in  claim 14 , wherein the plurality of fixed delay values indicate slots for a Distributed Coordination Function used by an IEEE 802.11 (WiFi) standard and the minimum delay is a minimum applied delay and the maximum delay is a maximum applied delay.