Scheduling for power savings in a wireless network

Abstract

In a wireless network, a wireless device may dynamically estimate how long it can remain in a sleep mode without missing out on a necessary opportunities to communicate within the network. In some embodiments, this estimate may be based on a combination of things such as the amount of data still queued up for transmission, recent history on data rates, a prediction on how long it will take another device (e.g., an access point) to accumulate enough data for another transmission, and/or how long the queued-up data can wait before it becomes stale.

1 . A method, comprising
 determining a sleep interval for a first communications device, the first communications device to communicate wirelessly with a second communications device in a wireless network, wherein the sleep interval is based at least partly on at least one of:
 an estimated delay for a flow between the first and second communications devices; 
 an estimated channel access delay for the first communications device; 
 an estimated time for a predetermined amount of data to accumulate in a transmit queue; 
 an estimated time to transmit data remaining in the transmit queue after a previous communications sequence; 
 a time until some of the data in the transmit queue becomes stale; and 
 a length of a transmit opportunity. 
   
   
   
       2 . The method of  claim 1 , wherein the sleep interval is based at least partly on the estimated time for the predetermined amount of data to accumulate in the transmit queue of the second device, minus the estimated channel access delay. 
   
   
       3 . The method of  claim 1 , wherein the sleep interval is based at least partly on the estimated time to transmit the data remaining in the transmit queue of the second device after the previous communications sequence, minus the estimated channel access delay. 
   
   
       4 . The method of  claim 1 , wherein the sleep interval is based at least partly on the time until some of the data in the transmit queue of the second device becomes stale, minus the estimated channel access delay. 
   
   
       5 . The method of  claim 1 , wherein the predetermined amount of data is based at least partly on the length of the transmit opportunity. 
   
   
       6 . The method of  claim 1 , wherein a new sleep interval is determined for each of multiple transmit opportunities. 
   
   
       7 . The method of  claim 1 , wherein the transmit queue is a transmit queue of the first communications device. 
   
   
       8 . The method of  claim 7 , wherein the sleep interval may be ended when the amount of data in the transmit queue reaches a particular level. 
   
   
       9 . An apparatus comprising
 a first communications device comprising:
 a processor; 
 a signal processing circuit coupled to the processor to communicate wirelessly with a second communications device; 
 a power control circuit coupled to the processor and the signal processing circuit, the power control circuit to place the signal processing circuit into a low power non-operational mode for certain periods of time; 
   wherein each of the certain periods of time are based at least partly on at least one of
 an estimated channel access delay for the first communications device; 
 an estimated time for a predetermined amount of data to accumulate in a transmit queue in the second communications device; 
 an estimated time to transmit data remaining in the transmit queue after a previous communications sequence; 
 a time until some of the data in the transmit queue becomes stale; and 
 a length of a transmit opportunity. 
   
   
   
       10 . The apparatus of  claim 9 , wherein the at least one of the certain periods of time is based at least partly on the estimated time for the predetermined amount of data to accumulate in the transmit queue, minus the estimated channel access delay. 
   
   
       11 . The apparatus of  claim 9 , wherein the at least one of the certain periods of time is based at least partly on the estimated time to transmit the data remaining in the transmit queue of the second device after the previous communications sequence, minus the estimated channel access delay. 
   
   
       12 . The apparatus of  claim 9 , wherein the at least one of the certain periods of time is based at least partly on the time until some of the data in the transmit queue of the second device becomes stale, minus the estimated channel access delay. 
   
   
       13 . The apparatus of  claim 9 , wherein the predetermined amount of data is based at least partly on the length of the transmit opportunity. 
   
   
       14 . The apparatus of  claim 9 , wherein a new certain period of time is determined for each of multiple transmit opportunities. 
   
   
       15 . The apparatus of  claim 9 , further comprising a battery coupled to the signal processing circuit. 
   
   
       16 . An article comprising
 a tangible machine-readable medium that contains instructions, which when executed by one or more processors result in performing operations comprising:
 determining a sleep interval for a first communications device, the first communications device to communicate wirelessly with a second communications device in a wireless network, wherein the sleep interval is based at least partly on at least one of:
 an estimated delay for a flow between the first and second communications devices; 
 an estimated channel access delay for the first communications device; 
 an estimated time for a predetermined amount of data to accumulate in a transmit queue; 
 an estimated time to transmit data remaining in the transmit queue after a previous communications sequence; 
 a time until some of the data in the transmit queue becomes stale; and 
 a length of a transmit opportunity. 
 
   
   
   
       17 . The article of  claim 16 , wherein the sleep interval is based at least partly on the estimated time for the predetermined amount of data to accumulate in the transmit queue of the second device, minus the estimated channel access delay. 
   
   
       18 . The article of  claim 16 , wherein the sleep interval is based at least partly on the estimated time to transmit the data remaining in the transmit queue of the second device after the previous communications sequence, minus the estimated channel access delay. 
   
   
       19 . The article of  claim 16 , wherein the sleep interval is based at least partly on the time until some of the data in the transmit queue of the second device becomes stale, minus the estimated channel access delay. 
   
   
       20 . The article of  claim 16 , wherein the predetermined amount of data is based at least partly on the length of the transmit opportunity. 
   
   
       21 . The article of  claim 16 , wherein the operations include determining a new sleep interval for each of multiple transmit opportunities. 
   
   
       22 . The article of  claim 16 , wherein the transmit queue is a transmit queue of the first communications device. 
   
   
       23 . The article of  claim 22 , wherein the operations include ending the sleep interval when the amount of data in the transmit queue reaches a particular level.