Slot-based power save improvement
An access point (AP) associated with a several mobile stations (STAs) implements a slot-based power save poll (PS-Poll) method. The AP divides a slot-based access period into multiple time slots and allocates each time slot to either a STA determined to have slot-based PS-Poll capabilities or a STA determined to have buffered data present at the AP. The AP creates a traffic indication map (TIM) having a number of bits equal to the number of stations associated with the AP, and then transmits a beacon including the TIM. The TIM indicates to a slot-based PS-Poll capable STA which time slots are assigned to a selected set of associated stations. After receiving the beacon from the AP, the STA refrains from attempting to communicate with the AP outside the time slot assigned to the STA, yet transmits information to the AP during the time slot assigned to the STA.
1. An access point device, comprising:
a transceiver configured to communicate with mobile stations; and
processing circuitry configured:
to associate with a plurality of stations,
to receive from one or more of the plurality stations one or more signals, each of the one or more signals indicating whether one of the plurality of stations has slot-based Power Save-Poll (PS-Poll) capabilities, wherein each of the one or more signals differentiates the one of the plurality of stations having slot-based PS-Poll capabilities from a non-slot-based power save station,
to determine a number of stations having slot-based PS-Poll capabilities within the plurality of associated stations based on the one or more signals,
to divide a slot-based access period into a plurality of time slots,
to allocate the slot-based access period per the number of the stations determined to have slot-based PS-Poll capabilities,
to allocate each time slot of the plurality of time slots to each of the plurality of stations having buffered data present at the access point device and determined to have slot-based PS-Pall capabilities; and
to transmit a first beacon frame including an indication of slot-based access period information.
2. The access point device of claim 1 , wherein the processing circuitry is further configured to determine whether an associated station has buffered data present at the access point.
3. The access point device of claim 1 , wherein the processing circuitry is further configured to assign each time slot of the plurality of time slots to the stations determined to have slot-based PS-Poll capabilities.
4. The access point device of claim 1 , wherein the processing circuitry is further configured to assign each time slot of the plurality of time slots to the stations determined to have buffered data present at the access point device and stations.
5. The access point device of claim 1 , wherein the processing circuitry is further configured to not assign a time slot to a station that does not have slot-based power save capabilities.
6. The access point device of claim 1 , wherein the first beacon frame includes an identification of a start time of the slot-based access period and a duration of the slot-based access period.
7. A mobile station, comprising:
a transmitter and receiver configured to communicate with an access point; and
processing circuitry configured:
to associate with the access point configured to divide a slot-based access period into a plurality of time slots;
to receive a first beacon frame from the access point, the first beacon frame including an indication of a time slot assigned to the mobile station;
in response to receiving the first beacon frame, to set a network allocation vector (NAV) and refrain from attempting to communicate with the access point during the slot-based access period; and
to transmit a signal that indicates to the access point whether the mobile station has slot-based Power Save-Poll (PS-Poll) capabilities, wherein the signal differentiates the mobile station having slot-based PS-Poll capabilities from a non-slot-based power save mobile station.
8. The mobile station or claim 7 , wherein the processing circuitry is further configured to receive a second beacon frame from an access point with which the mobile station is not associated.
9. The mobile station of claim 7 , wherein the beacon frame includes an identification of a start time of the slot-based access period and a duration of the slot-based access period.
10. The mobile station of claim 7 , wherein the processing circuitry is further configured to transmit information to the access point outside the slot-based access period.
11. The mobile station of claim 7 , wherein the processing circuitry is further configured to set the NAV to expire at the end of the slot-based access period.
12. A non-transitory computer-readable medium encoded with executable instructions that, when executed, cause processing circuitry to:
associate with a plurality of stations;
receive from one or more of the plurality of stations one or more signals, each of the one or more signals indicating whether one of the stations has slot-based Power Save-Poll (PS-Poll) capabilities, wherein each of the one or more signals differentiates the one of the plurality of stations having slot-based PS-Poll capabilities from a non-slot-based power save station:
determine a number of stations having slot-based Power Save-Poll (PS-Poll) capabilities within the plurality of associated stations based on the one or more signals;
divide a slot-based access period into a plurality of time slots;
allocate the slot-based access period per the number of stations determined to have slot-based PS-Poll capabilities;
allocate each time slot of the plurality of time slots to each of the plurality of stations having buffered data present at the access point device and determined to have slot-based PS-Poll capabilities: and
transmit a first beacon frame including an indication of the slot-based access period information.
13. The computer-readable medium of claim 12 , wherein the instructions, when executed, further cause processing circuitry to: not assign a time slot to a station that does not have slot-based power save capabilities.
14. The computer-readable medium of claim 12 , wherein the instructions, when executed, further cause processing circuitry to: include in the first beacon frame an identification of a start time of the slot-based access period and a duration of the slot-based access period.
15. The computer-readable medium of claim 12 , wherein the instructions, when executed, further cause processing circuitry to: assign each time slot of the plurality of time slots to the stations determined to have slot-based PS-Poll capabilities.
16. An access point device, comprising:
a transceiver, which in operation, communicates with a plurality of mobile stations;
a processor coupled to the transceiver; and
a memory coupled to the processor, the memory storing processor-executable instructions that, when executed by the processor, cause the access point device to:
associate with the plurality of mobile stations;
receive from one or more of the plurality of mobile stations one or more signals, each of the one or more signals indicating whether one of the mobile stations has slot-based Power Save-Poll (PS-Poll) capabilities, wherein each of the one or more signals differentiates the one of the plurality of mobile stations having slot-based PS-Poll capabilities from a non-slot-based power save mobile station;
determine a number of mobile stations having slot-based Power Save-Poll (PS-Poll) capabilities within the plurality of mobile stations based on the one or more signals;
allocate a plurality of slots included in a slot-based access period based on the number of the mobile stations determined to have slot-based PS-Poll capabilities;
allocate each time slot of the plurality of time slots to each of the plurality of mobile stations having buffered data present at the access point device and determined to have slot-based PS-Poll capabilities; and
transmit a beacon frame including an indication of slot-based access period information.
17. A method comprising:
associating an access point device with a plurality of mobile stations;
receiving from one or more of the plurality of mobile stations one or more signals, each of the one or more signals indicating whether one of the mobile stations has slot-based Power Save-Poll (PS-Poll) capabilities, wherein each of the one or more signals differentiates the one of the plurality of mobile stations having slot-based PS-Poll capabilities from a non-slot-based power save mobile station;
determining a number of mobile stations having slot-based Power Save-Poll (PS-Poll) capabilities within the plurality of mobile stations based on the one or more signals;
allocating a plurality of slots included in a slot-based access period based on the number of the mobile stations determined to have slot-based PS-Poll capabilities;
allocating each time slot of the plurality of time slots to each of the plurality of mobile stations having buffered data present at the access point device and determined to have slot-based PS-Poll capabilities; and
transmitting a beacon frame including an indication of slot-based access period information.