Methods and arrangements to assign slots in restricted access windows in wireless networks

• US 9,144,072 B2
• Filed: 12/29/2012
• Issued: 09/22/2015
• Est. Priority Date: 09/07/2012
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Park, Minyoung
• Primary Examiner(s): Wilson, Robert
• Assistant Examiner(s): Aung, Sai
• Application Number:
  US13/730,972
• Publication Number:
  US 20140071900A1
• Time in Patent Office: 997 Days
• Field of Search: 370/329, 370/338, 370/252, 370/442, 370/458
• US Class Current: 1/1
• CPC Class Codes: H04L 5/0092 Indication of how the channel is divided
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0891 for synchronized access
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Logic may implement a slot assignment scheme that uses information provided in traffic indication map (TIM) information element (IE) and restricted access window (RAW) parameter set (PS) IE to determine a station-to-slot mapping function for communication of slot assignments to stations for RAWs. The TIM IE may comprise a bitmap indicating paged and unpaged stations. The RAW PS IE may comprise a duration and a slot duration. Logic may implement the station-to-slot function by determining the number of slots in a RAW and correlating slot assignments for stations based upon a position for the station in the TIM bitmap. The TIM bitmap may identify each station via a bit on a page in the bitmap based upon an assignment of the station to a position in the TIM bitmap. The station-to-slot mapping function may use an offset for fair access.

Claims

1. A method comprising:

receiving, by a station, one or more frames comprising a traffic indication map (TIM) bitmap, a restricted access window slot duration, and a restricted access window duration;

determining, by the station, a number of slots in a restricted access window (RAW);

determining, by the station, based upon a mapping function, an index of a time slot, in which the station is allowed to start contending for a medium based on the mapping function;

wherein the mapping function is (x+Noffset) mod Nraw;

wherein x is a position index of an association identifier (AID) of the station if the RAW is restricted to stations whose AID bits in the TIM bitmap are set to 1;

wherein, if the RAW is not restricted to stations whose AID bits in the TIM bitmap are set to 1, x is the AID of the station;

wherein the Noffset is an offset value in the mapping function;

wherein the Nraw is a number of time slots in the RAW; and

contending, by the station, for access to an access point in the slot of the RAW.

2. The method of claim 1, further comprising storing a traffic indication map bitmap in a memory.

3. The method of claim 1, further comprising determining the Noffset based upon art of a frame check sequence FCS field of a beacon frame.

4. The method of claim 1, further comprising determining the Noffset via an offset field in a beacon frame from the access point.

5. The method of claim 1, further comprising determining the Noffset via one or more fields comprising a timestamp, FCS, and a beacon interval field in a beacon frame from the access point.

6. A device comprising:

a memory to store logic; and

a processor coupled with the memory to execute the logic, the processor, upon execution of the logic, to perform operations, wherein the operations comprise operations to;

receive one or more frames comprising a traffic indication map (TIM) bitmap, a restricted access window slot duration, and a restricted access window duration;

determine a number of slots in a restricted access window (RAW);

determine, based upon a mapping function, an index of a time slot, in which the device is allowed to start contending for a medium based on the mapping function;

wherein the mapping function is (x+Noffset) mod Nraw;

wherein x is a position index of an association identifier (AID) of the device if the RAW is restricted to stations whose AID bits in the TIM bitmap are set to 1;

wherein, if the RAW is not restricted to stations whose AID bits in the TIM bitmap are set to 1, x is the AID of the device;

wherein the Noffset is an offset value in the mapping function;

wherein the Nraw is a number of time slots in the RAW; and

contend for access to an access point in the slot of the RAW.

7. The device of claim 6, further comprising a receiver coupled with the processor, a radio, and one or more antennas coupled with the radio to receive the frame.

8. The device of claim 6, wherein the mapping function comprises the Noffset that is determined based upon part of a frame check sequence FCS field of a beacon frame.

9. The device of claim 8, wherein the Noffset is determined via an offset field in a beacon frame from the access point.

10. The device of claim 8, wherein the Noffset is determined via one or more fields of a beacon frame.

11. The device of claim 8, wherein the logic comprises logic to generate the Noffset, wherein the Noffset is determined based upon a timestamp divided by a beacon interval field in a beacon frame from the access point.

12. A machine-accessible product comprising:

a non-transitory medium containing instructions to assign slots in restricted access windows, wherein the instructions, when executed by the access point, causes the access point to perform operations, the operations comprising;

receiving, by a station, one or more frames comprising a traffic indication map (TIM) bitmap, a restricted access window slot duration, and a restricted access window duration;

determining, by the station, a number of slots in a restricted access window (RAW);

determining, by the station, based upon a mapping function, an index of a time slot, in which the station is allowed to start contending for a medium based on the mapping function;

wherein the mapping function is (x+Noffset) mod Nraw;

wherein x is a position index of an association identifier (AID) of the station if the RAW is restricted to stations whose AID bits in the TIM bitmap are set to 1;

wherein, if the RAW is not restricted to stations whose AID bits in the TIM bitmap are set to 1, x is the AID of the station;

wherein the Noffset is an offset value in the mapping function;

wherein the Nraw is a number of time slots in the RAW; and

contending, by the station, for access to an access point in the slot of the RAW.

13. The machine accessible product of claim 12, wherein the operations further comprise storing a TIM bitmap in a memory.

14. The machine accessible product of claim 12, wherein the operations further comprise the mapping function established by the access point during association.

15. The machine accessible product of claim 12, wherein the operations further comprise the mapping function comprises determining the Noffset based upon part of a frame check sequence (FCS) field of a beacon frame.

16. The machine accessible product of claim 15, wherein the operations further comprise determining the Noffset via an offset field in a beacon frame from the access point.

17. The machine accessible product of claim 15, wherein the operations further comprise determining the Noffset via one or more fields comprising a timestamp, FCS, and a beacon interval field in a beacon frame from the access point.

18. A system comprising:

a radio and one or more antennas;

a memory to store logic;

a processor coupled with the memory to execute the logic, the processor, upon execution of the logic, to perform operations, wherein the operations comprise operations to;

receive one or more frames comprising a traffic indication map (TIM) bitmap, a restricted access window slot duration, and a restricted access window duration;

determine a number of slots in a restricted access window (RAW);

determine, based upon a mapping function, an index of a time slot, in which the system is allowed to start contending for a medium based on the mapping function;

wherein the mapping function is (x+Noffset) mod Nraw;

wherein x is a position index of an association identifier (AID) of the system if the RAW is restricted to stations whose AID bits in the TIM bitmap are set to 1;

wherein, if the RAW is not restricted to stations whose AID bits in the TIM bitmap are set to 1, x is the AID of the system;

wherein the Noffset is an offset value in the mapping function;

wherein the Nraw is a number of time slots in the RAW; and

contend for access to an access point in the slot of the RAW; and

a transmitter coupled with the processor and coupled with the radio and the one or more antennas to transmit the frame.

19. The system of claim 18, wherein the logic comprises logic to transmit a frame comprising the offset for the mapping function.

20. The system of claim 18, wherein the mapping function comprises the Noffset that is determined based upon part of a frame check sequence FCS field of a beacon frame.

21. The system of claim 20, wherein the Noffset is determined via an offset field in a beacon frame from the access point.

22. The system of claim 20, wherein the Noffset is determined via one or more fields of a beacon frame.

23. The system of claim 20, wherein the logic comprises logic to generate the Noffset, wherein the Noffset is determined based upon a timestamp divided by a beacon interval field in a beacon frame from the access point.