Method and system for contention avoidance in multi-user multiple-input-multiple-output wireless networks

• US 8,953,578 B2
• Filed: 06/23/2010
• Issued: 02/10/2015
• Est. Priority Date: 06/23/2010
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Zhu, Chunhui, Chaplin, Clint
• Primary Examiner(s): Pham, Brenda H
• Application Number:
  US12/821,940
• Publication Number:
  US 20110317630A1
• Time in Patent Office: 1,693 Days
• Field of Search: 370/348, 370/349, 370/445, 370/443, 370/312, 370/314, 370/321, 370/322, 370/337, 370/432, 370/447, 370/461
• US Class Current: 370/349
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

Wireless medium reservation for simultaneous transmission of multiple downlink spatial streams to multiple receiver wireless stations during a multi-user transmit opportunity over a wireless medium, is provided. Such a reservation includes reserving a transmission period for simultaneously transmitting data from a transmitting station to multiple intended receiving stations on multiple downlink spatial streams over a wireless communication medium. Reserving the transmission period includes transmitting a request-to-send (RTS) frame to the multiple receiving stations, the RTS frame including a receiver address (RA) field comprising compressed addresses for the multiple receiving stations.

Claims

1. A method of wireless communication in a wireless network, comprising:

reserving a transmission period for simultaneously transmitting data from a transmitting station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium;

wherein reserving the transmission period comprises transmitting a request-to-send (RTS) frame to the multiple receiving wireless stations, the RTS frame including a receiver address (RA) field comprising a compressed RA field including compressed addresses for the multiple receiving wireless stations in the network,

wherein the transmitting station comprises a wireless access point (AP) station;

wherein each compressed address in the compressed RA field comprises an Association ID (AID) for each receiver wireless station assigned by the AP station; and

wherein the wireless AP station shuffling order of AIDs in the compressed RA field for the multiple receiver wireless stations for differentiating corresponding compressed addresses from actual addresses in the wireless network.

2. The method of claim 1 wherein:

the order of the AIDs in the compressed RA field indicates order of transmission of clear-to-send (CTS) frames from intended receiving wireless stations back to the wireless AP station over the wireless communication medium.

3. The method of claim 2, wherein:

the compressed RA field comprises six Octets capable of representing at least three AID values corresponding to at least three receiver wireless stations;

bit 0 of Octet 0 indicates whether the compressed RA field represents an individual receiver wireless station address or compressed addresses for multiple receiver wireless station addresses;

bits 1-5 of Octet 1 comprise Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in the wireless network; and

each AID comprises 14 bits, such an AID field is set to 0 if it is not used to indicate any receiver wireless station address, wherein the order of the AIDs presented in the compressed RA field indicates order of transmission of CTS frames from intended receiving wireless stations back to the AP wireless station over the wireless communication medium.

4. The method of claim 3, further comprising:

setting the three most significant bits (MSBs) of each 14-bit AID to zeros; and

a receiving wireless station utilizing the AID to differentiate a compressed RA field from an actual address in the wireless network.

5. The method of claim 3, further comprising:

shortening a 14-bit AID to an 11-bit AID by removing the three most significant bits (MSBs) of the 14-bit AID, allowing allocation of additional bits as compatibility bits up to 14 bits for a stronger bit pattern for a receiver wireless station to differentiate the compressed RA field from an actual RA field including an actual address in the wireless network.

6. The method of claim 3, further comprising:

shortening a 14-bit AID to a 10-bit AID by removing the four most significant bits (MSBs) of the 14-bit AID, allowing accommodation of four AIDs in a single compressed RA field.

7. The method of claim 2, wherein the AP wireless station shuffling the order of the AIDs in the compressed RA field comprises shuffling the order of the AIDs in the compressed RA field for four receiver wireless stations to differentiate the corresponding compressed addresses from actual addresses in the wireless network.

8. The method of claim 1, wherein:

each compressed address in the compressed RA field comprises a portion of actual address of a corresponding receiver wireless station, to uniquely represent that receiver wireless station.

9. The method of claim 8, wherein:

each compressed address in the compressed RA field comprises a Unique Octet of actual address of a corresponding receiver wireless station, to uniquely represent that receiver wireless station in the network.

10. The method of claim 8, wherein each Unique Octet comprises an 8-bit pattern that is unique in that specific position in the compressed RA field among all participating wireless stations in a Basic Service Set (BSS).

11. The method of claim 9, wherein the compressed RA field further comprises Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in the wireless network.

12. The method of claim 2, further comprising:

the AP wireless station specifying an inter-frame spacing period for responsive CTS frames from the receiver wireless stations to the AP wireless station in relation to the RTS frame.

13. The method of claim 12, wherein the inter-frame spacing period between said RTS frame and the first CTS frame which is of SIFS in length.

14. The method of claim 2, further comprising:

the AP wireless station specifying an inter-frame spacing period between multiple responsive CTS frames from the receiver wireless stations to the AP wireless station in relation to the RTS frame.

15. The method of claim 14, wherein the inter-frame spacing periods between multiple responsive CTS frames are set to twice reduced inter-frame spacing (RIFS), instead of short inter-frame spacing (SIFS), in order to reduce control overhead.

16. The method of claim 1, further comprising:

upon reserving a transmission period, simultaneously transmitting data from the transmitting station to multiple intended receiving wireless stations on multiple downlink spatial streams over the wireless communication medium.

17. The method of claim 1, wherein the transmitting station comprises a multiple-input-multiple-output (MIMO) wireless station.

18. The method of claim 1, wherein the wireless network comprises a wireless local area network (WLAN).

42. The method of claim 2, wherein the compressed RA field comprises six Octets for representing at least three AID values corresponding to at least three receiver wireless stations.

43. The method of claim 42, wherein one bit of a first Octet indicates whether the compressed RA field represents an individual receiver station address or compressed addresses for multiple receiver wireless station addresses.

19. A wireless station for wireless communication in a wireless network, comprising:

a communication physical layer configured for wireless communication over a wireless communication module; and

a channel access module configured for reserving a transmission period for simultaneously transmitting data from the wireless station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium, the channel access module further configured for utilizing the communication physical layer for transmitting a request-to-send (RTS) frame to the multiple receiving wireless stations, the RTS frame including a receiver address (RA) field comprising a compressed RA field including compressed addresses for the multiple receiving wireless stations in the wireless network;

wherein the wireless station comprises an access point (AP) wireless station;

each compressed address in the compressed RA field comprises an Association ID (AID) for each receiver wireless station assigned by the AP wireless station, and

wherein the AP wireless station shuffling order of the AIDs in the compressed RA field for the multiple receiver wireless stations for differentiating corresponding compressed addresses from actual addresses in the wireless network.

20. The wireless station of claim 19, wherein:

the order of the AIDs in the compressed RA field indicates order of transmission of clear-to-send (CTS) frames from intended receiving wireless stations back to the AP station over the wireless communication medium.

21. The wireless station of claim 20, wherein:

the compressed RA field comprises six Octets capable of representing at least three AID values corresponding to at least three receiver wireless stations;

bit 0 of Octet 0 indicates whether the compressed RA field represents an individual receiver wireless station address or compressed addresses for multiple receiver wireless station addresses;

bits 1-5 of Octet 1 comprise Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in the wireless network; and

each AID comprises 14 bits, such an AID field is set to 0 if it is not used to indicate any receiver wireless station address, wherein the order of the AIDs presented in the compressed RA field indicates order of transmission of CTS frames from intended receiving wireless stations back to the AP wireless station over the wireless communication medium.

22. The wireless station of claim 21, wherein:

the channel access module is further configured for setting the three most significant bits (MSBs) of each 14-bit AID to zeros for a receiver wireless station to differentiate a compressed RA field from an actual address in the wireless network.

23. The wireless station of claim 21, wherein:

the channel access module is further configured for shortening a 14-bit AID to an 11-bit AID by removing the three most significant bits (MSBs) of the 14-bit AID, allowing allocation of additional bits as compatibility bits up to 14 bits for a stronger bit pattern for a receiver wireless station to differentiate the compressed RA field from an actual RA field.

24. The wireless station of claim 21, wherein:

the channel access module is further configured for shortening a 14-bit AID to a 10-bit AID by removing the four most significant bits (MSBs) of the 14-bit AID, allowing accommodation of four AIDs in a single compressed RA field.

25. The wireless station of claim 20, wherein:

shuffling the order of the AIDs in the compressed RA field comprises shuffling the order of the AIDs in the compressed RA field for four receiver wireless stations to differentiate the corresponding compressed addresses from actual addresses in the wireless network.

26. The wireless station of claim 19, wherein:

each compressed address in the compressed RA field comprises a portion of actual address of a corresponding receiver wireless station, to uniquely represent that receiver wireless station.

27. The wireless station of claim 26, wherein:

each compressed address in the compressed RA field comprises a Unique Octet of actual address of a corresponding receiver wireless station, to uniquely represent that receiver wireless station in the wireless network.

28. The wireless station of claim 26, wherein each Unique Octet comprises an 8-bit pattern that is unique in that specific position in the compressed RA field among all participating wireless stations in a Basic Service Set (BSS).

29. The wireless station of claim 28, wherein the compressed RA field further comprises Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in the wireless network.

30. The wireless station of claim 20, wherein:

the channel access module is further configured for specifying an inter-frame spacing period for responsive CTS frames from the receiver wireless stations to the AP wireless station in relation to the RTS frame.

31. The wireless station of claim 30, wherein the inter-frame spacing period between said RTS frame and a CTS frame which is of short inter-frame spacing (SIFS) in length.

32. The wireless station of claim 20, wherein:

the channel access module is further configured for specifying an inter-frame spacing period between multiple responsive CTS frames from the receiver wireless stations to the AP wireless station in relation to the RTS frame.

33. The wireless station of claim 32, wherein the inter-frame spacing periods between multiple responsive clear-to-send frames are set to twice reduced inter-frame spacing (RIFS), instead of short inter-frame spacing (SIFS), in order to reduce control overhead.

34. The wireless station of claim 19, wherein:

the channel access module is further configured such that, upon reserving a transmission period, simultaneously transmitting data from the AP wireless station to multiple intended receiving wireless stations on multiple downlink spatial streams over the wireless communication medium.

35. The wireless station of claim 19, wherein the wireless station comprises a multiple-input-multiple-output (MIMO) wireless station.

36. The wireless station of claim 19, wherein the wireless network comprises a wireless local area network (WLAN).

37. A wireless station for communication in a wireless network, comprising:

a communication physical layer configured for wireless communication over a wireless communication module;

a channel access module configured for receiving a request-to-send (RTS) frame from an access point (AP) wireless station for reserving a transmission period for simultaneously transmitting data from the wireless station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium in the wireless network, wherein the RTS frame includes a receiver address (RA) field; and

the channel access module is further configured for determining if the RA field comprises an actual address in the wireless network or the RA field comprises a compressed RA field including compressed addresses for the multiple receiving wireless stations in the wireless network;

wherein each compressed address in a compressed RA field comprises an Association ID (AID) for each receiver wireless station assigned by the AP wireless station, such that the order of the AIDs presented in the compressed RA field indicates order of transmission of clear-to-send (CTS) frames from intended receiving wireless stations back to the AP wireless station over the wireless communication medium,

wherein order of the AIDs in the compressed RA field are shuffled for the receiving wireless stations for differentiating corresponding compressed addresses from actual addresses in the wireless network.

38. The wireless station of claim 37, wherein:

the channel access module is further configured such that, upon detecting that the wireless station is a targeted wireless receiver based on an actual address in the RA field, the wireless station transmitting a CTS reply after a SIFS time period.

39. The wireless station of claim 37, wherein:

the channel access module is further configured such that, upon detecting that the RA field comprises a compressed RA field;

upon determining that the wireless station is a targeted wireless receiver based on a compressed address in the RA field, if the wireless station is a first wireless receiver in order based on the AIDs in compressed RA field, the wireless station transmitting a CTS reply after a SIFS period, otherwise the wireless station calculating a CTS transmission time for hold off and transmitting a CTS reply after a SIFS period or PIFS period.

40. A method of wireless communication in a wireless network, comprising:

reserving a transmission period for simultaneously transmitting data from a transmitting station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium;

wherein reserving the transmission period comprises transmitting a request-to-send (RTS) frame to the multiple receiving wireless stations, the RTS frame including a receiver address (RA) field comprising a compressed RA field including compressed addresses for the multiple receiving wireless stations in the wireless network,

wherein each compressed address in the compressed RA field comprises an Association ID (AID) for each receiver wireless station assigned by the transmitting station;

wherein order of the AIDs presented in the compressed RA field indicates order of transmission of clear-to-send (CTS) frames from intended receiving wireless stations back to the transmitting station over the wireless communication medium;

wherein inter-frame spacing periods between multiple responsive CTS frames are set to twice reduced inter-frame spacing (RIFS), instead of short inter-frame spacing (SIFS), for reducing control overhead; and

wherein the order of the AIDs in the compressed RA field are arranged for the receiving wireless stations for differentiating corresponding compressed addresses from actual addresses in the wireless network.

41. A wireless station for wireless communication in a wireless network, comprising:

a communication physical layer configured for wireless communication over a wireless communication module; and

a channel access module configured for reserving a transmission period for simultaneously transmitting data from the wireless station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium, the channel access module further configured for utilizing the communication physical layer for transmitting a request-to-send (RTS) frame to the multiple receiving wireless stations, the RTS frame including a receiver address (RA) field comprising a compressed RA field including compressed addresses for the multiple receiving wireless stations in the wireless network;

wherein;

the wireless station comprises a wireless access point (AP) station; and

each compressed address in the compressed RA field comprises an Association ID (AID) for each receiver wireless station assigned by the AP wireless station;

the channel access module is further configured for specifying an inter-frame spacing period between multiple responsive CTS frames from the receiver wireless stations to the AP wireless station in relation to the RTS frame;

the inter-frame spacing periods between multiple responsive clear-to-send frames are set to twice reduced inter-frame spacing (RIFS), instead of short inter-frame spacing (SIFS), for reducing control overhead; and

order of the AIDs in the compressed RA field are arranged for the receiving wireless stations for differentiating corresponding compressed addresses from actual addresses in the wireless network.