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

• US 8,917,743 B2
• Filed: 10/05/2011
• Issued: 12/23/2014
• Est. Priority Date: 10/06/2010
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Zhu, Chunhui, Aboul-Magd, Osama, Kim, Youngsoo
• Primary Examiner(s): Mian, Omer S
• Application Number:
  US13/253,926
• Publication Number:
  US 20120087358A1
• Time in Patent Office: 1,175 Days
• Field of Search: 370/445, 370/447, 370/458, 370/461, 370/462
• US Class Current: 370/447
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• 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 multi-user request-to-send (MU-RTS) frame to the multiple receiving stations, the RTS frame including a receiver address (RA) field comprising compressed addresses for the multiple receiving stations. The MU-RTS frame includes an indication field that indicates the RTS frame as an MU-RTS without altering the RTS frame type/subtype.

Claims

1. A method of wireless communication, comprising:

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

wherein reserving the transmission period comprises;

generating a multi-user request-to-send (MU-RTS) frame including;

a receiver address (RA) field that comprises a compressed RA field, wherein the compressed RA field comprises compressed addresses for the multiple receiving stations;

an indication field that indicates the RTS frame as an MU-RTS without altering the RTS frame type/subtype; and

transmitting the MU-RTS frame to the multiple receiving stations,

wherein the compressed RA field comprises;

compatibility information for differentiating compressed addresses from any actual address in the wireless network, and a bit, wherein first setting of bit representing information that indicates that the compressed RA field represents an individual receiver station address, and second setting of the bit representing information that indicates that the compressed RA field represents compressed addresses for multiple receiver station addresses.

2. The method of claim 1, wherein:

a wireless transmitter station comprises a wireless access point (AP) station that transmits the data to the multiple intended receiving wireless stations;

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

the order of the AIDs presented in the compressed RA field indicates order of transmission of clear-to-send (CTS) frames from intended receiving stations back to the 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 four AID values corresponding to at least four receiver stations, wherein the bit is bit 0 of Octet 0;

bit 1 of Octet 0 indicates whether the compressed RA field represents a universally administered address or a locally administered address;

the compatibility information comprises bits 2-3 of Octet 1 comprise Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in a wireless network; and

each AID comprises 11 bits, such that an AID field is set to 0 if it is not used to indicate any receiver station address, wherein the order of the AIDs presented in the compressed RA field indicates order of transmission of CTS frames from intended receiving stations back to the AP station over the wireless medium.

4. The method of claim 1, wherein:

a wireless transmitter station comprises a wireless access point (AP) station that transmits the data to the multiple intended receiving wireless stations;

each compressed address in the compressed RA field comprises a partial Association ID (P_AID) for each receiver station assigned by the AP station; and

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

5. The method of claim 4, wherein:

the compressed RA field comprises six Octets capable of representing at least four AID values corresponding to at least four receiver stations, wherein the bit is bit 0 of the Octet;

bit 1 of Octet 0 indicates whether the compressed RA field represents a universally administered address or a locally administered address;

the compatibility information includes bits 2-3 of Octet 1 that comprise Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in a wireless network; and

each P_AID comprises 9 bits, such that a P_AID field is set to 0 if it is not used to indicate any receiver station address, wherein the order of the AIDs presented in the compressed RA field indicates order of transmission of CTS frames from intended receiving stations back to the AP station over the wireless medium.

6. The method of claim 5, wherein:

a P_AID includes 9 LSBs of an 11-bit AID.

7. The method of claim 1, wherein:

the indication field comprises a reused bit in the frame control field of a MAC header of the MU-RTS frame.

8. The method of claim 1, wherein:

the indication field comprises reserved bits in the VHT Service field of the MU-RTS frame.

9. The method of claim 1, wherein:

the indication field comprises a reserved bit in the VHT L-SIG field of the preamble of the MU-RTS flame.

10. The method of claim 1, wherein:

the indication field comprises a reserved bit in the VHT-SIG-A fields of the preamble of the MU-RTS flame.

11. The method of claim 2, further comprising:

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

12. The method of claim 11, wherein the inter-flame spacing period between said RTS flame and the first CTS flame which is of SIFS in length.

13. The method of claim 2, further comprising:

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

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

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

16. The method of claim 1, wherein during a downlink phase, a MU-RTS is transmitted from a transmitting wireless station to the intended receiving wireless stations, and during a corresponding uplink phase, a response CTS is transmitted from each of the intended receiving wireless stations to the transmitting wireless station.

30. The method of claim 1, wherein the compressed RA field comprises a plurality of Octets capable of representing at least four Association ID (AID) values corresponding to at least four wireless receiver stations.

31. The method of claim 1, wherein at least one Octet indicates whether the compressed RA field represents a universally administered address or a locally administered address.

32. The method of claim 1, wherein the compatibility information comprises Compatibility Bits (CB) configured to ensure that the compressed addresses do not equal any actual addresses in a wireless network.

17. 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 a transmitting wireless station to multiple intended receiving wireless stations on multiple downlink spatial streams over a wireless communication medium, wherein reserving the transmission period comprises generating a multi-user request-to-send (MU-RTS) frame including a receiver address (RA) field that comprises a compressed RA field,

wherein the compressed RA field comprises compressed addresses for the multiple intended receiving wireless stations in the wireless network, and an indication field that indicates the RTS frame as an MU-RTS without altering the RTS frame type/subtype, and transmission of the MU-RTS frame to the multiple intended receiving wireless stations, wherein the compressed RA field comprises;

compatibility information for differentiating compressed addresses from any actual address in the wireless network, and a bit, wherein first setting of bit representing information that indicates that the compressed RA field represents an individual receiver station address, and second setting of the bit representing information that indicates that the compressed RA field represents compressed addresses for multiple receiver station addresses.

18. The wireless station of claim 17, wherein:

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

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 station over the wireless communication medium.

19. The wireless station of claim 17, wherein:

a receiving wireless station utilizes the indication field to differentiate the RTS frame from the MU-RTS frame.

20. The wireless station of claim 17, wherein:

each compressed address in the compressed RA field comprises a partial Association ID (P_AID) for each wireless receiver station assigned by the AP station; and

the order of the P_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 station over the wireless communication medium.

21. The wireless station of claim 17, wherein:

the indication field comprises a reused bit in the frame control field of a MAC header of the MU-RTS frame.

22. The wireless station of claim 17, wherein:

the indication field comprises reserved bits in the VHT Service field of the MU-RTS frame.

23. The wireless station of claim 17, wherein:

the indication field comprises a reserved bit in the VHT L-SIG field of the preamble of the MU-RTS frame.

24. The wireless station of claim 17, wherein:

the indication field comprises a reserved bit in the VHT-SIG-A fields of the preamble of the MU-RTS frame.

25. The wireless station of claim 17, wherein:

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

26. The wireless station of claim 25, wherein:

the inter-frame spacing period between said RTS frame and the first CTS frame which is of SIFS in length.

27. The wireless station of claim 17, wherein:

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

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

29. The wireless station of claim 17, wherein the wireless network comprises a wireless local area network (WLAN).

33. A method of wireless communication, comprising:

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

wherein reserving the transmission period comprises;

generating a multi-user request-to-send (MU-RTS) frame including;

a receiver address (RA) field that comprises a compressed RA field, wherein the compressed RA field comprises compressed addresses for the multiple receiving stations;

an indication field that indicates the RTS frame as an MU-RTS without altering the RTS frame type/subtype;

transmitting the MU-RTS frame to the multiple receiving stations,

wherein the compressed RA field comprises;

compatibility information for differentiating compressed addresses from any actual addresses in the wireless network, and a bit, wherein first setting of bit representing information that indicates that the compressed RA field represents an individual receiver station address, and second setting of the bit representing information that indicates that the compressed RA field represents compressed addresses for multiple receiver station addresses;

and

utilizing the indication field by a receiving wireless station to differentiate the RTS frame from the MU-RTS frame.