METHOD AND APPARATUS OF LINK ADAPTATION IN WIRELESS LOCAL AREA NETWORK

• US 20130250904A1
• Filed: 12/01/2011
• Published: 09/26/2013
• Est. Priority Date: 12/01/2010
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kang, Byeong Woo, Lee, Dae Won, Seok, Yong Ho, Sohn, Illsoo
• Granted Patent: US 9,350,428 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0031 Multiple signaling transmission H04L1/1664, F15 take precedence
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method of link adaptation performed by an access point supporting multi user(MU) multiple input multiple output(MIMO) in wireless local area network system is provided. The method includes transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme(MCS) request(MRQ) and receiving, from the first station, a MCS feedback(MFB) in response to the MRQ, wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

Claims

1. A method of link adaptation performed by an access point supporting multi user(MU) multiple input multiple output(MIMO) in wireless local area network system, the method comprising:

transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme(MCS) request(MRQ); and

receiving, from the first station, a MCS feedback(MFB) in response to the MRQ;

wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

2. The method of the claim 1, wherein the PPDU is a single user(SU) PPDU that carries a single PLCP service data unit(PSDU) for the first station, and

wherein the SU PPDU is transmitted over at least one spatial stream allocated to the first station, and includes at least one long training field(LTF) used for channel estimation of all spatial streams used for MU-MIMO transmission of a MU PPDU that carries independent PSDUs for the destination stations.

3. The method of the claim 2, the number of the at least one LTF is different form the number of the at least one spatial stream allocated to the first station.

4. The method of the claim 2, the number of the at least one LTF is determined by the number of spatial streams for the destination stations.

5. The method of the claim 2, the method further comprising:

transmitting, to the destination stations, a MU PPDU;

wherein the MU PPDU includes data for the first station, the data being modulated and coded by a MCS value determined, by the access point, by referring the recommended MCS value.

6. The method of the claim 1, wherein the PPDU is a MU PPDU that carries independent PSDUs for the destination stations and is transmitted to the destination station by the MU-MIMO transmission.

7. The method of claim 6, wherein the MRQ is contained in a data field of the MU-PPDU, the data field being transmitted over at least one spatial stream allocated to the first station.

8. A method of link adaptation performed by an access point supporting multi user(MU) multiple input multiple output(MIMO) in wireless local area network system, the method comprising:

transmitting, to destination stations of MU-MIMO transmission, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing an indicator indicating a target station of a modulation and coding scheme(MCS) request(MRQ); and

receiving, from the target station, a MCS feedback(MFB);

wherein the target station is one of destination stations, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the target station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

9. The method of the claim 8, wherein the MFB is transmitted in a block acknowledgement(BA) frame transmitted, by the target station, to notify the access point of whether the PPDU for the target station is received successfully by the target stations.

10. The method of the claim 8, wherein the indicator is configured in an MFB indication field, the MFB indication field being included in a data field of the PPDU transmitted over at least one spatial stream allocated to the target station.

11. The method of the claim 8, wherein the PPDU further includes MFB type indicator indicating whether the target station transmits the MFB to the access point immediately or not.

12. A wireless apparatus comprising a processor configured to:

transmit, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme(MCS) request(MRQ); and

receive, from the first station, a MCS feedback(MFB) in response to the MRQ;

wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

13. The wireless apparatus of the claim 12, wherein the PPDU is a single user(SU) PPDU that carries a single PLCP service data unit(PSDU) for the first station, and

wherein the SU PPDU is transmitted over at least one spatial stream allocated to the first station, and includes at least one long training field(LTF) used for channel estimation of all spatial streams used for MU-MIMO transmission of a MU PPDU that carries independent PSDUs for the destination stations.

14. The wireless apparatus of the claim 13, the processor further configured to:

transmit, to the destination stations, a MU PPDU;

wherein the MU PPDU includes data for the first station, the data being modulated and coded by a MCS value determined, by the access point, by referring the recommended MCS value.

15. The wireless apparatus of the claim 12, wherein the PPDU is a MU PPDU that carries independent PSDUs for the destination stations and is transmitted to the destination station by the MU-MIMO transmission, and

wherein the MRQ is contained in a data field of the MU-PPDU, the data field being transmitted over at least one spatial stream allocated to the first station.