METHOD AND APPARATUS OF LINK ADAPTATION IN WIRELESS LOCAL AREA NETWORK

• US 20160242233A1
• Filed: 04/26/2016
• Published: 08/18/2016
• 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, SOHN, Ill Soo, LEE, Dae Won, SEOK, Yong Ho
• Granted Patent: US 9,807,817 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 for a wireless local area network, the method comprising:

receiving, by a responding station, a Multi User-Physical layer Protocol Data Unit (MU-PPDU) from a requesting station, the MU PPDU including a data frame,

wherein the data frame includes a Quality of Service (QoS) Null frame that includes an ACK policy field that identifies an ACK policy for the responding station,

wherein the ACK policy field is set to a value indicating that the ACK policy is an immediate ACK response, and

wherein the QoS Null frame further includes a Modulation and Coding Scheme Feedback Request (MRQ) field that indicates whether the responding station is requested to send a Modulation and Coding Scheme Feedback (MFB); and

transmitting, by the responding station, an acknowledgment (ACK) frame to the requesting station based on the ACK policy,

wherein only when the MRQ field indicates that the responding station is requested to send the MFB does the ACK frame include a MCS estimate that is estimated by the responding station based on the MU-PPDU.

2. The method of claim 1, wherein the MU-PPDU includes a plurality of data frames for a plurality of stations, and

wherein only one of the plurality of data frames includes the QoS Null frame that corresponds to the responding station and contains the ACK policy for the immediate ACK response.

3. The method of claim 2, wherein remaining data frames of the plurality of data frames do not contain ACK policies for the immediate ACK response.

4. The method of claim 2, wherein the MU-PPDU includes a group identifier indicating the plurality of stations.

5. The method of claim 1, wherein the ACK policy field in the QoS Null frame has two bits.

6. The method of claim 1, wherein the QoS Null frame has no data for the responding station.

7. The method of claim 1, wherein the MRQ field is included in a Medium Access Control (MAC) header of the QoS Null frame.

8. The method of claim 1, wherein the MRQ field has a single bit.

9. A device for a wireless local area network, the device comprising:

a transceiver configured to receive and transmit radio signals; and

a processor operatively coupled with the transceiver and configured to;

instruct the transceiver to receive a Multi User-Physical layer Protocol Data Unit (MU-PPDU) from a requesting station, the MU PPDU including a data frame,

wherein the data frame includes a Quality of Service (QoS) Null frame that includes an ACK policy field that identifies an ACK policy for the responding station,

wherein the ACK policy field is set to a value indicating that the ACK policy is an immediate ACK response, and

wherein the QoS Null frame further includes a Modulation and Coding Scheme Feedback Request (MRQ) field that indicates whether the device requested to send a Modulation and Coding Scheme Feedback (MFB); and

instruct the transceiver to transmit an acknowledgment (ACK) frame to the requesting station based on the ACK policy,

wherein only when the MRQ field indicates that the device is requested to send the MFB does the ACK frame include a MCS estimate that is estimated by the device based on the MU-PPDU.

10. The device of claim 9, wherein the MU-PPDU includes a plurality of data frames for a plurality of stations, and

wherein only one of the plurality of data frames includes the QoS Null frame that corresponds to the device and contains the ACK policy for the immediate ACK response.

11. The device of claim 10, wherein remaining data frames of the plurality of data frames do not contain ACK policies for the immediate ACK response.

12. The device of claim 10, wherein the MU-PPDU includes a group identifier indicating the plurality of stations.

13. The device of claim 9, wherein the ACK policy field in the QoS Null frame has two bits.

14. The device of claim 9, wherein the QoS Null frame has no data for the device.

15. The device of claim 9, wherein the MRQ field is included in a Medium Access Control (MAC) header of the QoS Null frame.

16. The device of claim 9, wherein the MRQ field has a single bit.