Link adaptation for 802.11 system

1. A method implemented by a first network device in a Wireless Local Area Network (WLAN) to provide Modulation Coding Scheme (MCS) feedback, the method comprising:

determining a reference payload size based on a payload size of a Physical Layer Protocol Data Unit (PPDU) received from a second network device that is used by the first network device to measure a link quality of a wireless communications link between the first network device and the second network device;

selecting an MCS that is determined to have a highest data rate among a plurality of available MCSes that when used to transmit a frame having the reference payload size over the wireless communications link between the first network device and the second network device results in a frame error rate that is less than or equal to a threshold error rate for a given set of transmission properties, wherein the given set of transmission properties include any one of a coding scheme, an allocated frequency resource unit size, a number of spatial streams, beamforming vectors/matrices, use of Space-time Block Codes (STBC) or Space-frequency Block Codes (SFBC), and use of Dual Carrier Modulation (DCM);

generating a frame having a Media Access Control (MAC) header, wherein a control field of the MAC header includes an indication of the selected MCS; and

transmitting the generated frame to the second network device through a wireless medium.

2. The method of claim 1 , wherein the threshold error rate is 10%.

3. The method of claim 1 , wherein the given set of transmission properties are determined based on one or more transmission properties of the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.

4. The method of claim 3 , wherein the PPDU received from the second network device includes an indication that MCS feedback is requested.

5. The method of claim 1 , wherein the MAC header of the generated frame includes an indication of a frame sequence number of a frame included in the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.

6. A first network device configured to provide Modulation Coding Scheme (MCS) feedback in a Wireless Local Area Network (WLAN), the first network device comprising:

a Radio Frequency (RF) transceiver;

a set of one or more processors; and

a non-transitory machine-readable medium having stored therein an MCS feedback component, which when executed by the set of one or more processors, causes the first network device to determine a reference payload size based on a payload size of a Physical Layer Protocol Data Unit (PPDU) received from a second network device that is used by the first network device to measure a link quality of a wireless communications link between the first network device and the second network device, select an MCS that is determined to have a highest data rate among a plurality of available MCSes that when used to transmit a frame having the reference payload size over the wireless communications link between the first network device and the second network device results in a frame error rate that is less than or equal to a threshold error rate for a given set of transmission properties, wherein the given set of transmission properties include any one of a coding scheme, an allocated frequency resource unit size, a number of spatial streams, beamforming vectors/matrices, use of Space-time Block Codes (STBC) or Space-frequency Block Codes (SFBC), and use of Dual Carrier Modulation (DCM), generate a frame having a Media Access Control (MAC) header, wherein a control field of the MAC header includes an indication of the selected MCS, and transmit the generated frame to the second network device through a wireless medium.

7. The first network device of claim 6 , wherein the threshold error rate is 10%.

8. The first network device of claim 6 , wherein the given set of transmission properties are determined based on one or more transmission properties of the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.

9. The first network device of claim 8 , wherein the PPDU received from the second network device includes an indication that MCS feedback is requested.

10. The first network device of claim 6 , wherein the MAC header of the generated frame includes an indication of a frame sequence number of a frame included in the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.

11. A non-transitory machine-readable medium having computer code stored therein, which when executed by a set of one or more processors of a first network device in a Wireless Local Area Network (WLAN), causes the first network device to perform operations for providing Modulation Coding Scheme (MCS) feedback, the operations comprising:

determining a reference payload size based on a payload size of a Physical Layer Protocol Data Unit (PPDU) received from a second network device that is used by the first network device to measure a link quality of a wireless communications link between the first network device and the second network device;

selecting an MCS that is determined to have a highest data rate among a plurality of available MCSes that when used to transmit a frame having the reference payload size over the wireless communications link between the first network device and the second network device results in a frame error rate that is less than or equal to a threshold error rate for a given set of transmission properties, wherein the given set of transmission properties include any one of a coding scheme, an allocated frequency resource unit size, a number of spatial streams, beamforming vectors/matrices, use of Space-time Block Codes (STBC) or Space-frequency Block Codes (SFBC), and use of Dual Carrier Modulation (DCM);

generating a frame having a Media Access Control (MAC) header, wherein a control field of the MAC header includes an indication of the selected MCS; and

transmitting the generated frame to the second network device through a wireless medium.

12. The non-transitory machine-readable medium of claim 11 , wherein the threshold error rate is 10%.

13. The non-transitory machine-readable medium of claim 11 , wherein the given set of transmission properties are determined based on one or more transmission properties of the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.

14. The non-transitory machine-readable medium of claim 13 , wherein the PPDU received from the second network device includes an indication that MCS feedback is requested.

15. The non-transitory machine-readable medium of claim 11 , wherein the MAC header of the generated frame includes an indication of a frame sequence number of a frame included in the PPDU received from the second network device that is used by the first network device to measure the link quality of the wireless communications link between the first network device and the second network device.