SUBCHANNEL FEEDBACK FOR OFDMA SYSTEMS

• US 20170063512A1
• Filed: 03/04/2015
• Published: 03/02/2017
• Est. Priority Date: 03/04/2014
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Wu, Tianyu, Liu, Jianhan, ULN, KIRAN, Pare, Thomas Edward Jr.
• Granted Patent: US 10,110,361 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0623 Auxiliary parameters, e.g. power control [PCB] or not acknowledged commands [NACK], used as feedback information
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• 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: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A method of sub-channel feedback in OFDMA systems is provided. A wireless receiving device (STA) receives a radio signal from a transmitting device (AP) over a wide channel in an OFDMA system. The radio signal is transmitted over multiple sub-channels of the wide channel. The STA estimates channel quality information based on the received radio signal for each sub-channel. The STA then sends feedback information to the transmitting device. The feedback information comprises the estimated channel quality information for a selected subset of sub-channels from the wide channel based on a predefined rule. In one embodiment, the feedback information is embedded within an ACK/BA frame or is carried in a frame immediately subsequent to the ACK/BA frame.

Claims

1. A method comprising:

(a) receiving a radio signal transmitted from a transmitting device over a wide channel by a receiving device in an OFDMA wireless system, wherein the radio signal is transmitted over multiple sub-channels of the wide channel;

(b) estimating channel quality information based on the received radio signal for each sub-channel; and

(c) sending feedback information to the transmitting device, wherein the feedback information contains the estimated channel quality information for a selected subset of sub-channels from the wide channel based on a predefined rule.

2. The method of claim 1, wherein the channel quality information comprises an average signal to noise ratio (SNR) of a selected sub-channel.

3. The method of claim 1, wherein the channel quality information comprises a sum throughput of all spatial streams in a selected sub-channel.

4. The method of claim 1, wherein the selected subset of sub-channels is based on a predefined channel quality threshold.

5. The method of claim 1, wherein the selected subset of sub-channels is based on a predefined number of sub-channels having the best channel quality.

6. The method of claim 1, further comprising:

receiving a channel state information (CSI) feedback request for an MU-MIMO sub-channel; and

sending a channel matrix report of the MU-MIMO sub-channel.

7. The method of claim 1, wherein the radio signal contains both OFDMA data field for multiple sub-channels and multiple training fields for channel sounding.

8. The method of claim 1, wherein the feedback information is carried in an acknowledgement (ACK) frame or a block acknowledgement (BA) frame.

9. The method of claim 1, wherein the feedback information is carried in a frame immediately subsequent to an ACK frame or a BA frame.

10. A wireless station, comprising:

a receiver that receives a radio signal transmitted from a transmitting device over a wide channel in an OFDMA wireless system, wherein the radio signal is transmitted over multiple sub-channels of the wide channel;

a channel estimation module that estimates channel quality information based on the received radio signal for each sub-channel; and

a transmitter that sends feedback information to the transmitting device, wherein the feedback information contains the estimated channel quality information for a selected subset of sub-channels from the wide channel based on a predefined rule.

11. The station of claim 10, wherein the channel quality information comprises an average signal to noise ratio (SNR) of a selected sub-channel.

12. The station of claim 10, wherein the selected subset of sub-channels is based on a predefined channel quality threshold.

13. The station of claim 10, wherein the selected subset of sub-channels is based on a predefined number of sub-channels having the best channel quality.

14. The station of claim 10, wherein the feedback information is carried in an acknowledgement (ACK) frame or a block acknowledgement (BA) frame.

15. The station of claim 10, wherein the feedback information is carried in a frame immediately subsequent to an ACK frame or a BA frame.

16. A method, comprising:

(a) transmitting a radio signal from a transmitting device to a plurality of receiving devices over a wide channel in an OFDMA wireless system, wherein the radio signal is transmitted over multiple sub-channels of the wide channel;

(b) receiving feedback information from the plurality of receiving devices, wherein the feedback information contains the estimated channel quality information for a subset of sub-channels from the wide channel for each receiving device; and

(c) selecting corresponding sub-channels for data transmission to the plurality of receiving devices based on the feedback information.

17. The method of claim 16, the channel quality information comprises an average signal to noise ratio (SNR) of a selected sub-channel.

18. The method of claim 16, further comprising:

determining a channel quality threshold such that the channel quality of each sub-channels from the subset of sub-channels is above the threshold.

19. The method of claim 16, further comprising:

transmitting a channel state information (CSI) feedback request for an MU-MIMO sub-channel; and

receiving a channel matrix report of the MU-MIMO sub-channel.

20. The method of claim 16, wherein the radio signal contains both OFDMA data field for multiple sub-channels and multiple training fields for channel sounding.

21. The method of claim 16, wherein the feedback information is carried in an acknowledgement (ACK) frame or a block acknowledgement (BA) frame.

22. The method of claim 16, wherein the feedback information is carried in a frame immediately subsequent to an ACK frame or a BA frame.