METHODS AND APPARATUS FOR CHANNEL ESTIMATION AND RATE FEEDBACK IN A PEER TO PEER NETWORK

• US 20090016285A1
• Filed: 07/02/2008
• Published: 01/15/2009
• Est. Priority Date: 07/10/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tavildar, Saurabh, Laroia, Rajiv, Wu, Xinzhou, Li, Junyi
• Granted Patent: US 8,687,479 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0023 characterised by the signalling
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0033 each allocating device acting autonomously, i.e. without negotiation with other allocating devices
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 28/0231 based on communication conditions dynamic wireless traffic scheduling definition based on channel quality criteria H04W72/54
• CPC Class Codes: H04W 28/0284 detecting congestion or overload during communication monitoring arrangements H04L43/00
• CPC Class Codes: H04W 28/12 using signalling between network elements
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

Methods and apparatus for performing channel estimation and reporting back channel information or other information such as a suggested traffic transmission rate are described. A signal including a pilot signal of interest is received. Portions of the signal corresponding to the pilot signal are analyzed to determine if any of the portions, e.g., signal portions corresponding to individual tone symbols used to communicate the pilot signal, were subject to excessive interference, such as might be the result of collisions, rendering the signal portions unreliable. Signal sub-portions determined to be unreliable are excluded from a determination of the amount of pilot signal energy that was received. Signal interference is determined from a portion of the received signal on which the pilot signal was not transmitted. Channel information in the form of information and/or a suggested traffic rate may be reported back to the device which transmitted the pilot signal.

Claims

1. A communications method, comprising:

identifying a first subset of communications resources out of a larger set of communications resources;

receiving on the larger set of communications resources a signal;

determining based on received energy corresponding to individual sub-portions of the received signal if one or more sub-portions of the received signal are reliable, said signal sub-portions corresponding to a first portion of said signal having been received on the first subset of communications resources; and

generating a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset.

2. The method of claim 1, wherein said communications resources are individual tone-symbols.

3. The method of claim 1, wherein identifying a first subset of communications resources includes:

selecting, as said first subset, resources corresponding to a device identifier of a peer to peer communications device implementing said method.

4. The method of claim 1, wherein identifying a first subset of communications resources includes:

selecting, as said first subset, resources corresponding to a connection identifier corresponding to a peer to peer communications device implementing said method.

5. The method of claim 1, wherein determining based on the received energy corresponding to individual sub-portions of the received signal if one or more sub-portions of the received signal are reliable includes:

generating an estimate of the average power per signal sub-portion corresponding to the first portion of said signal corresponding to the first subset of communications resources; and

determining that sub-portions having a sub-portion signal power within a threshold range of said average power are reliable.

6. The method of claim 1, wherein generating a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset includes:

generating a power estimate of a signal of interest based on the sub-portions determined to be reliable.

7. The method of claim 6, wherein generating a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset further includes:

generating a power estimate of interference based on received energy of the second portion of said signal.

8. The method of claim 7, wherein generating a channel quality estimate further includes:

generating a ratio of said power estimate of the signal of interest and the power estimate of interference.

9. The method of claim 7, further comprising:

identifying a second set of communications resources; and

transmitting, on the second set of communications resources, the channel quality estimate to a peer communications device from which said signal of interest was received.

10. The method of claim 7, further comprising:

selecting a transmission rate to be used for data transmission by a peer communications device from which a signal of interest was received.

11. The method of claim 10, further comprising:

identifying a second set of communications resources; and

transmitting to a peer communications device from which the signal of interest was received, on the second set of communications resources, the rate to be used for data transmission.

12. A communications device, comprising:

a resource identification module configured to identify a first subset of communications resources out of a larger set of communications resources;

a receiver configured to receive a signal on the larger set of communications resources;

a reliability determination module configured to determine based on the received energy corresponding to individual sub-portions of the received signal if one or more sub-portions of the received signal are reliable, said signal sub-portions corresponding to a first portion of said signal having been received on the first subset of communications resources; and

a channel quality estimate generation module configured to generate a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset.

13. The communications device of claim 12, wherein said communications resources are individual tone-symbols.

14. The communications device of claim 12, wherein the resource identification module includes:

a device identifier based selection sub-module configured to select, as said first subset, resources corresponding to a device identifier of said communications device.

15. The communications device of claim 12, wherein the resource identification module includes:

a connection identifier based selection sub-module configured to select, as said first subset, resources corresponding to a connection identifier corresponding to said communications device.

16. The communications device of claim 12, wherein said reliability determination module includes:

an average power estimation module for estimating the average power per signal sub-portion corresponding to the first portion of said signal corresponding to the first subset of communications resources; and

a threshold comparison module for determining which sub-portions have a sub-portion signal power within a threshold range of said average power, said sub-portions determined to have a sub-portion signal power within a threshold range of said average power being determined to be reliable.

17. The communications device of claim 12, wherein said channel quality estimate generation module includes:

a signal of interest power estimation module for generating a power estimate of a signal of interest based on the sub-portions determined to be reliable.

18. The communications device of claim 17, wherein said channel quality estimate generation module further includes:

an interference estimation module configured to generate a power estimate of interference based on received energy of the second portion of said signal.

19. The communications device of claim 18, wherein said channel quality estimate generation module includes:

a signal power to interference ratio generation module configured to generate a ratio of said power estimate of the signal of interest and the power estimate of interference.

20. The communications device of claim 18, further comprising:

a control resource determination module for selecting a second set of communications resources to be used for communicating control signals; and

a transmitter module configured to transmit on the second set of communications resources, a generated channel quality estimate to a peer communications device from which said signal of interest was received.

21. The communications device of claim 18, further comprising:

a transmission rate selection module configured to select a transmission rate to be used for data transmission by a peer communications device from which a signal of interest was received.

22. The communications device of claim 21, further comprising:

a control resource determination module for selecting a second set of communications resources to be used for communicating control signals; and

a transmitter module configured to transmit to a peer communications device from which said signal of interest was received, on the second set of communications resources, the rate to be used for data transmission.

23. A communications device, comprising:

resource identification means for identifying a first subset of communications resources out of a larger set of communications resources;

receiver means for receiving a signal on the larger set of communications resources;

reliability determination means for determining, based on the received energy corresponding to individual sub-portions of the received signal, if one or more sub-portions of the received signal are reliable, said signal sub-portions corresponding to a first portion of said signal having been received on the first subset of communications resources; and

channel quality estimate generation means for generating a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset.

24. The communications device of claim 23, wherein said communications resources are individual tone-symbols.

25. The communications device of claim 23, wherein the resource identification means includes:

device identifier based selection means for selecting, as said first subset, resources corresponding to a device identifier of said communications device.

26. A computer program product for use in a communications device, comprising:

computer readable medium comprising;

code for causing a computer to identify a first subset of communications resources out of a larger set of communications resources;

code for causing a computer to receive on the larger set of communications resources a signal;

code for causing a computer to determine based on the received energy corresponding to individual sub-portions of the received signal if one or more sub-portions of the received signal are reliable, said signal sub-portions corresponding to a first portion of said signal having been received on the first subset of communications resources; and

code for causing a computer to generate a channel quality estimate based on the sub-portions determined to be reliable and a second portion of said signal corresponding to communication resources in said larger set of communications resources which are not included in said first subset.

27. The computer program product of claim 26, wherein the computer readable medium further comprises:

code for causing a computer to select, as said first subset, resources corresponding to a device identifier of the communications device.

28. The computer program product of claim 26, wherein the computer readable medium further comprises:

code for causing a computer to select, as said first subset, resources corresponding to a connection identifier corresponding to the communications device.