TECHNIQUES FOR RECEIVER BEAMFORMING AND YIELDING-THRESHOLD ADJUSTMENTS IN PEER-TO-PEER NETWORKS

• US 20090015478A1
• Filed: 07/07/2008
• Published: 01/15/2009
• Est. Priority Date: 07/09/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jovicic, Aleksandar, Richardson, Thomas, Wu, Xinzhou, Li, Junyi
• Granted Patent: US 8,270,923 B2
• Time in Patent Office: Days
• US Class Current: 342/377
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/54 based on quality criteria

Abstract

To mitigate interference between multiple peer-to-peer devices, transmitter yielding and/or receiver yielding may be performed among devices operating in a peer-to-peer network. Generally, a transmitter device will yield communications on a time slot to a higher priority transmitter device if it will cause unacceptable interference to a higher priority receiver device. Likewise, a receiver device may yield use of the time slot if interference is unacceptably high. Both transmitter and receiver yielding may be improved by use of beamforming at a receiver device. By utilizing beamforming information to make the transmitter and/or receiver yielding decisions, better interference mitigation may be achieved.

Claims

1. A method of operating a second device equipped with a plurality of receive antennas for facilitating a wireless peer-to-peer connection with a first device, comprising:

receiving a first pilot signal from the first device over a shared frequency spectrum, the first pilot signal being received in each of the plurality of receive antennas;

determining a plurality of receive beamforming coefficients as a function of the received first pilot signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

calculating a signal-to-interference ratio of the first pilot signal by combining the first pilot signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients; and

sending a rate report signal to the first device, the rate report including control information determined by the signal-to-interference ratio of the first pilot signal.

2. The method of claim 1, further comprising:

receiving a traffic signal from the first device, the traffic signal being received in each of the plurality of receive antennas;

combining the traffic signal received from the plurality of receive antennas using the plurality of receive beamforming coefficients; and

decoding the combined traffic signal.

3. The method of claim 1, wherein the plurality of receive beamforming coefficients are determined to maximize the signal power of the combined first pilot signal when the plurality of receive beamforming coefficients are used to combine the first pilot signal received from the plurality of receive antennas.

4. The method of claim 1, further comprising:

receiving a second pilot signal from a third device, the second pilot signal being received in each of the plurality of receive antennas and representing interference to the second device; and

wherein the plurality of receive beamforming coefficients are determined also as a function of the received second pilot signals in each of the plurality of receive antennas.

5. The method of claim 4, wherein the plurality of receive beamforming coefficients are determined to minimize the interference power of the combined second pilot signal when the plurality of receive beamforming coefficients are used to combine the second pilot signal received from the plurality of receive antennas.

6. The method of claim 4, wherein the plurality of receive beamforming coefficients are determined to maximize the ratio of the signal power to the interference power, the signal power being the power of the combined first pilot signal and the interference power being the power of the combined second pilot signal when the plurality of receive beamforming coefficients are used to combine respectively the first and second pilot signals received from the plurality of receive antennas.

7. The method of claim 1, further comprising:

prior to receiving the first pilot signal, receiving a first transmission request signal from the first device over the shared frequency spectrum, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device;

monitoring the shared frequency spectrum to receive a second transmission request signal, the second transmission request signal being transmitted by a third device and indicating that the third device intends to transmit a traffic signal to a fourth device;

determining whether to transmit a request response signal to the first device, the request response signal indicating that the second device is ready to receive a traffic signal from the first device, as a function of the received power of the first and second transmission request signals; and

transmitting the request response signal to the first device if it is determined to transmit a request response signal.

8. The method of claim 7, wherein an instance of the first transmission request signal is received in each of the plurality of receive antennas and instance of the second transmission request signal is received in each of the plurality of receive antennas, the method further comprising:

determining a plurality of receive beamforming coefficients as a function of the received instances of the first and second transmission request signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

combining the instances of the first transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

combining the instances of the second transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

calculating the ratio of the power of the combined first transmission request signal to the power of the combined second transmission request signal; and

wherein whether to transmit a request response signal to the first device is determined as a function of the power ratio.

9. The method of claim 7, further comprising:

calculating the ratio of the received power of the first transmission request signal and the received power of the second transmission request signal; and

wherein it is determined to transmit a request response signal to the first device if the calculated power ratio is greater than or equal to a receiver yielding threshold.

10. The method of claim 9, wherein the value of the receiver yielding threshold depends on the number of the plurality of receive antennas, the value of the receiver yielding threshold decreasing as the number of receive antennas increases.

11. The method of claim 7, further comprising:

sending a control message to the third device, the control message including control information indicating that the second device is capable of receive beamforming and the control information also including the number of the plurality of receive antennas equipped at the second device.

12. A second device configured to communicate with a first device within a wireless peer-to-peer communication network, comprising:

a transmitter and receiver for establishing a wireless peer-to-peer communication connection with the first device;

a plurality of receive antennas coupled to the receiver; and

a processing circuit coupled to the transmitter and receiver, the processing circuit configured to;

receive a first pilot signal from the first device over a shared frequency spectrum, the first pilot signal being received in each of the plurality of receive antennas;

determine a plurality of receive beamforming coefficients as a function of the received first pilot signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

calculate a signal-to-interference ratio of the first pilot signal by combining the first pilot signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients; and

send a rate report signal to the first device, the rate report including control information determined by the signal-to-interference ratio of the first pilot signal.

13. The second device of claim 12, wherein the processing circuit is further configured to:

receive a traffic signal from the first device, the traffic signal being received in each of the plurality of receive antennas;

combine the traffic signal received from the plurality of receive antennas using the plurality of receive beamforming coefficients; and

decode the combined traffic signal.

14. The second device of claim 12, wherein the plurality of receive beamforming coefficients are determined to maximize the signal power of the combined first pilot signal when the plurality of receive beamforming coefficients are used to combine the first pilot signal received from the plurality of receive antennas.

15. The second device of claim 12, wherein the processing circuit is further configured to:

receive a second pilot signal from a third device, the second pilot signal being received in each of the plurality of receive antennas and representing interference to the second device; and

wherein the plurality of receive beamforming coefficients are determined also as a function of the received second pilot signals in each of the plurality of receive antennas.

16. The second device of claim 15, wherein the plurality of receive beamforming coefficients are determined to minimize the interference power of the combined second pilot signal when the plurality of receive beamforming coefficients are used to combine the second pilot signal received from the plurality of receive antennas.

17. The second device of claim 15, wherein the plurality of receive beamforming coefficients are determined to maximize the ratio of the signal power to the interference power, the signal power being the power of the combined first pilot signal and the interference power being the power of the combined second pilot signal when the plurality of receive beamforming coefficients are used to combine respectively the first and second pilot signals received from the plurality of receive antennas.

18. The second device of claim 12, wherein the processing circuit is further configured to:

receive a first transmission request signal from the first device over the shared frequency spectrum prior to receiving the first pilot signal, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device;

monitor the shared frequency spectrum to receive a second transmission request signal, the second transmission request signal being transmitted by a third device and indicating that the third device intends to transmit a traffic signal to a fourth device;

determine whether to transmit a request response signal to the first device, the request response signal indicating that the second device is ready to receive a traffic signal from the first device, as a function of the received power of the first and second transmission request signals; and

transmit the request response signal to the first device if it is determined to transmit a request response signal.

19. The second device of claim 18, wherein an instance of the first transmission request signal is received in each of the plurality of receive antennas and instance of the second transmission request signal is received in each of the plurality of receive antennas, the processing circuit is further configured to:

determine a plurality of receive beamforming coefficients as a function of the received instances of the first and second transmission request signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

combine the instances of the first transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

combine the instances of the second transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

calculate the ratio of the power of the combined first transmission request signal to the power of the combined second transmission request signal; and

wherein whether to transmit a request response signal to the first device is determined as a function of the power ratio.

20. The second device of claim 18, wherein the processing circuit is further configured to:

calculate the ratio of the received power of the first transmission request signal and the received power of the second transmission request signal; and

wherein it is determined to transmit a request response signal to the first device if the calculated power ratio is greater than or equal to a receiver yielding threshold.

21. The second device of claim 20, wherein the value of the receiver yielding threshold depends on the number of the plurality of receive antennas, the value of the receiver yielding threshold decreasing as the number of receive antennas increases.

22. The second device of claim 18, wherein the processing circuit is further configured to:

send a control message to the third device, the control message including control information indicating that the second device is capable of receive beamforming and the control information also including the number of the plurality of receive antennas equipped at the second device.

23. A second device equipped with a plurality of receive antennas for facilitating a wireless peer-to-peer connection with a first device, comprising:

means for receiving a first pilot signal from the first device over a shared frequency spectrum, the first pilot signal being received in each of the plurality of receive antennas;

means for determining a plurality of receive beamforming coefficients as a function of the received first pilot signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

means for calculating a signal-to-interference ratio of the first pilot signal by combining the first pilot signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients; and

means for sending a rate report signal to the first device, the rate report including control information determined by the signal-to-interference ratio of the first pilot signal.

24. The second device of claim 23, further comprising:

means for receiving a traffic signal from the first device, the traffic signal being received in each of the plurality of receive antennas;

means for combining the traffic signal received from the plurality of receive antennas using the plurality of receive beamforming coefficients; and

means for decoding the combined traffic signal.

25. The second device of claim 23, wherein the plurality of receive beamforming coefficients are determined to maximize the signal power of the combined first pilot signal when the plurality of receive beamforming coefficients are used to combine the first pilot signal received from the plurality of receive antennas.

26. The second device of claim 23, further comprising:

means for receiving a first transmission request signal from the first device over the shared frequency spectrum prior to receiving the first pilot signal, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device;

means for monitoring the shared frequency spectrum to receive a second transmission request signal, the second transmission request signal being transmitted by a third device and indicating that the third device intends to transmit a traffic signal to a fourth device;

means for determining whether to transmit a request response signal to the first device, the request response signal indicating that the second device is ready to receive a traffic signal from the first device, as a function of the received power of the first and second transmission request signals; and

means for transmitting the request response signal to the first device if it is determined to transmit a request response signal.

27. The second device of claim 26, wherein an instance of the first transmission request signal is received in each of the plurality of receive antennas and instance of the second transmission request signal is received in each of the plurality of receive antennas, the method further comprising:

means for determining a plurality of receive beamforming coefficients as a function of the received instances of the first and second transmission request signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

means for combining the instances of the first transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

means for combining the instances of the second transmission request signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients;

means for calculating the ratio of the power of the combined first transmission request signal to the power of the combined second transmission request signal; and

wherein whether to transmit a request response signal to the first device is determined as a function of the power ratio.

28. A circuit for interference mitigation in a peer-to-peer network, wherein the circuit operates in a second device having a plurality of receive antennas for facilitating a wireless peer-to-peer connection with a first device, wherein the circuit is adapted to:

receive a first pilot signal from the first device over a shared frequency spectrum, the first pilot signal being received in each of the plurality of receive antennas;

determine a plurality of receive beamforming coefficients as a function of the received first pilot signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

calculate a signal-to-interference ratio of the first pilot signal by combining the first pilot signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients; and

send a rate report signal to the first device, the rate report including control information determined by the signal-to-interference ratio of the first pilot signal.

29. A machine-readable medium comprising instructions for a second device equipped with a plurality of receive antennas to facilitate a wireless peer-to-peer connection with a first device, which when executed by a processor causes the processor to:

receive a first pilot signal from the first device over a shared frequency spectrum, the first pilot signal being received in each of the plurality of receive antennas;

determine a plurality of receive beamforming coefficients as a function of the received first pilot signals in each of the plurality of receive antennas, each of the plurality of receive beamforming coefficients corresponding to one receive antenna;

calculate a signal-to-interference ratio of the first pilot signal by combining the first pilot signal received from the plurality of receive antennas using the determined plurality of receive beamforming coefficients; and

send a rate report signal to the first device, the rate report including control information determined by the signal-to-interference ratio of the first pilot signal.

30. A method of operational in a third device in a peer to peer communication network, the third device having a wireless peer-to-peer connection with a fourth device, comprising:

receiving a control message, the control message including control information indicating that a second device is capable of receive beamforming;

transmitting a first transmission request signal to the fourth device, the first transmission request signal indicating that the third device intends to transmit a traffic signal to the fourth device;

monitoring to receive a first request response signal from the fourth device, the first request response signal indicating that the fourth device is ready to receive a traffic signal from the third device;

monitoring to receive a second request response signal from the second device, the second request response signal indicating that the second device is ready to receive a traffic signal from a first device;

calculating an interference cost to the second device, the interference cost being a function of the received power of the second request response signal;

determining whether to transmit a traffic signal to the fourth device by comparing the calculated interference cost with a transmitter yielding threshold;

transmitting a traffic signal to the fourth device if it is determined to transmit a traffic signal.

31. The method of claim 30, wherein the control information also includes the number of receive antennas equipped at the second device.

32. The method of claim 31, wherein the value of the transmitter yielding threshold depends on the number of receive antennas of the second device, the value of the transmitter yielding threshold increasing as the number of receive antennas of the second device increases.

33. A third device having a wireless peer-to-peer connection with a fourth device, comprising:

a transmitter and receiver for establishing the wireless peer-to-peer connection with the fourth device; and

a processing circuit adapted to perform transmitter yielding within a peer-to-peer network, the processing circuit configured to;

receive a control message, the control message including control information indicating that a second device is capable of receive beamforming;

transmit a first transmission request signal to the fourth device, the first transmission request signal indicating that the third device intends to transmit a traffic signal to the fourth device;

monitor to receive a first request response signal from the fourth device, the first request response signal indicating that the fourth device is ready to receive a traffic signal from the third device;

monitor to receive a second request response signal from the second device, the second request response signal indicating that the second device is ready to receive a traffic signal from a first device;

calculate an interference cost to the second device, the interference cost being a function of the received power of the second request response signal;

determine whether to transmit a traffic signal to the fourth device by comparing the calculated interference cost with a transmitter yielding threshold; and

transmit a traffic signal to the fourth device if it is determined to transmit a traffic signal.

34. The third device of claim 33, wherein the control information also includes the number of receive antennas equipped at the second device, the value of the transmitter yielding threshold depends on the number of receive antennas of the second device, the value of the transmitter yielding threshold increasing as the number of receive antennas of the second device increases.

35. A third device having a wireless peer-to-peer connection with a fourth device, comprising:

means for receiving a control message, the control message including control information indicating that a second device is capable of receive beamforming;

means for transmitting a first transmission request signal to the fourth device, the first transmission request signal indicating that the third device intends to transmit a traffic signal to the fourth device;

means for monitoring to receive a first request response signal from the fourth device, the first request response signal indicating that the fourth device is ready to receive a traffic signal from the third device;

means for monitoring to receive a second request response signal from the second device, the second request response signal indicating that the second device is ready to receive a traffic signal from a first device;

means for calculating an interference cost to the second device, the interference cost being a function of the received power of the second request response signal;

means for determining whether to transmit a traffic signal to the fourth device by comparing the calculated interference cost with a transmitter yielding threshold; and

means for transmitting a traffic signal to the fourth device if it is determined to transmit a traffic signal.

36. The third device of claim 35, wherein the control information also includes the number of receive antennas equipped at the second device, the value of the transmitter yielding threshold depends on the number of receive antennas of the second device, the value of the transmitter yielding threshold increasing as the number of receive antennas of the second device increases.

37. A circuit for interference mitigation in a peer-to-peer network, wherein the circuit operates in a third device having a wireless peer-to-peer connection with a fourth device, wherein the circuit is adapted to:

receive a control message, the control message including control information indicating that a second device is capable of receive beamforming;

transmit a first transmission request signal to the fourth device, the first transmission request signal indicating that the third device intends to transmit a traffic signal to the fourth device;

monitor to receive a first request response signal from the fourth device, the first request response signal indicating that the fourth device is ready to receive a traffic signal from the third device;

monitor to receive a second request response signal from the second device, the second request response signal indicating that the second device is ready to receive a traffic signal from a first device;

calculate an interference cost to the second device, the interference cost being a function of the received power of the second request response signal;

determine whether to transmit a traffic signal to the fourth device by comparing the calculated interference cost with a transmitter yielding threshold; and

transmit a traffic signal to the fourth device if it is determined to transmit a traffic signal.

38. The circuit of claim 37, wherein the control information also includes the number of receive antennas equipped at the second device, the value of the transmitter yielding threshold depends on the number of receive antennas of the second device, the value of the transmitter yielding threshold increasing as the number of receive antennas of the second device increases.

39. A machine-readable medium comprising instructions for a third device to communicate with a fourth device within a wireless peer-to-peer communication network while performing transmitter yielding, which when executed by a processor causes the processor to:

receive a control message, the control message including control information indicating that a second device is capable of receive beamforming;

transmit a first transmission request signal to the fourth device, the first transmission request signal indicating that the third device intends to transmit a traffic signal to the fourth device;

monitor to receive a first request response signal from the fourth device, the first request response signal indicating that the fourth device is ready to receive a traffic signal from the third device;

monitor to receive a second request response signal from the second device, the second request response signal indicating that the second device is ready to receive a traffic signal from a first device;

calculate an interference cost to the second device, the interference cost being a function of the received power of the second request response signal;

determine whether to transmit a traffic signal to the fourth device by comparing the calculated interference cost with a transmitter yielding threshold; and

transmit a traffic signal to the fourth device if it is determined to transmit a traffic signal.

40. The machine-readable medium of claim 39, wherein the control information also includes the number of receive antennas equipped at the second device, the value of the transmitter yielding threshold depends on the number of receive antennas of the second device, the value of the transmitter yielding threshold increasing as the number of receive antennas of the second device increases.