TECHNIQUES FOR CHOOSING AND BROADCASTING RECEIVER BEAMFORMING VECTORS IN PEER-TO-PEER (P2P) NETWORKS

• US 20090019150A1
• 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, Laroia, Rajiv, Wu, Xinzhou, Li, Junyi
• Granted Patent: US 8,078,110 B2
• Time in Patent Office: Days
• US Class Current: 709/224
• 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: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

One feature provides for establishing an ad hoc peer-to-peer network over an existing channel allocation for another network. To mitigate interference between multiple peer-to-peer devices, a plurality of receiver chains in a receiver device may be configured with beamforming coefficients so as to focus reception in the direction of an intended signal from a transmitter device while minimizing reception from other directions. Similarly, the receiver device may also use a plurality of antennas and a transmitter chain to beamform in the direction of the transmitter device, thereby focusing its transmission toward the transmitter device. The receiver device may also notify nearby devices that it is employing a plurality of receive antennas. This information can be used by the nearby devices to more intelligently perform transmitter yielding. By utilizing beamforming information to make the transmitter and/or receiver yielding decision, better interference mitigation may be achieved.

Claims

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

operating a plurality of receive chains each being coupled with one of the plurality of antennas;

receiving a first transmission request signal from the first device, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device, and the first transmission request signal being received in each of the plurality of antennas using the receive chains;

monitoring 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, and the second transmission request signal being received in each of the plurality of antennas;

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

transmitting 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.

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 antennas;

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

decoding the combined traffic signal.

3. The method of claim 2, wherein the second device is equipped with a plurality of transmit chains each being coupled with one of the plurality of antenna, and wherein the request response signal is transmitted via the transmit chains with the plurality of antennas, the method further comprising:

multiplying the request response signal with each of the plurality of receive beamforming coefficients to generate a weighted request response signal; and

transmitting each weighted request response signal with the corresponding one of the plurality of antennas.

4. The method of claim 2, wherein the second device is equipped with one transmit chain being connected via a switch to be coupled with one of the plurality of antenna at any given time, and wherein the request response signal is transmitted via the transmit chain with the plurality of antennas, the method further comprising:

multiplying the request response signal with a first one of the plurality of receive beamforming coefficients to generate a first weighted request response signal;

switching the transmit chain to be coupled with one of the plurality of antennas corresponding to the first one of the plurality of receive beamforming coefficients;

transmitting the first weighted request response signal with the corresponding one of the plurality of antennas in a first request response transmission time slot;

multiplying the request response signal with a second one of the plurality of receive beamforming coefficients to generate a second weighted request response signal; and

switching the transmit chain to be coupled with one of the plurality of antennas corresponding to the second one of the plurality of receive beamforming coefficients; and

transmitting the second weighted request response signal with the corresponding one of the plurality of antennas in a second request response transmission time slot, the second request response transmission time slot being subsequent to the first request response transmission time slot.

5. The method of claim 2, wherein the second device is equipped with one transmit chain being coupled to a first antenna from the plurality of antennas, and wherein the request response signal is transmitted via the transmit chain coupled to the first antenna.

6. The method of claim 5, further comprising:

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

combining 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 and the power of the combined second transmission request signal;

determining whether the calculated power ratio is acceptable by comparing the calculated power ratio with a threshold; and

sending a control message to the third device, the control message indicating that the third device is allowed to proceed to transmit a traffic signal, if it is determined that the calculated power ratio is acceptable.

7. The method of claim 5, further comprising:

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

calculating the power of the combined first transmission request signal;

calculating the spatial correlation coefficient of the first and second transmission request signals received from the plurality of receive antennas; and

determining the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and the spatial correlation coefficient.

8. The method of claim 7, wherein the transmission power of the request response signal is set to be the power of the combined first transmission request signal multiplied by the spatial correlation.

9. The method of claim 7, further comprising:

monitoring to receive a third transmission request signal in each of the plurality of antennas, the third transmission request signal being transmitted by another transmitter device and indicating that the another transmitter device intends to transmit a traffic signal to yet another receiver device;

calculating the spatial correlation coefficient of the first and third transmission request signals received from the plurality of receive antennas; and

determining the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and maximum of the spatial correlation coefficient of the first and second transmission request signals and the spatial correlation coefficient of the first and third transmission request signals.

10. 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 antennas; and

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

operate a plurality of receive chains each being coupled with one of the plurality of antennas;

receive a first transmission request signal from the first device, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device, and the first transmission request signal being received in each of the plurality of antennas using the receive chains;

monitor 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, and the second transmission request signal being received in each of the plurality of antennas;

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

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.

11. The second device of claim 10, 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 antennas;

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

decode the combined traffic signal.

12. The second device of claim 11, wherein each of the plurality of transmit chains is coupled to one of the plurality of antenna, and wherein the request response signal is transmitted via the transmit chains with the plurality of antennas, wherein the processing circuit is further configured to:

multiply the request response signal with each of the plurality of receive beamforming coefficients to generate a weighted request response signal; and

transmit each weighted request response signal with the corresponding one of the plurality of antennas.

13. The second device of claim 11, further comprising

a transmit chain selectively coupled via a switch to one of the plurality of antenna at any given time, and wherein the request response signal is transmitted via the transmit chain with the plurality of antennas, wherein the processing circuit is further configured to:

multiply the request response signal with a first one of the plurality of receive beamforming coefficients to generate a first weighted request response signal;

switch the transmit chain to be coupled with one of the plurality of antennas corresponding to the first one of the plurality of receive beamforming coefficients;

transmit the first weighted request response signal with the corresponding one of the plurality of antennas in a first request response transmission time slot;

multiply the request response signal with a second one of the plurality of receive beamforming coefficients to generate a second weighted request response signal;

switch the transmit chain to be coupled with one of the plurality of antennas corresponding to the second one of the plurality of receive beamforming coefficients; and

transmit the second weighted request response signal with the corresponding one of the plurality of antennas in a second request response transmission time slot, the second request response transmission time slot being subsequent to the first request response transmission time slot.

14. The second device of claim 11, further comprising:

a transmit chain coupled to a first antenna from the plurality of antennas, and wherein the request response signal is transmitted via the transmit chain coupled to the first antenna.

15. The second device of claim 14, wherein the processing circuit is further configured to:

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

combine 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 and the power of the combined second transmission request signal;

determine whether the calculated power ratio is acceptable by comparing the calculated power ratio with a threshold; and

send a control message to the third device, the control message indicating that the third device is allowed to proceed to transmit a traffic signal, if it is determined that the calculated power ratio is acceptable.

16. The second device of claim 14, wherein the processing circuit is further configured to:

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

calculate the power of the combined first transmission request signal;

calculate the spatial correlation coefficient of the first and second transmission request signals received from the plurality of receive antennas; and

determine the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and the spatial correlation coefficient.

17. The second device of claim 16, wherein the transmission power of the request response signal is set to be the power of the combined first transmission request signal multiplied by the spatial correlation.

18. The second device of claim 16, wherein the processing circuit is further configured to:

monitor to receive a third transmission request signal in each of the plurality of antennas, the third transmission request signal being transmitted by another transmitter device and indicating that the another transmitter device intends to transmit a traffic signal to yet another receiver device;

calculate the spatial correlation coefficient of the first and third transmission request signals received from the plurality of receive antennas; and

determine the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and maximum of the spatial correlation coefficient of the first and second transmission request signals and the spatial correlation coefficient of the first and third transmission request signals.

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

means for operating a plurality of receive chains each being coupled with one of a plurality of antennas;

means for receiving a first transmission request signal from the first device, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device, and the first transmission request signal being received in each of the plurality of antennas using the receive chains;

means for monitoring 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, and the second transmission request signal being received in each of the plurality of antennas;

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

means for transmitting 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.

20. The second device of claim 19, further comprising:

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

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

means for decoding the combined traffic signal.

21. The second device of claim 20, further comprising:

a plurality of transmit chains each being coupled with one of the plurality of antenna, and wherein the request response signal is transmitted via the transmit chains with the plurality of antennas;

means for multiplying the request response signal with each of the plurality of receive beamforming coefficients to generate a weighted request response signal; and

means for transmitting each weighted request response signal with the corresponding one of the plurality of antennas.

22. The second device of claim 20, further comprising:

a transmit chain;

means for multiplying the request response signal with a first one of the plurality of receive beamforming coefficients to generate a first weighted request response signal;

means for switching the transmit chain to be coupled with one of the plurality of antennas corresponding to the first one of the plurality of receive beamforming coefficients;

means for transmitting the first weighted request response signal with the corresponding one of the plurality of antennas in a first request response transmission time slot;

means for multiplying the request response signal with a second one of the plurality of receive beamforming coefficients to generate a second weighted request response signal; and

means for switching the transmit chain to be coupled with one of the plurality of antennas corresponding to the second one of the plurality of receive beamforming coefficients; and

means for transmitting the second weighted request response signal with the corresponding one of the plurality of antennas in a second request response transmission time slot, the second request response transmission time slot being subsequent to the first request response transmission time slot.

23. The second device of claim 20, further comprising:

a transmit chain coupled to a first antenna from the plurality of antennas, and wherein the request response signal is transmitted via the transmit chain coupled to the first antenna.

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

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

means for combining 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 and the power of the combined second transmission request signal;

means for determining whether the calculated power ratio is acceptable by comparing the calculated power ratio with a threshold; and

means for sending a control message to the third device, the control message indicating that the third device is allowed to proceed to transmit a traffic signal, if it is determined that the calculated power ratio is acceptable.

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

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

means for calculating the power of the combined first transmission request signal;

means for calculating the spatial correlation coefficient of the first and second transmission request signals received from the plurality of receive antennas; and

means for determining the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and the spatial correlation coefficient.

26. The second device of claim 25, further comprising:

means for monitoring to receive a third transmission request signal in each of the plurality of antennas, the third transmission request signal being transmitted by another transmitter device and indicating that the another transmitter device intends to transmit a traffic signal to yet another receiver device;

means for calculating the spatial correlation coefficient of the first and third transmission request signals received from the plurality of receive antennas; and

means for determining the transmission power of the request response signal transmitted to the first device as a function of the power of the combined first transmission request signal and maximum of the spatial correlation coefficient of the first and second transmission request signals and the spatial correlation coefficient of the first and third transmission request signals.

27. A circuit for facilitating peer-to-peer communications and beamforming, wherein the circuit operates in a second device having a plurality of antennas for facilitating a wireless peer-to-peer connection with a first device, wherein the circuit is adapted to:

operate a plurality of receive chains each being coupled with one of the plurality of antennas;

receive a first transmission request signal from the first device, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device, and the first transmission request signal being received in each of the plurality of antennas using the receive chains;

monitor 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, and the second transmission request signal being received in each of the plurality of antennas;

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

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.

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

operate a plurality of receive chains each being coupled with one of the plurality of antennas;

receive a first transmission request signal from the first device, the first transmission request signal indicating that the first device intends to transmit a traffic signal to the second device, and the first transmission request signal being received in each of the plurality of antennas using the receive chains;

monitor 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, and the second transmission request signal being received in each of the plurality of antennas;

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

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.

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

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

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

adding the received second and third response signals to form a combined signal;

calculating the power of the combined signal;

calculating an interference cost to the first device, the interference cost being a function of the calculated power of the combined signal;

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

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

30. The method of claim 29, further comprising:

prior to receiving the second and third request response signals, receiving a control message, the control message indicating that the second device is capable of receive beamforming.

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

32. 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;

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

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

add the received second and third response signals to form a combined signal;

calculate the power of the combined signal;

calculate an interference cost to the first device, the interference cost being a function of the calculated power of the combined 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.

33. The third device of claim 32, the processing circuit further configured to:

receiving a control message, the control message indicating that the second device is capable of receive beamforming.

34. The third device of claim 32, wherein the control message includes information indicative of the number of the plurality of receive antennas equipped at the second device.

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

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

means for adding the received second and third response signals to form a combined signal;

means for calculating the power of the combined signal;

means for calculating an interference cost to the first device, the interference cost being a function of the calculated power of the combined 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, further comprising:

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

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:

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

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

add the received second and third response signals to form a combined signal;

calculate the power of the combined signal;

calculate an interference cost to the first device, the interference cost being a function of the calculated power of the combined 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 circuit is further adapted to:

receive a control message, the control message indicating that the second device is capable of receive beamforming.

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:

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

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

add the received second and third response signals to form a combined signal;

calculate the power of the combined signal;

calculate an interference cost to the first device, the interference cost being a function of the calculated power of the combined 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, further comprising instructions which when executed by a processor causes the processor to:

receive a control message, the control message indicating that the second device is capable of receive beamforming.