Full duplex system in massive MIMO

Patent metadata

Field	Value
Publication number	US-9294259-B2
Application number	US-201314042107-A
Country	US
Kind code	B2
Filing date	Sep 30, 2013
Priority date	Sep 30, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A multiple input multiple output (MIMO) antenna system is implemented for communications in a wireless device. MIMO beamforming techniques are utilized to improve communications, and may be utilized in full-duplex mode. Techniques include the formation of beamforming patterns having orthogonal polarizations to one another at each communication device, but having matching polarization between transmit/receive pairs located at each respective communication device. Techniques also include the formation of beamforming patterns in a direction towards another communication device to maximize transmit power in that direction while inducing nulls in the beamforming pattern to reduce self-interference coupling via antennas configured for reception. Full-duplex communications are improved through monitoring of the self-interference coupling and adapting the beamforming patterns to reduce it. Beamforming vectors may be generated by solving a cost function that may include an additional constraint of reduction of self-interference coupling.

First claim

What is claimed is:

1. A communication device having a plurality of antennas, comprising:
a beamforming module configured to apply a beamforming matrix to a plurality of signals and to couple the plurality of signals to corresponding radio frequency (RF) chains from among a plurality of RF chains;
a coupling module configured to couple the plurality of signals from the corresponding RF chains to corresponding antennas from among the plurality of antennas of the communication device; and
a decision module configured to control the beamforming module to apply the beamforming matrix to the plurality of signals to form first and second beamforming patterns,
wherein the first beamforming pattern is configured to transmit a first signal to a second communication device using a first subset of antennas from among the plurality of antennas of the communication device,
wherein the second beamforming pattern is configured to receive a second signal from the second communication device using a second subset of antennas from among the plurality of antennas of the communication device, and
wherein the decision module is further configured to calculate the beamforming matrix to shape the first beamforming pattern to direct a null toward the second subset of antennas.

2. The communication device of claim 1 , wherein the plurality of RF chains is configured to facilitate full-duplex communications between the communication device and the second communication device, and
wherein the full-duplex communications occur within a Long-Term Evolution (LTE) frequency band.

3. The communication device of claim 1 , wherein the coupling module is further configured to couple a transmit port and a receive port of the plurality of RF chains to a common respective antenna from among the first subset of antennas and the second subset of antennas.

4. The communication device of claim 1 , wherein the first and second beamforming patterns are generated from the first and second subsets of antennas, respectively, and
wherein the first and second subsets of antennas are separate from one another.

5. The communication device of claim 1 , wherein the first and second beamforming patterns are generated from the first and second subsets of antennas, respectively, and
wherein the first and second subsets of antennas share a common antenna.

6. The communication device of claim 1 , wherein the first and second beamforming patterns are generated from the first and second subsets of antennas, respectively, and wherein the first and second subsets of antennas share identical antennas from among the plurality of antennas of the communication device.

7. The communication device of claim 1 , wherein the first and second beamforming patterns are generated from the first and second subsets of antennas, respectively,
wherein the first and second subsets of antennas communicate respectively with third and fourth, subsets of antennas from among a second plurality of antennas of the second communication device, and
wherein the third and fourth subsets of antennas have substantially the same polarizations as the first and second subsets of antennas, respectively.

8. The communication device of claim 1 , wherein the decision module is further configured to adjust the beamforming matrix based upon a comparison of a communication signal performance metric for the first signal and a threshold value.

9. The communication device of claim 8 , wherein the communication performance metric comprises:
a signal-to-noise-plus-interference ratio (SINR), and
wherein the decision module is configured to adjust the beamforming matrix when the SNR is less than the threshold value.

10. The communication device of claim 8 , wherein the communication performance metric is indicative of a source of interference, and
wherein the decision module is configured to adjust the beamforming matrix when a received signal strength indication (RSSI) associated with the source of interference is greater than the threshold value.

11. The communication device of claim 8 , wherein the communication performance metric comprises:
a self-interference coupling factor, and
wherein the decision module is configured to adjust the beamforming matrix when the self-interference coupling factor is greater than the threshold value.

12. The communication device of claim 8 , wherein the decision module is configured to receive the communication signal performance metric from the second communication device.

13. The communication device of claim 12 , wherein the communication performance metric comprises:
a signal strength of the first signal as received by the second communication device, and
wherein the decision module is configured to adjust the beamforming matrix when the signal strength is less than the threshold value.

14. In a communication device having a plurality of antennas, a method of selecting antennas from among the plurality of antennas of the communication device within a multiple-input multiple-output (MIMO) system for communications with a base station, the method comprising:
coupling respective signals of a set of a plurality of radio frequency (RF) chains to corresponding first and second subsets of antennas from among the plurality of antennas of the communication device;
applying a beamforming matrix to the respective signals to generate a first beamforming pattern for uplink transmissions to the base station via the first subset of antennas and a second beamforming pattern for downlink transmissions from the base station via the second subset of antennas, the beamforming matrix shaping the first beamforming pattern to direct a null toward the second subset of antennas; and
adjusting the beamforming matrix based upon a comparison of a communication signal performance metric for the uplink transmissions or the downlink transmissions and a threshold value.

15. The method of claim 14 , wherein the applying the beamforming matrix facilitates the uplink and downlink transmissions in full-duplex mode.

16. The method of claim 14 , further comprising:
adjusting the beamforming matrix to increase signal power received at the base station via the uplink transmissions when the communication signal performance metric for the uplink transmissions falls below the threshold value.

17. The method of claim 14 , further comprising:
adjusting the beamforming matrix to increase signal power received at the communication device via the downlink transmissions when the communication signal performance metric for the downlink transmission falls below the threshold value.

18. The method of claim 14 , further comprising:
adjusting the beamforming matrix to reduce a self-interference coupling factor when the communication signal performance metric for the uplink transmissions or the downlink transmissions is above the threshold value.

19. The method of claim 14 , further comprising:
adjusting the beamforming matrix to reduce interference received from other base stations when the communication signal performance metric for the uplink transmissions or the downlink transmissions is above the threshold value.

20. A communication device having a plurality of antennas, comprising:
a beamforming module configured to apply a beamforming matrix to a plurality of signals and to couple the plurality of signals to corresponding radio frequency (RF) chains from among a plurality of RF chains;
a coupling module configured to couple the plurality of signals from the corresponding RF chains to correspondi

Assignees

• Broadcom Corp

Inventors

• Jalloul Louay
• Mobasher Amin
• Alex Sam

Classifications

• H04B7/0617

  for beam forming · CPC title

• H04L5/143

  for modulated signals (H04L5/1469 takes precedence) · CPC title

• H04L5/1461 Primary

  Suppression of signals in the return path, i.e. bidirectional control circuits · CPC title

• H04B7/10

  Polarisation diversity; Directional diversity · CPC title