Methods and systems for full duplex wireless communications

• US 10,116,426 B2
• Filed: 02/11/2013
• Issued: 10/30/2018
• Est. Priority Date: 02/09/2012
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Hua, Yingbo, Liang, Ping
• Primary Examiner(s): Chowdhury, Harun
• Application Number:
  US14/378,093
• Publication Number:
  US 20140348032A1
• Time in Patent Office: 2,087 Days
• Field of Search: 370277, 370278, 370286, 370328, 370329, 370282, 375220, 455 9, 455570
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 7/15585 by interference cancellation
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04L 25/03885 adaptive
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

A node of a full duplex wireless transmission system may include cancellation signal generation elements. The cancellation signal generation elements may extract a waveform from received signals, for example signals transmitted from the node, and use the waveform to generate a prefilter or cancellation signal to apply to further received signals. The cancellation signal may cancel interference in received signals caused by signals transmitted from the node.

Claims

1. A method useful for full duplex radio communications, comprising:

transmitting a training signal by a node in a radio network;

extracting a waveform from a version of the training signal obtained from a receive chain of the node;

generating a cancellation signal using the waveform;

applying the cancellation signal to the receive chain of the node; and

iteratively;

transmitting the training signal, at increased power compared to prior transmissions of the training signal, by the node in the radio network,

extracting a further waveform from a version of the training signal transmitted at increasing power obtained from the receive chain of the node,

generating a further cancellation signal using the further waveform and the cancellation signal, and

applying the further cancellation signal to the receive chain of the node.

2. The method of claim 1, wherein the cancellation signal is determined using a sliding window weighted sum of the waveform.

3. The method of claim 2, wherein coefficients of a signal to be transmitted comprise weights of the weighted sum.

4. The method of claim 1, wherein the training signal is transmitted over a first antenna of the node, the receive chain is coupled to a second antenna of the node, and the version of the training signal obtained from the receive chain is a version of the training signal received by the second antenna.

5. The method of claim 1, wherein the training signal is transmitted over a first antenna of the node, the receive chain is coupled to the first antenna, and the receive chain receives the training signal through a circulator.

6. The method of claim 1, wherein the node includes n_r receive antennas and n_t transmit antennas, and further comprising transmitting a training signal a_i by each of the n_t transmit antennas, and wherein the version of the training signal obtained from the receive chain is a version of a combination of the a_i transmitted signals.

7. The method of claim 6, wherein each of the a_i transmitted signals are different signals.

8. The method of claim 6, wherein, for each of the n_r receive antennas, the following is performed,

extracting a waveform from a version of the training signal obtained from a receive chain of the node,

generating a cancellation signal using the waveform, and

applying the cancellation signal to the receive chain of the node.