Systems and Methods for Analog Cancellation for Division Free Duplexing for Radios Using MIMO

• US 20160094332A1
• Filed: 09/25/2014
• Published: 03/31/2016
• Est. Priority Date: 09/25/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Griffiths, James Gary, Oberhammer, Wolfgang, Moher, Michael, Hum, Eddy Shi-Ning
• Granted Patent: US 10,205,585 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

System and method embodiments are provided for analog cancellation for division free duplexing for radios using MIMO. In an embodiment, a system for minimizing transmitted signals from a transmitter appearing at a co-located receiver in a division free duplexing radio includes a transmitter to transmit an analog transmitted signal; an antenna; a circulator coupled to the transmitter and the antenna; a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

Claims

1. A system for minimizing transmitted signals from a transmitter appearing at a co-located receiver in a division free duplexing radio, the system comprising:

a transmitter to transmit an analog transmitted signal;

an antenna;

a circulator coupled to the transmitter and to the antenna;

a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and

a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

2. The system of claim 1, further comprising a cancellation coupling component coupled to an output of the multitap and to the received signal path, wherein the multitap cancellation component is configured to receive a copy of the analog transmitted signal and to receive gain, phase, and/or delay adjust values from the tuning algorithm component, and configured to provide a cancellation signal according to the analog transmitted signal and the gain, phase, and/or delay adjust values to a cancellation coupling component that couple the cancellation signal to the analog received signal.

3. The system of claim 2, wherein the tuning algorithm component is configured to determine the gain, phase, and/or delay adjust values such that a component of the analog transmitted signal appearing at the receiver is reduced.

4. The system of claim 2, wherein the cancellation coupling component is configured to couple the cancellation signal to the received signal at a point upstream from the point in the received signal path at which the received signal is sampled.

5. The system of claim 1, wherein the multitap cancellation component is configured to operate in an analog domain.

6. The system of claim 1, wherein the transmitter comprises a plurality of transmitters, wherein the antenna comprises a plurality of antennas, wherein the circulator comprises a plurality of circulators, and wherein the multitap cancellation component comprises a plurality of multitap cancellation components, wherein the number of multitap cancellation components per receiver is equal to the number of transmitters.

7. The system of claim 6, wherein each of the multitap cancellation components is configured to provide a cancellation signal to one of the receivers for one of the transmitters.

8. The system of claim 1, wherein the multitap cancellation component comprises at least one gain adjust component and at least one phase adjust component.

9. A network component configured for division free duplexing in a wireless network, comprising:

a processor;

transmitter coupled to the processor to transmit an analog transmitted signal as instructed by the processor;

an antenna;

a circulator coupled to the transmitter and to the antenna;

a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and

a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

10. The network component of claim 9, further comprising a cancellation coupling component coupled to an output of the multitap and to the received signal path, wherein the multitap cancellation component is configured to receive a copy of the analog transmitted signal and to receive gain, phase, and/or delay adjust values from the tuning algorithm component, and configured to provide a cancellation signal according to the analog transmitted signal and the gain, phase, and/or delay adjust values to a cancellation coupling component that couple the cancellation signal to the received signal.

11. The network component of claim 10, wherein the tuning algorithm component is configured to determine the gain, phase, and/or delay adjust values such that a component of the analog transmitted signal appearing at the receiver is reduced.

12. The network component of claim 10, wherein the cancellation coupling component is configured to couple the cancellation signal to the received signal at a point upstream from the point in the received signal path at which the received signal is sampled.

13. The network component of claim 9, wherein the multitap cancellation component is configured to operate in an analog domain.

14. The network component of claim 9, wherein the transmitter comprises a plurality of transmitters, wherein the antenna comprises a plurality of antennas, wherein the circulator comprises a plurality of circulators, and wherein the multitap cancellation component comprises a plurality of multitap cancellation components, wherein the number of multitap cancellation components per receiver is equal to the number of transmitters.

15. The network component of claim 14, wherein each of the multitap cancellation components is configured to provide a cancellation signal to one of the receivers for one of the transmitters.

16. The network component of claim 9, wherein the multitap cancellation component comprises at least one gain adjust component and at least one phase adjust component.

17. The network component of claim 9, wherein the network component is configured for multiple-input multiple-output (MIMO) division free duplexing.

18. A method for cancelling a transmitted signal from a received signal in a division free duplexing network component, the method comprising:

sampling an analog transmitted signal;

sampling an analog received signal;

determining, with the network component, gain and phase adjust values by which to modify the analog transmitted signal;

modifying with a cancellation component in the network component the analog transmitted signal to produce a cancellation signal according the gain and phase adjust values; and

adding the cancellation signal to the analog received signal at a point in a received signal path between an antenna and a receiver.

19. The method of claim 18, wherein the sampling of the analog received signal is performed at a point between the point in the received signal path that the cancellation signal is added to the received signal and the receiver.

20. The method of claim 18, further comprising splitting the analog transmitted signal into a plurality of split analog transmitted signals and adjusting a gain and phase of each split analog transmitted signal to produce a plurality of modified transmitted signals.

21. The method of claim 20, further comprising combining the plurality of modified transmitted signals to produce the cancellation signal.

22. The method of claim 18, further comprising:

sampling a second analog transmitted signal;

determining second gain, second phase, and second delay adjust values by which to modify the second analog transmitted signal;

modifying the second analog transmitted signal to produce a second cancellation signal according to the second gain, second phase, and second delay adjust values; and

adding the second cancellation signal to the analog received signal at a point in the received signal path between the antenna and the receiver.