Systems and methods for analog cancellation for division free duplexing for radios using MIMO

• US 10,205,585 B2
• Filed: 09/25/2014
• Issued: 02/12/2019
• Est. Priority Date: 09/25/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Griffiths, James Gary, Oberhammer, Wolfgang, Moher, Michael, Hum, Eddy Shi-Ning
• Primary Examiner(s): Atkins, George C
• Application Number:
  US14/496,850
• Publication Number:
  US 20160094332A1
• Time in Patent Office: 1,601 Days
• Field of Search: None
• 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 plurality of transmitters to transmit a plurality of analog transmitted signals according to respective ones of a plurality of baseband transmission signals;

a plurality of receivers to receive a plurality of analog received signals;

a plurality of antennas each coupled to a respective one of the transmitters and a respective one of the receivers;

a plurality of circulators each coupled to a respective one of the transmitters, a respective one of the antennas, and a respective one of the receivers;

an algorithm tuner configured to receive copies of the baseband transmission signals from the transmitters and sampled analog received signals from received signal paths from the circulators, each sampled analog received signal being sampled at a point in a respective received signal path before a corresponding analog received signal is provided to a corresponding one of the receivers, the algorithm tuner further configured to determine a plurality of phase parameters and a plurality of attenuation parameters in an analog domain for each received signal according to the plurality of baseband transmission signals; and

a plurality of multitap cancellers each coupled to the algorithm tuner and configured to receive the plurality of phase parameters and the plurality of attenuation parameters, the multitap cancellers each further configured to determine a cancellation signal according to the plurality of phase parameters and the plurality of attenuation parameters in the analog domain and to provide a cancellation signal to couple to the analog received signal for each received signal such that an amount of the analog transmitted signal appearing at each of the receivers is reduced.

2. The system of claim 1, further comprising a plurality of cancellation couplers each coupled to an output of a respective one of the multitap cancellers and to a respective one of the received signal paths, wherein the each multitap canceller is configured to receive a copy of the analog transmitted signals and to receive gain, phase, and/or delay adjust values from the algorithm tuner, 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 coupler that couple the cancellation signal to the analog received signal.

3. The system of claim 2, wherein the algorithm tuner 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 each cancellation coupler 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 a number of multitap cancellers per receiver is equal to a number of transmitters.

6. The system of claim 5, wherein each of the multitap cancellers is configured to provide a cancellation signal to one of the receivers for one of the transmitters.

7. The system of claim 1, wherein the each multitap canceller comprises at least one gain adjuster and at least one phase adjuster.

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

a processor;

a plurality of transmitters coupled to the processor to transmit a plurality of analog transmitted signals according to respective ones of a plurality of baseband transmission signals as instructed by the processor;

a plurality of receivers to receive a plurality of analog received signals;

a plurality of antennas each coupled to a respective one of the transmitters and a respective one of the receivers;

a plurality of circulators each coupled to a respective one of the transmitters, a respective one of the antennas, and a respective one of the receivers;

an algorithm tuner configured to receive copies of the baseband transmission signals from the transmitters and sampled analog received signals from received signal paths from the circulators, wherein each of the sampled analog received signals is sampled at a point in a respective received signal path before a corresponding analog received signal is provided to a receiver corresponding one of the receivers, the algorithm tuner further configured to determine a plurality of phase parameters and a plurality of attenuation parameters in an analog domain for each received signal according to the plurality of baseband transmission signals; and

a plurality of multitap cancellers each coupled to the algorithm tuner and configured to receive the plurality of phase parameters and the plurality of attenuation parameters, the multitap cancellers each further configured to determine a cancellation signal according to the plurality of phase parameters and the plurality of attenuation parameters in the analog domain and to provide a cancellation signal to couple to the analog received signal for each received signal such that an amount of the analog transmitted signal appearing at each of the receivers is reduced.

9. The network component of claim 8, further comprising a plurality of cancellation couplers each coupled to an output of a respective one of the multitap cancellers and to a respective one of the received signal paths, wherein each of multitap cancellers is configured to receive a copy of the analog transmitted signal signals and to receive gain, phase, and/or delay adjust values from the algorithm tuner, 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 coupler that couple the cancellation signal to the analog received signal.

10. The network component of claim 9, wherein the algorithm tuner 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.

11. The network component of claim 9, wherein the each cancellation coupler is configured to couple the cancellation signal to the received signal at a point upstream from the point in the received signal path al which the received signal is sampled.

12. The network component of claim 8, wherein a number of multitap cancellers per receiver is equal to a number of transmitters.

13. The network component of claim 12, wherein each of the multitap cancellers is configured to provide a cancellation signal to one of the receivers for one of the transmitters.

14. The network component of claim 8, wherein the each multitap canceller comprises at least one gain adjuster and at least one phase adjuster.

15. The network component of claim 8, wherein the network component is configured for multiple-input multiple-output (MIMO) division free duplexing.

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

sampling a plurality of baseband transmitted signals;

sampling a plurality of analog received signals;

determining in an analog domain, with the network component, a plurality of gain and phase adjust values by which to modify a plurality of analog transmitted signals for the plurality of baseband transmitted signals, each of the plurality of gain and phase adjust values corresponding to a different one of the plurality of analog transmitted signals, and each of the plurality of gain and phase adjust values determined according to the plurality of baseband transmitted signals;

modifying in an analog domain, with a cancellation component in the network component, each of the plurality of analog transmitted signals to produce a cancellation signal according to the plurality of gain and phase adjust values for each of the plurality of analog received signals; and

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

17. The method of claim 16, wherein the sampling of each of the analog received signals is performed at a point between the point in the respective received signal path that the respective cancellation signal is added to the respective received signal and the respective receiver.

18. The method of claim 16, further comprising splitting each of the analog transmitted signals 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.

19. The method of claim 18, further comprising combining, for each corresponding analog received signal, the plurality of modified transmitted signals to produce the cancellation signal for the corresponding analog received signal.