Intelligent backhaul radio with zero division duplexing

• US 8,422,540 B1
• Filed: 09/10/2012
• Issued: 04/16/2013
• Est. Priority Date: 06/21/2012
• Status: Active Grant

• Current Assignee: COMS IP Holdings LLC
• Original Assignee: CBF Networks, Inc. (COMSovereign Holding Corp.)
• Inventors: Negus, Kevin J., Proctor, James A. Jr.
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): HUGHES, EBONI N
• Application Number:
  US13/609,156
• Time in Patent Office: 218 Days
• Field of Search: 375/219, 370/210, 370/328, 370/338, 370/480, 455/67.11, 455/67.13, 455/452.1, 455/507
• US Class Current: 375/219
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/54 using the same frequency for two directions of communication H04B1/44 takes precedence
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04L 5/1423 for simultaneous baseband signals
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

A intelligent backhaul radio is disclosed, which can operate by zero division duplexing for use in PTP or PMP topologies, providing for significant spectrum usage benefits among other benefits. Specific system architectures and structures to enable active cancellation of multiple transmit signals at multiple receivers within a MIMO radio are disclosed. Further disclosed aspects include the adaptive optimization of cancellation parameters or coefficients.

Claims

1. An intelligent backhaul radio comprising:

a plurality of transmit radio frequency (RF) chains to convert from a plurality of transmit chain input signals to a plurality of respective RF transmit chain signals;

a plurality of adaptable RF transversal filter sets to convert a plurality of signals respectively derived from the plurality of RF transmit chain signals to a plurality of RF transmit leakage cancellation signals,

wherein each adaptable RF transversal filter set is comprised of a plurality of adaptable RF transversal filters, each for filtering a respective one of said plurality of signals respectively derived from the plurality of RF transmit chain signals to provide a respective adaptable RF transversal filtered signal, and a combiner for combining the plurality of adaptable RF transversal filtered signals within the filter set to produce one of said RF transmit leakage cancellation signals;

a plurality of RF cancellation combiners for respectively combining one of said plurality of RF transmit leakage cancellation signals with one of said plurality of RF receive signals to provide a plurality of RF receive chain input signals, and

a plurality of receive RF chains to convert from said plurality of RF receive chain input signals to a plurality of respective receive chain output signals;

a plurality of receive baseband cancellation combiners for combining a plurality of baseband transmit leakage cancellation signals with a respective one of said plurality of receive chain output signals to provide a plurality of baseband cancelled receive signals;

a plurality of adaptable baseband transversal filter sets to receive a plurality of signals respectively derived from the plurality of transmit chain input signals and provide a plurality of baseband transmit leakage cancellation signals respectively to each of the plurality of receive baseband cancellation combiners,

wherein each adaptable baseband transversal filter set is comprised of a plurality of adaptable baseband transversal filters, each for filtering a respective one of said plurality of signals respectively derived from the plurality of transmit chain input signals to provide a respective adaptable baseband transversal filtered signal, and a combiner for combining the plurality of the adaptable baseband transversal filtered signals of the filter sets to provide one of said baseband transmit leakage cancellation signals to one of said respective receive baseband cancellation combiners, a cancellation controller, for adapting each of said plurality of adaptable RF transversal filters of one or more of said plurality of adaptable RF transversal filter sets, wherein the cancellation controller utilizes a plurality of RF transmit leakage metrics respectively derived from each of said receive RF chains associated with each of said one or more adaptable RF transversal filters sets being adapted by said cancellation controller;

and wherein said cancellation controller is additionally for adapting each of said plurality of adaptable baseband transversal filters of one or more of said plurality of adaptable baseband transversal filter sets, wherein the cancellation controller utilizes a plurality baseband cancellation adaptation input signals derived directly or indirectly from each of said receive RF chains or from said baseband combiners associated with each of said one or more adaptable baseband transversal filter sets being adapted by said cancellation controller;

one or more demodulator cores, wherein each demodulator core demodulates one or more receive symbol streams to produce a respective receive data interface stream;

a frequency selective receive path channel multiplexer, interposed between the one or more demodulator cores and the plurality of receive baseband cancellation combiners, to produce the one or more receive symbol streams provided to the one or more demodulator cores from the plurality of baseband cancelled receive signals;

an antenna array comprising;

a plurality of directive gain antenna elements; and

one or more selectable RF connections that selectively couple certain of the plurality of directive gain antenna elements to certain of the plurality of receive RF chains, wherein the number of directive gain antenna elements that can be selectively coupled to receive RF chains exceeds the number of receive RF chains that can accept receive RF signals from the one or more selectable RF connections;

and a radio resource controller, wherein the radio resource controller sets or causes to be set the specific selective couplings between the certain of the plurality of directive gain antenna elements and the certain of the plurality of receive RF chains.

2. The intelligent backhaul radio of claim 1, wherein said RF transmit leakage metric is an Received Signal Strength Indication (RSSI) measurement.

3. The intelligent backhaul radio of claim 1, wherein said RF transmit leakage metric is further derived from said receive chain output signal, wherein the derivation of said RF transmit leakage metric comprises a correlation with one or more signals related to one or more of said transmit chain input signals.

4. The intelligent backhaul radio of claim 1, wherein said adapting by said cancellation controller of each of the plurality of adaptable RF transversal filters of one or more of said plurality of adaptable RF transversal filter sets utilizes an iterative adaptation algorithm so as to minimize or otherwise optimize said RF transmit leakage metrics.

5. The intelligent backhaul radio of claim 1, wherein said baseband cancellation adaptation input signals are respectively derived from said baseband cancelled receive signals.

6. The intelligent backhaul radio of claim 1, wherein said baseband cancellation adaptation input signals are respectively derived utilizing a correlation with one or more signals related to one or more of said transmit chain input signals, and wherein said adapting by said cancellation controller of each of the plurality of adaptable baseband transversal filters of one or more of said plurality of adaptable baseband transversal filter sets utilizes an iterative adaptation algorithm so as to minimize any remaining transmit leakage signal from the baseband cancelled receive signals.

7. The intelligent backhaul radio of claim 5, wherein said baseband cancellation adaptation input signals are respectively derived utilizing a correlation with one or more signals related to one or more of said transmit chain input signals, and wherein said adapting by said cancellation controller of each of the plurality of adaptable baseband transversal filters of one or more of said plurality of adaptable baseband transversal filter sets utilizes an iterative adaptation algorithm so as to minimize any remaining transmit leakage signal from the baseband cancelled receive signals.

8. The intelligent backhaul radio of claim 1 wherein said baseband cancellation adaptation input signals comprise signals related said transmit chain input signals, and further comprise one or more of said receive chain output signals, and wherein said adapting by said cancellation controller of each of the plurality of adaptable baseband transversal filters of one or more of said plurality of adaptable baseband transversal filter sets utilizes a closed form calculation utilizing said baseband cancellation adaptation input signals.

9. The intelligent backhaul radio of claim 8 wherein said closed form calculation involves a least squares or Minimum Mean Squared Error (MMSE) calculation.

10. An intelligent backhaul radio comprising:

a plurality of transmit radio frequency (RF) chains to convert from a plurality of transmit chain input signals to a plurality of respective RF transmit chain signals;

a plurality of transmit RF reference receive chains respectively coupled, directly or indirectly, to the output of said plurality of transmit RF chains, to convert a plurality of signals respectively derived from said respective RF transmit chain signals to respective baseband sampled RF transmit reference signals;

a plurality of receive baseband cancellation combiners for combining a plurality of baseband sampled RF transmit leakage cancellation signals with a respective one of a plurality of receive chain output signals to provide a plurality of baseband cancelled receive signals;

a plurality of first adaptable baseband transversal filter sets to receive the plurality of baseband sampled RF transmit reference signals and provide a plurality of baseband sampled RF transmit leakage cancellation signals respectively to each of the plurality of respective receive baseband cancellation combiners,

wherein each first adaptable baseband transversal filter set is comprised of a plurality of first adaptable baseband transversal filters, each for filtering a respective one of said plurality of baseband sampled RF transmit reference signals to provide a respective first baseband filtered signal, and a combiner for combining the plurality of respective first baseband filtered signals within the filter set to provide one of said plurality of baseband sampled RF transmit leakage cancellation signals to one of said respective receive baseband cancellation combiners;

a plurality of RF cancellation combiners for respectively combining one of a plurality of up-converted baseband transmit leakage cancellation signals with one of said plurality of RF receive signals to provide a plurality of RF receive chain input signals, and

a plurality of receive RF chains to convert from a plurality of said RF receive chain input signals to a plurality of said respective receive chain output signals;

a plurality of cancellation up-converter chains, each to receive a respective one of said plurality of baseband transmit leakage cancellation signals and respectively provide one of said plurality of the up-converted baseband transmit leakage cancellation signals to a respective one of said plurality of RF cancellation combiners;

a plurality of second adaptable baseband transversal filter sets to receive a plurality of signals respectively derived from the plurality of transmit chain input signals and provide the plurality of baseband transmit leakage cancellation signals respectively to each of the plurality of respective cancellation up-converter chains,

wherein each second adaptable baseband transversal filter set is comprised of a plurality of second adaptable baseband transversal filters, each for filtering a respective one of said plurality of signals respectively derived from the plurality of transmit chain input signals to provide a respective second baseband filtered signal, and a combiner for combining the plurality of the second baseband filtered signals of the filter set to provide one of said plurality of baseband transmit leakage cancellation signals to one of said respective cancellation up-converter chains,

a cancellation controller, for adapting each of said plurality of second adaptable baseband transversal filters of one or more of said plurality of second adaptable baseband transversal filter sets, wherein the adaptation controller utilizes a second transmit leakage metric derived, directly or indirectly, from each of said receive RF chains, or said receive baseband cancellation combiners associated with each of said one or more second adaptable transversal filter sets being adapted by said adaptation controller,

wherein said cancellation controller is additionally for adapting each of said plurality of said first adaptable baseband transversal filters of one or more of said plurality of first adaptable baseband transversal filter sets, wherein the adaptation controller utilizes a plurality of baseband cancellation adaptation input signals derived directly or indirectly from each of said receive RF chains, or receive baseband cancellation combiners associated with each of said one or more first adaptable baseband transversal filter sets being adapted by said adaptation controller.

11. The intelligent backhaul radio of claim 10, wherein said second RF transmit leakage metric is an Received Signal Strength Indication (RSSI) measurement.

12. The intelligent backhaul radio of claim 10, wherein said second RF transmit leakage metric is further derived from said receive chain output signal, wherein the derivation of said first or said second RF transmit leakage metric comprises a correlation with one or more signals related to one or more of said transmit chain input signals.

13. The intelligent backhaul radio of claim 10, wherein said adapting by said cancellation controller of each of the plurality of first or second adaptable RF transversal filters of one or more of said plurality of first or second adaptable RF transversal filter sets utilizes an iterative adaptation algorithm so as to minimize or otherwise optimize said RF transmit leakage metrics.

14. The intelligent backhaul radio of claim 10, wherein said baseband cancellation adaptation input signals are respectively derived said baseband cancelled receive signals.

15. The intelligent backhaul radio of claim 10, wherein said baseband cancellation adaptation input signals are respectively derived utilizing a correlation with one or more signals related to one or more of said transmit chain input signals, and wherein said adapting by said cancellation controller of each of the plurality of second adaptable baseband transversal filters of one or more of said plurality of second adaptable baseband transversal filter sets utilizes an iterative adaptation algorithm so as to minimize any remaining transmit leakage signal from the baseband cancelled receive signals.

16. The intelligent backhaul radio of claim 14, wherein said baseband cancellation adaptation input signals are respectively derived utilizing a correlation with one or more signals related to one or more of said transmit chain input signals, and wherein said adapting by said cancellation controller of each of the plurality of second adaptable baseband transversal filters of one or more of said plurality of second adaptable baseband transversal filter sets utilizes an iterative adaptation algorithm so as to minimize any remaining transmit leakage signal from the baseband cancelled receive signals.

17. The intelligent backhaul radio of claim 10 wherein said baseband cancellation adaptation input signals comprise signals related said transmit chain input signals, and further comprise one or more of said receive chain output signals, and wherein said adapting by said cancellation controller of each of the plurality of second adaptable baseband transversal filters of one or more of said second plurality of adaptable baseband transversal filter sets utilizes a closed form calculation utilizing said baseband cancellation adaptation input signals.

18. The intelligent backhaul radio of claim 17 wherein said closed form calculation involves a least squares or Minimum Mean Squared Error (MMSE) calculation.

19. An intelligent backhaul radio comprising:

a plurality of transmit radio frequency (RF) chains to convert from a plurality of transmit chain input signals to a plurality of respective RF transmit chain signals;

a plurality of adaptable RF transversal filter sets to convert a plurality of signals respectively derived from the plurality of RF transmit chain signals to a plurality of RF transmit leakage cancellation signals,

wherein each adaptable RF transversal filter set is comprised of a plurality of adaptable RF transversal filters, each for filtering a respective one of said plurality of signals respectively derived from the plurality of RF transmit chain signals to provide a respective adaptable RF transversal filtered signal, and a combiner for combining the plurality of adaptable RF transversal filtered signals within the filter set to produce one of said RF transmit leakage cancellation signals;

a plurality of RF cancellation combiners for respectively combining one of said plurality of RF transmit leakage cancellation signals with one of said plurality of RF receive signals to provide a plurality of RF receive chain input signals, and

a plurality of receive RF chains to convert from said plurality of RF receive chain input signals to a plurality of respective receive chain output signals;

a cancellation controller, for adapting each of said plurality of adaptable RF transversal filters of one or more of said plurality of adaptable RF transversal filter sets, wherein the cancellation controller utilizes a plurality of RF transmit leakage metrics respectively derived from each of said receive RF chains associated with each of said one or more adaptable RF transversal filters sets being adapted by said cancellation controller;

one or more demodulator cores, wherein each demodulator core demodulates one or more receive symbol streams to produce a respective receive data interface stream;

a frequency selective receive path channel multiplexer, interposed between the one or more demodulator cores and the plurality of receive RF chains, to produce the one or more receive symbol streams provided to the one or more demodulator cores from the plurality of receive chain output signals;

an antenna array comprising;

a plurality of directive gain antenna elements; and

one or more selectable RF connections that selectively couple certain of the plurality of directive gain antenna elements to certain of the plurality of receive RF chains, wherein the number of directive gain antenna elements that can be selectively coupled to receive RF chains exceeds the number of receive RF chains that can accept receive RF signals from the one or more selectable RF connections;

and a radio resource controller, wherein the radio resource controller sets or causes to be set the specific selective couplings between the certain of the plurality of directive gain antenna elements and the certain of the plurality of receive RF chains.