Single channel full duplex wireless communication

• US 9,432,174 B2
• Filed: 02/03/2016
• Issued: 08/30/2016
• Est. Priority Date: 12/14/2011
• Status: Active Grant

• Current Assignee: Aviat U.S., Inc. (Aviat Networks Incorporated)
• Original Assignee: Redline Communications Inc. (Aviat Networks Incorporated)
• Inventors: Sarca, Octavian
• Primary Examiner(s): Patel, Parth
• Assistant Examiner(s): HARLEY, JASON A
• Application Number:
  US15/014,782
• Publication Number:
  US 20160156456A1
• Time in Patent Office: 209 Days
• Field of Search: 370/277, 455/63.1
• US Class Current: 1/1
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• 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
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

A single channel full duplex wireless communication system includes a processor, a transmitter, a receiver, a secondary transmission path, a combining element, a primary transmission feedback path and a secondary transmission feedback path. The transmitter transmits a transmission signal via a transmission path. The receiver receives a received signal via a reception path. The transmitter and the receiver utilize one channel to transmit and receive signals. The transmission signal causes self-interference. The processor estimates a first transfer function and feeds the secondary transmission path with the transmission signal adjusted by the first transfer function to reduce the transmission signal leaked to the reception path. The combining element combines the transmission signal with the adjusted secondary transmission path signal to remove the self-interference. The primary transmission feedback path output is modified by a second transfer function. The secondary transmission feedback path output is modified by a third transfer function.

Claims

1. A wireless communications device, comprising:

a processor, the processor comprising a summing unit;

a transmitter coupled to the processor, the transmitter transmitting a transmission signal via a transmission path;

a receiver coupled to the processor, the receiver receiving a first signal from an output of a reception path, wherein the transmitter and the receiver simultaneously utilize shared frequencies on a single channel to transmit the transmission signal and to receive a received signal;

a secondary transmission path coupled to the processor;

a combiner receiving inputs from the output of the secondary transmission path and the received signal, the combiner output coupled to the input to the reception path; and

a transmission feedback path, the transmission feedback path input coupled to the output of the transmission path, the transmission feedback path output coupled to the processor and modified by a second transfer function to produce a second signal, the second transfer function being an estimate of the transfer function from the input of the transmission path to the input to the reception path;

a secondary transmission feedback path, the secondary transmission feedback path input coupled to the output of the secondary transmission path, the secondary transmission feedback path output coupled to the processor and being modified by a third transfer function to produce a third signal, the third transfer function being an estimate of the transfer function from the input of the secondary transmission path to the input to the reception path;

the processor determining a first transfer function, the first transfer function having an input comprising the transmission signal and an output comprising the transmission signal adjusted by the first transfer function, the output of the first transfer function being the input to the secondary transmission path, the first transfer function calculated to cancel the effects of the second transfer function and the third transfer function; and

the summing unit combines the first signal, the second signal, and the third signal to produce a processed received signal.

2. The wireless communications device of claim 1, wherein the second transfer function and the third transfer function are estimated using adaptive filters.

3. The wireless communications device of claim 2, wherein the coefficients of the adaptive filters are calculated using previously collected statistical data.

4. The wireless communications device of claim 2, wherein the coefficients of the adaptive filters are recalculated based on received sample data.

5. A wireless communications device, comprising:

a processor, the processor comprising a summing unit;

a transmitter coupled to the processor, the transmitter transmitting a transmission signal via a transmission path;

a receiver coupled to the processor, the receiver receiving a first signal from an output of a reception path, wherein the transmitter and the receiver simultaneously utilize shared frequencies on a single channel to transmit the transmission signal and to receive a received signal;

a combiner receiving inputs from the output of the secondary transmission path and the received signal, the combiner output coupled to the input to the reception path; and

a transmission feedback path, the transmission feedback path input coupled to the output of the transmission path, the transmission feedback path output coupled to the processor and modified by a second transfer function to produce a second signal, the second transfer function being an estimate of the transfer function from the input of the transmission path to the input to the reception path;

the processor determining a third transfer function, the third transfer function having an input comprising the transmission signal and an output comprising the transmission signal adjusted by the third transfer function, the output of the third transfer function being a third signal, the third transfer function being an estimate of the transfer function from the input of the transmission path to the output of the reception path;

the processor determining a first transfer function, the first transfer function having an input comprising the transmission signal and an output comprising the transmission signal adjusted by the first transfer function, the output of the first transfer function being the input to a secondary transmission path, the first transfer function calculated to cancel the effects of the second transfer function and the third transfer function; and

the summing unit combines the first signal, the second signal, and a third signal to produce a processed received signal.

6. The wireless communications device of claim 5, wherein the second transfer function and the third transfer function are estimated using adaptive filters.

7. The wireless communications device of claim 6, wherein the coefficients of the adaptive filters are calculated using previously collected statistical data.

8. The wireless communications device of claim 6, wherein the coefficients of the adaptive filters are recalculated based on received sample data.