Self-interference-cancelled full-duplex relays

A multiple-input multiple-output (MIMO) self-interference-cancelled full-duplex relay comprising:

• a first receiver, coupled to first and second signal paths of the relay, that receives a first analog receive signal at a first signal frequency via the first signal path and a second analog receive signal at a second signal frequency via the second signal path, converts the first analog receive signal to a first digital receive signal, converts the second analog receive signal to a second digital receive signal, and jointly processes the first and second digital receive signals to generate a first combined digital receive signal;
• wherein the first combined digital receive signal contains a first message;
• a first transmitter, coupled to the first and second signal paths of the relay, that converts a first digital transmit signal to first and second analog transmit signals, transmits the first analog transmit signal at the first signal frequency, and transmits the second analog transmit signal at the second signal frequency;
• wherein the first and second analog transmit signals are combinable by a MIMO receiver;
• wherein the first digital transmit signal also contains the first message;
• a second receiver, coupled to third and fourth signal paths of the relay, that receives a third analog receive signal at a third signal frequency via the third signal path and a fourth analog receive signal at a fourth signal frequency via the fourth signal path, converts the third analog receive signal to a third digital receive signal, converts the fourth analog receive signal to a fourth digital receive signal, and jointly processes the third and fourth digital receive signals to generate a second combined digital receive signal;
• wherein the second combined digital receive signal contains a second message;
• a second transmitter, coupled to the third and fourth signal paths of the relay, that converts a second digital transmit signal to third and fourth analog transmit signal, transmits the third analog transmit signal at the third signal frequency, and transmits the fourth analog transmit signal at the fourth signal frequency;
• wherein the third and fourth analog transmit signals are combinable by a MIMO receiver;
• wherein the second digital transmit signal also contains the second message;
• and
• a first self-interference canceller that generates a first homo-channel self-interference cancellation signal based on at least one of the first digital transmit signal, the first analog transmit signal, and the second analog transmit signal, and combines the first homo-channel self-interference cancellation signal with at least one of the first analog receive signal, the second analog receive signal, the first digital receive signal, the second digital receive signal, and the first combined digital receive signal, resulting in a reduction of self-interference in the first combined digital receive signal;
• wherein the first self-interference canceller further generates a second homo-channel self-interference cancellation signal based on at least one of the second digital transmit signal, the third analog transmit signal, and the fourth analog transmit signal, and combines the second homo-channel self-interference cancellation signal with at least one of the third analog receive signal, the fourth analog receive signal, the third digital receive signal, the fourth digital receive signal, and the second combined digital receive signal, resulting in a reduction of self-interference in the second combined digital receive signal;
• wherein the first receiver may receive during transmission of the first transmitter or transmission of the second transmitter;
• wherein the second receiver may receive during transmission of the first transmitter or transmission of the second transmitter;
• wherein the first and second receivers may receive simultaneously.