Analog compensation circuit and method

A method of tuning an analog compensation circuit for a full-duplex transceiver, comprising:

• transmitting a transmit signal up-converted from a baseband transmit signal;
• receiving a self-interference signal resulting from the transmitting;
• sampling the self-interference signal in a time domain, thereby generating a sampled self-interference signal;
• converting the sampled self-interference signal into a digital baseband self-interference signal;
• computing a plurality of complex gains in a frequency domain according to the digital baseband self-interference signal and the baseband transmit signal;
• and
• applying the plurality of complex gains to an analog compensator.

A full-duplex transceiver, comprising:

• an isolation block coupled to a common antenna at a transmit port, and having an input port and an output port;
• a transmit chain coupled to the input port of the isolation block and configured to generate a baseband transmit signal that is up-converted to a transmit signal for transmission through the isolation block and the common antenna;
• and
• a receive chain, through which a self-interference signal is receivable, having:
• a primary receive path coupled to the output port of the isolation block,
• a secondary receiver coupled to the primary receive path and configured to receive and convert a sampled self-interference signal to a baseband self-interference signal,
• a tuner coupled to the secondary receiver and the transmit chain, and configured to:
• receive the baseband transmit signal from the transmit chain, and
• compute a plurality of complex gains according to the baseband transmit signal and the baseband self-interference signal, and
• an analog compensator coupled to the transmit chain, the tuner, and the primary receive path, having a plurality of branches, and configured to:
• receive the plurality of complex gains from the tuner,
• adjust respective attenuators and phase shifters of the plurality of branches using the plurality of complex gains, and
• process a sample of another transmit signal from the transmit chain using the plurality of branches to yield a compensation signal for coupling into the primary receive path.

An analog compensation circuit for a multi-transmitter full-duplex transceiver having N transmitters and N transmit chains, comprising:

• a secondary receiver configured to receive and convert N samples of an aggregate self-interference signal to N baseband self-interference signal samples;
• a tuner coupled to the secondary receiver and configured to:
• receive N baseband transmit signal samples from each of the N transmit chains, wherein a total of N×N baseband transmit signal samples are received, and
• compute a plurality of complex gains according to the N×N baseband transmit signal samples and the N baseband self-interference signal samples;
• and
• an analog compensator coupled to the tuner, having a plurality of branches, and configured to:
• receive the plurality of complex gains,
• adjust respective attenuators and phase shifters of the plurality of branches using the plurality of complex gains, and
• process respective samples of N transmit signals from the N transmit chains using the plurality of branches, wherein the N transmit signals are respectively up-converted from N baseband transmit signals.