A 0.78mm² Co-Channel Interference Canceller in 130nm SOI RF CMOS with Novel Passive Phase Shifters and Combiner Circuitry

An increasingly congested frequency spectrum has presented an unfortunate opportunity for two independent radios on the same device to exist co-channel. Currently, co-channel coexistence requires temporal scheduling to prevent co-channel interference from disrupting downlink communications. This work develops a method of front end co-channel cancellation within the receive chain of a co-channel transceiver to allow for simultaneous operation. An extremely compact co-channel interference canceller (CCIC) is presented. A polar modulator in a feed-forward path creates an inverted copy of the on-board interference signal at RF and recombines in the front end LNA for cancellation. The system contains novel phase shifters and digital capacitor architectures and a novel front end combination circuit. The system provides 6 bits of phase control and 5 bits of amplitude control and 25dB of cancellation is demonstrated. The measured IIP3 was +7dBm and the measured noise figure was 1.5dB with 14dB of LNA gain at 2.2GHz.