Base-band training of carrier leakage canceller in 5.8-GHz full-duplex transceivers

This article introduces a training technique suitable for an active analog carrier leakage canceller, based on base-band signal processing. The proposed training approach leads to the optimum canceller parameters by observing at base-band the magnitude of a pilot signal amplitude-modulating the carrier, which is generated by the base-band processor in the transmitter and received due the leakage through the receiver chain. An experimental characterization applied to a road-side unit operating in full-duplex mode for an electronic toll collection system, under regulation ETSI ES200674, demonstrates that the leakage mitigation reaches up to 35 dB with the leakage between transmitter and receiver maintained below −60 dB, and resulting in a signal-noise ratio enhancement of 30 dB