Analog and digital self-interference cancellation in full-duplex MIMO-OFDM transceivers with limited resolution in A/D conversion

We analyze the performance of full-duplex MIMO-OFDM transceivers with subtractive self-interference cancellation in analog and/or digital domain, i.e., before and/or after analog-to-digital converters (ADCs). In particular, the non-ideal ADCs are modeled by assuming uniform b-bit quantization which allows us to derive closed-form expressions for the signal to interference and noise ratio when including the effects of the residual self-interference due to imperfect cancellation and the clipping-plus-quantization noise due to the limited dynamic range of ADCs. Consequently, this facilitates a study on the fundamental trade-off between ADC resolution, maximum transmit power, minimum physical isolation and sufficient signal to self-interference ratio needed to avoid receiver saturation. We also highlight the benefit of combining analog and digital cancellation: if the former attenuates interference sufficiently well such that all received signals fit within the limited dynamic range of ADCs, the latter can handle the residual self-interference efficiently.