Characterization of the residual self-interference power in full-duplex wireless systems

Full-duplex wireless communication systems are capable of transmitting and receiving signals in the same band. An important performance indicator of full-duplex systems is the amount of uncanceled self-interference, a.k.a. residual self-interference. This work investigates the distribution of the residual self-interference (SI) power in an analog post-mixer canceler. First, we focus on the impact of the SI channel coherence time on the distribution of the residual SI power and we analyze in detail the impact of the phase-noise caused by the up/down-conversion oscillators. The results achieved in this study confirm that the coherence time of the SI channel strongly impacts the distribution of the residual SI power. Considering a SI Rayleigh channel, we show that the residual SI power only follows a Gamma distribution in the limit case, when the coherence time tends to infinity (time-invariant channel). This work is the first step to understand the stochastic properties of the residual SI power, which is an important feature when digital-domain cancellation is jointly adopted with analog-domain cancellation to account for the estimated effects of the propagation channel.