OFDM Full-Duplex DF Relaying Under I/Q Imbalance and Loopback Self-Interference

We analyze the outage probability of dual-hop full-duplex (FD) decode-and-forward (DF) relaying for an orthogonal frequency-division multiplexing (OFDM) system in the presence of in-phase and quadrature-phase (I/Q) imbalance (IQI). We derive tight analytical approximations that quantify the outage probability's functional dependence on the IQI level and the residual loopback self-interference (LSI) average power level. In addition, we derive the condition at which direct transmission outperforms FD-DF relay-assisted transmission in the presence of IQI. Furthermore, we investigate an opportunistic relaying (OR) approach and demonstrate its robustness against the detrimental effects of IQI and residual LSI. Our numerical results confirm the accuracy of our analysis.