Dual-hop OFDM opportunistic AF relaying under joint transmit/receive I/Q imbalance

We study the outage performance of orthogonal frequency-division multiplexing dual-hop opportunistic amplify-and-forward relaying in the presence of I/Q imbalance in all of the nodes´ transceivers. We derive a closed-form expression for the end-to-end outage probability for the general case, where each node suffers from a different I/Q imbalance level and under the assumption that the distance between source and relay is not the same for all relays. Our simulation results show excellent match to our analysis and both demonstrate that uncompensated I/Q imbalance can be detrimental but it can also be effectively mitigated using a few relays. This result has a significant impact on relay deployment in future wireless communication networks.