Relay Selection for Full-Duplex Cooperative Networks with Outdated CSI in an Interference-Limited Environment

In this paper, considering the scenario that the available channel state information (CSI) used for relay selection (RS) is outdated, we propose a RS scheme for full-duplex (FD) cooperative networks in an interference-limited environment, where the residual loop interference (RLI) at the relay and the interference comes from the direct link both affect the cooperative transmission. Specifically, based on the statistical CSI, power allocation under the sum power constraint is performed firstly according to the signal-to-interference-ratio (SIR) balancing condition, and then with the known outdated CSI and the correlation coefficient between the outdated CSI and the real one, the conditional outage probability (COP) associated with each relay is derived in a closed form. The relay with the minimum COP is selected to participate in transmission. It is shown that the proposed scheme can provide a significant performance improvement over the conventional RS schemes for both symmetric and asymmetric network configurations. Simulations are provided to validate our results.