On the performance of the Rotate-and-Forward protocol in the two-hop relay channels

In wireless cooperative systems, the outage probability is a relevant performance measure from the information theoretic point of view. Deriving its exact value with respect to the relaying protocol parameters and for all the range of the Signal to Noise Ratio is in general a hard task. Instead, one can extract the outage gain in order to approximate the outage probability as the SNR goes to infinity at a fixed rate R. In this paper, we consider the layered two-hop relay channel, operating under the linear Rotate-and-Forward (RF) protocol, where each relay rotates its received signal and forwards it towards the destination. We consider two network configurations for which we derive exact outage gain values. We use the outage gain to compare the performance of the RF scheme to that of other schemes having the same diversity order. The derived outage gain values are verified through numerical simulations.