Relay misbehavior detection for robust diversity combining in cooperative communications

Most previous studies on cooperative communications assume that the relays operate normally and are trustworthy. However, this assumption may not always be true in practice. Accordingly, this study proposes a robust cooperative communication scheme in the physical layer for combating relay misbehavior. Two models for cooperative communications are considered, namely with direct path (WDP) and without direct path (WODP). For each model, a signal-correlation detection scheme is proposed in which the destination identifies the misbehaving relays within the network and then excludes their messages when performing diversity combining to infer the symbols of interest sent by the source. The proposed signal-correlation-detection rules are designed in such a way as to minimize the probability of error in identifying the misbehaving relays. The simulation results show that the proposed schemes yield an excellent detection performance in cooperative communication networks with relay misbehavior.