Cooperative Jamming for Secure Communications in MIMO Relay Networks
Secure communications can be impeded by eavesdroppers in conventional relay systems. This paper proposes cooperative jamming strategies for two-hop relay networks where the eavesdropper can wiretap the relay channels in both hops. In these approaches, the normally inactive nodes in the relay network can be used as cooperative jamming sources to confuse the eavesdropper. Linear precoding schemes are investigated for two scenarios where single or multiple data streams are transmitted via a Decode-and-Forward (DF) relay, under the assumption that global Channel State Information (CSI) is available. For the case of single data stream transmission, the authors derive closed-form jamming beamformers and the corresponding optimal power allocation.