A Novel Differential Decode and Forward Scheme for Channel-Unaware Two-Way Relay Networks

We consider channel-unaware two-way relay net-works in which two single-antenna nodes communicate through a single-antenna half-duplex decode-and-forward relay. To over-come the drawbacks of conventional signalling, we develop a novel differential signalling scheme. This scheme not only elimi-nates error propagation but also removes the unitarity restriction on the transmitted symbols in conventional differential signalling. Using non-unitary symbols in the differential signalling doubles the degrees of design freedom and yields better performance, which is confirmed by numerical results.