The Capacity of Successive DF Relaying and Using Soft Multiple-Symbol Differential Sphere Detection

The conventional single-relay aided two-phase cooperative network employing a so-called soft-input soft-output multiple-symbol differential sphere detection (SISO-MSDSD) and operating in a distributed turbo decoding mode incurs a high complexity and imposes a 50% half-duplex relaying induced throughput loss. In this paper, we combat both of these critical problems. We commence by evaluating the Discrete-input Continuous-output Memoryless Channel (DCMC) capacity of the Decode-and-Forward (DF) based successive relaying aided networks (SRAN) as our theoretical benchmark. Then a relay-aided SISO-MSDSD is designed, which is then incorporated in the DF based SRAN. As our novel contribution, we demonstrate that the proposed transceiver is capable of significantly reducing the system´s complexity, whilst recovering the 50% half-duplex relaying induced throughput loss. The system is capable of performing within 2.9 dB from the corresponding noncoherent DCMC capacity.