  Short message noisy network coding with rate splitting (SNNC-RS) encoding
strategy is presented. It has been shown by Hou and Kramer that mixed
cooperative strategies in which relays in favorable positions perform
decode-and-forward (DF) and the rest of the relays perform short message noisy
network coding (SNNC) can outperform noisy network coding (NNC). Our proposed
strategy further improves the rate performance of such mixed SNNC-DF
cooperative strategy. In the proposed scheme, superposition coding is
incorporated into the SNNC encoding in order to facilitate partial interference
cancellation at DF relays, thereby increasing the overall rate. To demonstrate
gains of the proposed SNNC-RS strategy, the achievable rate is analyzed for the
discrete memoryless two-relay network with one DF relay and one SNNC-RS relay
and compared to the case without rate-splitting. The obtained rate is evaluated
in the Gaussian two-relay network and gains over the rate achieved without rate
splitting are demonstrated.
