An improved coded cooperation scheme using hierarchical modulation

This paper proposes a new coded cooperation scheme based on hierarchical modulation (HM), which can achieve full diversity gain for slow and fast fading. In the proposed scheme, a user multiplexes its own data and its partner´s data as high and low priority streams in the HM. We show by an analysis of the pairwise error probability that the proposed scheme achieves a higher diversity order than other cooperation schemes. Moreover, the optimal priority level in the HM is determined by minimizing the outage probability. Numerical results are provided to demonstrate the superior performance of the proposed scheme over other existing methods.