Vijayan T
It is a new way of combating the effect of signal fading. The main goal of this communication is to maximize throughput and to improve spectral efficiency. The main aim is to minimize the bit error rate (BER) for Cooperative Communication systems with hierarchical modulation over additive white Gaussian noise (AWGN) and Rayleigh fading channel. The error rate performances can be analyzed by each of the transmission bits. a criterion is proposed to choose the optimal distance parameters for minimizing the BER of the refinement bits while guaranteeing the BER requirement of the base bits. Simulation results validate the correctness of the derived BERs of the base bits and the refinement bits.