CTH05-5: Evaluation of Bit Error Rate for Packet Combining with Constellation Rearrangement

In this paper, we propose a method to evaluate analytically the bit error rate (BER) for packet combining with Gray mapping and constellation rearrangement (CoRe) between retransmissions - a mapping diversity scheme adopted in the high speed downlink packet access (HSDPA) standard. We first develop the model for the logarithmic likelihood ratios (LLR) and show that their conditional probability density functions (pdf) are piecewise Gaussian. We then present the derivation of the BER and illustrate it with simulation results that validate our formulation.