Enhanced Constellation Rearrangement for HARQ with Symbol Combining

A new signal constellation rearrangement for HARQ method is presented in this paper, where symbol-combining mappings are used for retransmission and at the receiver, the symbol combination is implemented before demodulation, and then the combined signal is demodulated with a new constellation. The new constellation has the larger minimum Euclidean distance and the complexity is reduced for its less constellation points. Simulation results show that the proposed method outperforms conventional HARQ constellation rearrangement.