An enhanced Hybrid ARQ technique employing signal constellation rearrangement with 64QAM

As one of key techniques of 3G and future mobile communication system, link adaptation can significantly increase the spectral efficiency and render various levels of services by changing available power, data rate, modulation and channel coding parameters. In this paper, we focus on 64QAM Gray constellation. A novel algorithm for searching enhanced hybrid ARQ (HARQ) schemes with constellation rearrangement (CoRe) is proposed, which is suitable for arbitrary retransmission times. The advanced HARQ strategies got by computer search can efficiently reduce the reliability variances of different bits after soft combining. Simulation results show that the novel approach can achieve better BER and throughput performance than traditional ones.