MIMO Hybrid-ARQ Utilizing Lower Rate Retransmission over Mobile WiMAX System

A novel multiple-input multiple-output (MIMO)hybrid automatic retransmission request (HARQ) scheme usinga different MIMO mode retransmission, called Lower RateRetransmission (LRR) scheme, is proposed in this paper. AMIMO mode with a higher diversity order than the initialtransmission is used for retransmission to enhance the performance.The performance of LRR scheme has been investigatedvia Monte Carlo simulations. The proposed scheme can achievebetter performance with a lower complexity as compared toconventional MIMO-HARQ schemes used in IEEE 802.16e.