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

A novel multiple-input multiple-output (MIMO) hybrid automatic retransmission request (HARQ) scheme using a different MIMO mode retransmission, called lower rate retransmission (LRR) scheme, is proposed in this paper. A MIMO mode with a higher diversity order than the initial transmission is used for retransmission to enhance the performance. The performance of LRR scheme has been investigated via Monte Carlo simulations. The proposed scheme can achieve better performance with a lower complexity as compared to conventional MIMO-HARQ schemes used in IEEE 802.16e.