HARQ Transmission State Control Algorithm for MIMO Systems with IC Detection

The goal of this paper is to develop a hybrid automatic repeat request (HARQ) transmission state control algorithm for multiple-input multiple- output (MIMO) systems with interference cancellation (IC) detection to improve throughput. The HARQ transmission state is defined as the distribution of the initial packets and retransmission packets transmitted during a transmission time slot. In such a system, the retransmission packets normally have a lower error probability than initial packets. However, in terms of throughput, successful decoding of an initial packet is more rewarding than a retransmission packet. The proposed algorithm generates the transmission state in which initial packets and retransmission packets are sent together. The outcome is that it achieves a lower error probability for initial packets by exploiting the IC process and a significantly higher throughput than the conventional HARQ system, which is verified by simulation results.