Performance analysis of incremental redundancy hybrid ARQ in mobile ad hoc networks

In this paper, the performance of hybrid automatic repeat request with incremental redundancy (HARQ-IR) in a mobile ad hoc network (MANET) is analyzed. Based on the theory of stochastic geometry, both interference and the randomness in nodes´ locations are incorporated into our analysis. The outage probability after the kth retransmission is analyzed and the outage performance of HARQ-IR is compared with that of Type-I HARQ and HARQ with chase combining (HARQ-CC). Our analysis reveals that the performance gains of HARQ-IR over Type-I HARQ and HARQ-CC increase with the number of retransmissions while they decrease with the path loss exponent. The network throughput in terms of transmission capacity is also analyzed. The results indicate that a certain small number of retransmissions is sufficient to achieve the maximal transmission capacity. Meanwhile, the optimal intensity of source nodes to maximize the transmission capacity is shown to be within a specific interval.