Packet Error Rate Analysis and Power Allocation for CC-HARQ Over Rayleigh Fading Channels

In this letter, a novel approach is developed to evaluate the average packet error rate (PER) for chase combining (CC) based hybrid automatic repeat request (HARQ) protocol over block Rayleigh fading channels for the long packet system. A simple approximated expression for the average PER at the high signal-to-noise ratio (SNR) region is further proposed. Based on the approximation, the optimal power allocation (OPA) scheme for CC-HARQ is studied. The closed-form optimal assignment solution at the high SNR is derived to minimize the average total power consumption under packet loss rate (PLR) and maximum number of transmission rounds constraints. Furthermore, the impact of transmission parameters on the OPA scheme is investigated. It is found that the ratios among the optimal power sequence just depend on the targeted PLR and the maximum number of transmission rounds.