Performance Analysis of Hybrid ARQ Systems

In this paper we analyze the average delay and total energy consumption of a hybrid automatic repeat request (ARQ) system taking into account the energy of the transmitter and receiver. We use the random coding bound and cutoff rate in our analysis. We demonstrate that there is an optimum code rate that achieves the minimum delay and energy consumed. To illustrate our analysis, we give examples using binary phase shift keying (BPSK) and 8PSK coherent detection over an additive white Gaussian noise (AWGN) channel. The results show that there is an optimum code rate that achieves a minimum delay and energy consumed. When the receiver´s energy is negligible compares to the transmitter´s energy, BPSK has a better performance than 8PSK. The case is reverse if receiver´s energy requirement dominates the total energy consumed.