Asymptotic Energy Efficiency Analysis for Noisy Relay Systems with Interference-Limited Destination

This paper analyzes the asymptotic energy efficiency performance in relay systems with the destination perturbed by the co-channel interference. The interference is caused by the time slot sharing in the relay-transmit phase. The closed-form expression for the energy per good-bit constrained by a certain bit error rate is derived. The energy consumption model does not only include the transmit and circuit energy, but also considers the energy required for retransmission. The retransmission probability depending on the link reliability is determined by the outage probability under the Rayleigh fading channel assumption. The numerical results analyze the impact of the interferer number on the system energy efficiency performance. How the energy consumption varies with the interference power distribution is presented. They also investigate the variation of the energy efficiency with the constellation size constrained by different bit error rates. Some interesting implications can be observed from the analysis.