Energy-Effiecient Power Allocation in OFDM-based Relaying Networks

Abstract

This study deals with the energy-efficient (EE) power allocation for orthogonal frequency division multiplexing (OFDM)-based two-hop relaying networks under different relaying scenarios including amplify-and-forward (AF) and decode-and-forward (DF) with or without diversity. Firstly, we develop the equivalent channel gain (ECG) for any given subcarrier pair under every relaying scenario, and formulate the optimal EE problem. For the sake generality, a weighted factor is assigned to rate transmitted by the source on every subcarrier to reflect different priorities or quality-of service (QoS) requirements. Then, by exploring the inherent structure and property of the EE design, we prove the quasiconcave relation between the EE and the transmit power, and provide an optimal solution for the EE maximum. Ordered subcarrier pairing (OSP) scheme is also introduced to further improve the EE for the relaying system. Simulation results are shown to compare the EE performance under different scenarios.