Lifetime Optimization for Multi-Source Multi-Relay Cooperative OFDM Systems

This communication presents a resource allocation strategy for maximizing the lifetime of Amplifyand- forward (AF) dual-hop cooperative OFDM networks. The high computational complexity for optimization necessitates our study of suboptimal approaches. Our centralized scheme is implemented in two steps. Specifically, during each transmission interval, source-relay selection and subcarrier pairing can be decided according to channel state information of the relay links and residual energy information at each terminal. Next, energy-aware power loading can be solved by employing standard Lagrange techniques. Numerical examples verify the effectiveness of our proposal.