Energy-Efficient Resource Optimization for Relay-Aided Uplink OFDMA Systems

In this paper, the energy-efficient resource allocation in relay-aided uplink multiuser system is studied. We adopt the orthogonal frequency division multiplexing (OFDM) as the physical layer modulation technique. Assuming that the BS has all the channel state information (CSI), an energy-efficiency optimization problem through joint subcarrier assignment, bit and power allocation is formulated. Due to the computational complexity restriction, a suboptimal solution based on decomposition is presented to solve the problem with low complexity. Considering the fairness constraint, a joint resource allocation algorithm is further proposed, which is proved to achieve a considerable improvement in terms of energy-saving and simultaneously decreases rate outage probability by simulation results.