Relay Selection Fairness and Resource Allocation for OFDMA Networks

In this paper, resource allocation for a relay-based multi-user Orthogonal Frequency-Division Multiple Access (OFDMA) uplink system is studied. All the relays adopt the decode-and-forward protocol and assist the transmission from the source to destination. In current wireless networks, the terminal depends more on battery power. Given that, battery life is limited, prolonging the service life of equipment is a key problem in ensuring the information transmission and in reducing the financial burden of the batteries. We aim to maximize the survival time of the relay system and to reduce the rate of loss. Therefore, we formulate the problem in which the subcarriers select the optimal relay based on both the channel gain and the residual capacity of the relays. We also consider a weighting factor that reflects the residual capacity of different relays. Simulation results show that the proposed algorithms can achieve longer survival time of the relay systems.