Adaptive Resource Allocation in OFDMA Relay Networks with Network Coding

This paper investigates the user and channel diversity in OFDMA wireless systems with network coding. In particular, the paper introduces an adaptive resource allocation scheme to minimize the total transmit power while maintaining a required end-to-end BER. The proposed adaptive sub-carrier allocation scheme de-couples the bit loading of the network coded OFDMA system into three independent bit loadings on three OFDM links. This approach allows the deployment of a conventional bit loading algorithm for OFDM on individual links. The simulation results show that, in frequency selective Rayleigh fading channels, the proposed low-complexity resource allocation scheme can significantly reduce the total power consumption in the network and maintain a targeted BER.