Cross-Layer Scheduling for OFDMA Amplify-and-Forward Relay Networks

In this paper, we consider cross-layer scheduling for the downlink of amplify-and-forward (AF) relay assisted orthogonal frequency division multiple access (OFDMA) networks. The proposed cross-layer design takes into account the effects of imperfect channel state information at transmitter (CSIT) in slow fading. The rate adaptation, power adaptation, and subcarrier allocation policies are optimized to maximize the system goodput (bits/s/Hz successfully received by the mobiles). The optimization problem is solved by using dual decomposition resulting in a highly scalable distributed resource allocation algorithm. Simulation results illustrate that the proposed distributed cross-layer scheduler requires only a small number of iterations to achieves practically the same performance as the optimal centralized scheduler.