Uplink Radio Resource Allocation in AF and DF Relay-Assisted Networks With Limited Rate Feedback

In this paper, we develop quantized ergodic resource allocation in uplink orthogonal frequency-division multiple-access (OFDMA)-based relay-assisted networks in which both amplify-and-forward (AF) and decode-and-forward (DF) protocols are investigated. The main objective is to maximize the average sum rate subject to the power constraint at the users and relays. Using the dual-decomposition technique and the block-coordinate descent algorithm (BCDA), we then obtain a near-optimal solution for the proposed problems. The proposed methods significantly decrease the required feedback information, which reduce the overhead on the bandwidth and the cost. Furthermore, we investigate the impact of the noisy feedback channel on the system performance. Extensive simulation results are also presented, which indicate that DF outperforms AF in various conditions. It is also observed that by increasing the number of quantization regions, the average sum rate approaches the case in which full channel state information is available.