Cooperative Strategies and Fairness-Aware Resource Allocation in Selection-Based OFDM Networks

This paper considers a multi-source orthogonal frequency division multiplexing (OFDM)-based network of access points wherein dedicated relays use the decode-and-forward relaying. We investigate the joint problem of transmission strategy selection (relaying v/s direct), relay assignment, and power allocation to maximize the minimum rate across sources in two different cooperative scenarios: subcarrier-based and block-based relaying. In the subcarrier-based scheme, each subcarrier is treated as an independent transmission; however, in addition to the synchronization problems caused, it is likely impractical for a relay to decode a subset of subcarriers. Thus, we study relay selection for the entire OFDM block. The key difference from previous work is that we consider resource allocation across source-relay, relay-destination, and source-destination channels. Second, a simple, distributed, block-based scheme is proposed. Simulation results using the COST-231 channel model reveals that the performance of this heuristic scheme tracks that of the optimum block-based scheme while it significantly decreases the required computational complexity.