Optimal Channel and Relay Assignment in OFDM- based System using AF and DF Relay Strategies

Abstract: We consider a 2-hop wireless relay network where multiple user pairs conduct bidirectional communication via multiple relays based on orthogonal frequency division multiplexing transmission (OFDM). Channel optimization and relay assignment, including sub-carrier pairing, sub-carrier allocation as well as relay selection, for total throughput maximization is formulated for different relay strategies. Using a graph theoretical approach, we solve the problem optimally in polynomial time by transforming it into a maximum weighted bipartite matching (MWBM) problem. Simulations studies are carried out to evaluate the network total throughput versus transmit power per node for AF and DF and the number of relay nodes for different number of subcarriers