Optimizing dual-hop systems under orthogonal transmission and relay selection schemes

In this paper, we explore resource optimization problem in dual hop multi-carrier amplify and forward (AF) based relay networks. First, we consider an orthogonal transmission where the source and relay stations transmit information in different time slots. We investigate the joint optimization of subcarrier matching over two hops and the power allocation over different subcarriers at the source and the relay nodes. Although the joint optimization problem under power and subcarrier constraints is a mixed integer programming problem, we propose an efficient solution based on the dual decomposition approach. Then, we present a selection scheme where a single best relay is selected for the dual hop communication. Finally, simulation results are provided to corroborate the proposed studies.