Joint Bit Loading and Subcarrier Matching in Two-Hop Cooperative Systems

Relaying and cooperative communications are key technologies present in 4G (4th Generation) and probably in 5G (5th Generation) networks. Efficient RRA (Radio Resource Allocation) applied in relay networks has the potential to fully exploit the performance gains in terms of spatial diversity, coverage and spectral/energy efficiency. Previous works in the literature have studied RRA for relay networks considering the unrealistic assumption of continuous mapping between SNR (Signal-to-Noise Ratio) and transmit data rate. In fact, the mapping between channel quality state and transmit data rates in real systems is discrete and depends on the employed MCSs (Modulation and Coding Schemes). In this work we reformulate the total data rate maximization problem with this new assumption, show an approach to obtain the optimal solution and propose lowcomplexity quasi-optimal solutions to the considered scenario.