Joint-design of PHY/MAC layers for throughput optimization

This article develops a unified analytical framework for maximizing the user throughput of a cooperative multi-relay network over generalized wireless channels using the symbol rate, packet length and constellation size of M-ary PSK/QAM digital modulation schemes as optimization variables. Optimization equations for each of the above degrees of freedom are derived in closed-form. A low-complexity discrete optimization algorithm for finding the “optimal” parameter-triplet is also developed to solve the resulting non-linear joint optimization problem. Numerical results reveal that it is sufficient to adapt the number of cooperating relay nodes as well as the symbol rate in the low SNR regime while a joint-optimization of both the packet length and the constellation size parameters is desirable in the high SNR regime to achieve the maximum throughput.