Bit loading Optimization for naval PLC systems

In this work a procedure for the optimization of the bit loading in a PLC system implementing OFDM modulation is presented. The optimization strategy aims to find the best compromise between Signal Power, Bit Rate (BR), Bit Error Rate (BER) and Peak-to-Average Power Ratio (PAPR). The problem is approached from two points of view. First, the conflicting objectives of Signal Power, Bit Rate and Bit Error Rate are optimized off line by means of a Multi-Objective approach. A Tabu Search-based search engine has been adapted to the Multi Objective Optimization in order to find a set of Pareto solutions, among which the designer has to take the final choice on the basis of the custom requirements. Secondly, the Selected Mapping method is used on line to reduce the PAPR, finding the best compromise between maximum Bit Rate and minimum PAPR. A semi analytical procedure, described in the paper, is used to determine the optimal phase factor vector. The suitability of the approach has been evaluated referring to the real case of a PLC system implemented in a mega yacht.