Evolutionary Strategy-Based Approaches for Subcarrier, Bit, and Power Allocation for Multiuser OFDM Systems

An evolutionary strategy (ES) scheme is proposed to solve the subcarrier, bit, and power allocation problem in this paper. By the property of the real-valued representation in the evolutionary strategy, the difficulties in coding with the genetic-based algorithms (GA) are conquered. This paper utilizes the method of the binary integer programming to perform the bit loading to overcome the limitation met in the water-filling algorithm. A fuzzy logic controller (FLC) is introduced to adjust the mutation probability in the iteration process. A simple subcarrier assignment modification step is also introduced to speed up the convergence rate and improve the performance. Simulation results are conducted to verify the features of better convergence rates with the proposed schemes, and the performance is improved.