A fuzzy rule base system aided rate enhancement scheme for OFDM systems

Adaptive communication is one the key attributes of almost all communication systems nowadays. In this way, available resources are optimally used to enhance the overall throughput of system while satisfying certain constraints. In this paper a similar constrained optimization problem is formulated. A fuzzy rule based system (FRBS) is designed and used for solution of the problem. The parameters being optimized for the system are forward error correction (FEC) code and modulation scheme. FRBS suggests how to change these parameters according to varying channel state information (CSI) on Orthogonal Frequency Division Multiplexing (OFDM) channel that throughput can be maximized. Multilevel codes, Quadrature Amplitude Modulation (QAM) are used as FEC and Modulation scheme respectively. Moreover, a modified iterative algorithm is used for decoding the multilevel codes. Significance of proposed scheme is shown by simulations.