Performance of Modified Iterative Decoding Algorithm for Multilevel Codes in Adaptive OFDM System

Abstract

In this paper, the Modified Iterative Decoding Algorithm (MIDA) is investigated for decoding Multi-level codes. Adaptive Orthogonal Frequency Division Multiplexing (AOFDM) system is used as system model for this experiment. MIDA is a hard decision decoder that was initially proposed for decoding of Product codes and later for Multi-level codes by same authors. As Multi-level codes are matrix codes we have found that they have structural compatibility with OFDM systems. In OFDM system each subchannel may have different channel state information (CSI) which may be varying over the time. So a Multilevel code with suitable combination of constituent row codes can play a vital role in combating poor channel conditions on OFDM subchannels. A fuzzy rule based system (FRBS) is used for selection of suitable most Multilevel code and modulation symbol. Performance is shown by simulations.