An efficient technique based on firefly algorithm for pilot design process in OFDM-IDMA systems

Abstract

Accurate placement of pilot tones has been a crucial task in multicarrier transmission technologies since thereis a strong relation between pilot positions and channel estimation performance. Therefore, the firefly algorithm (FA) isproposed for achieving the optimal pilot distribution by optimizing the pilot positions in order to minimize the estimationerrors of the least squares algorithm employed in orthogonal frequency division multiplexing-interleave division multipleaccess (OFDM-IDMA) systems. According to the simulation results, our proposed FA-based pilot optimizer provides agreat performance increase in OFDM-IDMA systems by obtaining the most appropriate pilot distribution pattern amongthe considered pilot placement strategies. The upper bound of mean square error (MSE) is used as the fitness functionin the optimization process for avoiding the matrix inversion operation that is needed when calculating MSE itself.