DOA estimation based on an improved hybrid PSOGSA approach for CDMA system

Abstract

In this paper, we consider the problem of estimating the direction-of-arrival (DOA) of code-division multiple access (CDMA) signals. It has been shown that the searching complexity and estimating accuracy of the conventional spectral searching methods strictly depend on the number of search grids used during the search. It is time consuming and the required number of search grids is not easy to determine. As proposed in this paper, a hybrid population-based algorithm (PSOGSA) is proposed with the combination of particle swarm optimization (PSO) and gravitational search algorithm (GSA). The main idea is to integrate the ability of exploitation in PSO with the ability of exploration in GSA to synthesize both algorithms' strength. However, the proposed technique offers a much faster convergence compared to the PSO. For the purpose to increase the estimation accuracy, we also propose an improved PSOGSA with adaptive multiple velocity, which depend on first-order Taylor series expansion of the objective function. In conjunction with an improved PSOGSA for angle searching, the proposed approach can achieve the advantages of reducing search complexity and more accurate estimate over existing conventional spectral searching method. Finally, several computer simulation examples are provided for illustration and comparison.