Direction-of-Arrival Estimation Based on Particle Swarm Optimization Searching Approaches for CDMA Signals

This paper deals with direction-of-arrival (DOA) estimate problem based on multiple signal classification (MUSIC) criterion with particle swarm optimization (PSO) for code-division multiple access signals. It is shown that the computational complexity and estimate accuracy of the traditional spectral searching MUSIC estimator strictly depends on the number of search grids used during the search. The more accurate DOA estimation, the more searching grids are needed. In conjunction with PSO algorithm, the computational complexity of DOA estimation of MUSIC estimator can be reduced, while the accuracy of estimation performance can be enhanced. But, the optimum solution searching and the convergence of standard PSO iteration process are restricted by using the linearly decreasing intra weights the hard limited conditions of particles moving velocities and position clipping. To promote accurate DOA finding, a modified PSO estimator with the decision strategy of particle velocities and particle position clipping is presented in this paper. In addition, this paper also presents adaptive multiple inertia weights with Newton–Raphson method to speeding up the convergence of modified PSO iteration process. Several computer simulation examples are provided for illustration and comparison.