Spatial Correlation of Multiple Antenna Arrays in Wireless Communication Systems

This paper investigates the spatial correlation characteristics of multiple antenna arrays deployed in wireless communication systems. First, we derive a general closed-form formula for the spatial correlation function (SCF) of a multiple antenna array with arbitrary array configuration under uniform signal angular energy distribution. Based on this formula, we then explore the characteristics of the SCF for several multiple antenna arrays with different array geometries. It is found that a multiple antenna array with a three-dimensional (3-D) array geometry can reduce the magnitude of its SCF and hence, improve the ergodic channel capacity (ECC) of wireless communication systems. Accordingly, we present a method to find the optimum 3-D antenna array geometry for maximizing the ECC of a wireless communication system. This method develops a novel objective function to incorporate with a particle swarm optimization (PSO) for solving the resulting optimization problem. Simulation results are provided for confirming the validity and the effectiveness of the proposed method.