The Range Increase of Adaptive Versus Phased Arrays in Mobile Radio Systems

In this paper, we compare the increase in range with multiple-antenna base stations using adaptive array combining to that of phased array combining. With adaptive arrays, the received signals at the antennas are combined to maximize signalto-interference-plus-noise ratio (SINR) rather than only form a directed beam. Although more complex to implement, adaptive arrays have the advantage of higher diversity gain and antenna gain that is not limited by the scattering angle of the multipath at the mobile. Here, we use computer simulation to illustrate these advantages for range increase in both narrow-band and spreadspectrum mobile radio systems. For example, our results show that for a 3 scattering angle (typical in urban areas), a 100element array base station can increase the range 2.8 and 5.5-fold with a phased array and an adaptive array, respectively. Also, for this scattering angle, the range increase of a phased array with 100 elements can be achieved by an adaptive array with only ten elements.