Effects of element pattern for adaptive array in W-CDMA mobile radio

Abstract

The next generation of land mobile communication systems must offer high bit data rates for multimedia and high-quality services. Adaptive arrays are considered to be a key technology to satisfy these demands, and applying them to land mobile radio has been investigated extensively. However, those reports mainly focus on structures of adaptive receivers or adaptive algorithms, few reports consider antenna arrays, especially the effect of the pattern of the antenna elements of the array antenna on adaptive array performance. The effects of the antenna element pattern on performance have been reported, but the investigation was of adaptive array characteristics for a TDMA cellular system. Recently, W-CDMA has been investigated extensively as an access technology for the third-generation mobile radio, IMT-2000. Interference environments are so different between the TDMA system and W-CDMA (DS-CDMA) system, that it is unknown whether their study can be applied to W-CDMA adaptive arrays or not. We examine the performance of an adaptive array receiver of a base station for a W-CDMA system by computer simulation from the viewpoint of the element pattern of the array antenna. We then discuss the relationship between 3 dB element beamwidth and service area in satisfying a bit error rate (BER) of <10/sup -3/.