Performance Analysis of Multiuser Transmission with Adaptive Antenna Arrays Using Spatial Classes

CDMA system capacity is interference limited. The multiuser transmission (MUT) with adaptive antenna arrays for the downlink direction is considered to increase system capacity and to eliminate the multiple-access interference (MAI) and the inter-symbol interference (ISI) of the CDMA system. In this paper, the angular gain of the spatial filter is modeled by a piece-line function to analysis the interference difference between the in-beam users and the out-beam users. Based on this analysis, a lower complexity MUT scheme using spatial classes is proposed for avoiding MUT computation complexity, which can achieve the nearly same performance with the conventional MUT scheme. The bit-error probability approximation of this MUT scheme is also analyzed as well. The simulation result is used to confirm the availability of this lower complexity MUT scheme.