Adaptive arrays for high rate data communications

A wideband TDMA system for high rate communications with an adaptive antenna array at base stations is proposed. This system is based on the recursive least squares (RLS) adaptive algorithm. The adaptive array provides a way to suppress the co-channel interference (CCI) and intersymbol interference (ISI). A method to generate a reference signal for the RLS algorithm is presented. We also propose two multipath diversity schemes, tapped delay lines (TDL) and parallel array processors (PAP), to cope with the urban cellular multipath environment and enhance the performance of the adaptive array system. The performance of the proposed system is quantified by comparison with an one-element omnidirectional antenna system. It is shown that the adaptive antenna system has a substantial improvement in performance over the one-element antenna system. Two different multipath diversity schemes are compared corresponding to signal-to-noise ratio (SNR) and multipath angle of arrival (AOA) spread. The simulation results illustrate that, for a wide AOA spread, the PAP outperforms the TDL scheme. However, the TDL is a better scheme for a narrow AOA spread