An adaptive antenna array based propagation delay CDMA communication systems

This paper discusses the propagation delay estimation problem for DS-CDM4 based on an adaptive antenna array whzch can suppress interfering signals. The tap weights of the adaptzve beamformer are controlled by two adaptive algorithms such as direct matrzx inver.won (DM7) and linearly constrained minimum variance (LCW). The large sample maximum likelihood (ZSML) estimator is applied to the beamformer output data for estimating the propagation delay of a desired user in multi-user scenarios. The proposed approach is shown to provide better performance than that of a single antenna based LS34L estzrnator v~a simulation resulrs for O dB and 10 dB near-far ratio (NFR) situations. In addition, the Cramer-Rao bound (CRB) gwen M observation bits of received signals from multiple antenna sensors is derived for the parameter estimation problem.