ADAPTIVE SPREAD-SPECTRUM SYSTEMS USING LEAST-SQUARES LATTICE ALGORITHMS.

A description is given of exact least-squares (LS) recursive lattice algorithms which resolve the uncertainties in a direct-sequence spread-spectrum digital communication system. These uncertainties relate to the direction, timing, and distortion of the desired signal, and the spectral and spatial distribution of the interference, all of which may change with time. The adaptive LS algorithm is recursive both in order and time and converges rapidly to the uncertain parameters. Different configurations of optimal time-discrete receivers are presented and transformed into adaptive receivers by taking advantage of the spectral properties of the different kinds of LS filters. Simulation results are presented and some guidelines are given for the architecture of an adaptive direct-sequence spread-spectrum system.