Adaptive Beamforming for Slow Fading Rayleigh Signals
R. DeLap, Alfred O. Hero · 2005
In this paper we develop an adaptive beamsummer for direction of arrival (DOA) estimation of slow fading Raleigh signals, using a new design approach, termed "Adaptive Detection/Estimation for sPecific Tasks" (ADEPT). For DOA estimation, the ADEPT method yields a weight adaptation criterion which is optimized for those weights that minimize the Cramer-Rao (CR) lower bound on achievable mean-square-error of any unbiased DOA estimator constructed on the beamsummer outputs. Simulation results are provided which show that the ADEPT DOA beamsummer yields DOA estimates whose meansquared error (MSE) approaches that of the more complex maximum likelihood implementation. 1. PROBLEM STATEMENT Figure 1 shows an m-element linear beamsumming array on which impinge p signals arriving from directions `1 ; : : : ; `p . At the k-th time instant a snapshot Y k = [Y k 1 ; : : : ; Y k m ] T of the m-sensors is acquired, k = 1; : : : ; n. We assume the following model for slow Rayleigh fading [1...