Patent ID: 7714781

Claim:
A method of analog beamforming in a wireless communication system, comprising the steps of: constructing analog beamforming coefficients by: performing an iterative beam acquisition process based on beam search training; and determining optimized beamforming weighting coefficients based on the iterative beam acquisition process, wherein determining includes determining optimized beamforming phase weighting coefficients based on the iterative beam acquisition process, wherein each iteration includes separately estimating receive and transmit analog beamforming coefficients alternately, until the receive and transmit beamforming coefficients converge, wherein estimating the receive analog beamforming coefficients comprises: estimating a matrix B based on frequency channel response, forming a matrix R B =B H B, define {right arrow over (b)}(θ) [1, e jkd cos θ , e j2kd cos θ , . . . , e j(N−1)kd cos θ ] H , form a function π ⁡ ( θ ) = 1 b H _ ⁡ ( θ ) ⁢ R B - 1 ⁢ b _ ⁡ ( θ ) determine a peak of π(θ) and a corresponding θ*, where θ* is an estimated angle of departure, and estimating a transmit beamforming vector as {right arrow over (w)}={right arrow over (b)}(θ*); and wherein estimating the transmit analog beamforming coefficients comprises: estimating a matrix A based on frequency channel response and {right arrow over (w)}, forming a matrix R A =A H A, defiine {right arrow over (a)}(φ)=[1, e jkd cos φ , e j2kd cos φ , . . . , e j(N−1)kd cos φ ] H and form a function ρ ⁡ ( ϕ ) = 1 a H _ ⁡ ( ϕ ) ⁢ R A - 1 ⁢ a _ ⁡ ( ϕ ) determine a peak of ρ(φ) and a corresponding φ*, where φ* is an estimated angle of arrival, and estimating a receive beamforming vector as {right arrow over (v)}={right arrow over (a)}(φ*), where d is an inter-antenna distance, φ is the angle of departure and θ is the angle of arrival, N is a number of transmit antennas, M is a number of receive antennas, K is a number of subcarriers, j is a positive integer.