Patent Number: 6,295,311

Title: Method and apparatus for compensating for phase differences in received signals

Abstract: A method and apparatus for estimating the phase of noncoherently detected signals is provided. The received signals are in-phase and quadrature-phase signals from fingers of a rake receiver. A joint detection and estimation strategy is employed to increase the received signal-to-noise ratio of a code-division multiple access (CDMA) communication system. An orthogonally encoded signal is noncoherently detected and select signal components from the received signal are used in estimating the unknown phase and strength of the signal. Values are determined by a Fast Hadamard Transform indicative of a likelihoods that estimated signals correspond to the transmitted signal. Corresponding values are summed and the index of the largest sum is used to select likelihood values. A weight is developed by accumulating a plurality of the selected values over a predefined time period and calculating an average of the plurality, or a subset of the plurality. The likelihood values are then scaled, by multiplying them by the weight, and again combined by summing corresponding values.

Inventors: Sun; Feng-Wen (Germantown, MD)

Assignee: Hughes Electronics Corporation

International Classification: H04B 1/707 (20060101); H04K 001/00 ()

Expiration Date: 09/25/2018