DOA ESTIMATION IN DS-CDMA SYSTEMS OVER FREQUENCY-SELECTIVE FADING CHANNELS USING DECORRELATING DETECTOR AND APERTURE-EXTENDED MUSIC ALGORITHM

摘要

In the paper, we develop an effective direction of arrival (DOA) estimation method for the synchronous DS-CDMA systems over frequency-selective fading channels. The approach is applied in array antenna receiver at base station. To effectively suppress multiple access interferences (MAI) and estimate DOAs in multipath CDMA channel, multiple parallel code-matched filters with multipath delay and a decorrelating multiuser detector are used to detect each path of desired signal for each mobile user. In the output of the detector, a cumulant-based aperture-extended MUSIC algorithm is developed to estimate each resolvable direction of multipath users. The method can adapt to a larger number of mobile users in practical systems by perfect MAI suppression. Also, each sub-path signal DOA can be accurately estimated with higher resolution than the previous methods because array aperture is extended. By the use of higher order cumulant, it also has advantage of eliminating the spatially colored Gaussian noise or correlative noise in wireless channels.