Multiuser detection and interference suppression techniques for direct sequence spread spectrum systems in which all users employ same spreading code

摘要

The present invention considers a direct sequence spread spectrum system wherein every user employs the same spreading code. In a preferred embodiment, received signal is correlated with the training signal. Peaks of correlator output are used to identify the delays corresponding to the significant multipath components. The delays that are within a predetermined number of chips of each other are associated with a hypothesized user. In an alternate embodiment, a user separation technique is used which is based on the observation that after the training period, different users send uncorrelated data. In another alternate embodiment, linear minimum mean squared error (LMMSE) based correlators locked to individual users are employed. These correlators only provide multipath components of their corresponding users as output.