Orthogonalizing matched filtering (OMF) detector for DS-CDMA mobile communication systems

This paper proposes a new blind interference suppression scheme for direct-sequence code-division multiple-access (DS-CDMA) mobile communication systems. The proposed detector, the orthogonalizing matched filtering (OMF) detector, consists of a bank of despreading filters and a signal combiner. The received composite signal is first despread by the filters in the bank. The despreading filter outputs are then weighted and combined. The weight vector is adaptively determined and updated so that the average combined signal power is minimized while keeping the combiner´s response to the desired signal constant. The proposed algorithm for OMF weight updating requires neither knowledge about other users´ spreading sequences nor desired user´s signal reference. The similarity between the proposed OMF detector and Applebaum´s sidelobe canceller adaptive array is discussed in detail. Results of computer simulations are shown to demonstrate the OMF performance in various mobile communications environments