Chip-based joint processing adaptive array and equalizer for DS-CDMA packet mobile communication systems

摘要

This report proposes a chip-based joint processing adaptive array and equalizer for DS-CDMA packet mobile communications. The proposed receiver consists of an adaptive array antenna and an MLSE equalizer. The adaptive array part has fractional tap-spacing transversal filters at all the elements, and suppresses co-channel interferences from other cells and ISI (Inter-Symbol Interference) due to delayed paths with relatively large delay time. The MLSE equalizer part, which employs DDFSE (Delayed Decision-Feedback Sequence Estimation) so as to reduce the computational complexity, estimates the chip-level transmitted signals by removing ISI components from the array output. The equalizer output is despread by matched filters, of which the outputs are utilized for the signal detection. In case of the QPSK modulation, computer simulations under frequency selective fading conditions demonstrate that the proposed scheme is superior to the conventional linear chip-based equalization in both the BER performance and the packet throughput.