Distributed antenna system using RAKE combining diversity for amulti-carrier DS/CDMA in a frequency selective fading channel

摘要

DS/CDMA suffers from ISI (intersymbol interference) caused by themultipath propagation in a frequency selective fading channel, itgreatly deteriorates BER performance. Since multi-carriers have highcorrelations among subcarriers with one antenna, it does not have enoughdiversity gain. In this paper, we propose a combined system with pathdiversity gain of the distributed antennas and frequency diversity gainof multicarrier. The base station consists of the distributed antennas,whose multi-carriers are effective for the robustness against ISI andICI in frequency selective channel fading, because each carrier hasnon-frequency selective channel fading. It is assigned to severalsub-carriers for each antenna. A set of antennas are fed by a commonsignal with time delay processing to the de-correlated signals. Itcreates a path diversity effect with multi-carriers for each antennawhich can be combined by a RAKE receiver. As a result, we can obtaineffective combined path diversity and frequency diversity gain by theRAKE combining of distributed antennas