PERFORMANCE EVALUATION OF ACTIVE CODES DETECTION ALGORITHM IN DOWNLINK TD-SCDMA SYSTEMS

摘要

Joint Detection (JD) algorithm is one of the key technologies in TD-SCDMA systems. In downlink, one desired user should know all of the active codes in one time slot when JD algorithm is used in the receiver. However, according to the active code identification method in current 3GPP TD-SCDMA specifications, only part not all of the exact information of the active codes are available in some application cases. Then JD algorithms will encounter the problems of degrading the system performance. Active codes detection algorithm has been proposed to solve the problems in some literatures. In this paper, we carry out the simulation about ZF-BLE, one of typical JD algorithm in downlink TD-SCDMA, to test the performance of the current active codes detection algorithm. The simulation results show that active codes detection algorithm cannot make ZF-BLE achieve the best detection performance in downlink TD-SCDMA, and will bring great performance loss in some 3GPP standard multipath fading channels. The better solution is to let the desired user know the exact active codes of the other users directly from the base station.