【摘要】 针对频率选择性时变信道下的正交频分复用直接序列码分多址 (OFDMDS CDMA)系统的上行链路 ,提出一种联合检测算法 .它使用改进的部分并行干扰消除算法实现多用户检测 ,并在导频辅助下估计时变信道 .在不同的车载速度下检验本文算法的性能 ,仿真结果表明 :在车速不超过 1 2 0km/h时 ,本文算法能有效抑制多址干扰 ;当车辆速度超过 2 5 0km/h时 ,必须对多普勒效应引起的频率偏移进行估计并纠正以消除信道间干扰 .更多还原

【Abstract】 A joint detection algorithm is proposed for the uplink of OFDM DS-CDMA (direct sequence code division multiple access) systems over frequency-selective time-varying (TV) channels. The multi-user detection is realized by the modified partial parallel interference cancellation (PPIC),and estimates TV channels aided by pilots. The proposed algorithm is tested by simulations under different work conditions,and simulation results show that it can effectively compress multiple access interference (MAI) and correctly estimate TV channels when the speed of terminals is below 120 km/h. While the speed is over 250 km/h,the frequency offset caused by Doppler effect must be estimated and corrected to delete inter-carrier interference (ICI).更多还原