A low-complexity adaptive receiver for DS-CDMA systems in unknown code delay environment

作者：Chen, Jun-Da; Ueng, Fang-Biau^*; Lin, Pi-Feng

来源：International Journal of Communication Systems, 2011, 24(2): 225-238.

DOI：10.1002/dac.1151

• DS/CDMA
• LMS
• adaptive receiver

In direct-sequence code division multiple access (DS/CDMA) multiuser communication systems in multipath channels, both intersymbol interference (ISI) and multiple-access interference (MAI) must be considered. The multipath channel characterizes the propagation effects including the timing offset and delays, etc. Traditionally, we use the delay-locked loop (DLL) code tracking loop to recover the timing delay. But DLL cannot work well in multipath environment. In this paper, we propose a low-complexity adaptive receiver to suppress ISI/MAI and solve the timing offset problems without using conventional DLL code tracking loop. The proposed receiver employs an adaptive filter whose weights are adapted using a block least-mean square error algorithm with fractional sampling. Simulations confirm the good performance, including learning curves and theoretical analysis of minimum mean-square error, of the proposed receiver.

• 出版日期2011-2