Adaptive equalization for DS-CDMA multi-user communication system based on adaptive Laguerre lattice filter

Abstract

This paper deals with an adaptive equalizer based on Laguerre lattice filter and the recursive least square (RLS) adaptive algorithm for direct sequence-code division multiple access (DS-CDMA) communication system. Intersymbol interference (ISI) arises due to multipath propagation, which destroys the code orthogonality, gives rise to multiple access interference(MAI). Therefore, the objective of this paper is to minimize the effect of ISI with a long impulse response environment based on the proposed receiver. Because of the stability of Laguerre structure is sharing the characteristic of finite impulse response (FIR) filter and infinite impulse response (IIR) filter and the low sensitively of lattice filter is an attractive characteristic. Therefore, we propose the adaptive equalization based on adaptive Laguerre lattice filter for improve the bit error rate (BER) performance of the receiver. Our simulation results show that the performance of the proposed receiver in terms of BER and the stability are better than the conventional Laguerre filter and FIR filter receivers.