Adaptive forgetting factor RLS algorithm equalizer for DS-CDMA system based on adaptive Laguerre lattice filter

Abstract

A new RLS adaptive algorithm with variable forgetting factor for direct sequence code division multiple access (DS-CDMA) communication system is presented.Intersymbol interference (lSI) 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 lSI with a long impulse response environment based on the proposed receiver. We consider an adaptive Laguerre lattice equalizer which applies an optimal method based on the variable step-size least mean square (VSLMS) algorithm for adaptable forgetting factor RLS algorithm to improve bit error rate (BER) performance of the receiver.

Adaptive equalizer for DS-CDMA multi-user communication system based on Laguerre filter structure with sign-algorithm

“…߬ ݇,݉ is assume to be a multipath of ܶ ܿ . The path attenuation ܽ ݇,݉ is complex Gaussian random process with zero mean, where ܽ ݇,݉ can be written by [2,6] …”

“…However, the intensive ISI and the other noise, it was turned to the long impulse response system. Fortunately, adaptive equalization at chip level can be applied to recover orthogonalization of the channel code and minimize the effected of MAI [1][2][3][4][5][6][7][8][9][10][11]. A basically implementation of adaptive equalizer is a digital filter working with an adaptive algorithm.…”