Interference Suppression in Multiuser Systems Based on Bidirectional Algorithms

TL;DR

This paper introduces adaptive bidirectional algorithms that leverage channel correlation to enhance interference suppression in multiuser DS-CDMA systems over fast-fading channels.

Contribution

It proposes novel bidirectional normalized least mean-square and conjugate gradient algorithms with adaptive mixing for improved channel estimation and interference suppression.

Findings

Enhanced tracking of fast-fading channels.

Improved interference suppression performance.

Robustness against time-varying channel conditions.

Abstract

This paper presents adaptive bidirectional minimum mean-square error parameter estimation algorithms for fast-fading channels. The time correlation between successive channel gains is exploited to improve the estimation and tracking capabilities of adaptive algorithms and provide robustness against time-varying channels. Bidirectional normalized least mean-square and conjugate gradient algorithms are devised along with adaptive mixing parameters that adjust to the time-varying channel correlation properties. An analysis of the proposed algorithms is provided along with a discussion of their performance advantages. Simulations for an application to interference suppression in multiuser DS-CDMA systems show the advantages of the proposed algorithms.