Adaptive Reduced-Rank Processing Using a Projection Operator Based on Joint Iterative Optimization of Adaptive Filters For CDMA Interference Suppression

TL;DR

This paper introduces a new adaptive reduced-rank filtering method for CDMA interference suppression that jointly optimizes filters iteratively, achieving better performance with lower computational cost.

Contribution

It presents a novel joint iterative optimization scheme for adaptive filters, improving interference suppression in CDMA systems over existing reduced-rank methods.

Findings

Significantly outperforms state-of-the-art reduced-rank schemes

Requires lower computational complexity

Effective in CDMA interference suppression

Abstract

This paper proposes a novel adaptive reduced-rank filtering scheme based on the joint iterative optimization of adaptive filters. The proposed scheme consists of a joint iterative optimization of a bank of full-rank adaptive filters that constitutes the projection matrix and an adaptive reduced-rank filter that operates at the output of the bank of filters. We describe minimum mean-squared error (MMSE) expressions for the design of the projection matrix and the reduced-rank filter and simple least-mean squares (LMS) adaptive algorithms for its computationally efficient implementation. Simulation results for a CDMA interference suppression application reveals that the proposed scheme significantly outperforms the state-of-the-art reduced-rank schemes, while requiring a significantly lower computational complexity.