Blind Adaptive Successive Interference Cancellation for Multicarrier DS-CDMA

TL;DR

This paper introduces a blind adaptive SIC receiver for multicarrier DS-CDMA that enhances interference suppression and frequency diversity gain, outperforming conventional methods in challenging fading and near-far conditions.

Contribution

It proposes a novel blind adaptive SIC method with interference suppression within despreading, improving detection and cancellation in multicarrier DS-CDMA systems.

Findings

Significantly improved MAI suppression compared to conventional methods

Enhanced performance under severe fading and near-far conditions

Effective exploitation of frequency diversity with low added complexity

Abstract

A new adaptive receiver design for the Multicarrier (MC) DS-CDMA is proposed employing successive interference cancellation (SIC) architecture. One of the main problems limiting the performance of SIC in MC DS-CDMA is the imperfect estimation of multiple access interference (MAI), and hence, the limited frequency diversity gain achieved in multipath fading channels. In this paper, we design a blind adaptive SIC with new multiple access interference suppression capability implemented within despreading process to improve both detection and cancellation processes. Furthermore, dynamic scaling factors derived from the despreader weights are used for interference cancellation process. This method applied on each subcarrier is followed by maximum ratio or equal gain combining to fully exploit the frequency diversity inherent in the multicarrier CDMA systems. It is shown that this way of MAI estimation on individual subcarrier provides significantly improved performance for a MC DS-CDMA system compared to that with conventional matched filter (MF) and SIC techniques at a little added complexity. Performance evaluation under severe nearfar, fading correlation and system loading conditions are carried out to affirm the gain of the proposed adaptive receiver design approach.