A Novel Detection Algorithm Efficient for Turbo coded CDMA Signals in Detect and Forward Cooperative Channels

TL;DR

This paper introduces a new detection algorithm for turbo coded CDMA signals in cooperative channels, enhancing system performance and robustness against decision errors through a novel combining scheme.

Contribution

It proposes a new combining algorithm tailored for turbo coded CDMA in cooperative channels, improving robustness and diversity gains.

Findings

Significant performance improvement with the new combining scheme.

Enhanced robustness against decision errors in partner links.

Diversity gains observed in simulations with channel estimation.

Abstract

In this paper, a new detection algorithm is proposed for turbo coded Code Division Multiple Access (CDMA) signals in detect and forward cooperative channels. Use of user cooperation makes much improvement in the performance of CDMA systems. Due to the special structure of CDMA systems, cooperative schemes increase the sum and cutoff capacities of CDMA based wireless systems and improve the quality of user-partner link which enhances the overall performance of the system. In this paper, a new combining scheme is proposed that makes the receiver more robust against the decision errors in the partner link. This structure is simulated for punctured 1/2 rate 4 states turbo code in a channel with first-order Markov time variation and different Rice factor variances. Through various simulations, it is shown when the channel estimates are available in the partner and receiver, the cooperation between users provides much diversity gain especially while using the new proposed combining algorithm.