Minimum Mean-Squared Error Iterative Successive Parallel Arbitrated Decision Feedback Detectors for DS-CDMA Systems

TL;DR

This paper introduces a novel iterative decision feedback detection scheme for DS-CDMA systems that improves interference cancellation and mitigates error propagation, enhancing detection performance in multiuser environments.

Contribution

It proposes a new MMSE-based iterative successive parallel arbitrated decision feedback structure with a low complexity user ordering algorithm for DS-CDMA systems.

Findings

The proposed detector outperforms linear receivers in simulations.

The new scheme effectively reduces error propagation effects.

Simulation results validate the improved performance in uplink scenarios.

Abstract

In this paper we propose minimum mean squared error (MMSE) iterative successive parallel arbitrated decision feedback (DF) receivers for direct sequence code division multiple access (DS-CDMA) systems. We describe the MMSE design criterion for DF multiuser detectors along with successive, parallel and iterative interference cancellation structures. A novel efficient DF structure that employs successive cancellation with parallel arbitrated branches and a near-optimal low complexity user ordering algorithm are presented. The proposed DF receiver structure and the ordering algorithm are then combined with iterative cascaded DF stages for mitigating the deleterious effects of error propagation for convolutionally encoded systems with both Viterbi and turbo decoding as well as for uncoded schemes. We mathematically study the relations between the MMSE achieved by the analyzed DF structures, including the novel scheme, with imperfect and perfect feedback. Simulation results for an uplink scenario assess the new iterative DF detectors against linear receivers and evaluate the effects of error propagation of the new cancellation methods against existing ones.