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

Abstract

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. 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 efÞcient 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.Index Terms-DS-CDMA systems, multiuser detection, decision feedback structures, iterative detection, iterative decoding.

Single Antenna Interference Cancellation Algorithm Based on Lattice Reduction

“…, {} q denotes an integer rounding operation. The final detection result for the transmission symbols is then obtained by ˆ{ } q S TS (14) Given that S contains 1 () sn , 1 () sn can thus be obtained directly from S .…”

Low-complexity iterative receiver design for mobile OFDM systems

“…These are symbol-interleaved to produce μ x and ν x . As described in (8), μ x is used to remove the ICI interference, whereas ν x is used in the channel estimator to determine the reliability of μ x . The ICIremoved data is fed to the LLR computer to generate more reliable LLRs to further improve the output bit estimate.…”

“…In [3], an iterative decision feedback equalizer (DFE) is proposed to perform ICI cancelation such that the modified system matrix becomes diagonal in the frequency domain. (b) Successive cancelation of the interference [5][6][7][8]. In [5], ICI is removed in the time domain.…”

“…A modified low-complexity MMSE equalizer that takes the decision error into account is then derived. In the context of interference cancelation in CDMA systems, authors of [8] propose a MMSE estimator where the estimate of the desired signal is computed repeatedly, each time rearranging the order of interference cancelation using a novel algorithm. They then select the most likely estimate (that has the least error) from the above list.…”

Successive interference cancellation aided sphere decoder for multi-input multi-output systems

“…For the complexity reduction, the authors in [3][4][5][6][7][8] have studied different search strategies and enumeration schemes. Additionally, some suboptimal methods with linear and decision feedback equalization (DFE) [9,10] have been proposed to approach the ML performance. In most applications, the complex-valued system is decoupled and reformulated as an equivalent real-valued system.…”