Fidelity Charts and Stopping/Termination Criteria for Iterative Multiuser Detection
Conference: TURBO - CODING - 2006 - 4th International Symposium on Turbo Codes & Related Topics; 6th International ITG-Conference on Source and Channel Coding
04/03/2006 - 04/07/2006 at Munich, Germany
Proceedings: TURBO - CODING - 2006
Pages: 6Language: englishTyp: PDF
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Authors:
Shepherd, David P.; Reed, Mark C. (National ICT Australia, Australian National University, Canberra, Australia)
Brännström, Fredrik (Dept. of Signals and Systems, Chalmers University of Technology, 412 58 Göteborg, Sweden)
Abstract:
An iterative multiuser detection (IMUD) receiver is considered for a code-division multiple-access (CDMA) system with turbo codes. Fidelity is considered as a metric for convergence analysis and an approximation of fidelity as a function of variance of the log-likelihood ratios is introduced. Fidelity charts are compared with extrinsic information transfer (EXIT) charts as tools for convergence analysis and a close approximation of the relationship between fidelity and mutual information is proposed. We then use this function to approximate a closed form expression for the EXIT function of an interference canceller. Further, we propose a new stopping criterion for the turbo decoder and the IMUD receiver which achieves complexity saving of up to 50% over conventional designs.