Arc Hyperbolic Tangent representation scheme for APP decoders working on the dual code

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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Srinivasan, Sudharshan; Pietrobon, Steven S. (Institute for Telecommunications Research, University of South Australia, Mawson Lakes SA 5095, Australia)
Pietrobon, Steven S. (Small World Communications, 6 First Avenue, Payneham South SA 5070, Australia)

An a posteriori probability (APP) decoder working on the trellis of the dual code is preferred if the code rate is high. However, the nature of the metrics in a dual-APP decoder makes a hardware realisation quite complex, due to very fine quantisation requirements. This paper points out the problem associated with a traditional log domain approach and proposes a new metric representation scheme. The arithmetic operations involved in a trellis based implementation are discussed and simulation results for a turbo code are given.