SNR and Channel Mismatch Effect on Iterative (Turbo) Detection Performance from EXIT Chart Analysis

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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Ahmed-Ouameur, Messaoud; Massicotte, Daniel (Department of Electrical and Computer Engineering, Université du Québec à Trois-Rivières, C.P. 500, Trois-Rivières, Québec, Canada, G9A 5H7)

In this paper, EXIT chart analysis is used to investigate the effect of SNR and channel mismatch on the performance of iterative (turbo) detectors. As an example, a soft Interference Canceller (IC) followed by a Soft Input Soft Output (SISO) MMSE filter, whose coefficients are thought to be the solution of an MMSE-optimization problem based on a (forced) real valued filter output rather than a complex one, is examined. When overestimated, SNR mismatch has more negative effect. Moreover, EXIT charts reveal that a 2% error in channel estimates seems to be quite enough to degrade the overall performance.