On the distribution of extrinsic L-values in gray-mapped 16-QAM

A. Alvarado, L.L. Szczecinski, R. Feick

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

4 Citations (Scopus)


In this paper we address the issue of probabilistic modelling of the extrinsic L-values, used as reliability metrics in the context of bit interleaved coded modulation with iterative demapping (BICM-ID). Starting with a simple piece-wise linear model of the L-values obtained via the max-log approximation, we derive the expressions for the cumulative distribution functions of the L-values, that differentiated produce the desired forms of the probability density functions for Gray-mapped 16-QAM. To illustrate the usefulness of our analytical expressions we applied them to efficiently compute the so-called EXIT functions of the demapper for different values of SNR. The proposed analytical expressions are also compared to thehistograms of the L-values obtained through time-consuming simulations.
Original languageEnglish
Title of host publication2007 AMC International Wireless Communications and Mobile Computing Conference (IWCMC)
Place of PublicationNew York
PublisherAssociation for Computing Machinery, Inc
ISBN (Print)978-1-59593-695-0
Publication statusPublished - 2007
Eventthe 2007 international conference - Honolulu, Hawaii, USA
Duration: 12 Aug 200716 Aug 2007


Conferencethe 2007 international conference


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