Probability Density Functions of Reliability Metrics for 16-QAM-Based BICM Transmission in Rayleigh Channel

Paper i proceeding, 2007

In bit interleaved coded modulation (BICM), the probability density function (PDF) of the reliability metrics (L-values) fully defines the BICM transmission and may be used to analyze it from an information-theoretic point of view. In this paper, the closed-form expressions for the PDF of the L-values in Rayleigh fading channels for 16-QAM with Gray mapping are derived and contrasted with histograms of the L-values obtained via numerical simulations. The obtained closed-forms show that the PDF is either a sum of exponentials or is bounded by such a sum.