Evaluate the Word Error Rate of Binary Block Codes with Square Radius Probability Density Function

摘要

The word error rate (WER) of soft-decision-decoded binary block codes rarelyhas closed-form. Bounding techniques are widely used to evaluate theperformance of maximum-likelihood decoding algorithm. But the existing boundsare not tight enough especially for low signal-to-noise ratios and becomelooser when a suboptimum decoding algorithm is used. This paper proposes a newconcept named square radius probability density function (SR-PDF) of decisionregion to evaluate the WER. Based on the SR-PDF, The WER of binary block codescan be calculated precisely for ML and suboptimum decoders. Furthermore, for along binary block code, SR-PDF can be approximated by Gamma distribution withonly two parameters that can be measured easily. Using this property, twoclosed-form approximative expressions are proposed which are very close to thesimulation results of the WER of interesting.