Patent ID: 6801588
Filing Date: 2004-10-05
Classification: H03M

Abstract:
In a digital communication system wherein source information is quantized into bits and entropy-coded into code words of variable length and the entropy-coded words are channel coded, a decoder comprising:a combined channel and entropy variable length decoder using maximum likelihood information generated by the channel decoder portion of the combined channel and entropy decoder; said decoder includes a buffer for storing likelihood values, means for determining a unique code word by searching for it in a bit pattern or likelihood value and loading candidate code words, means for computing code-word likelihood for a given code-word bit pattern, and means for comparing said code-word likelihood values and providing a selected code; said means for computing code-word likelihood candidates computed according to Pm=&Sum;k=0Nm=1&it;â€ƒ&it;ck&it;lk,where Nm is the length of the code, m denotes the mth code word in the set, ck(k=0, . . . , Nm) represents the code-word bit sequence and lk the likelihood values obtained from the channel decoder.