On the Asymptotic Performance of Bit-Wise Decoders for Coded Modulation

• Two decoder structures for coded modulation over the Gaussian channel are studied: the maximum likelihood symbol-wise decoder, and the (suboptimal) bit-wise decoder based on the bit-interleaved coded modulation paradigm. We consider a 16-ary quadrature amplitude constellation labeled with a Gray labeling. It is shown that the asymptotic loss in terms of pairwise error probability, for any two codewords caused by the bit-wise decoder, is bounded by 1.25 dB. The analysis also shows that the asymptotic loss is zero for a wide range of linear codes, including all rate-1/2 convolutional codes.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Telekommunikation (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Telecommunications (hsv//eng)

Keyword

pulse-amplitude modulation

coded modulation

logarithmic likelihood ratio

Gray code

bit-interleaved coded modulation

pairwise error probability

Additive white Gaussian noise

Publication and Content Type

art (subject category)

ref (subject category)