Punctured and Irregular High-Rate Gallager Codes

David J C MacKay

Gallager codes with rates about 0.9 and block length about 2000 or 4000 bits have previously been shown to have promising performance [cite{MacKayHighRate98}]. In this paper we investigate puncturing as a possible method for increasing the rate of such codes.

At low signal-to-noise ratios, high-rate punctured Gallager codes appear to be inferior to unpunctured Gallager codes constructed `beyond the Steiner limit'. We find evidence, however, that the punctured codes have superior performance at higher signal-to-noise ratio.

We also explore the possible benefits of irregular constructions. For these rates and blocklengths, it seems hard to beat regular Gallager codes.

postscript (Cambridge UK).

postscript (Canada mirror).


related papers.
David MacKay's: home page, publications. bibtex file.
Canadian mirrors: home page, publications. bibtex file.