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Summary of codes' performances

  Figure 1.12 shows the performance of repetition codes and the Hamming code. It also shows the performance of a family of linear block codes that are generalizations of Hamming codes, `BCH' codes.

  figure1437
Figure: Error probability tex2html_wrap_inline3165 versus rate for repetition codes, the (7,4) Hamming code and BCH codes with block lengths up to 1023 over a binary symmetric channel with f=0.1. The right hand figure shows tex2html_wrap_inline3165 on a logarithmic scale.


This figure shows that we can, using linear block codes, achieve better performance than repetition codes; but the asymptotic situation still looks rather grim. Design an error correcting code and a decoding algorithm for it, compute its probability of error, and add it to figure 1.12.



David J.C. MacKay
Sat May 10 23:05:10 BST 1997