Bounds on the minimum distance of linear codes
Bounds on linear codes [256,6] over GF(4)
Construction of a linear code [256,6,188] over GF(4):
: [255, 7, 187] "BCH code (d = 187, b = 1)" Linear Code over GF(2^2)
BCHCode with parameters 255 187
: [256, 7, 188] Linear Code over GF(2^2)
ExtendCode  by 1
: [256, 6, 188] Linear Code over GF(2^2)
Subcode of 
last modified: 2001-12-17
From Brouwer's table (as of 2007-02-13)
Lb(256,6) = 188 is found by taking a subcode of:
Lb(256,7) = 188 XBC
Ub(256,6) = 190 follows by a one-step Griesmer bound from:
Ub(65,5) = 47 is found by considering truncation to:
Ub(62,5) = 44 is found by construction B:
[consider deleting the (at most) 3 coordinates of a word in the dual]
Extended BCH code.
- All codes establishing the lower bounds were constructed using
- Upper bounds are taken from the tables of Andries E. Brouwer, with the exception of codes over GF(7) with n>50.
For most of these codes, the upper bounds are rather weak.
Upper bounds for codes over GF(7) with small dimension have been provided by Rumen Daskalov.
- Special thanks to John Cannon for his support in this project.
- A prototype version of MAGMA's code database over GF(2) was
written by Tat Chan in 1999 and extended later that year by
Damien Fisher. The current release version was
developed by Greg White over the period 2001-2006.
- Thanks also to Allan Steel for his MAGMA support.
- My apologies to all authors that have contributed codes to this table for not giving specific credits.
- If you have found any code improving the bounds or some errors, please send me an e-mail:
codes [at] codetables.de
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Last change: 30.12.2011