Bounds on the minimum distance of linear codes
Bounds on linear codes [216,7] over GF(4)
lower bound: | 153 |
upper bound: | 159 |
Construction
Construction of a linear code [216,7,153] over GF(4):
[1]: [226, 7, 161] Linear Code over GF(2^2)
Take the first 225 points of the orbit of the companion matrix of x^7 + x^6 + w*x^5 + w*x^4 + w*x^3 + w*x^2 + 1 as columns of the generator matrix and
append the column vectors [
( 1 w 1 0 w 1 w^2)
]
[2]: [217, 7, 154] Linear Code over GF(2^2)
Puncturing of [1] at { 10, 26, 51, 72, 81, 141, 143, 168, 212 }
[3]: [216, 7, 153] Linear Code over GF(2^2)
Puncturing of [2] at { 217 }
last modified: 2004-10-25
From Brouwer's table (as of 2007-02-13)
Lb(216,7) = 152 is found by truncation of:
Lb(219,7) = 155 MTS
Ub(216,7) = 159 follows by a one-step Griesmer bound from:
Ub(56,6) = 39 follows by a one-step Griesmer bound from:
Ub(16,5) = 9 follows by a one-step Griesmer bound from:
Ub(6,4) = 2 is found by construction B:
[consider deleting the (at most) 4 coordinates of a word in the dual]
References
MTS:
Tatsuya Maruta, Mito Takenaka, Maori Shinohara & Yukie Shobara, Constructing
new linear codes from pseudo-cyclic codes, pp. 292-298 in Proc. 9th
International Workshop on Algebraic and Combinatorial Coding Theory(ACCT) in
Kranevo, Bulgaria, 2004.
Notes
- All codes establishing the lower bounds were constructed using
MAGMA.
- 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