New optimal ternary linear codes

The class of quasi-twisted (QT) codes is a generalization of the class of quasi-cyclic codes, similar to the way constacyclic codes are a generalization of cyclic codes. In this paper, rate 1/p QT codes over GF(3) are presented which have been constructed using integer linear programming and heuristic combinatorial optimization. Many of these attain the maximum possible minimum distance for any linear code with the given parameters, and several improve the maximum known minimum distances. Two of these new codes, namely (90, 6, 57) and (120, 6, 78), are optimal and so prove that [d.sub.3](90, 6) = 57 and [d.sub.3](120, 6) = 78. Index Terms - Quasi-twisted codes, heuristic search, optimal codes over GF(3).