New good quasi-cyclic codes and codes with improved minimum distance
One of the most important and challenging problems in coding theory is to construct codes with optimal parameters. As a generalization of cyclic codes, quasi-cyclic (QC) codes as well as quasi-twisted (QT) codes have been shown to contain record-breaking codes. In this paper, various computer algorithms have been used to search for good QC codes. A lot of good new QC codes have been found and they have been used to construct new linear codes. A total 11 new codes that improve the bound on the minimum distance are presented.