A class of constacyclic codes

A class of q/sup m/-ary constacyclic codes is defined which has the property that the q-ary image is equivalent to a class of shortened cyclic codes. This description leads to the construction of nonlinear codes. As an example one can construct nonlinear codes of length N=q/sup m/+1 over the field GF(q/sup m'/), m'/spl les/m, with a minimum distance greater than N(1-R)m'/m, where R is the rate. For higher rates these codes are the best known. The codes are easily encoded and decoded.<
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