Cyclic unequal error protection codes constructed from cyclic codes of composite length

The unequal error correction capabilities of binary cyclic codes of composite length aye investigated. Under certain conditions, direct sums of concatenated codes have unequal error correction capabilities. By a modified Hartmann and Tzeng algorithm, it is shown that a binary cyclic code of composite length is equivalent to the direct sum of concatenated codes. With this, some binary cyclic unequal error protection (UEP) codes are constructed. Finally, a special class of two-level UEP cyclic direct-sum codes is presented.