Cyclically permutable codes
نویسنده
چکیده
Brevity is the soul of wit. William Shakespeare A cyclically permutable code is a set of codewords having the property that no codeword is a cyclic shift of another codeword. We study the problem of constructing cyclically permutable codes of large size and low correlation. Cyclically permutable codes are used in code-division multiple-access systems realized by e.g. direct-sequence modulation or frequency-hopping. Advantages of code-division multiple-access to conventional access methods, such as time-division and frequency-division, include greater flexibility, better robustness and that no synchronization among the transmitters is needed. Among our main results are an efficient method of selecting cyclically distinct codewords from linear cyclic codes, a new family of sequences for direct-sequence modulation, several constructions of hopping-sequences for multiple-access coupled with a decoding algorithm for asynchronous communication. We have also constructed new binary constant-weight codes of high minimum distance.
منابع مشابه
Constructions for optimal constant weight cyclically permutable codes and difference families
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