2,721 research outputs found
A Recursive Method for Enumeration of Costas Arrays
In this paper, we propose a recursive method for finding Costas arrays that
relies on a particular formation of Costas arrays from similar patterns of
smaller size. By using such an idea, the proposed algorithm is able to
dramatically reduce the computational burden (when compared to the exhaustive
search), and at the same time, still can find all possible Costas arrays of
given size. Similar to exhaustive search, the proposed method can be
conveniently implemented in parallel computing. The efficiency of the method is
discussed based on theoretical and numerical results
Frequency permutation arrays
Motivated by recent interest in permutation arrays, we introduce and
investigate the more general concept of frequency permutation arrays (FPAs). An
FPA of length n=m lambda and distance d is a set T of multipermutations on a
multiset of m symbols, each repeated with frequency lambda, such that the
Hamming distance between any distinct x,y in T is at least d. Such arrays have
potential applications in powerline communication. In this paper, we establish
basic properties of FPAs, and provide direct constructions for FPAs using a
range of combinatorial objects, including polynomials over finite fields,
combinatorial designs, and codes. We also provide recursive constructions, and
give bounds for the maximum size of such arrays.Comment: To appear in Journal of Combinatorial Design
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