Results 221 to 230 of about 663 (237)

A Structural Constraint for Golomb Costas Arrays

IEEE Transactions on Information Theory, 2010
A structural constraint (symmetry property) of Golomb Costas arrays constructed in finite fields of odd size is presented, analogous to the anti-reflective symmetry of Welch Costas arrays.
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Optimum Costas-like decompositions of Costas arrays for channel characterization and communications

Proceedings of ICASSP '94. IEEE International Conference on Acoustics, Speech and Signal Processing, 2002
In the paper we show that any subset or decomposition of Costas arrays are themselves non-full Costas arrays with ideal auto-, and cross-ambiguity and multiple access properties. The decomposed waveform's "thumbtrack" like auto-ambiguity functions, and their low cross-ambiguity or mutual interference would make them applicable in various multiple ...
Sanjay K. Mehta, Edward L. Titlebaum
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Accelerated costas array enumeration using FPGAs

2008 42nd Annual Conference on Information Sciences and Systems, 2008
Costas array enumeration is an NP-complete problem with a highly parallelize-able solution. This paper examines the implementation of a solution to this problem on an FPGA platform and examines the elements of what makes the most efficient solution to this problem.
Jim Devlin, Scott Rickard
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A Regularity Property of Golomb-Costas Arrays

2006 40th Annual Conference on Information Sciences and Systems, 2006
A Golomb-Costas array is an arrangement of dots and blanks, defined for each positive integer power of a prime and satisfying certain unusual conditions. A dot occurring in such an array is an even/even position if it occurs in the i-th row and j-th column, where i and j are both even integers, and there are similar definitions of odd/odd, even/odd and
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On the parity populations of Welch-constructed Costas arrays

2006 40th Annual Conference on Information Sciences and Systems, 2006
We prove that, in the case of Welch-constructed Costas arrays, the number of dots whose coordinates are both even (ee), both odd (oo), even and odd (eo), and odd and even (oe) are all equal if the prime p used has the property that p mod 4 = 1; and that, if p mod 4 = 3, the relation between these 4 quantities can again be determined, and that it ...
Konstantinos Drakakis, Rod Gow, Scott Rickard   +2 more
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The density of Costas arrays and three-free permutations

2012 IEEE Statistical Signal Processing Workshop (SSP), 2012
We describe how 3-free permutations might be used to improve Davies's density result for Costas arrays. We associate both Costas arrays and 3-free permutations with a pair consisting of a lattice point and a hyperplane arrangement to establish relationships between the two and compare how the exponential decay predicted by bounds on the number of 3 ...
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Ambiguity and Deficiency in Costas Arrays and APN Permutations

2010
We introduce the concepts of weighted ambiguity and deficiency for a mapping between two finite Abelian groups of the same size. Then we study the optimum lower bounds of these measures for a permutation of ℤn and give a construction of permutations meeting the lower bound by modifying some permutation polynomials over finite fields. These permutations
Daniel Panario, Brett Stevens, Qiang Wang 0012   +2 more
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Survey on Costas Arrays and Their Generalizations

2003
The major constructions of Costas array s are for lengths n = p−l, p m −2, p m −3 for any prime p. The last construction of Costas arrays dates back almost twenty years and there are many n for which no Costas arrays are known. This paper surveys three new concepts: extended Costas arrays, quasi-Costas arrays, and extended quasi-Costas arrays, that ...
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The enumeration of Costas arrays of order 28 and its consequences

Advances in Mathematics of Communications, 2011
Konstantinos Drakakis, Francesco Iorio, Scott Rickard   +2 more
exaly  

Results of the Enumeration of Costas Arrays of Order $27$

IEEE Transactions on Information Theory, 2008
Konstantinos Drakakis, Scott Rickard, James K Beard   +2 more
exaly