In Searching of Long Skew-symmetric Binary Sequences with High Merit Factors (original) (raw)

2020, ArXiv

In this paper we present best-known merit factors of longer binary sequences with odd length. Finding low autocorrelation binary sequences with optimal merit factors is difficult optimization problem. High performance computations with execution of a stochastic algorithm in parallel, enable us searching skew-symmetric binary sequences with high merit factors. After experimental work, as results we present sequences with odd length between 301 and 401 that are skew-symmetric and have merit factor F greater than 7. Moreover, now all sequences with odd length between 301 and 401 with F > 7 have been found.

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Low Autocorrelation Binary Sequences

2016

Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time Θ(N 1.73^N). We computed all optimal sequences for N≤ 66 and all optimal skewsymmetric sequences for N≤ 119.

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Two-phase Optimization of Binary Sequences with Low Peak Sidelobe Level Value

2021

The search for binary sequences with low peak sidelobe level value represents a formidable computational problem. To locate better sequences for this problem, we designed a stochastic algorithm that uses two fitness functions. In these fitness functions, the value of the autocorrelation function has a different impact on the final fitness value. It is defined with the value of the exponent over the autocorrelation function values. Each function is used in the corresponding optimization phase, and the optimization process switches between these two phases until the stopping condition is satisfied. The proposed algorithm was implemented using the compute unified device architecture and therefore allowed us to exploit the computational power of graphics processing units. This algorithm was tested on sequences with lengths L = 2 − 1, for 14 ≤ m ≤ 20. From the obtained results it is evident that the usage of two fitness functions improved the efficiency of the algorithm significantly, ne...

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Finding low autocorrelation binary sequences with memetic algorithms

Applied Soft Computing, 2009

This paper deals with the construction of binary sequences with low autocorrelation, a very hard problem with many practical applications. The paper analyzes several metaheuristic approaches to tackle this kind of sequences. More specifically, the paper provides an analysis of different local search strategies, used as stand-alone techniques and embedded within memetic algorithms. One of our proposals, namely a memetic algorithm endowed with a Tabu Search local searcher, performs at the state-of-the-art, as it consistently finds ...

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A NOVEL APPROACH TO DETECT LOW AUTOCORRELATION BINARY SEQUENCES USING IMPROVISED TABU SEARCH ALGORITHM

The Detection of low autocorrelation binary sequences (LABS) is one of the classic problems. These binary sequences have many practical applications, particularly in the area of radar communications. In the literature of computational complexity, we call this as nondeterministic polynomial time hard problem (NP-Hard).Gallardo [1] in his paper has described a Tabu search approach for tackling this issue. We improvised this algorithm, and we achieved better results in doing so. There are two main areas in the algorithm that we have improvised.one is the Tabu Tenure parameter, another is the implementation of a novel local restart strategy called “set”. Our algorithm improved the execution rates significantly. We were able to achieve new optimal solutions with our improved algorithm (especially for instances greater than 60 and less than 101) to that of previous method [1].Instead of finding optimal solutions for odd skew-symmetric instances we found the optimal solutions for all the instances.

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