122 research outputs found

    Maximum distance separable 2D convolutional codes

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    Maximum distance separable (MDS) block codes and MDS 1D convolutional codes are the most robust codes for error correction within the class of block codes of a fixed rate and 1D convolutional codes of a certain rate and degree, respectively. In this paper, we generalize this concept to the class of 2D convolutional codes. For that, we introduce a natural bound on the distance of a 2D convolutional code of rate k/nk/n and degree deltadelta , which generalizes the Singleton bound for block codes and the generalized Singleton bound for 1D convolutional codes. Then, we prove the existence of 2D convolutional codes of rate k/nk/n and degree deltadelta that reach such bound when ngeqk(((lfloor(delta/k)rfloor+2)(lfloor(delta/k)rfloor+3))/2)n geq k (({(lfloor ({delta }/{k}) rfloor + 2)(lfloor ({delta }/{k}) rfloor + 3)})/{2}) if knmiddeltak {nmid } delta , or ngeqk((((delta/k)+1)((delta/k)+2))/2)n geq k (({(({delta }/{k}) + 1)(({delta }/{k}) + 2)})/{2}) if kmiddeltak mid delta , by presenting a concrete constructive procedure

    Cyclone Codes

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    We introduce Cyclone codes which are rateless erasure resilient codes. They combine Pair codes with Luby Transform (LT) codes by computing a code symbol from a random set of data symbols using bitwise XOR and cyclic shift operations. The number of data symbols is chosen according to the Robust Soliton distribution. XOR and cyclic shift operations establish a unitary commutative ring if data symbols have a length of p1p-1 bits, for some prime number pp. We consider the graph given by code symbols combining two data symbols. If n/2n/2 such random pairs are given for nn data symbols, then a giant component appears, which can be resolved in linear time. We can extend Cyclone codes to data symbols of arbitrary even length, provided the Goldbach conjecture holds. Applying results for this giant component, it follows that Cyclone codes have the same encoding and decoding time complexity as LT codes, while the overhead is upper-bounded by those of LT codes. Simulations indicate that Cyclone codes significantly decreases the overhead of extra coding symbols

    Lifted MDS Codes over Finite Fields

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    MDS codes are elegant constructions in coding theory and have mode important applications in cryptography, network coding, distributed data storage, communication systems et. In this study, a method is given which MDS codes are lifted to a higher finite field. The presented method satisfies the protection of the distance and creating the MDS code over the FqF_q by using MDS code over $F_p.

    Hankel Rhotrices and Constructions of Maximum Distance Separable Rhotrices over Finite Fields

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    Many block ciphers in cryptography use Maximum Distance Separable (MDS) matrices to strengthen the diffusion layer. Rhotrices are represented by coupled matrices. Therefore, use of rhotrices in the cryptographic ciphers doubled the security of the cryptosystem. We define Hankel rhotrix and further construct the maximum distance separable rhotrices over finite fields

    Lectures on Designing Screening Experiments

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    Designing Screening Experiments (DSE) is a class of information - theoretical models for multiple - access channels (MAC). We discuss the combinatorial model of DSE called a disjunct channel model. This model is the most important for applications and closely connected with the superimposed code concept. We give a detailed survey of lower and upper bounds on the rate of superimposed codes. The best known constructions of superimposed codes are considered in paper. We also discuss the development of these codes (non-adaptive pooling designs) intended for the clone - library screening problem. We obtain lower and upper bounds on the rate of binary codes for the combinatorial model of DSE called an adder channel model. We also consider the concept of universal decoding for the probabilistic DSE model called a symmetric model of DSE.Comment: 66 page

    Twisted Reed-Solomon Codes

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    We present a new general construction of MDS codes over a finite field Fq\mathbb{F}_q. We describe two explicit subclasses which contain new MDS codes of length at least q/2q/2 for all values of q11q \ge 11. Moreover, we show that most of the new codes are not equivalent to a Reed-Solomon code.Comment: 5 pages, accepted at IEEE International Symposium on Information Theory 201
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