Both reliability and security are two important subjects in modern digital communications, each with a variety of subdisciplines. In this paper we introduce a new proposed secure turbo coding system which combines chaotic dynamics and turbo coding reliability together. As we utilize the chaotic maps as a tool for hiding and securing the coding design in turbo coding system, this proposed system model can provide both data secrecy and data reliability in one process to combat problems in an insecure and unreliable data channel link. To support our research, we provide different schemes to design a chaotic secure reliable turbo coding system which we call chaotic-switched turbo coding schemes. In these schemes the design of turbo codes chaotically changed depending on one or more chaotic maps. Extensions of these chaotic-switched turbo coding schemes to half-duplex relay systems are also described. Results of simulations of these new secure turbo coding schemes are compared to classical turbo codes with the same coding parameters and the proposed system is able to achieve secured reasonable bit error rate performance when it is made to switch between different puncturing and design configuration parameters especially with low switching rates. Hindawi Publishing Corporation

Abstract-Combining both reliability and security in one block is very important in modern digital communications, each with a variety of sub-disciplines. In this paper, a new polar codes scheme for secure data transmission based on one dimensional chaotic map with a pre-shared secret initial condition is proposed. In this scheme we utilize the logistic map as a tool for generating binary hidden frozen bits assigned for the polar code bad channels. This strategy makes it difficult for those decoders that do not have the chaotic secret initial condition to correctly decode the information message. To increase the system security we support our scheme with hidden both frozen and information bits. This proposed scheme can provide both data secrecy and data reliability in one process to combat problems in an insecure and unreliable data channel link.

Abstract-It is known that one of the essential building blocks of turbo codes is the interleaver and its design using random, semi-random (S-Random) and deterministic permutations. In this paper, two new types of turbo code interleavers, Modified Block S-Random (MBSR) interleaver and Modified Matched S-Random (MMSR) interleaver are proposed. The design algorithm for the new interleavers is described in depth, and the simulation results are compared to the two new interleavers with different existing interleavers based on the BER (Bit Error Rate) performances of the turbo codes. Through the simulation, we find a better performance of the MBSR interleaver than random and practical interleavers.In addition, the performance of MMSR interleaver is close to the code matched interleaver at different frame sizes and with less complex design.Index Terms-Interleaver, semi random, turbo codes, weight distribution. I. INTRODUCTIONA typical turbo code (TC) was first introduced in 1993 by Berrou et al.,[1] as a class of near channel capacity achieving codes. This turbo code is constructed by concatenating two parallel convolutional codes via an interleaver as shown in Fig. 1. The interleaver is an indexing function given by a permutation of bits index in the information frames with N frame length that plays a crucial role in the turbo codes architecture. Interleaver has three main functions: a) it constructs a long code from small memory convolutional codes by permuting the input bits such that the two constituent encoders are operating on different order input bits. b) Provides "scrambled" information data to the second constituent encoder to decorrelate the inputs of the two decoders, so that an iterative suboptimum decoding algorithm based on "uncorrelated" information exchange between the two constituent decoders can be applied. c) It changes theweight distribution of turbo codes such that, the overall weight for the generated codeword depends on how the outputs from the two constituent encoders are teamed together.The main two properties characterize any interleaver are the interleaver spreading property which is the distance between adjacent bits before interleaving, and the randomness property that provides a non-fixed indexing function which is a good factor for correction in the iterative decoding. Turbo code interleaver types have been Manuscript received May 31, 2014; revised July 17, 2014. This work was supported in part by College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaThe authors are with the Nanjing university of Aeronautics and Astronautics, College of Electronic and Information Engineering, Nanjing (e-mail: thms78@gmail.com, saqibejaz@gmail.com).extensively studied in different ways, and they fall into two main classes: Random interleavers and Deterministic interleavers. A random interleaver is simply a random permutation with new positions produced by an indexing function based on the uniform probability distribution. While in majo...

Abstract. Labeling diversity is an efficient technique recently proposed in the literature and aims to improve the Bit Error Rate (BER) performance of Wireless Local Area Network (WLAN) systems with two transmit and two receive antennas without increasing the transmit power and bandwidth requirements. In this paper, we employ labeling diversity with different space-time channel codes such as convolutional, turbo and Low Density Parity Check (LDPC) for both point-to-point and coded-cooperative communication scenarios. Joint iterative decoding schemes for distributed turbo and LDPC codes are also presented. BER performance bounds at an Error Floor (EF) region are derived and verified with the help of numerical simulations for both cooperative and non-cooperative schemes. Numerical simulations show that the coded-cooperative schemes with labeling diversity achieve better BER performances and use of labeling diversity at the source node significantly lowers relay outage probability and hence the overall BER performance of the coded-cooperative scheme is improved manifolds.

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