Errors In Communication Channels Research Articles

Insdel codes from subspace and rank-metric codes

Insertion and deletion (insdel in short) codes are designed to deal with synchronization errors in communication channels caused by insertions and deletions of message symbols. These codes have received a lot of attention due to their applications in diverse areas such as computational biology, DNA data storage, race-track memory error corrections, language processing, and synchronous digital communication networks. In the present work, we study constructions and limitations of insdel codes from rank metric and subspace codes. This paper studies and improves the idea of the work [4] by Hao Chen on the connection between insdel codes and subspace codes.We discuss why subspace code is a natural choice for constructing insdel codes and show that the interleaved Gabidulin codes can be used to construct nonlinear insdel codes approaching the Singleton bound. Then we show that the indexing scheme of transforming efficient Hamming metric codes to efficient insdel codes can be adapted for the class of rank metric codes. And that improves the base field size of the construction of insdel codes from lifted rank-metric codes. It is also shown that the size of the insdel code from a subspace code can be improved significantly than in the previously proposed construction. We give an algebraic condition for a linear Gabidulin rank metric code to be optimal insdel code adapting the condition proved for Reed-Solomon codes. Moreover, we give constructions of linear and nonlinear insdel codes from Sidon spaces.

Compression Coding Method Using Internal Restructuring of Information Space

The subject of the study in this article is data transmission processes of the video information resource in the information communication systems of the air segment under the conditions of errors in the data transmission channel. The purpose of the article is the development of the method of compression coding in order to ensure an increase in the level of reliability of video information resources under the conditions of errors in communication channels. The following tasks are identified: to develop a method of compression coding using structural decomposition of statistical space; analyze the effectiveness of the developed method from the standpoint of ensuring the required level of reliability. The following results are obtained: the developed method of encoding video information allows increasing the level of reliability in the conditions of the transmission of video information resources in the information communication systems of the air segment due to the localization of the action of errors.

Optimal combination of forward error correction and selective state feedback for wireless feedback control systems

In wireless feedback control systems, loss of control packets due to unreliable wireless channels is one of the most important problems. To cope with this problem, we have proposed a novel concept that combines forward error correction (FEC) and selection of important state feedback while keeping a fixed packet length. In this paper, we provide its optimization based on a control layer’s theorem. Numerical results show that the proposed method can achieve the best control performance against communication channel errors.

Introduction to Semi-Classical Analysis for Digital Errors of Qubit in Quantum Processor.

In recent years, remarkable progress has been achieved in the development of quantum computers. For further development, it is important to clarify properties of errors by quantum noise and environment noise. However, when the system scale of quantum processors is expanded, it has been pointed out that a new type of quantum error, such as nonlinear error, appears. It is not clear how to handle such new effects in information theory. First of all, one should make the characteristics of the error probability of qubits clear as communication channel error models in information theory. The purpose of this paper is to survey the progress for modeling the quantum noise effects that information theorists are likely to face in the future, to cope with such nontrivial errors mentioned above. This paper explains a channel error model to represent strange properties of error probability due to new quantum noise. By this model, specific examples on the features of error probability caused by, for example, quantum recurrence effects, collective relaxation, and external force, are given. As a result, it is possible to understand the meaning of strange features of error probability that do not exist in classical information theory without going through complex physical phenomena.

Telecommunication Systems with Multiple Access Based on Data Factorial Coding

The paper outlines methods for constructing telecommunication systems based on the principle of time division of channels and using factorial code in order to maintain the cyclic phase of receiver/transmitter and ensure information security. These systems provide integrated data protection (against errors in communication channel and attempts of unauthorized access to information), as well as the ability to allocate system resources (bandwidth) between its subscribers. The purpose of this work is to develop and research the approach of building telecommunication systems with multiple access to a common channel for collective use, based on the property of factorial codes to keep clock and frame synchronism with a working signal. The basic idea is to choose the permutations to transfer information with a single set of properties or attributes. This provides opportunities of dividing channel into subchannels, bandwidth sharing on transmission accuracy, and dividing plurality of network users into closed groups. The channel resource sharing procedure based on factorial coding is described. Examples of multiplex cycle organization and the order of occupying/releasing multiplex cycle time channels by users are given. The system load and the subchannel bandwidth are estimated.

Modeling of sectionally continuous communication channel with inhomogeneously distributed tissues.

This study aimed to investigate effects on the transmission channel caused by heterogeneous distribution in tissues and joint characteristics. Human arm section scans were taken using CT technology, and zoned, following which, a circumference measurement experiment was performed to analyze the effect of inhomogeneous distribution of tissues. In order to analyze the arm joint's effect on channel transmission, we proposed a piecewise modeling method in combination with connection conditions. It can be seen from the experiment that, in the quasi-static mode, the communication channel error caused by the inhomogeneous distribution of tissues is small enough to be negligible. The error between calculated and experimental results is reduced by 3.93 dB in this experiment relative to models that did not include joint characteristics, and the average error is lowered by 0.73 dB. The variation curve fit to experimental data is also improved in this method. As such, it can be quantitatively determined that a channel model with joint characteristics is superior to models excluding joint characteristics.

FACTORIAL CODING WITH ERROR CORRECTION

Context. Factorial data coding allows combining operations of cryptographic protection, intentional alteration of data, and errorcorrecting coding which leads to the decrease of redundancy introduced by transmitter and to the increase of data rate and effective throughput. At the same time, the described methods of factorial coding do not correct errors, which limits their use. Objective of this work is to develop a method of factorial coding with data recovery that provides a comprehensive solution of cryptographic protection and error control coding and allows combining the functions of communication channel errors detecting and correcting. Method. The basic idea of the proposed coding method is to increase the distance between the allowed code words that represent permutations calculated for all information bits of a data block and represented in a binary form. The methods of distance increasing based on Euclidean and Hamming metrics are investigated. The basic properties of factorial code with error correction are defined for each of these methods. The estimate of probability characteristics is done on the condition of independence of communication channel errors and their binomial distribution. The receiver structures are developed. Decoding rules implemented in receiver are based on the maximum likelihood criteria and provide both forward error correction and error detection with further correction by retransmission of damaged data block. Results. The factorial error-correcting codes using Euclidean and Hamming metrics are implemented. The comparative analysis of the probability of an undetected error, the residual probability of erroneous reception, energy gain, and the relative transmission rate is done for these codes. It is shown that code characteristics are not invariant to the set of allowed code words, and the codes that use Hamming metric are the most efficient codes between the presented codes. Conclusions. The method of factorial coding data recovery by permutation has been further developed. Due to the combination of error correction and detection functions, it can increase the rate loss dynamic component and, consequently, the relative transmission rate, compared to error-detecting factorial coding by reducing its noise immunity. The experiments confirmed the effectiveness of the factorial error-correcting codes.

Comparative analysis of the performance of selective and group repeat transmission modes in a transport protocol

We propose a model of a virtual connection controlled by a transport protocol in the selective and group failure modes as a Markov chain with discrete time that accounts for the influence of protocol parameters of window size and timeout duration for waiting for acknowledgements, probabilities of distorting segments in individual links of the data transmission path on the throughput of a transport connection. We have analyzed how the throughput of the control procedure depends on protocol parameters, level of errors in communication channels, and round-trip delay. We have proposed a method for choosing protocol parameters.

COMBINED FACTORIAL CODING AND ITS PROPERTIES

In this paper the authors propose a method of combined factorial data coding directed to the information integrity control that provides a comprehensive protection against intentional alteration of data and communication channel errors. The basic idea of the proposed method consists in combining of procedures of full factorial coding that uses a permutation as a codeword check value, and a cyclic redundancy coding (CRC). In this case a codeword check value of combined factorial code is generated from a codeword check value of full factorial code represented by a polynomial, by the CRC polynomial modulo. The basic properties of the combined factorial code are defined. The assessments of transmission reliability, cryptographic strength and strength against intentional alteration of data are evaluated. A comparative analysis of detecting ability (probability of an error undetected by the code) and energy gain for the full and combined factorial coding is done on the condition of independence of errors that appear in communication channel and their binomial distribution. The ways of improvement of the presented assessment of the probability of an undetected by factorial code error are defined. Recommendations for the use of full and combined factorial coding are given.

Video temporal error concealment using improved directional boundary matching algorithm

Nowadays some systems such as multimedia systems try to present a high quality of digital videos every day. Because of the possible errors in communication channels, compressed video data would be damaged in the sending process. Error concealment is a useful technique for concealing the effects of sending errors at the decoder. In this paper, an improved directional boundary matching algorithm is presented, in which by using adjacent macroblocks (MBs) of the damaged MB a direction is identified for each boundary. Then every boundary of candidate MBs is compared to an identified direction. Finally, the candidate motion vector (MV) that has the minimum improved directional matching function is selected as the MV of the damaged MB. Furthermore, to increase the accuracy in damaged MV estimation, a specific weight is given to the boundaries of adjacent MBs. Conforming to the experimental results, the proposed algorithm not only outperforms subjective visual evaluation compared to classic boundary matching, outer boundary matching, and directional boundary matching algorithms, but also it is able to improve the objective quality of reconstructed video frames effectively.

Target Localization in Wireless Sensor Networks for Industrial Control with Selected Sensors

This paper presents a novel energy-based target localization method in wireless sensor networks with selected sensors. In this method, sensors use Turbo Product Code (TPC) to transmit decisions to the fusion center. TPC can reduce bit error probability if communication channel errors exist. Moreover, in this method, thresholds for the energy-based target localization are designed using a heuristic method. This design method to find thresholds is suitable for uniformly distributed sensors and normally distributed targets. Furthermore, to save sensor energy, a sensor selection method is also presented. Simulation results showed that if sensors used TPC instead of Hamming code to transmit decisions to the fusion center, localization performance could be improved. Furthermore, the sensor selection method used can substantially reduce energy consumption for our target localization method. At the same time, this target localization method with selected sensors also provides satisfactory localization performance.

A High- Speed LFSR Design by the Application of Sample Period Reduction Technique for BCH Encoder

Error correction is one of the important technique for detecting and correcting errors in communication channels, memories etc., BCH codes are widely been used for error detection and correction. The generated check bits of the BCH encoder along with the message bits called codeword is sent to the receiver to detect any error during the transmission. One of the main components of BCH encoder is LFSR (Linear Feedback Shift Register). LFSR find its wider application in Built-in-Self-Test, signature analyzer etc., whereas here it is used to form parity bits to concatenate with message bits for the formation of a codeword. The main advantage of LFSR is that it is simple to construct and it operates at very high clock speed, but its main drawback is that the inputs are given in bit serial. To overcome these drawbacks, DSP algorithms such as unfolding and parallel processing can be used by selecting the unfolding factor based on some design criteria. Selecting a better unfolding value reduces the sample period, decreases the clock cycle and increases the speed. .Keywords- Bose Chaudhuri-Hocquengham (BCH), Cyclic Redundancy Check (CRC), Computational Time (CT), Galois Field (GF), LFSR, unfolding, sample period reduction.

Robust Speech Coding Algorithm

Speech communication in Electronic Warfare (EW) environment should be resistant to interception, masquerade and tolerant to communication channel errors. In this paper, we described an algorithm which provides speech compression, strong encryption, error tolerance and speaker authentication features. This Robust Speech Coder (RSC) is backward compatible with the existing codecs with capability to opt for additional features as and when required.

Robust Speech Coding Algorithm

Speech communication in Electronic Warfare (EW) environment should be resistant to interception, masquerade and tolerant to communication channel errors. In this paper, we described an algorithm which provides speech compression, strong encryption, error tolerance and speaker authentication features. This Robust Speech Coder (RSC) is backward compatible with the existing codecs with capability to opt for additional features as and when required.

A block-oriented restoration in gray-scale images using full range autoregressive model

This paper introduces a novel approach, i.e. block oriented-restoration, based on a Family of Full Range Autoregressive (FRAR) model to restore the information lost, and this adopts the Bayesian approach to estimate the parameters of the model. The Bayesian approach, by combining the prior information and the observed data known as posterior distribution, makes inferences. The loss of information caused is due to errors in communication channels, through which the data are transmitted. In most applications, the data are transmitted block wise. Even if there is loss of a single bit in a block, it causes loss in the whole block and the impact may reflect on its consecutive blocks. In the proposed technique, such damaged blocks are identified, and to restore it, a priori information is searched and extracted from uncorrupted regions of the image; this information and the pixels in the neighboring region of the damaged block are utilized to estimate the parameters of the model. The estimated parameters are employed to restore the damaged block. The proposed algorithm takes advantage of linear dependency of the neighboring pixels of the damaged block and takes them as source to predict the pixels of the damaged block. The restoration is performed at two stages: first, the lone blocks are restored; second, the contiguous blocks are restored. It produces very good results and is comparable with other existing schemes.

Progressive transmission of images using MAP detection over channels with memory

We propose a new maximum a posteriori (MAP) detector, without the need for explicit channel coding, to lessen the impact of communication channel errors on compressed image sources. The MAP detector exploits the spatial correlation in the compressed bitstream as well as the temporal memory in the channel to correct channel errors. We first present a technique for computing the residual redundancy inherent in a compressed grayscale image (compressed using VQ). The performance of the proposed MAP detector is compared to that of a memoryless MAP detector. We also investigate the dependence of the performance on memory characteristics of the Gilbert-Elliott channel as well as average channel error rate. Finally, we study the robustness of the proposed MAP detector's performance to estimation errors.

Two concatenated coding schemes for ARQ protocols

The application of concatenated coding to increase throughput in automatic repeat request (ARQ) protocols is described. In the proposed schemes, which are implemented with an inner error detection-correction code and an outer error-detection code, the inner code's dual-function structure significantly enhances ARQ efficiency, especially in cases of high communication channel error rate. Results of a comparative analysis show that the proposed schemes outperform other similar ARQ protocols.