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Impulse noise error modeling over M-QAM-based power line communication channel using software-defined approach

- Iyiola, Akintunde Oluremi

  • Authors: Iyiola, Akintunde Oluremi
  • Date: 2020
  • Subjects: Digital communications , Modulation (Electronics) , Coding theory , Error-correcting codes (Information theory) , Electric lines
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/480143 , uj:43454
  • Description: Abstract: Data transmission through the indoor Power Line Communication (PLC) channel is severely affected by uncoordinated operation of electrical devices connected to the network as well as from external disturbances resulting into high amplitude impulse noise and burst error. In order to address these challenges, recent research efforts have concentrated on developing stable, effective and functional data transmission methods using old methods or developing new methods that can improve the efficiency of transmission as well as the transmission capacity of existing PLC networks... , M.Ing. (Electrical and Electronic Engineering)
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Efficient construction of balanced and constant-weight sequences for communication

- Mambou, Elie Ngomseu

Combating impulsive noise and narrowband interference as a mixture in a power line communications channel

- Bolaji, Abiola

Constrained Codes capable of correcting insertion/deletion burst errors by using markers

- Smith, Dylan

Balancing of non-binary sequences using Gray code prefixes

- Mambou, Elie Ngomseu

Concatenated permutation codes to correct substitution, deletion or transposition errors

- Heymann, Reolyn

Design of balanced q-ary interleaved sequences

- Musarurwa, Dadiso Florence

Error control coded data transmision over FM supplementary signal transmission radio channels

- Steyn, Pieter

Correcting bursts of adjacent deletions by adapting product codes

- Buys, Stephanie

  • Authors: Buys, Stephanie
  • Date: 2015-03-25
  • Subjects: Error-correcting codes (Information theory) , Synchronous data transmission systems , Reed-Solomon codes
  • Type: Thesis
  • Identifier: uj:13517 , http://hdl.handle.net/10210/13569
  • Description: M.Ing. (Electrical and Electronic Engineering) , In this study, the problem of correcting burst of adjacent deletions by adapting product codes was investigated. The first step in any digital transmission is to establish synchronization between the sending and receiving nodes. This initial synchronization ensures that the receiver samples the information bits at the correct interval. Unfortunately synchronization is not guaranteed to last for the entire duration of data transmission. Though synchronization errors rarely occur, it has disastrous effects at the receiving end of transmission. These synchronization errors are modelled as either insertions or deletions in the transmitted data. In the best case scenario, these errors are restricted to single bit errors. In the worst case scenario, these errors lead to bursts of bits being incorrect. If these synchronization errors are not detected and corrected, it can cause a shift in the transmitted sequence which in turn leads to loss of synchronization. When a signal is subjected to synchronization errors it is difficult accurately recover the original data signal. In addition to the loss of synchronization, the information transmitted over the channel is also subjected to noise. This noise in the channel causes inversion errors within the signal. The objective of this dissertation is to investigate if an error correction scheme can be designed that has the ability to detect and correct adjacent bursts of deletions and random inversion errors. This error correction scheme needed to make use of a product code matrix structure. This product matrix needed to incorporate both an error correction and synchronization technique. The chosen error correcting techniques were Hamming and Reed-Solomon codes. The chosen synchronization techniques for this project were the marker technique or an adaptation of the Hamming code technique. In order to find an effective model, combinations of these models were simulated and compared. From the research obtained and analyzed in this document it was found that, depending on the desired performance, complexity and code rate, an error correction scheme can be used in the efficient correction of bursts of adjacent deletions by adapting product codes.
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Application of spectral shaping techniques to synchronization error correcting codes

- Clarke, Willem Adriaan

  • Authors: Clarke, Willem Adriaan
  • Date: 2015-02-25
  • Subjects: Error-correcting codes (Information theory)
  • Type: Thesis
  • Identifier: uj:13351 , http://hdl.handle.net/10210/13365
  • Description: M.Ing. (Electrical and Electronic Engineering) , In this thesis, spectral shaping techniques are applied to the insertion/deletion error correcting codes. Spectral shaping techniques are introduced and applied to insertion/deletion error correcting codes. The attainable rates for subcodes with spectral properties are computed and presented. The theory of comma-free codes is briefly reviewed and a new construction method is given : for comma-free insertion/deletion correcting codes. This method serves as a lower bound on the cardinality of comma-free insertion/deletion codes. The idea of a marker is introduced as an alternative method of finding word boundaries. Rules are given for governing the construction of marker code books that can differentiate between additive and insertion/deletion errors. The marker code books are then used in such: a way as not to violate the spectral properties of the abovementioned insertion/deletion correcting codes. A new class of codes is presented that has higher order spectral zeros at both DC and the Nyquist frequency. It is shown that these codes are insertion/deletion and additive error correcting. Besides this, it is shown that the abovementioned class of codes can correct two adjacent additive errors.
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'n Kriptologiese stawingsanalise en getalteoretiese stroomsyfer

- Van der Walt, Werner

  • Authors: Van der Walt, Werner
  • Date: 2014-03-18
  • Subjects: Cryptography , Error-correcting codes (Information theory) , Digital communications
  • Type: Thesis
  • Identifier: uj:4391 , http://hdl.handle.net/10210/9739
  • Description: M.Ing. (Electric and Electrical Engineering) , From the day the first 'apple' was eaten, a species of people existed that wants to misuse other people, This species is normally the first to use new technology to their advantage. It is essential for our own security to restrict the boundaries of their playing-field and to fill the field it self with potholes. This however should be a continuous process, for their dexterity tends to evolveas fast as new techniques are mastered. Firstly this thesis entails the analysis of the boundaries of the playing field of authentication systems without security. The boundaries of authentication systems with security is established with a unique technique. Concluding the first part of the thesis, a new method of code designing for this playing-field is proposed. Reordering the potholes on the playing-field is the subject of the second part of the thesis. Anew public key system is described for this purpose. A novel implementation of insertion/deletion error correcting codes is presented in this new system. To conclude the thesis, a thorough analysis of this public key system is presented.
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Ternary error correcting line codes

- Hope, John Francis

Undetected error behaviour of linear block codes on channels with memory

- Swarts, Francis

  • Authors: Swarts, Francis
  • Date: 2014-03-10
  • Subjects: Digital communications , Information storage and retrieval systems - Engineering , Error-correcting codes (Information theory)
  • Type: Thesis
  • Identifier: uj:4240 , http://hdl.handle.net/10210/9599
  • Description: D.Ing. (Electrical and Electronic) , In this thesis, the problem of undetected errors in digital communication systems employing error detection as the only means of error control, is investigated. In the past, the undetected error probability of linear block codes, was mainly investigated on the binary symmetric channel, which is memoryless. With this thesis, the main aim was to investigate the undetected error probability for linear block codes, on channels with memory. The channel models investigated are the Gilbert-Elliott and Fritchman channel models. Three techniques for calculating the undetected error probability on channels with memory are investigated. These techniques are: (i) Exhaustive codeword generation, (ii) Simulation and (iii) A trellis based technique. The trellis description of a block code based on the states of a syndrome calculating linear feedback shift register, formed the basis of the latter technique. The calculation of the weight spectrum of binary linear block codes, is still largely an unsolved problem. Using the trellis description of a binary linear block code, referred to earlier, we propose a description of binary linear block codes based on graphs, and from this we develop a technique for calculating the weight spectrum of binary linear block codes. The weight spectra of block codes determine the undetected error probability of these codes when used on the binary symmetric channel. Very favourable results were obtained through the application of the techniques developed for undetected error probability calculation as well as weight spectrum calculation.
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Constrained sequences and coding for spectral and error control

- Botha, Louis

  • Authors: Botha, Louis
  • Date: 2014-02-11
  • Subjects: Error-correcting codes (Information theory) , Digital communications
  • Type: Thesis
  • Identifier: uj:3799 , http://hdl.handle.net/10210/9172
  • Description: D.Ing. , When digital information is to be transmitted over a communications channel or stored in a data recording system, it is first mapped onto a code sequence by an encoder. The code sequence has certain properties which makes it suitable for use on the channel, ie the sequence complies to the channel input restrictions. These input restrictions are often described in terms of a required power spectral density of the code sequence. In addition, the code sequence can also be chosen in such a way as to enable the receiver to correct errors which occur in the channel. The set of rules which governs the encoding process is referred to as a line code or a modulation code for the transmission or storage of data, respectively. Before a new line code or modulation code can be developed, the properties that the code sequence should have for compliance to the channel input, restrictions and possession of desired error correction capabilities have to be established. A code' construction algorithm, which is often time consuming and difficult to apply, is then used to obtain the new code. In this dissertation, new classes of sequences which comply to the input restrictions and error correction requirements of practical channels are defined, and new line codes and recording codes are developed for mapping data onto these sequences. Several theorems which show relations between' information theoretical aspects of different classes of code sequences are presented. Algorithms which can be used to transform an existing line code or modulation code into a new code for use on another channel are introduced. These algorithms are systematic and easy to apply, and precludes the necessity of applying a code construction algorithm.
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Error monitoring for leased line data communication services

- Gildenhuys, Burgert

  • Authors: Gildenhuys, Burgert
  • Date: 2014-02-11
  • Subjects: Error-correcting codes (Information theory) , Telecommunication systems - South Africa , Telecommunication systems - Technological innovations
  • Type: Thesis
  • Identifier: uj:3788 , http://hdl.handle.net/10210/9162
  • Description: M.Ing. (Electrical & Electronic Engineering) , This thesis investigates the problems associated with providing end to end in-service performance monitoring on leased line data networks. These problems are of both practical and theoretical nature. A solution to this problem is presented and is based on linear block coding using some overhead bandwidth available within the channel. The coding scheme relies on the characteristics of shortened cyclic codes. A method is given to obtain the undetected error probability for an arbitrary code generation polynomial with a specified degree of shortening. References to the literature explain why this type of calculation is not straightforward. This method is used to compare various candidate codes. A method is discussed which facilitates rapid isolation of groups of favourable candidate codes for further study. Software is developed to aid in the code selection process and optimum codes are selected for leased line application. It is shown that in most cases improvements in undetected error probability are achievable, when comparison is made to previously published codes, proposed for error detection. This is because code generators optimum at their published or natural coding rate are seldom optimum at the rate which results from shortening the code.
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Error control with constrained codes

- Helberg, Albertus Stephanus Jacobus

  • Authors: Helberg, Albertus Stephanus Jacobus
  • Date: 2014-02-04
  • Subjects: Telecommunication lines , Error-correcting codes (Information theory)
  • Type: Thesis
  • Identifier: uj:7984 , http://hdl.handle.net/10210/8922
  • Description: M.Ing.(Electrical and Electronic Engineering) , In the ideal communication system no noise is present and no errors will be made. However, in practice, communication is over noisy channels which cause errors in the information. There is thus a necessity for the control of these errors. Furthermore, several channels impose runlength or disparity constraints on the bit stream. Until recently, the error control on these channels was applied separately to imposing the input restrictions with constrained codes. Such a system leads to poor performance under certain conditions. and is more complex and expensive to apply than systems where the error control is an integral part of the constrained code or decoder. In this study, we firstly investigate the error multiplication phenomena of constrained codes. An algorithm is presented that minimizes the error propagation probabilities of memoryless decoders according to two criteria. Another algorithm is presented along with the first to calculate the resulting bit error probabilities. The second approach to the error control of constrained codes is the construction of combined error-correcting constrained finite-state machine codes. We investigate the known construction techniques and construct several new codes using extensions of the known techniques. These codes complement or improve on the known error-correcting constrained codes with regards to either complexity, rate or error-correcting capability. Furthermore, these codes have good error behaviour and favourable power spectral densities.
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Coding and bounds for correcting insertion/deletion errors

- Swart, Theo G.

  • Authors: Swart, Theo G.
  • Date: 2012-09-10
  • Subjects: Error-correcting codes (Information theory) , Coding theory
  • Type: Thesis
  • Identifier: uj:9925 , http://hdl.handle.net/10210/7324
  • Description: M.Ing. , Certain properties of codewords after deletions or insertions of bits are investigated. This is used in the enumeration of the number of subwords or superwords after deletions or insertions. Also, new upper bounds for insertion/deletion correcting codes are derived from these properties. A decoding algorithm to correct up to two deletions per word for Helberg's s = 2 codes is proposed. By using subword and superword tables, new s = 2 codebooks with greater cardinalities than before are presented. An insertion/deletion channel model is presented which can be used in evaluating insertion/deletion correcting codes. By changing the parameters, various channel configurations can be attained. Furthermore, a new convolutional coding scheme for correcting insertion/deletion errors is introduced and an investigation of the performance is done by using the presented channel model.
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Coding structure and properties for correcting insertion/deletion errors

- Clarke, Willem Adriaan

  • Authors: Clarke, Willem Adriaan
  • Date: 2012-08-08
  • Subjects: Error-correcting codes (Information theory) , Digital communications
  • Type: Thesis
  • Identifier: uj:8945 , http://hdl.handle.net/10210/5418
  • Description: D. Ing. , The digital transmission of information necessitates the compensation for disturbances introduced by the channel. The compensation method usually used in digital communications is error correcting coding. The errors usually encountered are additive in nature, i.e. errors where only symbol values are changed. Understandably, the field of additive error correcting codes has become a mature research field. Remarkable progress has been made during the past 50 years, to such an extent that near Shannon capacity can be reached using suitable coding techniques. Sometimes the channel disturbances may result in the loss and/or gain of symbols and a subsequent loss of word or frame synchronisation. Unless some precautions were made, a synchronisation error may propagate and corrupt large blocks of data. Typical precautions taken against synchronisation errors are: out-of-band clock signals distributed to the transmission equipment in a network; stringent requirements on clock stability and jitter; limits on the number of repeaters and regeneration to curb jitter and delays; line coding to facilitate better clock extraction; and - use of framing methods on the coding level. Most transmission systems in use today will stop data transmission until reliable synchronisation is restored. El multiplexing systems are still the predominantly used technology in fixed telephone line operators and GSM operators, and recovering from a loss of synchronisation (the FAS alarm) typically lasts approximately 10 seconds. Considering that the transmission speed is 2048 KB/s, a large quantity of data is lost in during this process. The purpose of this study is therefore to broaden the understanding of insertion/deletion correcting binary codes. This will be achieved by presenting new properties and coding techniques for multiple insertion/deletion correcting codes. Mostly binary codes will be considered, but in some instances, the results may also hold for non-binary codes. As a secondary purpose, we hope to generate interest in this field of study and enable other researchers to continue to deeper explore the mechanisms of insertion and/or deletion correcting codes.
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Multiple insertion/deletion correcting and detecting codes : structural analysis, constructions and applications

- Paluncic, Filip

  • Authors: Paluncic, Filip
  • Date: 2012-08-01
  • Subjects: Error-correcting codes (Information theory) , Coding theory , Engineering mathematics
  • Type: Thesis
  • Identifier: uj:8894 , http://hdl.handle.net/10210/5366
  • Description: D.Ing. , This thesis is dedicated to an analysis of fundamental topics and issues related to deterministic insertion/deletion correcting and detecting codes. The most important contributions in this respect are the construction of a multiple insertion/deletion correcting code for run-length limited sequences and the construction and applications of multiple deletion (insertion) detecting codes. It is shown how run-length constraints and higher order moments can be combined to create a code which is simultaneously multiple insertion/deletion error correcting and runlength constrained. A systematic form of this code is presented, whereby any arbitrary run-length constrained sequence can be made into a multiple insertion/deletion correcting codeword by adding a prefix. This prefix is appended to the run-length constrained sequence in such a way that the resulting codeword is itself run-length constrained. Furthermore, it is shown that, despite the run-length constraints, the resulting code is guaranteed to have a better asymptotic rate than the Helberg code, the only other known non-trivial deterministic multiple insertion/deletion correcting code. We consider insertion/deletion detecting codes and present a multiple deletion (insertion) detecting code. It is shown that this code, which is systematic, is optimal in the sense that there exists no other systematic multiple deletion (insertion) detecting code with a better rate. Furthermore, we present a number of applications of such codes. In addition, further related topics of interest are considered. Firstly, jitter as a fundamental cause of insertion/deletion errors is investigated and as a result a counterpart to the signal-to-noise ratio in the amplitude domain is proposed for the time domain. Secondly, motivated by the correspondence of Levenshtein and Varshamov-Tenengol’ts codes, we investigate the insertion/deletion correcting capability of the single asymmetric error correcting Constantin-Rao codes within a wider framework of asymmetric error correcting and insertion/deletion correcting code structure correspondences. Finally, we propose a generalisation of Tenengol’ts’ construction for multiple non-binary insertion/deletion correction.
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Spectral shaping and distance mapping with permutation sequences

- Ouahada, Khmaies Taher

  • Authors: Ouahada, Khmaies Taher
  • Date: 2012-06-04
  • Subjects: Mappings (Mathematics) , Error-correcting codes (Information theory) , Permutations
  • Type: Thesis
  • Identifier: uj:2344 , http://hdl.handle.net/10210/4800
  • Description: D.Ing. , In this thesis we combined two techniques, namely a spectral shaping technique and a distance-preserving mapping technique to design new codes with both special spectrum shaping and error correction capabilities, in order to overcome certain communication problems like those that occur in a power-line communication channel. A new distance-preserving mapping construction based on graph theory is firstly presented. The k-cube graph construction from binary sequences to permutation sequences reached the upper bound on the sum of the Hamming distances for certain lengths of the permutation sequences and achieves the same sum of the Hamming distances as the best previously published constructions for most of the rest of the lengths. The k-cube graph construction is considered to be a simple and easy construction to understand the concept of mappings and especially the concept of a distance-reducing mapping.
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