Browsing by Author "Michael, Kisangiri"

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    Design of soft viterbi algorithm decoder enhanced with non-transmittable codewords for storage media
    (Cornell University, 2017) Hassan, Kilavo; Michael, Kisangiri; Mrutu, Salehe I.
    Viterbi Algorithm Decoder Enhanced with Non-transmittable Codewords is one of the best decoding algorithm which effectively improves forward error correction performance. However Viterbi decoder enhanced with NTCs is not yet designed to work in storage media devices. Currently Reed Solomon (RS) Algorithm is almost the dominant algorithm used in correcting error in storage media. Conversely, recent studies show that there still exist low reliability of data in storage media while the demand for storage media increases drastically. This study proposes a design of the Soft Viterbi Algorithm decoder enhanced with Non-transmittable Codewords (SVAD-NTCs) to be used in storage media for error correction. Matlab simulation was used in this design in order to investigate behavior and effectiveness of SVAD-NTCs in correcting errors in data retrieving from storage media. Sample data of one million bits are randomly generated, Additive White Gaussian Noise (AWGN) was used as data distortion model and Binary Phase- Shift Keying (BPSK) was applied for simulation modulation. Results show that, behaviors of SVAD-NTC performance increase as you increase the NTCs, but beyond 6NTCs there is no significant change and SVAD-NTCs design drastically reduce the total residual error from 216,878 of Reed Solomon to 23,900.
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    Forward error correction for storage media: An overview
    (Pittsburgh PA: IJCSIS Publication, 2015) Hassan, Kilavo; Michael, Kisangiri; Mrutu, Salehe I.
    As the adoption of Information and Communication Technology (ICT) tools in production and service rendering sectors increases, the demand for digital data storage with large storage capacity also increases. Higher storage media systems reliability and fault tolerance are among the key factors that the existing systems sometimes fail to meet and therefore, resulting into data loss. Forward error correction is one of the techniques applied to reduce the impact of data loss problem in digital data storage. This paper presents a survey conducted in different digital data storage companies in Dar es Salam, Tanzania. Data were collected and analyzed using Statistical Package for Social Sciences (SPSS). Secondary data were captured from user and manufacturer technical reports. It was revealed that data loss is still a predominant challenge in the digital data storage industry. Therefore, the study proposes the new storage media FEC model using locked convolutional encoder with the enhanced NTCViterbi decoder.
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    Performance of soft viterbi decoder enhanced with non-transmittable codewords for storage media
    (Taylor and Francis, 2018) Hassan, Kilavo; Michael, Kisangiri; Mrutu, Salehe
    The introduction of Non-Transmittable Codewords (NTCs) into Viterbi Algorithm Decoder has emerged as one of the best ways of improving performance of the Viterbi Algorithm Decoder. However, the performance has been tested only in hard decision Viterbi Decoder in telecommunication systems, but not in soft decision Viterbi Decoder and storage media. Most storage media use Reed Solomon (RS) Algorithm Decoder. Yet, the field experience still shows failure of the algorithm in correcting burst errors in reading data from the storage media; leading into data loss. This paper introduces the Soft Viterbi Algorithm Decoding enhanced with Non-Transmittable Codewords for storage media. Matlab software was used to simulate the algorithm and the performance was measured by comparing residual errors in a data length of one million bits. Additive White Gaussian Noise model was applied to distort the stored data. The performance comparison was made against the Reed Solomon code, Normal Soft Viterbi and Hard decision Viterbi enhanced with NTCs. The results showed that the Soft Viterbi Algorithm enhanced with NTCs performed remarkably better by 88.98% against RS, 84.31% against Normal Soft Viterbi and 67.26% against Hard Viterbi enhanced with NTCs.