Browsing by Author "Mrutu, Salehe"

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Assessment of non transmittable codewords enhancement to Viterbi Algorithm Decoding
(LJS Publishing, 2014-09) Mrutu, Salehe; Sam, Anael; Mvungi, Nerey
Researchers have shown that practical mobile communication channels introduce errors that are concentrated in a certain locality rather than random errors. These are burst errors caused by deep fading of the wireless channel or a lightning strike. The existing Viterbi Algorithm (VA) capable of correcting random errors is inefficient in correcting burst errors and therefore resulting in unacceptable amount of residual errors. This paper presents an assessment of Non- Transmittable Codewords (NTCs) enhancement technique to VA in decoding the received signals subjected to burst errors that may occur in poor channels. A hard decision, 1/2 rate and constraint length K is equal to 3 Viterbi Algorithm decoding technique, Binary Phase- Shift Keying (BPSK) and Additional White Gaussian Noise (AWGN) are components used in MATLAB software based simulation when assessing the proposed technique. Applying 6NTCs to VA decoder enables the decoder to reduce 83.7 percent of its residual errors. However, the technique reduces the encoder’s data transmission rate from 1/2 to 1/6
Bandwidth Aware FEC Algorithms for Wireless Communication Systems
(IISTE, 2013) Mrutu, Salehe; Kalolo, Sadath; Byanyuma, Mastidia; Nyakyi, Christina; Sam, Anael
Forward Error Correction (FEC) codes used by receivers to correct transmission errors without retransmission add a considerable amount of redundant bits to data bits. The addition of redundant bits lowers the overall network throughput, thus increasing the demand for more required bandwidth. In this paper we investigate and discuss various techniques used in FEC and show their effects to data communication in terms of bandwidth utilization. Additionally we propose improvement of (2, 1, 2) Convolutional encoder to (3, 2, 3) encoder. The proposed improvements increase the code rate from 1/2 to 2/3 hence reducing error control information and increasing bit rate. The received codeword can be decoded by Soft-Output Viterbi Algorithm
Design of soft viterbi algorithm decoder enhanced with non-transmittable codewords for storage media
(International Journal of Computer Science, Engineering and Applications, 2017-02) Hassan, Kilavo; Michael, Kisangiri; Mrutu, Salehe
Viterbi Algorithm Decoder Enhanced with Non-transmittable Codewords is one of the best decoding algorithm which effectively improves forward error correction performance. HoweverViterbi 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
Electrical & Electronic Engineering | Research Article Performance Of Soft Viterbi Decoder Enhanced With Non-Transmittable Codewords For Storage Media
(Cogent Engineering, 2018-01-12) 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.
Safety Zone Determination For Wireless Cellular Tower-A Case Study From Tanzania
(IJRET, 2013-09) Nyakyi, Christina; Mrutu, Salehe; Sam, Anael; Anatory, Justinian
Safety zone determination for wireless cellular towers has attracted attention from many researchers in the last decade. This is caused by the rapid growth of the wireless cellular industry which has led to the installation of towers even in the residential areas. There are many reports and ongoing researches regarding the biological and thermal effects of wireless cellular electromagnetic fields exposures to people. Cancer, hyperthermia, neural and behaviour effects of people exposed to these electromagnetic fields have been reported. This motivates the research to determine safety zones from wireless cellular towers to assure safety to those living in the vicinity of these towers. A model for safety zone determination is developed. The model takes the received power at the object, power transmitted by the transmitter and gain of the transmitter as inputs to determine the safe distance from the radiation of a wireless cellular transmitter. The power density received by the object and its geographical location from the radiation source are measured using the selective radiation meter. Transmitted power and the gain of the transmitter together with the height of the tower were obtained from the respective wireless cellular network operator. Based on the geographical location of the object, the distance from the radiation source was calculated using the haversine formula. These inputs are then used to determine the safety zone based on the standards and guidelines developed by WHO and ICNIRP.