Performance of asymmetrically clipped optical OFDM and DC-biased optical OFDM based on fast Fourier transform/discrete Hartley transform for powerline communication-visible light communication systems under impulsive noise
- Authors: Mapfumo, Irvine
- Date: 2020
- Subjects: Electric lines - Carrier transmission , Signal processing - Digital techniques , Wireless communication systems , Computer networks
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/480256 , uj:43468
- Description: Abstract: Hybrid PLC-VLC systems have generated a lot of research attention lately due to high data speeds and low implementation costs they offer. Owing to the increased number of devices connected to the internet, there has been an abrupt rise of data congestion in the RF spectrum, hence there is need to relieve it to allow high speed data communication access. Research output has provided evidence that PLC and VLC technologies can be integrated successfully to provide an alternate and cost-effective solution to relieve the RF spectrum... , M.Ing. (Electrical and Electronic Engineering Science)
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Worldwide interoperability for microwave access performance simulations using Markov model and simulators
- Authors: Nkaule, Sandla
- Date: 2017
- Subjects: IEEE 802.16 (Standard) , Wireless communication systems , Signal processing - Digital techniques , Microwave transmission lines , Markov processes
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/262611 , uj:27728
- Description: M.Tech. (Electrical Engineering) , Abstract: Wireless communication has been part of communication for decades and continues to evolve in a radical manner. These days communication cannot be separated with various technologies and newly developed devices tend to be integrated to support wireless. WiMAX is a wireless industry coalition and is part of the latest wireless infrastructure which includes 3G and LTE and needs to supports both communication and other technologies. WiMAX is seen as WiFi that supports greater distances of up to about 50 kms in radius. In this study we simulate the WiMAX performance - simulations are done using OPNET, NS-3 and Markov Chains are also used to evaluate the performance and compare the results. The study looks at the delay and the throughput in the WiMAX network as we increase numbers of connected devices from 20 to 50, 75 and lastly 100 mobile devices. The results of these performance indicators were analyzed and OPNET was found to be the best simulation tool amongst the three that was user friendly and easy to work with, which also returned results that are satisfactory and resembles reality.
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Error control coded data transmision over FM supplementary signal transmission radio channels
- Authors: Steyn, Pieter
- Date: 2015-10-13
- Subjects: Radio frequency modulation - Transmitters and transmission , Data transmission systems , Signal theory (Telecommunication) , Electronic noise , Signal processing - Digital techniques , Error-correcting codes (Information theory)
- Type: Thesis
- Identifier: uj:14289 , http://hdl.handle.net/10210/14748
- Description: M.Ing. (Electrical and Electronic Engineering) , With all the talk about the Information Highway and its construction, there is also a channel which is highly underestimated and thus almost ignored. On normal FM radio transmissions extra bandwidth exists, suitable for the transmission of audio and data. In this thesis the effects of interference on data transmission over the Supplementary Signal Transmission (SST) channel are analysed. The channel is characterized in terms of the Bit Error Rate (BER) versus field strength and distance from a transmitter ...
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Cattle monitoring and theft prevention system using ZigBee and WiFi
- Authors: Nkwari, Patrick Kibambe Mashoko
- Date: 2015-09-16
- Subjects: Animal radio tracking , Livestock - Losses - Prevention , Signal processing - Digital techniques , Wireless communication systems , IEEE 802.16 (Standard) , ZigBee
- Type: Thesis
- Identifier: uj:14129 , http://hdl.handle.net/10210/14566
- Description: M.Ing. , Please refer to full text to view abstract
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A supply friendly AC/DC converter for use in pulsed laser power supplies
- Authors: Truter, Neill
- Date: 2014-02-10
- Subjects: Signal processing - Digital techniques , Electric current converters
- Type: Thesis
- Identifier: uj:3740 , http://hdl.handle.net/10210/9119
- Description: M.Ing. (Electrical And Electronic Engineering) , An AC/DC force commutated controlled converter, designed for use in a pulsed laser power supply, is presented here. The converter is controlled with a digital signal processor (DSP). The converter has to supply a stable DC voltage to the load, while drawing sinusoidal currents at unity power factor from the supply grid. The design of such a converter is discussed here, as well as the experimental evaluation of a prototype converter able to supply 30kW to a load.
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M-ary frequency mapping techniques for power-line communications
- Authors: Lukusa, Tedy Mpoyi
- Date: 2013-05-27
- Subjects: Signal theory (Telecommunication) , Frequency mapping , Signal processing - Digital techniques , Wireless communication systems
- Type: Thesis
- Identifier: uj:7536 , http://hdl.handle.net/10210/8394
- Description: M.Ing. (Electrical and Electronic Engineering) , Power line communications have been in use since the early 1900‟s. The early use of this technology was mostly found within utility companies where it was used for intra telephonic service over the electrical distribution network. This technology has evolved remarkably to include not only low voltage medium and high voltage electric network but it has also extended to home automation and network. Literature on power line communications has pointed out major hindrances such as cable characteristics, impedance variations and noise signals from various sources. Most importantly, noisy characteristics of power line channels make it difficult to transmit information data in an effective and reliable way. More often data transmitted through power line channels is corrupted by three main types of noise, the background noise, the impulse noise and the permanent frequency disturbances. Consequently, researchers have focused on the optimum use of power line channel through combining channel coding and modulation schemes. In this study, we have, through simulations and practical experimentations, investigated the performance of a new mapping technique called “frequency mapping” over power line channel. The study material began with reviews of channel coding, modulation and permutation codes schemes. Further we presented through computer simulation, the inherent benefit of using permutation codes obtained through construction technique. Secondly, we detailed the use of Hadamard transform to produce frequency sequences. In reality, sign changes, drawn from observing Hadamard matrix and Walsh functions, were conceptualised as frequencies from which frequency sequences were produced. This technique termed “frequency mapping” showed effectiveness against narrow band noise in simulation environment. The study closed with an experimental verification of this new technique through custom designed communication system on a real power line channel where we observed a net BER performance gain when frequency sequences are ordered through Hadamard transform.
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