Performance analysis of wireless mesh networks for underground mines
- Authors: Shibalala, Jeremiah
- Date: 2020
- Subjects: Wireless communication systems , Mine communication systems
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/453022 , uj:39977
- Description: Abstract: Underground mines are harsh environments that have unique challenges that limit wireless communication. To ensure the safety and efficiency of mining operations, communication systems play a vital role. Despite the major developments in communication technologies, underground mines are still challenging environments for wireless communication, however, the advent of wireless mesh networks offers a cutting-edge solution to the mining industry and understanding the performance of this technology is fundamental to its application in dynamic areas of underground mines. This research project aims at conducting a performance analysis of wireless mesh networks by developing a prototype system set up of wireless mesh transceivers to conduct a feasibility study of data transmission on the network in underground mines. The second aspect of this study investigates network parameters, such as latency, throughput, and signal-to-noise, as a function of increasing mesh nodes on the network and internode spacing of mesh nodes. By combining theoretical models with real-time performance of the mesh system, realistic conclusions and better recommendations can be given to mining companies with regards to deploying wireless mesh systems in their underground mines. , M.Ing. (Electrical and Electronic Engineering Science)
- Full Text:
- Authors: Shibalala, Jeremiah
- Date: 2020
- Subjects: Wireless communication systems , Mine communication systems
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/453022 , uj:39977
- Description: Abstract: Underground mines are harsh environments that have unique challenges that limit wireless communication. To ensure the safety and efficiency of mining operations, communication systems play a vital role. Despite the major developments in communication technologies, underground mines are still challenging environments for wireless communication, however, the advent of wireless mesh networks offers a cutting-edge solution to the mining industry and understanding the performance of this technology is fundamental to its application in dynamic areas of underground mines. This research project aims at conducting a performance analysis of wireless mesh networks by developing a prototype system set up of wireless mesh transceivers to conduct a feasibility study of data transmission on the network in underground mines. The second aspect of this study investigates network parameters, such as latency, throughput, and signal-to-noise, as a function of increasing mesh nodes on the network and internode spacing of mesh nodes. By combining theoretical models with real-time performance of the mesh system, realistic conclusions and better recommendations can be given to mining companies with regards to deploying wireless mesh systems in their underground mines. , M.Ing. (Electrical and Electronic Engineering Science)
- Full Text:
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)
- Full Text:
- 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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BiCMOS millimetre-wave active bandpass filter
- Authors: Chaturvedi, Saurabh
- Date: 2018
- Subjects: Bipolar integrated circuits , Computer-aided engineering , Radio frequency microelectromechanical systems , Wireless power transmission , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/286034 , uj:30943
- Description: D.Ing. (Electrical and Electronic Engineering) , Abstract: The various available unlicensed frequency bands around 60 GHz make the millimetre-wave (mm-wave) spectrum relevant for high-speed wireless data transfer. The continuous development in communication technology has supported wireless communication systems with higher operating frequencies. Filters are key front-end components in these communication systems. In a radio frequency (RF) receiver of a communication system, a bandpass filter (BPF) is used to allow in-band signals and to attenuate out-of-band signals sufficiently. High-quality BPFs are essential for the improvement of the overall performance of an RF receiver. This research work entailed an investigation into mm-wave active BPFs with low loss, low noise and low power dissipation. The research showed that this could be achieved using a...
- Full Text:
- Authors: Chaturvedi, Saurabh
- Date: 2018
- Subjects: Bipolar integrated circuits , Computer-aided engineering , Radio frequency microelectromechanical systems , Wireless power transmission , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/286034 , uj:30943
- Description: D.Ing. (Electrical and Electronic Engineering) , Abstract: The various available unlicensed frequency bands around 60 GHz make the millimetre-wave (mm-wave) spectrum relevant for high-speed wireless data transfer. The continuous development in communication technology has supported wireless communication systems with higher operating frequencies. Filters are key front-end components in these communication systems. In a radio frequency (RF) receiver of a communication system, a bandpass filter (BPF) is used to allow in-band signals and to attenuate out-of-band signals sufficiently. High-quality BPFs are essential for the improvement of the overall performance of an RF receiver. This research work entailed an investigation into mm-wave active BPFs with low loss, low noise and low power dissipation. The research showed that this could be achieved using a...
- Full Text:
An efficient web services framework for approximate data collection in wireless sensor networks
- Authors: Madhav, Kuthadi Venu
- Date: 2017
- Subjects: Wireless sensor networks , Sensor networks , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/263067 , uj:27803
- Description: D.Ing. (Electrical Engineering) , Abstract: A wireless sensor network usually has a sensor to monitor physical and environmental conditions. The popularity of the wireless network has led to the need to update networks with a reliable and efficient communication mechanism and to ensure speed and security. In this research an energy-efficient network is proposed by reducing the data size by maximising the network lifetime, enhancing the security pattern for safe transmission of packets over a network, an adaptive pre-processing technique for streaming through wireless network and an efficient Time Division Multiple Access (TDMA) scheduling method for data collection minimisation using multiple sinks over a wireless sensor network. In the research, the network lifetime has been maximised using the data compression mechanism with the Huffman code, LEACH and Dijkstra algorithm which show efficient nodes for data transmission. During transmission, a major problem occurs in terms of security mainly in the military or other high security fields where many attackers try to hack the data. Thus, the research performed on the network security set out to generate a security pattern to safeguard data that is transmitted over a network. Some of the other common problems caused in a network during packet transmission are noise, redundancy and missing values. To solve these problems, the work performed introduced an adaptive pre-processing technique using Principal Component Analysis (PCA) and Hyperbolic Hopfield Neural Network (HHNN) to make streaming data efficient. This process provides higher efficiency by increasing the prediction accuracy. The other major problem with the WSN is data collection and scheduling in multiple sink environments. To overcome the problem, the study used TDMA scheduling to preempt the delay in data collection and reduce high energy consumption while the pocket-driven trajectories (PDT) algorithm reduces the iteration. The results show the success of the research in the simulation. The simulation results indicate high-performance efficiency in terms of reducing delay, increasing network lifetime, increasing security, reducing energy consumption and reducing data loss during data transmission in the wireless sensor network. Thus, the proposed research ended successfully by giving better results than other existing methods that are used to solve certain problems handled by wireless sensor networks.
- Full Text:
- Authors: Madhav, Kuthadi Venu
- Date: 2017
- Subjects: Wireless sensor networks , Sensor networks , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/263067 , uj:27803
- Description: D.Ing. (Electrical Engineering) , Abstract: A wireless sensor network usually has a sensor to monitor physical and environmental conditions. The popularity of the wireless network has led to the need to update networks with a reliable and efficient communication mechanism and to ensure speed and security. In this research an energy-efficient network is proposed by reducing the data size by maximising the network lifetime, enhancing the security pattern for safe transmission of packets over a network, an adaptive pre-processing technique for streaming through wireless network and an efficient Time Division Multiple Access (TDMA) scheduling method for data collection minimisation using multiple sinks over a wireless sensor network. In the research, the network lifetime has been maximised using the data compression mechanism with the Huffman code, LEACH and Dijkstra algorithm which show efficient nodes for data transmission. During transmission, a major problem occurs in terms of security mainly in the military or other high security fields where many attackers try to hack the data. Thus, the research performed on the network security set out to generate a security pattern to safeguard data that is transmitted over a network. Some of the other common problems caused in a network during packet transmission are noise, redundancy and missing values. To solve these problems, the work performed introduced an adaptive pre-processing technique using Principal Component Analysis (PCA) and Hyperbolic Hopfield Neural Network (HHNN) to make streaming data efficient. This process provides higher efficiency by increasing the prediction accuracy. The other major problem with the WSN is data collection and scheduling in multiple sink environments. To overcome the problem, the study used TDMA scheduling to preempt the delay in data collection and reduce high energy consumption while the pocket-driven trajectories (PDT) algorithm reduces the iteration. The results show the success of the research in the simulation. The simulation results indicate high-performance efficiency in terms of reducing delay, increasing network lifetime, increasing security, reducing energy consumption and reducing data loss during data transmission in the wireless sensor network. Thus, the proposed research ended successfully by giving better results than other existing methods that are used to solve certain problems handled by wireless sensor networks.
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Interfacing power line communications and visible light communications based on phase shift keying and colour shift keying
- Authors: Ndjiongue, Alain Richard
- Date: 2017
- Subjects: Telecommunication systems , Digital communications , Signal theory (Telecommunication) , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/233107 , uj:23794
- Description: D.Ing. , Abstract: Please refer to full text to view abstract
- Full Text:
- Authors: Ndjiongue, Alain Richard
- Date: 2017
- Subjects: Telecommunication systems , Digital communications , Signal theory (Telecommunication) , Wireless communication systems
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/233107 , uj:23794
- Description: D.Ing. , Abstract: Please refer to full text to view abstract
- Full Text:
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.
- Full Text:
- 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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Performance of cognitive radio mac protocols using simulations and software defined radio
- Authors: Loubser, Coert Johannes
- Date: 2016
- Subjects: Cognitive radio networks , Software radio , Radio frequency allocation , Wireless communication systems
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/225335 , uj:22756
- Description: Abstract: With the constant advances in wireless technology and the constant increase of mobile users and applications, radio spectrum has become a very scarce resource. Cognitive Radio (CR) has emerged as a viable way to deal with our scares, inefficient use of our radio spectrum by utilizing unused spectrum holes or white space as it is referred to. Using Software Defined Radio (SDR) we are able to evaluate the adaptive features and the unique properties of CRs. Most of the research that has been done on CR protocols has been based on analytical assessments and simulations. By prototyping these protocols, we will be able to validate the results achieved in simulations by comparing it to results achieved in an actual prototyped environment. In this paper we code and compare two CR specific Medium Access Control (MAC) protocols through simulations using a CR specific chosen simulator. We then prototype the two protocols using the Universal Software Radio Peripheral (USRP) and an SDR specific software development toolkit. Lastly, we then compare the results obtained from the simulations and SDR prototyping to see how close the simulated results come to an actual prototyped implementation. , M.Ing.
- Full Text:
- Authors: Loubser, Coert Johannes
- Date: 2016
- Subjects: Cognitive radio networks , Software radio , Radio frequency allocation , Wireless communication systems
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/225335 , uj:22756
- Description: Abstract: With the constant advances in wireless technology and the constant increase of mobile users and applications, radio spectrum has become a very scarce resource. Cognitive Radio (CR) has emerged as a viable way to deal with our scares, inefficient use of our radio spectrum by utilizing unused spectrum holes or white space as it is referred to. Using Software Defined Radio (SDR) we are able to evaluate the adaptive features and the unique properties of CRs. Most of the research that has been done on CR protocols has been based on analytical assessments and simulations. By prototyping these protocols, we will be able to validate the results achieved in simulations by comparing it to results achieved in an actual prototyped environment. In this paper we code and compare two CR specific Medium Access Control (MAC) protocols through simulations using a CR specific chosen simulator. We then prototype the two protocols using the Universal Software Radio Peripheral (USRP) and an SDR specific software development toolkit. Lastly, we then compare the results obtained from the simulations and SDR prototyping to see how close the simulated results come to an actual prototyped implementation. , M.Ing.
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Spectrum analysis of hybrid power line and visible light communications channels
- Authors: Nlom, Stephane Martin
- Date: 2016
- Subjects: Telecommunication systems , Wireless communication systems , Digital communications , Smart power grids
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/233806 , uj:23879
- Description: M.Ing. , Abstract: Please refer to full text to view abstract
- Full Text:
- Authors: Nlom, Stephane Martin
- Date: 2016
- Subjects: Telecommunication systems , Wireless communication systems , Digital communications , Smart power grids
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/233806 , uj:23879
- Description: M.Ing. , Abstract: Please refer to full text to view abstract
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Cattle monitoring and theft prevention system using ZigBee and WiFi
- Nkwari, Patrick Kibambe Mashoko
- 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
- Full Text:
- 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 preliminary investigation of the UHF properties of LV cable for WiFi over power line communications
- Jordaan, Sean, Janse van Rensburg, Petrus A., De Beer, Arnold S., Ferreira, Hendrik C., Han Vinck, A. J.
- Authors: Jordaan, Sean , Janse van Rensburg, Petrus A. , De Beer, Arnold S. , Ferreira, Hendrik C. , Han Vinck, A. J.
- Date: 2015-03-29
- Subjects: Power line communications , Wireless protocol , Wireless communication systems
- Type: Article
- Identifier: uj:5244 , http://hdl.handle.net/10210/14844
- Description: In pursuit of a wireless (contactless) power line communications (W-PLC) system for low voltage (LV) power distribution networks, a commonly utilized bundled low voltage electrical cable called Cabtyre, was energized with a range of frequencies up to 3 GHz. The intention was to characterize the cable from a radio frequency radiation perspective for the utilization of standard low voltage distribution cables as antennas in ultra high frequency (UHF) PLC systems. The range of test frequencies extends 550 MHz beyond the present IEEE 802.11g protocol which has a centre frequency of 2.45 GHz and a 80 MHz total bandwidth. The applied tests therefore allow adequately for the maximum bandwidth required with 40 MHz modulation on either side of the 2.45 GHz centre frequency.
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- Authors: Jordaan, Sean , Janse van Rensburg, Petrus A. , De Beer, Arnold S. , Ferreira, Hendrik C. , Han Vinck, A. J.
- Date: 2015-03-29
- Subjects: Power line communications , Wireless protocol , Wireless communication systems
- Type: Article
- Identifier: uj:5244 , http://hdl.handle.net/10210/14844
- Description: In pursuit of a wireless (contactless) power line communications (W-PLC) system for low voltage (LV) power distribution networks, a commonly utilized bundled low voltage electrical cable called Cabtyre, was energized with a range of frequencies up to 3 GHz. The intention was to characterize the cable from a radio frequency radiation perspective for the utilization of standard low voltage distribution cables as antennas in ultra high frequency (UHF) PLC systems. The range of test frequencies extends 550 MHz beyond the present IEEE 802.11g protocol which has a centre frequency of 2.45 GHz and a 80 MHz total bandwidth. The applied tests therefore allow adequately for the maximum bandwidth required with 40 MHz modulation on either side of the 2.45 GHz centre frequency.
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Wireless LAN receiver with image rejection
- Authors: Sheri, Ashraf
- Date: 2014-09-23
- Subjects: Wireless LANs , Wireless communication systems , Network performance (Telecommunication)
- Type: Thesis
- Identifier: uj:12371 , http://hdl.handle.net/10210/12155
- Description: M.Ing. (Electrical And Electronic Engineering) , This dissertation presents a fully integrated image rejection receiver, the design of a wireless local area network receiver, by using CMOS transistors, including circuit implementations, as well as the design of a low noise amplifier, down conversion mixer, LC oscillators passive on-chip inductor, IF mixer, and low-pass filter based on CMOS active inductor. The study compares receiver topologies, heterodyne architecture, image rejection and associated problems, direct conversion, low- IF and wideband IF architecture, and DC offset, and presents the chosen circuit configurations for a 2.4 GHz CMOS wireless-LAN receiver. It also compares different topologies of a low noise amplifier, mixers, and oscillators. On-chip passive devices are also presented. The fully integrated image rejection receiver consists of a first stage LNA with input 2.4 GHz and NF equal to 2 dB , output of the LNA signal at 2.4 GHz, with a gain of 24 dB mixing with LC Local oscillator signal 1.2 GHz in the RF Mixer, and the out-mixing signal mixed again with the quadrature Oscillator 1.2 GHz in the IF Mixer. The final stage presents a differential low-pass filter based on a CMOS active inductor 100 MHz. This receiver design operates in the 2.4 GHz frequency. The ultimate aim of this project is to design a small-area IC chip and a low-power fullyintegrated 2.4 GHz CMOS receiver. CMOS was selected as the technology of choice because of its cost advantages in comparison with other processes.
- Full Text:
- Authors: Sheri, Ashraf
- Date: 2014-09-23
- Subjects: Wireless LANs , Wireless communication systems , Network performance (Telecommunication)
- Type: Thesis
- Identifier: uj:12371 , http://hdl.handle.net/10210/12155
- Description: M.Ing. (Electrical And Electronic Engineering) , This dissertation presents a fully integrated image rejection receiver, the design of a wireless local area network receiver, by using CMOS transistors, including circuit implementations, as well as the design of a low noise amplifier, down conversion mixer, LC oscillators passive on-chip inductor, IF mixer, and low-pass filter based on CMOS active inductor. The study compares receiver topologies, heterodyne architecture, image rejection and associated problems, direct conversion, low- IF and wideband IF architecture, and DC offset, and presents the chosen circuit configurations for a 2.4 GHz CMOS wireless-LAN receiver. It also compares different topologies of a low noise amplifier, mixers, and oscillators. On-chip passive devices are also presented. The fully integrated image rejection receiver consists of a first stage LNA with input 2.4 GHz and NF equal to 2 dB , output of the LNA signal at 2.4 GHz, with a gain of 24 dB mixing with LC Local oscillator signal 1.2 GHz in the RF Mixer, and the out-mixing signal mixed again with the quadrature Oscillator 1.2 GHz in the IF Mixer. The final stage presents a differential low-pass filter based on a CMOS active inductor 100 MHz. This receiver design operates in the 2.4 GHz frequency. The ultimate aim of this project is to design a small-area IC chip and a low-power fullyintegrated 2.4 GHz CMOS receiver. CMOS was selected as the technology of choice because of its cost advantages in comparison with other processes.
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Maximum entropy based analysis of a DS/SSMA diversity system
- Van Rooyen, Pieter Gert Wessel
- Authors: Van Rooyen, Pieter Gert Wessel
- Date: 2014-02-13
- Subjects: Wireless communication systems
- Type: Thesis
- Identifier: uj:3976 , http://hdl.handle.net/10210/9334
- Description: D.Ing. , This thesis sets out to propose and analyze a cellular Direct Sequence Spread Spectrum Multiple Access (DSjSSMA) system for the Indoor Wireless Communication (IWC) Nakagami fading channel. The up- and downlink of the system implement Differential Phase Shift Keying (DPSK) and Coherent Phase Shift Keying (CPSK) as modulation schemes respectively, and are analyzed using Maximum Entropy (MaxEnt) principles due to its reliability and accuracy. As a means to enhance system capacity and performance, different forms of diversity are investigated; for the up- and downlink, respectively, RAKE reception and Maximum Ratio Combining (MRC) diversity together with Forward Error Control (FEC) coding are assumed. Further, the validity of the Gaussian Assumption (GA) is quantified and investigated under fading and non-fading conditions by calculating the missing information, using Minimum Relative Entropy (MRE) principles between the Inter- User Interference (IUI) distribution and a Gaussian distribution of equal variance.
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- Authors: Van Rooyen, Pieter Gert Wessel
- Date: 2014-02-13
- Subjects: Wireless communication systems
- Type: Thesis
- Identifier: uj:3976 , http://hdl.handle.net/10210/9334
- Description: D.Ing. , This thesis sets out to propose and analyze a cellular Direct Sequence Spread Spectrum Multiple Access (DSjSSMA) system for the Indoor Wireless Communication (IWC) Nakagami fading channel. The up- and downlink of the system implement Differential Phase Shift Keying (DPSK) and Coherent Phase Shift Keying (CPSK) as modulation schemes respectively, and are analyzed using Maximum Entropy (MaxEnt) principles due to its reliability and accuracy. As a means to enhance system capacity and performance, different forms of diversity are investigated; for the up- and downlink, respectively, RAKE reception and Maximum Ratio Combining (MRC) diversity together with Forward Error Control (FEC) coding are assumed. Further, the validity of the Gaussian Assumption (GA) is quantified and investigated under fading and non-fading conditions by calculating the missing information, using Minimum Relative Entropy (MRE) principles between the Inter- User Interference (IUI) distribution and a Gaussian distribution of equal variance.
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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.
- Full Text:
- 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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Aspects of multipath channel characterization
- Authors: Swarts, Jacobus Stephanus
- Date: 2012-08-17
- Subjects: Wireless communication systems
- Type: Thesis
- Identifier: uj:2642 , http://hdl.handle.net/10210/6088
- Description: M.Ing. , In this thesis we investigated the characterization of wireless communication channels. The characterization of the channel itself focused on the analog as well as the discrete domains. This was done to provide a more complete treatment than that which is usually found in the literature (which normally focuses" on either one of the domains). We also provide a discussion on the basic issues that arise when trying to characterize a wireless communication channel. The analog characterization proceeded by means of the impulse response of the chan nel. We calculated the scattering function of the channel as well as the Delay and Doppler Power Spectra. From the wideband data we also derived the equivalent Narrowband en velope and phase and investigated the probability density functions of these. We also implemented the GMSK modulation scheme, used in the GSM system, in software. This included a simulation of the additive white Gaussian noise channel as well as the Rayleigh fading channel, the two most common assumed models. A complete discussion is provided on this implementation. The implementation above was used to obtain discrete channel models of GMSK on a Rayleigh fading channel. This also provided us with the opportunity to compare the performance of three of the most common discrete channel models : the Gilbert model, the Gilbert-Elliott model and the Fritchman model. Lastly we obtained equations that describe the behaviour of the Gilbert model's parameters as a function of average signal to-noise ratio.
- Full Text:
- Authors: Swarts, Jacobus Stephanus
- Date: 2012-08-17
- Subjects: Wireless communication systems
- Type: Thesis
- Identifier: uj:2642 , http://hdl.handle.net/10210/6088
- Description: M.Ing. , In this thesis we investigated the characterization of wireless communication channels. The characterization of the channel itself focused on the analog as well as the discrete domains. This was done to provide a more complete treatment than that which is usually found in the literature (which normally focuses" on either one of the domains). We also provide a discussion on the basic issues that arise when trying to characterize a wireless communication channel. The analog characterization proceeded by means of the impulse response of the chan nel. We calculated the scattering function of the channel as well as the Delay and Doppler Power Spectra. From the wideband data we also derived the equivalent Narrowband en velope and phase and investigated the probability density functions of these. We also implemented the GMSK modulation scheme, used in the GSM system, in software. This included a simulation of the additive white Gaussian noise channel as well as the Rayleigh fading channel, the two most common assumed models. A complete discussion is provided on this implementation. The implementation above was used to obtain discrete channel models of GMSK on a Rayleigh fading channel. This also provided us with the opportunity to compare the performance of three of the most common discrete channel models : the Gilbert model, the Gilbert-Elliott model and the Fritchman model. Lastly we obtained equations that describe the behaviour of the Gilbert model's parameters as a function of average signal to-noise ratio.
- Full Text:
Resale pricing models for IP-based services over wireless MESH networks
- Authors: Zhu, Hailing
- Date: 2012-06-04
- Subjects: Wireless communication systems , Internet service providers , Internet industry - Prices , Internet rates
- Type: Thesis
- Identifier: uj:2337 , http://hdl.handle.net/10210/4794
- Description: M.Ing. , The development of Wireless Local Area Network (WLAN) technologies offers a novel platform for IP-based service resale via Wireless Mesh Networks (WMNs) that provide high network coverage and lower infrastructure cost. In this IP-based service resale business, the Access Point (AP) providers sets their pricing policies as IP-based service resellers to maximize their profits, while the resale-users (end users of the WMNs) who are price- and quality-of-service (QoS)- sensitive, respond to AP providers’ pricing policies by controlling their usage. This research exploits the efficiency of dynamic pricing by integrating pricing into best effort based WMNs as an economic control tool to optimize the profit of the AP providers and improve the utilization of their limited uplink bandwidth by taking into consideration the resale-users’ price- and QoS- sensitivity. Two cases are presented in this thesis: a monopoly, where a single AP provider aims to maximize its profit while guaranteeing its resale-users with a minimum allocated bandwidth; and a duopoly, where two AP providers compete to maximize their individual profits based on the resale-users’ price- and delay- sensitivity. For both cases, the limited uplink bandwidth of the AP providers is considered as a bottleneck of the WMN. We propose two dynamic pricing models for these two cases respectively and investigate how pricing depends on the assumptions that we make about the market. Indeed, the pricing model proposed for the monopoly is a preliminary study for the duopoly pricing model. In formulating and analyzing these two pricing models, we see how prices are driven by the profit-maximizing aim of one AP provider and the competition between two AP providers.
- Full Text:
- Authors: Zhu, Hailing
- Date: 2012-06-04
- Subjects: Wireless communication systems , Internet service providers , Internet industry - Prices , Internet rates
- Type: Thesis
- Identifier: uj:2337 , http://hdl.handle.net/10210/4794
- Description: M.Ing. , The development of Wireless Local Area Network (WLAN) technologies offers a novel platform for IP-based service resale via Wireless Mesh Networks (WMNs) that provide high network coverage and lower infrastructure cost. In this IP-based service resale business, the Access Point (AP) providers sets their pricing policies as IP-based service resellers to maximize their profits, while the resale-users (end users of the WMNs) who are price- and quality-of-service (QoS)- sensitive, respond to AP providers’ pricing policies by controlling their usage. This research exploits the efficiency of dynamic pricing by integrating pricing into best effort based WMNs as an economic control tool to optimize the profit of the AP providers and improve the utilization of their limited uplink bandwidth by taking into consideration the resale-users’ price- and QoS- sensitivity. Two cases are presented in this thesis: a monopoly, where a single AP provider aims to maximize its profit while guaranteeing its resale-users with a minimum allocated bandwidth; and a duopoly, where two AP providers compete to maximize their individual profits based on the resale-users’ price- and delay- sensitivity. For both cases, the limited uplink bandwidth of the AP providers is considered as a bottleneck of the WMN. We propose two dynamic pricing models for these two cases respectively and investigate how pricing depends on the assumptions that we make about the market. Indeed, the pricing model proposed for the monopoly is a preliminary study for the duopoly pricing model. In formulating and analyzing these two pricing models, we see how prices are driven by the profit-maximizing aim of one AP provider and the competition between two AP providers.
- Full Text:
An S-Parameter based modeling of a MIMO channel using half-wave dipole antennas
- Paul, B.S., Bhattacharjee, R
- Authors: Paul, B.S. , Bhattacharjee, R
- Date: 2007
- Subjects: Wireless communication systems , Space time codes , MIMO systems
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/18201 , uj:15970 , Paul, B.S. & Bhattacharjee, R. 2007. An S-parameter based modeling of a MIMO channel using half-wave dipole antennas. In: Proceedings of the Thirteenth National Conference on Communications (NCC). 26th – 28th January, 2007, IIT Kanpur, India.
- Description: Abstract: In this paper we have introduced an S-parameter based approach for computation of MIMO channel matrix where the entire channel model is developed using half-wave dipoles. For the model under consideration, suitably terminated dipole antennas represent scatterers with different scattering coefficients. We first validate our approach by comparing results obtained by our method with the results already reported in literature for similar model evaluated using different method. Using our proposed method, we determine the variation of capacity of a MIMO link as function of separation of antennas in the mobile station for a macrocellular scenario where the scattering environment is represented by a ring of scatterers surrounding the mobile station. We further extend our approach for modeling a dual polarized MIMO system. Simulation results on capacity match with the expected results that further corroborate the effectiveness of our approach.
- Full Text:
- Authors: Paul, B.S. , Bhattacharjee, R
- Date: 2007
- Subjects: Wireless communication systems , Space time codes , MIMO systems
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/18201 , uj:15970 , Paul, B.S. & Bhattacharjee, R. 2007. An S-parameter based modeling of a MIMO channel using half-wave dipole antennas. In: Proceedings of the Thirteenth National Conference on Communications (NCC). 26th – 28th January, 2007, IIT Kanpur, India.
- Description: Abstract: In this paper we have introduced an S-parameter based approach for computation of MIMO channel matrix where the entire channel model is developed using half-wave dipoles. For the model under consideration, suitably terminated dipole antennas represent scatterers with different scattering coefficients. We first validate our approach by comparing results obtained by our method with the results already reported in literature for similar model evaluated using different method. Using our proposed method, we determine the variation of capacity of a MIMO link as function of separation of antennas in the mobile station for a macrocellular scenario where the scattering environment is represented by a ring of scatterers surrounding the mobile station. We further extend our approach for modeling a dual polarized MIMO system. Simulation results on capacity match with the expected results that further corroborate the effectiveness of our approach.
- Full Text:
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