Hendrik Christoffel Ferreira

Hendrik Christoffel Ferreira
University of Johannesburg | uj · Department of Electrical and Electronic Engineering

D. Sc. (Eng.)

About

377
Publications
142,570
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3,965
Citations
Citations since 2016
46 Research Items
1821 Citations
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Additional affiliations
January 1983 - present
University of Johannesburg
Position
  • Professor (Full)

Publications

Publications (377)
Article
Full-text available
In the indoor environment of multiple-story buildings, the line-of-sight (LOS) radio frequency (RF) signal is generally obstructed by walls and slabs. As a solution to this dilemma, power line communication (PLC) is an alternative to overcome the LOS RF penetration issue. PLC is a cost-effective system that uses an alternative technology approach,...
Article
Full-text available
Signals from indoor access points in a wireless fidelity (WiFi) suffer from high attenuation as a result of the thick walls and metal structures in the multilevel-storey buildings where they are deployed. This is due to the scattering of the retransmitted signals by the thick walls and metal structures. Power line communication (PLC) technology is...
Article
Full-text available
A simple scheme was proposed by Knuth to generate binary balanced codewords from any information word. However, this method is limited in the sense that its redundancy is twice as that of the full sets of balanced codes. The gap between Knuth's algorithm redundancy and that of the full sets of balanced codes is significantly considerable. This pape...
Article
Full-text available
A simple scheme was proposed by Knuth to generate binary balanced codewords from an information word. 4 However, this method is limited in the sense that its redundancy is twice as that of the full sets of balanced codes. The 5 gap between Knuth's algorithm redundancy and that of the full sets of balanced codes is significantly considerable. This 6...
Article
Full-text available
Visible light communications (VLC) technology has emerged as a solution for the radio frequency relief and can be implemented, for example, through light fidelity. In most applications, VLC relies on a backbone technology due to its short-range nature. Hence, a combination technique is required to join the backbone network and VLC, preferably in an...
Conference Paper
Full-text available
Visible light communications (VLC) technology is a relatively new emerging telecommunication paradigm. It offers the opportunity to design cost-effective communication systems due to the dual use of the light sources, which are exploited as illumination devices and as communication antennas. However, this technology is mostly deployed in short-rang...
Preprint
Full-text available
In this paper, two moment balancing schemes, namely a variable index scheme and a fixed index scheme, for either single insertion/deletion error correction or multiple substitution error correction are introduced for coded sequences originally developed for correcting substitution errors only. By judiciously flipping bits of the original substituti...
Article
Full-text available
After more than two decades since intensive research began on power line communications (PLC) technology, this interesting field of telecommunication engineering is still progressing towards maturity. Despite some factors that delay it's worldwide acceptance, its implementation is starting to take off. Research in PLC is motivated (i) by many facto...
Article
Full-text available
This article investigates and evaluate a handover exchange scheme between two secondary users (SUs) moving in different directions across the handover region of neighbouring cell in a cognitive radio network. More specifically, this investigation compares the performance of SUs in a cellular cognitive radio network with and without channel exchange...
Article
Full-text available
The radio frequency spectrum has become very congested and scarce. A response to this dilemma is the implementation of visible light communications (VLC) technology, which is enabled by the dramatic development of light emitting diodes (LEDs) and laser diodes (LDs). VLC has become the most popular emerging telecommunication technology. This is due...
Article
Full-text available
Queuing regime is one outstanding approach in improving channel aggregation. If well designed and incorporated with carefully selected parameters, it enhances the smooth rollout of fifth/next generation wireless networks. While channel aggregation is the merging of scattered TV white space (spectrum holes) into one usable chunk for secondary users...
Article
Full-text available
In visible light communication (VLC) technology, the channel is generally modeled as a multi-path propagation environment. This is due to the presence, on the photo-detector, of specular and non-specular signal components. The Rician $K $ -factor is exploited in such environments to measure the dominance of the line-of-sight (LoS) signal power ove...
Article
Full-text available
Networked light-emitting diode (LED) lighting systems form an important part of smart buildings and the internet of things. Plug-and-play extra-low voltage LED lighting systems are attractive because they can be installed and reconfigured or expanded by the end user. Adding network / control / programming abilities to these LED lighting systems, in...
Article
Full-text available
In visible light communications (VLC) technology, the outdoor applications are less explored when compared to those indoors. This is due to the fact that: (i) the dual use of light emitting diodes (LEDs) is not always practicable in the outdoor VLC environment; (ii) the level of interference and noise is considerably higher in outdoor VLC; (iii) ma...
Article
Full-text available
High peak demand is often a challenge to the grid and could result into measures such as procurement of additional plants to meet the peak demand, higher tariffs for consumers, undesirable load shedding or even blackouts. However, these issues can be mitigated by introducing Demand Side Management (DSM) techniques for effective energy management of...
Article
Full-text available
Channel aggregation (CA) is one of the newest concept which cognitive radio network is bringing to bear for the smooth role out of fifth/next generation wireless networks. This is the combining of several unused primary user spectrum holes into a logic usable channel. However, several of these strategies have been investigated considering the varyi...
Article
Full-text available
In this paper, we provide a review of the different approaches used to detect activities inside a building using through-the-wall radar. We classify two main types of radar that are used in detection activities behind the wall. Stepped frequency and pulse compression radar are the most frequently used types of radar in through-the-wall radar imagin...
Article
Full-text available
Telecommunication engineering may substantially benefit from the integration of power line communications (PLC) and visible light communications (VLC) technologies. This integration is firstly enabled by the ubiquitous nature of PLC and VLC infrastructures, and secondly by the recent advances made in both technologies, and will be effective with th...
Article
Full-text available
In communication systems, amplitude phase shift keying (APSK) arises as a potential solution to mitigate performance degradations due to channel non-linearities. Since it combines the characteristics of phase shift keying (PSK) and those of amplitude shift keying (ASK), APSK is also likely to be robust in systems influenced by phase noise. It is th...
Article
Full-text available
The contributions of Distributed Energy Generation (DEG) and Distributed Energy Storage (DES) for Demand Side Management (DSM) purposes in a smart macrogrid or microgrid cannot be over-emphasised. However, standalone DEG and DES can lead to under-utilisation of energy generation by consumers and financial investments; in grid-connection mode, thoug...
Conference Paper
Full-text available
This paper focuses on the determination of the Channel Frequency Response (CFR) for a length of power cable which is crucial in determining the channel performance. The per-unit-length (PUL) parameters of a power line cable is used to calculate the CFR theoretically. This is verified by real world measurement. A new approach is introduced to model...
Conference Paper
Full-text available
This paper proposes a constellation design for color shift keying (CSK) based on phase shift keying (PSK) conversion, to be used in cascaded power line communications (PLC) and visible light communications (VLC) systems integration. We optimize the design of MPSK-CSK constellations and analyze the performance of MPSK-CSK systems based on the optimi...
Conference Paper
Full-text available
Spectral shaping codes are digital codes especially designed in such a manner that their alphabets give rise to predetermined frequency spectrum envelopes. This implies that the signal energy of these alphabets will be concentrated into a predetermined range of a given frequency spectrum. The design of digital codes in the above mentioned fashion i...
Conference Paper
Full-text available
With the widespread of light emitting diodes (LEDs) as a primary source of illumination, visible light communication (VLC) offers a lot of potentials by providing both resources and energy saving advantages. This paper presents a practical implementation of an integration of Power Line Communication (PLC) and VLC. The system uses spread frequency s...
Article
Full-text available
We report a new concept involving an adaptive mixture of different sets of permutation codes (PC) in a single DPSK-OFDM modulation scheme. Since this scheme is robust and the algorithms involved are simple, it is a good candidate for implementation for OFDM-based power line communication (PLC) systems. By using a special and easy concept called Ham...
Conference Paper
Full-text available
In this a paper, we propose a simplistic channel model for cascaded PLC-VLC system which highlights the noise scenario in such hybrid systems. The model utilises previously proposed channel transfer functions of both PLC and VLC channels and highlights the effects of the LED supply in the system. The noise scenario implemented on the model is based...
Conference Paper
Full-text available
In this paper, it is shown how a power line can be used to conductively carry and re-radiate 2.45GHz Wi-Fi signals over a distance. This can be useful when a conventional RF links' line-of-sight operation at 2.45GHz is obscured for example in multiple story buildings where Wi-Fi has difficulty penetrating. Commercial Wi-Fi modems were used to trans...
Article
Full-text available
The analysis of hybrid phase shift keying-color shift keying (MPSK-CSK) systems under the additive white Gaussian noise model is presented. MPSK-CSK systems are formed by mapping phase shift keying symbols to color shift keying using hue-saturation-value color space. Analytical expressions of bit error rate are given for M = 2, 4, 8 and 16, to vali...
Article
Full-text available
The role of Demand Side Management (DSM) with Distributed Energy Storage (DES) has been gaining attention in recent studies due to the impact of the latter on energy management in the smart grid. In this work, an Energy Scheduling and Distributed Storage (ESDS) algorithm is proposed to be installed into the smart meters of Time-of-Use (TOU) pricing...
Article
We present the construction of interleaving arrays for correcting clusters as well as diffuse bursts of insertion or deletion errors in constrained data. In this construction, a constrained information sequence is systematically encoded by computing a small number of parity checks and inserting markers such that the resulting code word is also cons...
Article
Full-text available
This paper presents an efficient technique to map phase shift keying (PSK) signalling to colour shift keying (CSK) constellation, to establish a full link in hybrid systems involving the radio frequency (RF) and the visible spectrum. It fits in systems combining (first link) wireless communication technologies such as the wireless fidelity (WiFi) o...
Conference Paper
Full-text available
This paper describes the implementation of a helium gas balloon flying system equipped with a camera and tracking subsystem for aerial photography. This is partially the results of a successful project conducted in November 2012 by a group of electrical and electronic students from the University of Johannesburg. The goal of this project was to tak...
Conference Paper
Full-text available
For the past 15 years since its appearance, Internet of Things (IoT) technology has been leading the planet towards a smart world where all devices and physical objects, referred to as “things”, will be connected via electronic sensors through the Internet. The distribution of medication to patients at a pharmacy in certain regions is still very tr...
Conference Paper
This paper presents the implementation of an integration technique used to combine power line communications (PLC) and visible light communications (VLC) channels in inter-building scenarios. It considers the narrow band PLC (NBPLC). Phase-shift keying (PSK) is used to convey the information over the PLC link and colour shift keying (CSK) technique...
Chapter
Full-text available
This article gives an overview of noise modeling of the two most problematic types of noise in powerline communications (PLC), namely, impulse noise (broadband noise) and frequency disturbers (narrow-band interference (NBI)). The models for these two types of noise are studied for orthogonal frequency-division multiplexing (OFDM) systems. The first...
Conference Paper
Full-text available
Growing peak demand has necessitated the introduction of Time-of-Use (TOU) pricing to Demand Side Management (DSM) in order to cause some peak demand to be shifted from peak to off-peak periods. Therefore, in this work, a Daily Maximum Energy Scheduling (DMES) — DSM technique is proposed. The DMES-DSM device is proposed to be installed into consume...
Conference Paper
Full-text available
Electricity is a scarce resource and ought to be saved. Users are often reluctant to save electricity because of many reasons, one of which is the physical effort that it entails. We present a method of saving electricity through the use of wireless smart plugs communicating to a wireless smart controller which have been designed and constructed so...
Conference Paper
Full-text available
Electricity is a scarce resource and ought to be saved. Users are often reluctant to save electricity because of many reasons, one of which is the physical effort that it entails. We present a method of saving electricity through the use of wireless smart plugs communicating to a wireless smart controller which have been designed and constructed so...