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Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels
Thesis (PhD (Electronic Engineering))--University of Pretoria, 2025.
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University of Pretoria
2025
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| author2 | Myburgh, Hermanus Carel |
| author_browse | Myburgh, Hermanus Carel |
| author_facet | Myburgh, Hermanus Carel |
| collection | Thesis |
| dc_rights_str_mv | © 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD (Electronic Engineering))--University of Pretoria, 2025. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/107213 |
| institution | University of Pretoria (South Africa) |
| language | English |
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| publishDate | 2025 |
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| publisher | University of Pretoria |
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| spelling | oai:repository.up.ac.za:2263/107213 Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels Myburgh, Hermanus Carel kealeboga.mokise@up.ac.za Mokise, Kealeboga UCTD Sustainable Development Goals (SDGs) Powerline communication Hybrid powerlinewireless communication Composite fading Shadowing Thesis (PhD (Electronic Engineering))--University of Pretoria, 2025. New-generation radio networks are often accompanied by increased usage of spectral and temporal resources. As a result, interaction between the propagating radio signal and the propagation environment becomes increasingly complex. This inherent complexity of signal propagation has prompted the development of channel models that capture the stochastic nature of the channel that arise from physical phenomena such as shadowing, clustering of multipath propagation components, power variation between the line-of-sight (LOS) and non-line-of-sight (NLOS) multipath propagation components and the simultaneous fading effect shadowing and multipath fading, commonly referred to as composite fading. Composite fading arises when the instantaneous variations of the received signal strength caused by multipath fading are superimposed on the long-term variations caused by shadowing. Composite fading provides a realistic account for the signal strength variation behaviour of the received signal, and therefore, it is crucial to characterise such fading behaviour to analyse the performance of radio communication systems. Various composite fading models have been proposed to characterise the simultaneous impact of multipath and shadowing in various radio communications scenarios. Composite fading models can be broadly classified into LOS shadowing, which describes shadowing of the dominant signal component, and multiplicative shadowing, which describes propagation conditions whereby both the LOS component and scattered signal components of the received signal are jointly shadowed. In the current literature, composite fading, including the other aforementioned physical phenomena of communication channels, has been intensively studied and validated in wireless communication (WLC) scenarios. The powerline communication (PLC) channel is a known medium of radio signal propagation, and it exhibits propagation characteristics which are apparent in wireless channels, such as multipath propagation and signal propagation path-loss. These common propagation characteristics shared by the PLC and WLC channels facilitate the propagation of radio signals between the two channels with minimal signal coupling requirements, which means a hybrid PLC-WLC communication system can be established by integrating the PLC and WLC technologies to leverage the different spectral resources and diversity between powerline and wireless channels. In the current literature, previous works on PLC-WLC channel characterisation primarily focus on the frequency-selective behaviour of such channels, and PLC-WLC propagation environments are typically investigated with both the transmitter and receiver remaining stationary during channel measurements. Therefore, there is a significant lack of time-selective behaviour characterisation and characterisation of hybrid PLC-WLC propagation scenarios involving relative motion between the PLC and WLC devices. Moreover, there is currently no channel model that describes the unified powerline-wireless propagation environment. Having identified these knowledge gaps and other limiting factors of hybrid PLC-WLC communication systems, this thesis focuses on three main fronts to address these gaps and limitations. The first contribution of this thesis deals with the multipath clustering problem in PLC and hybrid PLCWLC communication channels with the objective of characterising multipath clustering behaviour in indoor stationary PLC and hybrid PLC-WLC communications channels using a model-based clustering approach. The multipath clustering problem formulation is considered in wideband communication scenarios, where multipath components arrive in clusters which share similar parameters such as the arrival time delay. Using a sequence-based wideband channel sounding method, channel measurements with high-temporal resolution are obtained. An eigenvalue estimator is used to determine the number of multipath components and the space-alternating generalised expectation-maximization (SAGE) algorithm is used to extract magnitude-delay parameters of multipath components. A method for estimating a feasible range of clusters is proposed and applied in both the distance-based and model based clustering approaches. The model-based framework employs a range of finite-mixture models(FMMs) to identify clusters, while distance-based approaches use methods such as kMeans. A maximum likelihood (ML) approach is used for ftting the FMMs to the extracted multipath components, which proved to be efficient in estimating parameters for both closed-form and update-expression solutions of the likelihood functions. The corrected Akaike’s information criterion (AICc) metric was used to determine the best-ft FMM to the measurements, while the Davies-Bouldin (DB) and Calinski-Harabasz (CH) validation indexes are used to compare the model-based to the distance-based clustering methods. The obtained results indicate that both PLC and hybrid PLC-WLC communication channels present clusters of multipath components. Moreover, the results show that the model-based clustering obtains the best performance in terms of within-cluster compactness and between-cluster separation in the delay domain compared to distance-based methods. The second contribution of this thesis deals with the investigation and characterisation of fading behaviour in hybrid PLC-WLC channels with the objective of characterising the short-term (multipath) and long-term (shadowing) fading behaviour observed in indoor hybrid PLC-WLC communications channels for narrowband communications involving relative motion between the PLC and WLC devices. Novel insights into the problem formulation of composite fading behaviour in the context of PLC-WLC communication systems, considering relative motion between the PLC and WLC devices, are provided. Two new long-term fading models, namely, Gamma-Rayleigh (GR) and inverse Gamma Rayleigh (IGR), are proposed. The utility and validity of the proposed GR and IGR fading models are demonstrated through a proposed procedure of approximating the popular and well-established long-term fading models, such as the lognormal and inverse Gaussian shadowing models, using method-of-moments (MoM) estimators approach, which demonstrated excellent approximation of the probability density function (PDF) statistics. An extensive measurement campaign is carried out considering various hybrid PLC-WLC propagation scenarios classified by the powerline branching characteristics of the PLC portion of the hybrid PLC-WLC channels. Then, the Generalised Lee method is used to separate short-term and long-term fading components from the received signal envelope. The estimated long-term fading signal components are fitted to the lognormal, gamma, inverse gamma, inverse Gaussian, and the proposed GR and IGR long-term fading models. The estimated short-term fading signal components are fitted to the Rayleigh, Rician, κ-µ and Nakagami candidate short-term fading models. The obtained results indicate that the amount of short-term and long-term fading increases as more branches or discontinuities (non-idealities) are added to the PLC portion of the hybrid PLC-WLC channel. This results in increased instantaneous signal strength fluctuations and increased random mean power fluctuations in the received signal, and consequently increased composite fading behaviour of the hybrid PLC-WLC channel. The third contribution of this thesis deals with the investigation and characterisation composite fading behaviour, that is, the combined effect of short-term (multipath) and long-term (shadowing) fading, in hybrid PLC-WLC channels with the objective of proposing a new and general composite fading models to characterise composite fading behaviour observed in indoor low-voltage PLC-WLC communications scenarios involving relative motion between the PLC and WLC devices. Two new general composite fading models are proposed, namely, the κ-µ / Gamma-Rayleigh (κ-µ / GR) model and the κ-µ / inverse Gamma-Rayleigh (κ-µ / IGR) model. The κ-µ / GR is a LOS shadowing model which accounts for composite fading scenarios where shadow fading is assumed to only affect the dominant signal components, while the κ-µ / IGR is a multiplicative shadowing model which accounts for scenarios where shadowing is assumed to affect both the dominant and scattered signal components. For both models, analytical expressions are derived for the probability density function (PDF), cumulative distribution function (CDF), amount-of-fading (AF), general moments and the moment generating function (MGF) of the models, along with performance metrics such as outage probability (OP), average symbol error probability (ASEP) and average channel capacity. The validity of the derived expressions is confirmed through Monte Carlo simulations. An extensive measurement campaign is carried out considering various hybrid PLC-WLC propagation scenarios classified by the powerline branching characteristics of the PLC portion of the hybrid PLC-WLC channels, and the empirical data is fitted to the proposed models and other existing composite fading models using a non-linear fitting process. The obtained results indicate that increased branching, discontinuities and terminations in the PLC portion of a hybrid PLC-WLC channel result in enhanced multipath and shadowing effects, thereby intensifying the composite fading behaviour observed in such PLC-WLC systems. Moreover, the obtained results indicate that the appropriateness of a LOS or a multiplicative composite fading model depends on the strength of dominant signal components and the power disparity between dominant and scattered signal components. Consequently, the proposed LOS and multiplicative shadowing models proved to be generalised and necessary for accurately modelling time-selective fading across various PLC-WLC signal propagation scenarios. Electrical, Electronic and Computer Engineering PhD (Electronic Engineering) Unrestricted Faculty of Engineering, Built Environment and Information Technology SDG-09: Industry, innovation and infrastructure 2025-12-10T12:53:21Z 2025-12-10T12:53:21Z 2026 2025 Thesis * A2026 http://hdl.handle.net/2263/107213 10.25403/UPresearchdata.30849017 en © 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Sustainable Development Goals (SDGs) Powerline communication Hybrid powerlinewireless communication Composite fading Shadowing Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title | Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title_full | Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title_fullStr | Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title_full_unstemmed | Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title_short | Modelling and characterisation of signal fading behaviour in hybrid powerline-wireless communication channels |
| title_sort | modelling and characterisation of signal fading behaviour in hybrid powerline wireless communication channels |
| topic | UCTD Sustainable Development Goals (SDGs) Powerline communication Hybrid powerlinewireless communication Composite fading Shadowing |
| url | http://hdl.handle.net/2263/107213 |