Browsing by Author "Nleya, Bakhe"

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Availability and operability in optical transport network architectures
(IEEE, 2020-08) Gomba, Masimba; Nleya, Bakhe; Chidzonga, Richard F.
A typical optical transport network interconnects multitudes of offices. With the advent of the Internet of Things (IoT) networking approach, it has become necessary for such transport structures to be flexible enough to accommodate heterogeneous communication services that generate escalating traffic loads every time. It is also key not only to accommodating continuously escalating traffic levels, but also to maintain a consistent Quality of Service, operability as well availability. This can only be achieved through the provisioning of effective and dynamic network control. In this paper, we explore the various operational issues such as incompatibilities in terms of physical layer transmission requirements and other control and management challenges emerging in present and future/ (envisaged) optical transport networks.
Availability and operability in optical transport network architectures
(Solid State Technology, 2020-10-12) Nleya, Bakhe
A typical optical transport network interconnects multitudes of offices. With the advent of the Internet of Things (IoT) networking approach, it has become necessary for such transport structures to be flexible enough to accommodate heterogeneous communication services that generate escalating traffic loads every time. It is also key not only to accommodating continuously escalating traffic levels, but also to maintaining a consistent Quality of Service, operability as well availability. This can only be achieved through the provisioning of effective and dynamic network control. In this paper, we explore the various operational issues such as incompatibilities in terms of physical layer transmission requirements and other control and management challenges emerging in present and future/ (envisaged) optical transport networks.
Balancing between demand and trading in microgrids
(IEEE, 2020-01) Gomba, Masimba; Chidzonga, Richard; Nleya, Bakhe; Khumalo, Philani
The envisaged future generation power or smart grid (SG) will incorporate ICT technologies as well as innovative ideas for advanced integrated and automated power systems. The bidirectional information and energy flows within the envisaged advanced SG together with other aiding devices and objects, promote a new vision to energy supply and demand response. Meanwhile, the gradual shift to the next generation fully fledged SGs will be preceded by individual isolated microgrids voluntarily collaborating in the managing of all the available energy resources within their control to optimally serve both demand and distribution. In so doing, innovative applications will emerge that will bring numerous benefits as well as challenges in the SG. This paper introduces a power management approach that is geared towards optimizing power distribution, trading, as well as storage among cooperative microgrids (MGs). The initial task is to formulate the problem as a convex optimization problem and ultimately decompose it into a formulation that jointly considers user utility as well as factors such as MG load variance and associated transmission costs. It is deduced from obtained analytical results that the formulated generic optimization algorithm characterizing both aggregated demand and response from the cooperative microgrids assist greatly in determining the required resources hence enabling operational cost viability of the entire system.
A bursts contention avoidance scheme based on streamline effect awareness and limited intermediate node buffering in the core network
(Blue Eyes Intelligence Engineering and Sciences Publication, 2020-08-30) Nleya, Bakhe; Chidzonga, Richard F.
In an Optical Burst Switched (OBS) network, data packets sourced from peripheral networks are assembled into huge sized data bursts. For each assembled data burst, an associated control signal in the form of a burst control packet is (BCP) is gen-erated and scheduled at an offset time ahead of the data burst. The offset timing is to allow for the pre-configuration of required re-sources at all subsequent intermediate nodes prior to the actual data burst’s arrival. In that way, the data burst will fly-by each node and hence no requirement for temporary buffering at all in-termediate nodes. An operational requirement of an OBS network is that it be loss-less as in that way a consistent as well as acceptable quality of service (QoS) for all applications and services it serves as a platform can be guaranteed. Losses in such a network are mainly caused by improper provisioning as well as dimensioning of re-sources thus leading to contentions among bursts and consequently discarding of some of the contending data bursts. Key to both pro-visioning as well as proper dimensioning of the available resources in an optimized way is the implementation of effective routing and wavelength (RWA) that will seclude any data losses due to conten-tion occurrences. On the basis of the effects of the streamline effect (SLE), that is, effectively secluding primary contention among flows (streams) in the network, we propose in this paper a limited intermediate buffering that couples with SLE aware prioritized RWA (LIB-PRWA) scheme that combats secondary contention as well. The scheme makes routing decisions such as selection of pri-mary and deflection routes based on current resources states in the candidate paths. A performance comparison of the proposed scheme is carried out and simulation results demonstrate its com-parative abilities to effectively reduce losses as well as maintaining both high network resources utilization as well as QoS.
A controlled deflection routing and wavelength assignment based scheme in Optical Burst Switched (OBS) networks
(Walter de Gruyter GmbH, 2020-07-05) Nleya, Bakhe; Khumalo, Zephaniah Philani; Mutsvangwa, Andrew
Abstract - Heterogeneous IoT-enabled networks generally accommodate both jitter tolerant and intolerant traffic. Optical Burst Switched (OBS) backbone networks handle the resultant volumes of such traffic by transmitting it in huge size chunks called bursts. Because of the lack of or limited buffering capabilities within the core network, burst contentions may frequently occur and thus affect overall supportable quality of service (QoS). Burst contention(s) in the core network is generally characterized by frequent burst losses as well as differential delays especially when traffic levels surge. Burst contention can be resolved in the core network by way of partial buffering using fiber delay lines (FDLs), wavelength conversion using wavelength converters (WCs) or deflection routing. In this paper, we assume that burst contention is resolved by way of deflecting contending bursts to other less congested paths even though this may lead to differential delays incurred by bursts as they traverse the network. This will contribute to undesirable jitter that may ultimately compromise overall QoS. Noting that jitter is mostly caused by deflection routing which itself is a result of poor wavelength and routing assigning, the paper proposes a controlled deflection routing (CDR) and wavelength assignment based scheme that allows the deflection of bursts to alternate paths only after controller buffer preset thresholds are surpassed. In this way, bursts (or burst fragments) intended for a common destination are always most likely to be routed on the same or least cost path end-to-end. We describe the scheme as well as compare its performance to other existing approaches. Overall, both analytical and simulation results show that the proposed scheme does lower both congestion (on deflection routes) as well as jitter, thus also improving throughput as well as avoiding congestion on deflection paths.
A D2D communication based lightweight customer side data securing scheme in smart grids
(2022-08-20) Nleya, Bakhe; Khumalo, Phlani
With the emergence of modernized power grids into smart equivalents referred to as smart grids (SGs) the bulk generation, transmission, distribution, and end-user infrastructures must be appropriately long-term planned concurrently with the required privacy and security. Notably, the objectives of modern SGs are to minimize power energy losses through theft or physical dissipation. The embedded device-to-device (D2D) communication technology in 5G networks will enable an affordable fail-safe ICT subsystem platform for the SGs. However, Privacy preservation is necessary for D2D services in SGs. In this paper, we propose an anonymity privacy-preserving, and data aggregation scheme. We carry out both security and performance and obtained theoretical analysis and simulation results the privacy algorithm is effective and at the same time, fewer communication overheads are exchanged.
Efficient index modulation techniques for 5G and beyond
(IEEE, 2023-11-16) Mgobhozi, Bhekinkosi; Nleya, Bakhe
Index modulation (IM) techniques are emerging as promising approaches to improve spectral efficiency and reliability for 5G/future wireless networks. This paper pro vides an overview of key IM schemes including spatial modula tion, orthogonal frequency division multiplexing with index modulation (OFDM-IM), and enhanced variants like SIM OFDM. The spectral efficiency gains of these techniques are quantified mathematically. Spatial modulation uses antenna indices to convey additional information bits, while OFDM-IM utilizes subcarrier indices. SIM-OFDM further activates sub carriers selectively based on incoming bits. Experiments demonstrate spectral efficiency improvements over classical OFDM.
Energy demand and trading optimization in isolated microgrids
(IEEE, 2020-04-30) Chidzonga, Richard; Gomba, Masimba; Nleya, Bakhe
Future generation or smart grid (SG) will incorporate ICT technologies as well as innovative ideas for advanced integrated and automated power systems. The bidirectional information and energy flows within the envisaged advanced SG together with other aiding devices and objects, promote a new vision to energy supply and demand response. Meanwhile, the gradual shift to the next generation fully fledged SGs will be preceded by individual isolated microgrids voluntarily collaborating in the managing of all the available energy resources within their control to achieve optimality in both demand and distribution. In so doing, innovative applications will emerge that will bring numerous benefits as well as challenges in the SG. This paper introduces a power management approach that is geared towards optimizing power distribution, trading, as well as storage among cooperative microgrids (MGs). The initial task is to formulate the problem as a convex optimization problem and ultimately decompose it into a formulation that jointly considers user utility as well as factors such as MG load variance and associated transmission costs. It is deduced from obtained analytical results that the formulated generic optimization algorithm characterizing both overall demand and response by the cooperative microgrids assist greatly in determining the required resources hence leading to cost effectiveness of the entire system.
An energy efficient resource provisioning scheme for joint all photonic and wireless networks
(IEEE, 2022-08-04) Molefe, Mlungisi; Nleya, Bakhe
Flexible joint all photonic and wireless transport networks are a promising backbone network technological solution to accommodate the various dynamic bandwidth natured applications. In this paper, we mitigate methods aimed at maximizing available resources in a joint-photonic and wireless transport network in an energy-efficient manner. In so doing, we take into account challenges posed by transmission impairments as they tend to degrade signals and reduce their optical reach. We thus propose a state-of-the-art and innovative network architecture that can efficiently process a large amount of data. This architecture is designed to cater for bandwidth-hungry and bandwidth-dynamic applications and services. We further propose a load aware energy efficient resource optimization scheme using LERA algorithm, which couples with related service reconfiguration functions to maximize higher spectral efficiencies and minimal blocking in both optical and wireless sections of the composite network. Performance analysis shows that the proposed architectural scheme based on the LERA algorithm outperforms traditional benchmark techniques in achieving minimal blocking while efficiently maximizing spectral utilization compared to legacy benchmark approaches. Hence this scheme drastically enhances the utilization of the available resources and the overall network throughput.
An energy efficient resources allocation scheme for flexible translucent optical transport networks
(Psychology and Education, 2021-03-02) Nleya, Bakhe; Molefe, Mlungisi; Chidzonga, Richard
The present study attempts to explore how academic streams and learning styles play role in the preferences of coping strategies among prospective teachers. A quantitative approach was selected to explore the relationship. A survey was conducted with 300 prospective teachers (150 of science stream and 150 of humanities stream). A multi-stage random sampling technique was used to collect relevant information. Research instrument to measure coping strategies was developed by the researcher himself and Learning Style Inventory (LSI) by Ritu Dangwal & Sugata Mitra, 1997 was used to measure learning styles of prospective teachers. Statistical techniques i.e. mean, S.D., multivariate ANOVA were applied. Results revealed an essential significant effect of academic streams and learning styles on preference of coping strategies among prospective teachers. It is recommended that teacher training institutions should establish guidance or counseling centers to provide counseling to prospective teachers regarding coping skills and learning styles
Energy optimization for a smart prosumer
(PONTE International Scientific Researches Journal, 2020-04) Chidzonga, Richard F.; Nleya, Bakhe
This paper outlines the optimization of cost of electrical energy consumption for a small microgrid typical of a residential area where each household has renewable generation capability and the daily load is portioned into essential none-interruptible and schedulable or interruptible loads. Dual tariffs exist, for buying and the other for in-feed into the utility grid. The optimization makes appliances scheduling decisions to suit prevailing power availability as well amount of power to sell or procure from the utility depending on availability and prevailing real time pricing. We assume availability of time-variant energy parameters, then formulate a global optimization problem whose solutions leads to quantification of the optimal amount of energy purchased and sold for each of the individual households. When the unrealistic assumption of availability of information is removed from the implementation of the global optimization, an online algorithm that only requires the current values of the time varying supply and demand processes shows by simulation that the distributed algorithm can realise credible scheduling of prosumer household electricity usage. This is imperative as the very requirement of involving the consumer for appliances scheduling defeats the optimization cause as humans are not suitable for such repetitive and mundane tasks.
Energy-aware lightpath routing algorithm for optical transport networks
(TELKOM, 2019-09-01) Gomba, Ndadzibaya Masimba; Nleya, Bakhe; Dewa, Mendon; Mutsvangwa, Andrew; Khumalo, Zephaniah Philani
Current as well as future applications and services are characterized by bandwidth intensiveness and as such are directly driving the need for the deployment as well as operation of backbone networks that optimize on bandwidth provisioning. Since infrastructural hardware equipment requirements are trebling every two years because of continued surging bandwidth demands, the telecommunication industry is also a growing direct contributor to worldwide greenhouse gases (GHG) emissions as well as energy consumption. This is driving necessities to research on more energy efficient networking approaches. A novel optimized energy-aware lightpath routing (OEA-LR) algorithm is herein proposed. It primarily takes into account the effects of physical layer impairments (PLI) since their effects in high capacity translucent optical networks may not be ignored when formulating routing and wavelength assignment (RWA) algorithms. We assume an all-optical network hence connection requests from source to destination are entirely provisioned in the optical domain, thus optical-electrical-optical (OEO) conversions are not utilised. Both analytical and simulation results indicate that the proposed algorithm improves both energy efficiency operation as well as resource utilization of the network. We further conclude on a general observation of reciprocations between energy savings and blocking performance.
An energy-efficient impairment-aware routing algorithm for optical transport networks
(IEEE, 2021-03) Molefe, Mlungisi; Nleya, Bakhe; Chidzonga, R.; Bopape, Lebogang; Sibiya, K.
Flexible Translucent optical Transport networks have the capability to provision multiple data rate demands much more efficiently than the traditional wavelength routed optical backbone networks. By design, in order to suffice the signal reach constraint, traditional optical networks also include several repeaters that are located sparsely along each signal path so as to facilitate successful end-to end transmission of those lightpath connection signals that otherwise would exceed the optical reach. The presence of physical impairments coupled with the inclusion of repeaters that facilitate signal amplification, timing and refreshing means more overall operational power requirements. Thus, energy efficient operation of flexible Translucent Optical Transport Networks is quite crucial. Thus, in this paper we propose a combined physical impairments-aware as well as energy-efficient available network resources allocation algorithm that bases on path availability, considering the impact of energy consumption minimization versus quality of transmission (QoT). We consider the impact of physical impairments in the formulation of the algorithm. We carry out simulation validations of the proposed algorithm which generally indicate to an improvement of energy efficiency as well as other key network resources utilization.
Enhanced congestion management for minimizing network performance degradation in OBS networks
(Institute of Electrical and Electronics Engineers (IEEE), 2018-03) Nleya, Bakhe; Mutsvangwa, Andrew
Societa Editrice il Mulino. All rights reserved. Current global data traffic is increasingly dominated by delay and loss intolerant IP traffic which generally displays a structural self-similarity. This has necessitated the introduction of optical burst switching (OBS) as a supporting optical backbone network switching technology. Due to the buffer-less nature of optical burst switched (OBS) networks, contention/congestion in the core network can quickly lead to degradation in overall network performance at moderate to high traffic levels due to heavy burst loses. Several approaches have been explored to address this problem, notably measures that would minimize burstification delays, congestion, blocking at the same time enhancing end-to-end throughput as well as rational and fair utilization of the links. The aim is to achieve a consistent quality of service (QoS). Noting that congestion minimization is key to a consistent QoS provisioning, in this paper we propose a congestion management approach called enhanced congestion management (ECM) that seeks to guarantee a consistent QoS as well as rational and fair use of available links. It is primarily a service differentiation based scheme that aims at congestion, blocking and latency minimization, by way of combining time averaged delay segmented burstification as well as random shortest path selection based deflection routing and wavelength assignment. Simulation results show that ECM can effectively minimise congestion and at the same time improve both throughput and effective utilization, under moderate to high network traffic conditions. Overall, we show that the approach guarantees a consistent QoS.
Evaluation of wavelength congestion in transparent optical transport networks
(IEEE, 2020-08) Gomba, Ndadzibaya Masimba; Nleya, Bakhe; Mutsvangwa, Andrew; Chidzonga, Richard F.
Transparent Optical networks are generally regarded as a possible solution for the provisioning of ultrahigh speed transmission and switching capabilities to accommodate bandwidth hungry applications and services. Most of such applications and services involve streaming of high-definition video. However, since al source and destination pair establishments within a given Transparent optical transport network are assumed to be within optical signal reach, such networks do not incorporate regenerators. The lack of regenerators often leads to a serious degradation of the signal to noise ratio as a result of the effects of physical layer impairments accumulated as it traverses the network. This motivates us to propose and present a Q-factor tool that takes into account the various physical layer impairments. The proposed tool’s efficacy is evaluated by way of simulation.
Intermediate node buffering-based contention minimization scheme
(TELKOM, 2019-09-01) Khumalo, Philani; Nleya, Bakhe; Mutsvangwa, Andrew; Boysen, Gys
Optical burst switching (OBS) is a candidate switching paradigm for future backbone all-optical networks. However, data burst contention can be a major problem especially as the number of lightpath connections as well as the overall network radius increases. Furthermore, the absence of or limited buffering provision in core nodes, coupled with the standard one-way resources signalling aggravate contention occurrences resulting in some of the contending bursts being discarded. In this paper we propose and analyze a restricted intermediate Node Buffering based routing and wavelength assignment scheme (RI-RWA) scheme in which intermediate buffering provisioning is implemented for contending data bursts have already propagated more than half the network’s diameter. The aim is not to discard such bursts as they would have already utilized a considerable amount of available network resources. We comparatively evaluate the scheme’s performance in terms of performance indicators such as fairness, load balancing as well as throughput.
A lightweight based data aggregation scheme for smart grid power systems
(2022-08-20) Khumalo, Philani; Nleya, Bakhe
To accomplish data aggregation securely and efficiently, it is necessary to design a scheme that is low in both computational as well as communication overheads. Thus in this paper, we propose and analyze a novel secured data aggregation scheme that ensures both privacy preservation as well as data integrity. The scheme is centered on forecasting power consumption demands for a particular neighborhood, and overall, because most attacks occur, during the transmission of data across the ICT subsystem, it thus focuses on limiting that. It does so by first forecasting its demands, and only links with the utility operator when adjustments have become necessary. The scheme utilizes a lightweight efficient noninteractive authentication mechanism in the generation and sharing of session keys. Overall, both the security analysis and performance evaluation demonstrate its efficacy in guaranteeing both privacy and security in addition to minimizing computational and communication overheads.
A limited intermediate node buffering based RWA scheme in OBS backbone networks
(Ponte Academic Journal, 2019-11) Nleya, Bakhe; Mutsvangwa, Andrew
An all optical backbone Optical Burst Switched (OBS) network comprises of a multitude of optical transport sub-systems erected in commercial, residential as well as industrial ar-eas. The heterogeneous nature of the large volumes of traffic gen-erated by various applications and services ideally requires an op-tical backbone network infrastructure to accommodate it. Such a network must be continuously adaptable to the changing nature of the traffic as well as its spontaneous growth with time. In so doing, it has to ensure high end-to-end quality of service (QoS), availabil-ity as well as provision adaptable controllability in cooperation with peripheral (service) layer networks. To successfully design and deploy a cost-effective backbone network, consideration must be taken with regards to system configuration, as well as in applied devices manufacturing. This is to ensure that any component failure does not add any noticeable performance degradation as the network will quickly reconfigure itself accordingly. At operational level, ef-fective routing approaches are necessary to ensure minimized con-gestion as well as contention occurrences. The aggregation of both transit and local traffic at a node influences each other such as to aggravate congestion and to a certain extent reduce contention oc-currences (due to the streamline effect). In this paper, we propose a priority based intermediate Node Buffering based PIB-RWA scheme to combat the problem of contention occurrences and to prevent bursts discarding. It basically selects primary as well as deflection paths/links based on past contention frequency occurrences as well as current resources states in the candidate paths. Furthermore, the scheme also augments intermediate buffering provisioning for con-tending data bursts that are almost reaching the destination. Simu-lation results show that the scheme performs well in terms of key QoS metrics such as network throughput, data burst loss probabil-ities as well as load balancing.
A mutual authentication protocol for telecare services in an IoT network
(Auricle Technologies, Pvt., Ltd., 2021-05-05) Nleya, Bakhe
The emergence of Internet of Things (IoT), Cloud computing as well as the introducing of device to device communication for devices in proximity has resulted in the emerging of new innovative services such as Tele-care in the health sector. However, issues such as privacy and security associated with such a service (Tele-care) are a challenge as most of the associated devices are resource constrained in terms of both operational power and computing capability requirements. As such it becomes problematic to implement any traditional as well as current privacy and security measures. Thus, in this paper, we mitigate on a framework to that will ensure a robust privacy as well as security for a Tele-care service. Notably our focus is in ensuring computational simplicity, privacy preservation as well as energy efficiency. Overall analysis shows that the proposed protocol has improved performance in comparison with existing ones.
A mutual lightweight authentication scheme for fog-cloud-based e-health services
(Turkish Online Journal of Qualitative Inquiry (TOJQI), 2021-12-30) Nleya, Bakhe
The new version Internet network, now referred to as the Internet of Things (IoT) facilitates interconnectivity among various objects and devices. The introduction of both Cloud and Fog computing paradigms, device device-to-device (D2D) communication standards, as well as enabling privacy and security approaches, have all contributed to the practical realization of E-health services in IoT-enabled networks. Gen-erally, Fog layer nodes are often located in public places, where they are easily accessible and thus vulnerable to various securi-ty threats. Should this occur, the current and previously gener-ated security keys, as well as device identities, must be kept secret thus ensuring anonymity, unlinkability, forward secrecy, e.t.c. Thus in this paper, we introduce an E-Health authenti-cation and security architecture for the D2D-Aided fog compu-ting model, that facilitates verification of key components such as patients and peripheral devices without involving a central-ized cloud server. This is followed by a proposal for a light-weight anonymous authentication protocol (LAAP) to carry out authentication of the various parties in an E-health system. The proposed protocol is evaluated for various scenarios in D2D-Aided fog computing. Lightweight crypto- graphic primi-tives such as exclusive-or operations and one-way hash func-tion are relied upon to facilitate the inclusion of resource-constrained end-user devices mostly incorporated in body area networks (BANs). Ultimately we carry out an evaluation of the proposed proposal in terms of its efficacy, and security. The proposed protocol is generally found to be practically feasible for implementation in E-health service infrastructures.