ResearchSpace :: Browsing by Author "Lysko, Albert A"

Browsing by Author "Lysko, Albert A"

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4G RAN infrastructure sharing by 5G virtualized mobile network operators: A tutorial
(2021-09) Mamushiane, Lusani; Mboweni, Lawrence S; Kobo, Hlabishi; Mudumbe, Mduduzi J; Mwangama, J; Lysko, Albert A
Active radio access network (RAN) infrastructure sharing has emerged as a promising solution for efficient spectrum utilization, capital and operational cost savings, improved MVNO penetration rates and lower broadband retail prices in both emerging and developed markets. This paper presents a tutorial on the testbed implementation of an active RAN sharing architecture, leveraging multi-vendor virtualized 5G and 4G core networks running on commodity hardware and proprietary 4G RAN equipment (eNodeB). Troubleshooting techniques used for different implementation challenges encountered are also presented in this contribution. The performance of the proposed architecture was validated using end-user quality of experience (QoE) as the key performance indicator. The results show no performance degradation when RAN sharing is being utilized.
5G network slice resource overbooking: An opportunity for telcos to boost their revenue
(2022-08) Mamushiane, Lusani; Mwangama, J; Lysko, Albert A; Kobo, Hlabishi I
The global impact of COVID-19 has been unprecedented, with over-the-top (OTT) services consumption growing at a staggering rate. While OTT does consume revenue-generating data, OTT services are gradually substituting the traditional primary sources of revenue, voice and SMS services, with “freemium-based” alternatives such as WhatsApp and Telegram. This has driven telcos to reconsider their strategies and revenue sources. We believe that 5G network slicing (a type of 5G infrastructure sharing) is a potential solution that telcos could adopt to boost their revenue. In particular, this paper introduces the concept of network slice resource overbooking. We consider leveraging machine learning (ML) to maximise network resource utilisation which translates to maximum revenue gains for telcos. The concept of overbooking is unique and novel in network slicing. To realise this objective, we intend to build a mathematical model of the overbooking strategy, and integrate the model into a resource orchestration platform for evaluation on an emulated 3GPP (Release 16) compliant 5G testbed.
A brief performance comparison of bare-metal and kubernetes deployments for 5G Core Control plane network functions using Open5GS
(2024-10) Mukute, T; Santos de Brito, M; Lysko, Albert A; Mwangama, J; Magedanz, T
This paper investigates the performance difference of critical 5G User Equipment (UE) procedures when deployed on a Kubernetes platform versus a traditional bare-metal deployment. We leverage Open5GS, an open-source implementation of the 5G Core (5GC), to evaluate the impact of containerisation on key performance metrics. The research answers (i) how the performance of critical 5G UE procedures differs when 5GC is deployed on a Kubernetes environment compared to a traditional bare-metal deployment and (ii) provides the measurable cost introduced by Kubernetes in terms of key 5G performance metrics. We evaluated throughput and latency. The paper analyses the observed performance differences against theoretical expectations arising from the Kubernetes architecture overhead and insights from related work. Our study reveals a 7% performance degradation in throughput for UE procedures running on Kubernetes compared to bare-metal when handling more than 300 initiated UE devices.
Addressing accessibility, affordability and sustainability barriers for broadband internet access and penetration in rural areas
(2023-10) Ngwenya, SO; Heymann, R; Swart, TG; Lysko, Albert A
It has been said that the spread of Information and Communications Technology (ICT) and global interconnectedness has a great potential to accelerate human progress, to bridge the “digital divide” and to develop knowledge societies, in countries where it is available. However, it has also been determined that certain barriers, more prevalent in rural communities, pose an incessant impediment to the access and penetration trends of broadband internet networks and infrastructure in rural areas. These barriers have been identified as ‘accessibility’, ‘affordability’, and ‘sustainability’. It is hereby asserted, therefore, that a concerted effort is required to address these barriers, with great deliberation and haste, if digital inclusion is to be achieved in rural areas. This paper proposes a broadband internet system that is aimed at addressing these barriers, through a proposed model, which is intended to be implemented as a Proof of Concept (PoC) in the rural area of Mbazwana, located in the province of KwaZulu-Natal (KZN), South Africa (SA). The model has been presented to the community, and subsequently followed by a survey to determine the feasibility of the implementation thereof. This paper will present the proposed model, as well as the results obtained from the research conducted.
Analysis of uniformity in steering capability of an ESPAR antenna
(2022-11) Ebrahim, Rozeena; Mthethwa, Nosipho B; Lysko, Albert A
This paper looks at design considerations for an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna suitable for inexpensive large-scale wireless network technologies. This can help address the demand for a cheaper, simpler, and low power alternative to fully adaptive antennas. We use simulations to consider the effect of the number of elements on the beam-forming and steering capabilities of an ESPAR antenna with a single ring of parasitic elements. Our results validated well against published results and provide the best possible gain over the parasitic element loads considered. It was also found that at least three parasitic elements are required to achieve a reasonably high maximum gain and deep nulls. Based on our results, a 10- element ESPAR offers the most continuous and uniform steering. In addition to smart low power applications, this advantage may be translated into improving the accuracy of triangulation for positioning, localisation, and navigation applications with ESPAR antennas.
Antenna research directions for 6G: A brief overview through sampling literature
(2021-03) Olwal, TO; Chuku, PN; Lysko, Albert A
Antennas are a critical component in any wireless link. The significance of their role continues to grow, together with the rise of machine-to-machine (M2M) communications and telecommunications starting to move from the fourth generation (4G, or Long-Term Evolution, LTE) to the fifth generation (5G) and beyond 5G (B5G), and also due to the prominence of the convenience promised by the ubiquitous wireless communications. The antennas, or more precisely their large size and appearance, also become a subject of public debate, leading to the need for better antennas, which are can do both: provide high performance and offer visually attractive or nearly invisible/transparent designs. This work reviews several key research trends in antennas to fulfill these demands for the fifth generation of communications (5G) and beyond, especially 6G, and considers novel antenna techniques and designs needed to increase the smartness of the antenna systems and to provide improved beamforming and security.
Antenna research directions for 6G: A brief overview through sampling literature
(2021-03) Olwal, TO; Chuku, PN; Lysko, Albert A
Antennas are a critical component in any wireless link. The significance of their role continues to grow, together with the rise of machine-to-machine (M2M) communications and telecommunications starting to move from the fourth generation (4G, or Long-Term Evolution, LTE) to the fifth generation (5G) and beyond 5G (B5G), and also due to the prominence of the convenience promised by the ubiquitous wireless communications. The antennas, or more precisely their large size and appearance, also become a subject of public debate, leading to the need for better antennas, which are can do both: provide high performance and offer visually attractive or nearly invisible/transparent designs. This work reviews several key research trends in antennas to fulfill these demands for the fifth generation of communications (5G) and beyond, especially 6G, and considers novel antenna techniques and designs needed to increase the smartness of the antenna systems and to provide improved beamforming and security.
Beam steering for circular switched parasitic arrays using a combinational approach
(IEEE Africon 2011, 2011-09) Mofolo, ROM; Lysko, Albert A; Olwal, TO; Clarke, WA
In this paper, the authors present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic elements, usually with only one parasitic element open-circuited at a time. For the SPA antenna with few parasitic elements, this results in low azimuth beam steering resolution. In the proposed method, the authors iterate through different combinations of parasitic elements and the possible switch states of the lumped impedance loads connected to the parasitic elements. Their method aims to increase the azimuth beam steering resolution of the circular SPA antennas. The method is verified using a combination of simulation (using both MATLAB and WIPL-D) and a SPA antenna prototype implementation. The MATLAB code uses the induced EMF method, while the WIPL-D uses the Methods of Moment (MoM) for solving the antenna impedances. The three sets of results (simulations and measurement) match very well at 2.4 GHz. The results indicate the availability of more options (different loading configurations) for electronic beam switching that can be adopted to improve the beam steering resolution of circular SPA antennas.
Calculation of radiation field integrals for higher-order basis functions in conical thin wire MoM formulation
(6th WSEAS International Conference on Applied Electromagnetics, Wireless and Optical Communications (ELECTROSCIENCE '08), 2008-07) Lysko, Albert A
An efficient method of integration for far field calculations is derived. The method applies to the integrals arising from calculation of far field pattern with higher-order polynomial basis functions and moment method. The integral under consideration is a product of a power and exponential functions. Depending on the electrical length of the integration path and the required accuracy, either integration by parts or small parameter expansion is applied, in a recursive manner. The speed performance of a Matlab implementation indicates that the presented method is favourable compared to the commercial software “WIPL-D” used as a reference
Classification of SDN distributed controller approaches: a brief overview
(IEEE, 2016-11) Nkosi, M; Lysko, Albert A; Ravhuanzwo, L; Nyandeni, T; Engelbrecht, A
Software defined networking offers a capability of separating control plane from data plane. The control plane is the key component of a network which ensures smooth management and operation of the entire network. However, network’s resiliency and availability offered by SDN single centralized controller architecture is prone to single point of failure. Network operators are rather looking at distributed controllers’ deployment to ensure better network resiliency and availability. This paper gives a brief overview of approaches available for distributed controller deployment and also highlights some of the challenges experienced in the SDN distributed controller environments.
A comparative analysis of urban and rural broadband penetration and access trends in South Africa
(2023-07) Ngwenya, SO; Heymann, R; Swart, TG; Lysko, Albert A
This paper considers the differences between rural and urban access to Information and Communication Technology (ICT) through non-intrusive research methodologies that are deemed effective in obtaining the relevant information required to that end, in an effort to ascertain the cause of this disparity. It is further asserted that the slow pace of internet penetration and access in rural areas is attributed primarily to the fact that rural areas are commonly characterized by low income, poverty, underdeveloped infrastructure, illiteracy, and unemployment. These are demonstrated in this paper using results obtained from a broadband survey conducted by the authors. This paper further aims to highlight the extent of the digital divide, in South Africa (SA) through the same survey, which has been conducted in both rural and urban areas. This comparative study was done to highlight the disparity in broadband access and penetration statistics between the rural and urban communities in South Africa observed in recent years, with the aim to better understand the extent of the digital divide, as it persists today. The parameters that are used to achieve this is employment trends, availability of enabling infrastructure and broadband services, and technology availability trends, including the broadband data rates thereof. These results will clearly demonstrate the status of the ICT sector, particularly highlighting the discrepancy between rural and urban communities in SA, and these will be unpacked in this paper.
A comparative evaluation of the performance of popular SDN controllers
(IEEE, 2018-04) Mamushiane, Lusani; Lysko, Albert A; Dlamini, Sabelo V
Software Defined Networking (SDN) is an architecture that decouples the routing intelligence from the forwarding functions, using an entity called 'controller'. It is paramount that the performance of the controller is thoroughly understood prior to its deployment. However, the rapid introduction of many new controllers in the research community makes it difficult to choose a suitable controller. This paper studies and evaluates the performance of several popular open source controllers such as ONOS, Ryu, Floodlight and OpenDayLight in terms of latency and throughput using an OpenFlow benchmarking tool called Cbench. Additionally, a feature-based comparison of the controllers is presented. These experimental tests provide a decision making guideline when selecting a controller.
Comparison of MANET routing protocols using a scaled indoor wireless grid
(Springer Science & Business Media, 2008-04) Johnson, DL; Lysko, Albert A
Predicting the performance of ad-hoc networking protocols has typically been performed by making use of software based simulation tools. Experimental study and validation of such predictions is vital to obtaining more realistic results, but may not be possible under the constrained environment of network simulators. This paper presents experimental comparisons of routing protocols using a 7 × 7 grid of closely spaced WiFi nodes. It firstly demonstrates the usefulness of the grid in its ability to emulate a real world multi-hop ad-hoc network. It specifically compares hop count, routing traffic overhead, throughput, delay and packet loss for three protocols which are listed by the Internet Engineering Task Force Mobile Ad-hoc Networks (MANET) working group. These are the Ad-hoc on demand distance vector routing protocol (AODV), the optimized link state routing protocol (OLSR) and the dynamic MANET on demand routing protocol (DYMO).
Comparison of metaheuristic algorithms for interface-constrained channel assignment in a hybrid Dynamic Spectrum Access – Wi-Fi infrastructure WMN
(2022-02) Zlobinsky, N; Johnson, DL; Mishra, AK; Lysko, Albert A
In this work, we evaluate the application of four different metaheuristic optimisation algorithms for solving the channel assignment problem in a multi-radio multi-channel Wireless Mesh Network (WMN) using Dynamic Spectrum Access (DSA). The work advances a near optimal channel assignment in a WMN that uses DSA by applying soft computing methods. While CA in a WMN is well-studied, and CA for secondary user cognitive radio networks has also been studied in the literature, CA for our specific scenario of an infrastructure DSA-WMN is novel. This scenario poses new challenges because nodes are spread out geographically and so may have different allowed channels and experience different levels of external interference in different channels. A solution must meet two conflicting requirements simultaneously: 1) to avoid interference within the network and with external interference sources, and 2) maintain connectivity within the network; all while staying within the radio interface constraint, i.e., only assigning as many channels to a node as it has radios. Our method is unique in that it is protocol-agnostic, being able to avoid interference from external sources that use different protocols and standards.We present a novel algorithm, used alongside the metaheuristic optimisation algorithms, which ensures the feasibility of solutions in the search space. Average Signal to Interference and Noise Ratio (SINR) over the network is used as the performance measure, with the goal of optimisation being to find the highest average SINR. This is a more realistic performance measure than the binary on/off conflict-based measures most common in the literature. Our energy-based method also has the unique advantage that it is protocol-agnostic, being able to avoid interference from external sources that use different protocols and standards. The algorithms that are compared in this work are Simulated Annealing (SA), the Genetic Algorithm (GA), Particle Swarm Optimisation (PSO), and Differential Evolution (DE). These algorithms were evaluated through the use of simulation in Network Simulator 3. Various parameters were experimented with for each of the employed algorithms. The resultant best set of parameters was used for the comparison of the four metaheuristic algorithms. It was found that the population-based algorithms (PSO, GA, and DE) all perform satisfactorily for this problem, although DE is superior to the others. SA can give acceptable solutions, but performs poorly in comparison to the population-based algorithms. The paper also considers the computational complexity of the methods. It is found that SA and DE perform well in this regard.
Comparison of the modelled maximum wireless link distance for TVWS and Wi Fi within South African regulatory constraints: Which technology wins and in which scenarios?
(IEEE, 2019-08) Lysko, Albert A; Burger, Chris R; Hagopian, E
The work compares Wi-Fi and television white space (TVWS) technologies for practical broadband communication links, specifically in rural areas. The paper starts with an overview of advantages and limitations of Wi-Fi and TVWS in terms of practically important parameters including propagation attenuation. The maximum range with the maximum transmit power limits permitted by South African regulations are calculated. 5.8 GHz Wi-Fi has more lenient restrictions on the EIRP and is found to offer longer range, whilst TVWS better handles vegetation.
Considerations for coexistence: DVB-T2 broadcasting and LTE basestations in 700/800 MHz bands in South Africa
(IEEE, 2018-11) Lysko, Albert A; Dludla, Angeline G
This work considers coexistence of DVB-T2 and LTE in South Africa. The protection ratios for protecting DVB T2 transmission against interference from LTE are calculated based to the DVB-T2 specifications used in South Africa. An approach is proposed and model developed to apply the protection ratios to evaluate the appropriate separation distances, as a function to frequency and power separation, ignoring the possibility of overload and desentisation. One of key findings is that an easy way of coexistence is by placing the LTE base stations on the same towers as the broadcasting DVB-T2 transmitters.
Considering the connectivity options for a smart water management system deployment
(2022-12) Lysko, Albert A; Ngcama, Lwando; Shingwenyana, Rhulani K; Ramotsoela, D
Smart water utility management is gaining strong momentum as it can help to identify leaks and control the water flow, level and pressure. The latter can be used to reduce leaks, reduce bursts and prolong the life of pipes. All these factors improve the efficiency of water usage and service delivery. Management functions may include monitoring and control. Both require reliable and secure connectivity between the operator at a management plant, i.e. to connect to a node with a flow or level meter or a valve. In remote locations, the connectivity options are usually limited. This paper overviews a spectrum and throughput measurement campaign made to determine some of the options for connectivity for a pilot installation on an existing water distribution network. It was found that for the area of interest, a mobile network offers the most straightforward solution.
Control plane performance benchmarking and feature analysis of popular open-source 5G core networks: OpenAirInterface, Open5GS, and free5GC
(2024-08) Mukute, T; Mamushiane, Lusani; Lysko, Albert A; Modroiu, ER; Magedanz, T; Mwangama, J
This study examines the maturity and state of open-source 5G Core (5GC) networks, with a focus on their support of 5G procedures and Network Function (NF) operations. The research emphasises the importance of optimising the virtualised resource usage of 5GC control plane functions. Given the large set of NF operations and procedures defined for 5GC networks, the study presents a framework that correlates NF operations with 5G procedures, thus facilitating the assessment of 5GC implementations. Furthermore, the study introduces macro-benchmarking and micro-benchmarking approaches to assess the performance of 5GC control plane functions. Our 5G traffic generator is used to generate User Equipment (UE) registration traffic for benchmarking. Macro-benchmarking measures the time taken for a specific number of UEs to complete UE procedures. In contrast, micro-benchmarking analyses the system calls made by the 5GC, presenting their latency and frequency and the processes responsible for generating them. Our findings revealed a direct correlation between macro-level performance and micro-benchmarking results. This suggests that optimising micro-level implementations is crucial for enhancing overall system performance. Moreover, examining micro-benchmarking data can provide valuable insights into how the system’s performance will scale under varying workloads. We use the correlation of benchmarking results to identify performance improvement points in each 5GC and to provide recommendations for software architectural changes that can optimise the usage of virtualised resources. The study includes artefacts and source code to enable replication of the work and results.
Controller placement optimization for Software Defined Wide Area Networks (SDWAN)
(2021-03) Mamushiane, Lusani; Mwangama, J; Lysko, Albert A
Software Defined Networking (SDN) has emerged as a promising solution to revolutionize network deployment, operations and economic growth. This paradigm aims to address management and configuration complexities in legacy networks so as to reduce the total cost associated with deploying and running telecommunication infrastructures. At the heart of SDN is a controller which oversees orchestration of resources. An important problem that must be addressed during the initial design of an SDN-based network deployment is to find the optimal number of controllers and their locations, to achieve desired operational efficiency. This problem constitutes competing objectives such as latency, load balancing, and reliability. We apply Silhouette Analysis, Gap statistics and the Partition Around Medoids (PAM) algorithms and, unlike previous works, we add a new method for solving the controller placement problem using an emulation orchestration platform. Our approach aims to optimize controller-to-node latency, alleviate control plane signaling overhead and ensure control plane resiliency. Our results for South African national research network (SANReN) reveal that deploying two controllers yields lowest latency, reduces control plane signaling overhead and guarantees control plane resiliency. Our approach can be used by network operators as a guideline to start integrating SDN or plan a new SDN deployment, by helping them make quick automatic decisions regarding optimal controller placement.
A correlation between RSSI and height in UHF band and comparison of geolocation spectrum database view of TVWS
(2016-12) Maliwatu, R; Lysko, Albert A; Johnson, David L; Hadzic, S
An investigation into the Received Signal Strength Indicator (RSSI) dependency on receiver antenna height in UHF band is conducted. The results show a high correlation between RSSI and height on channels with high signal strength. There is approximately 2.5 dBm RSSI gain per 1m increase in height above ground up to 8.5 m. From 8.5 m to 12 m, there is no consistent observable increase in RSSI. Further more, the geolocation spectrum databases (GLSD) view of white space in the television band is compared with the ground truth. Results show signal presence on some of the channels indicated free by the spectrum database. These findings imply that an increase in transmission range of UHF links can be achieved by increasing receiver height. White space devices using A GLSD should additionally require spectrum scanning to determine clear channels.

Browsing by Author "Lysko, Albert A"

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