Dr Roz Wyatt-Millington

This paper is focused on the design of an adaptive Connection Admission Control (CAC) algorithm for a Universal Mobile Telecommunication System (UMTS) based satellite system with variable link capacity. The main feature of the proposed algorithm is to maximize the resource utilization by adapting to the link conditions and the antenna gain of the users. The link quality of the user may vary depending on the weather condition, user mobility and any other propagation factors. The algorithm is compared against a non-adaptive admission control algorithm under different test cases. The proposed CAC algorithm is simulated using MATLAB and the performance results are obtained for a mix of multimedia traffic classes such as video streaming, web browsing, netted voice and email. The simulation results indicate a higher system performance in terms of the blocking ratio and the number of admitted connections.

A compact dual U-shaped slot PIFA antenna with Electromagnetic Bandgap (EBG) material on a relatively low dielectric constant substrate is presented. Periodic structures have found to reduce mutual coupling and decrease the separation of antenna and ground plane. A design with EGB material suitable for a small terminal mobile handset operating at 2.4 GHz was studied. Simulated and measured scattering parameters are compared for U-shaped slot PIFA antenna with and without EBG structures. An evaluation of MIMO antennas is presented, with analysis of the mutual coupling, correlation coefficient, total active reflection coefficient (TARC), channel capacity and capacity loss. The proposed antenna meets the requirements for practical application within a mobile handset.

A compact microstrip antenna design to be used in breast cancer detection is presented. The antenna consists of a radiating patch mounted on two vertical plates, fed by coaxial cable. A study is carried out on different parameters of the antenna. Simulation results show that the antenna possesses a wide bandwidth and this is confirmed experimentally. In experiments, a homogeneous dielectric box, having similar properties to human tissue is used to study the interaction of the antenna with tissue. Even without added matching medium or lumped loads there is good matching when the antenna is in contact with the tissue. Finally a two-element antenna array is investigated numerically, with promising results.

The cdma2000 system is an evolutionary enhancement of the IS-95 standards which support 3G services defined by the International Telecommunications Union (ITU). cdma2000 comes in two phases: 1XRTT and 3XRTT (1X and 3X indicates the number of 1.25 MHz wide radio carrier channels used and RTT stands for Radio Transmission Technology). The cdma2000 1XRTT, which operates within a 1.25 MHz bandwidth, can be utilized in existing IS-95 CDMA channels as it uses the same bandwidth, while 3XRTT requires the commitment of 5 MHz bandwidth to support higher data rates. This paper describes a software model implementation of the cdma2000 reverse link and its application for evaluating the effect of rake receiver design parameters on the system performance under various multipath fading conditions. The cdma2000 models were developed at the National Institute of Standards and Technology (NIST), using SPW (Signal Processing Worksystem) commercial software tools. The model has been developed in a generic manner that includes all the reverse link six radio configurations and their corresponding data rates, according to cdma2000 specifications. After briefly reviewing the traffic channel characteristics of the cdma2000 reverse link (subscriber to base station), the paper discusses the rake receiver implementation including an ideal rake receiver. It then evaluates the performance of each receiver for a Spreading Rate 3 (3XRTT) operation, which is considered as a true "3G" cdma2000 technology. These evaluations are based on the vehicular IMT-2000 (International Mobile Telecommunication 2000) channel model using the link budget defined in cdma2000 specifications for the reverse link.

This paper is focused on the design of an adaptive Connection Admission Control (CAC) framework for a Multimedia Broadcast Multicast Service (MBMS) compatible satellite system. The main feature of the proposed framework is the ability to maximize the resource utilization by adapting to the link conditions of the users. The link quality of the user may vary depending on the weather condition, user mobility and any other propagation factors. The framework also features the ability to admit a higher priority connection by pre-empting an existing lower priority connection for multimedia traffic with varying bandwidth requirements. The proposed CAC framework is simulated using MATLAB and the performance results are obtained for a mix of multimedia traffic classes such as videostreaming, webbrowsing, netted voice and email. ©2009 IEEE.

The emphasis of this paper is on investigating the performance of signalling protocols designed for a mobility management scheme, which uses Mobile IP for inter-segment mobility in a hybrid space and terrestrial environment. Initially, the system architecture, which consists of three wireless access networks attached to an IP backbone, is presented. This is followed by a description of the proposed mobility procedures employed in the system, which aim at minimising modifications to existing satellite and terrestrial network protocols. The mobility procedures are simulated in order to evaluate their performance and determine their effectiveness in an operational environment. Results verify the efficiency of the protocols and show that the additional signalling time introduced by the procedures is minimal. © 2001 Elsevier Science B.V. All rights reserved.

This paper is focused on the design of an adaptive Connection Admission Control (CAC) algorithm for a Universal Mobile Telecommunication System (UMTS) based satellite system with variable link capacity. The main feature of the proposed algorithm is to maximize the resource utilization by adapting to the link conditions and the antenna gain of the users. The link quality of the user may vary depending on the weather condition, user mobility and any other propagation factors. The algorithm is compared against a non-adaptive admission control algorithm under different test cases. The proposed CAC algorithm is simulated using MATLAB and the performance results are obtained for a mix of multimedia traffic classes such as video streaming, web browsing, netted voice and email. The simulation results indicate a higher system performance in terms of the blocking ratio and the number of admitted connections. © 2013 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.

This paper proposes a novel call admission control (CAC) algorithm and develops a two-dimensional markov chain processes (MCP) analytical model to evaluate its performance for heterogeneous wireless network. Within the context of this paper, a hybrid UMTS-WLAN network is investigated. The designed threshold-based CAC algorithm is launched basing on the user's classification and channel allocation policy. In this approach, channels are assigned dynamically in accordance with user class differentiation. The two-dimensional MCP mathematical analytic method reflects the system performance by appraising the dropping likelihood of handover traffics. The results show that the new CAC algorithm increases the admission probability of handover traffics, while guarantees the system quality of service (QoS) requirement. © 2013 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.

The pre-emption procedure is an important part of the radio resource management when dealing with the emergency traffic. It allows resources to be allocated to higher priority connections by pre-empting lower priority connections. The provision of the pre-emption mechanism becomes much more important in the case of satellite systems such as the Inmarsat Broadband Global Area Network system, which aids in providing the communication during a catastrophe. This paper focuses on the pre-emption framework for a Universal Mobile Telecommunications System-based satellite systems. Three algorithms have been proposed, Greedy, SubSetSum and Fuzzy pre-emption algorithm. Extensive simulations are carried out for the three algorithms, and their performances are compared against each other. Simulation results show that the Fuzzy pre-emption algorithm performs better than the other two algorithms.

This paper is concerned with the effects on the network performance of moving parts of what is considered traditionally to belong to the ground segment to on board the satellite. Initially, an overview of geostationary satellite communication systems and payload technology is presented, followed by a description of the network architecture and protocols that are the basis of the simulation models. The results obtained from this testbed are presented before concluding with a discussion of the results obtained. © 2007 IEEE.

In this paper, a fuzzy logic call admission control (CAC) mechanism is proposed for an integrated UMTS-WLAN network. This paper grounds a novel dynamic CAC algorithm on a class - based CAC method. It uses fuzzy logic theory to generate the optimal quantity of the channel thresholds so as to assign radio resource efficiently and guarantee the Quality-of-Service (QoS) requirement. The new fuzzy logic algorithm exhibits its superiority by comparing the handover dropping probability with that of threshold - based approach. The simulation results verify that the evolved threshold-based CAC with fuzzy logic provides a lower handover dropping probability. © 2011 IEEE.

Connection Admission Control is a mechanism put in place to guarantee that a call will be accepted and the associated QOS requirements can be supported for the entire duration of the call without affecting the QOS of the existing calls on the network. This paper is focused on the design, simulation and implementation of a Hybrid CAC algorithm for a Hybrid Network comprising of Satellite, UMTS, WiMAX and Wi-Fi as the underlying network entities. The performance metrics of a CAC algorithm includes: Throughput, delay, fairness, power consumption and multimedia support. An in-depth review of previous approaches to CAC policy is explored from various literatures. The past, present and future modifications on various CAC policies is also highlighted. The basic components of a CAC algorithm, as well as the features of various CAC strategies are used in making a comparative analysis of the various types of CAC algorithms; introducing the Hybrid CAC with an edge over the previous policies adopted. The Hybrid Network Architecture is realised from interconnection of the network entities, the structure of these underlying networks is also explored along with their various QOS service classes. A Framework of the Hybrid CAC is established in the simulation scenario with OPNET software. The Project Model, Node Model and Process Model is realised, compiled and simulated to yield results which were analysed, using network performance indicators. Conclusions on this thesis were based on these performance indicators. An idea of future work on the Hybrid CAC is highlighted.

The major driving force behind the research and development of future mobile technologies, services and applications is now the convergence of mobile and Internet Protocol(IP) based technologies. One project that aims to address these issues is SUITED: Multi-Segment System for Broadband Ubiquitous Access to InTErnet Services and Demonstrator. SUITED is a project funded under the EC's Fifth Framework Information Societies Technology (IST) Programme. SUITED is being undertaken by an 11 partner pan-European consortium, led by Alenia Spazio. It aims to build on the results of the related projects SECOMS/ABATE, ASSET and ACCORD, which addressed 20/30 GHz mobile satellite issues under the EC's 4

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Legionnaire’s disease presents a significant public health risk, yet current monitoring methods remain reactive. Traditional methods involve engineers conducting monthly site visits to collect temperature data from sentinel outlets. While effective, this approach has significant environmental and financial costs due to frequent travel. The rise of Internet of Things (IoT) technology has enabled remote monitoring across various industries, including water management. By transitioning to remote monitoring, this reduces annual site visits from twelve to one, which significantly cuts carbon emissions, water wastage, time and hence costs. This study presents the findings of two independent case studies assessing the environmental and operational impacts of implementing IoT-enabled remote monitoring. The first case study evaluates five sites (A to E). For instance, results from Site A indicating that replacing on-site monitoring with remote systems can reduce CO₂ emissions by 1,993 kg annually—a 96% decrease—alongside fuel cost savings of approximately £1,020. When extrapolated across all Aquatrust monitoring sites, requiring extensive travel, potential annual savings reach 49 tonnes of CO₂ and £24,500. The second case study, based on four representative outlet locations typical to these sites, shows a 90% reduction in water wastage, saving approximately 9,843 litres per year. Together, the findings highlight the significant sustainability and efficiency benefits of remote monitoring, including reduced manual intervention, improved regulatory compliance, and enhanced predictive maintenance enabled by continuous data collection. Additionally, IoT-driven systems improve efficiency by reducing manual testing and maintenance costs while ensuring compliance with water safety regulations. Furthermore, continuous data feeds enable trend analysis, allowing for predictive maintenance and early intervention. However, despite the clear benefits, challenges such as initial implementation costs, data security concerns, and industry resistance must be addressed. Nevertheless, pilot studies and regulatory incentives can facilitate a broader adoption. This approach represents a transformative step in Legionella risk management, offering scalable solutions for both industrial and domestic applications. Future research should focus on optimising deployment strategies and addressing industry-specific challenges, ensuring technology and sustainability continue to drive advancements in water hygiene management.

This paper proposes a load scheduling approach for a residential home in an islanded PV microgrid scenario based on a Genetic Algorithm (GA). The primary aim is to inform on how a Demand Side Management (DSM) could reduce the capital cost of the residential home energy use and operational cost of the microgrid by minimizing the use of fossil fuel generator. The research study proposes and describes the design for load allocation to achieve utilization of solar PV resources optimally. The proposed scheme is based on the time-of-use (TOU) and improvement of electricity users' comfort. The demonstration of the concept is presented and discussed based on a single smart home scenario using a solar PV microgrid and battery in a rural community of Enugu State, Nigeria.