48 research outputs found
Modern VLSI Analogue Filter Design: Methodology and Software Development
This thesis describes various approaches for the design of modern analogue filters and provides a practical filter and equaliser design aids system XFILT. The thesis begins by placing the analogue filter design technique and software into a historical and technology perspective. The evolution of the analogue filter is traced from early work, through the passive-RLC to transconductor-C and switched-current realisations. The software development in VLSI analogue filter automation is reviewed. For SC filter design, a cascade SC design approach which includes a novel pole-zero pairing method and a comprehensive comparison of SC filter realisation using different biquads are presented. Very useful guidelines for the choice of a suitable biquad structure according to the nature of the filter problem are presented. The canonical realisations of SC filter are studied. The multirate SC system design is described. Several strategies and the algorithms for multirate SC system design are proposed. In transconductor-C filter design research, the definition of a canonical ladder based transconductor-C filter is introduced, and two canonical ladder based transconductor-C filter design approaches are proposed. The ladder based transconductor-C equaliser design is also discussed. A practical video frequency transconductor-C filter and equaliser design is given to demonstrate the utility of the matrix design method and the design software. A new approach to realise exact ladder based SI filter with first and second generation memory cell has been proposed. The bilinear transformation is used in the design procedure. Eight different SI ladder based structures can be obtained for one prototype ladder. Therefore it provides SI filter designers with various circuit choices based on different requirement such as area, maximum ratio of transistor aspect ratio limit, sensitivity or noise performance. Techniques to improve dynamic range and reduce circuit parameter spread are also presented. The proposed approach is well suited for a computer compiler implementation. A suitability study of each decomposition method for different filtering applications is also carried out and a general guideline for the choice of different decomposition methods is obtained. A comparison study on SI filter sensitivity performance based on first generation and second generation memory cells is carried out. Using four filter examples, it is demonstrated that SI filters based on a second generation SI memory cell have good sensitivity performance. For SI filters based on first generation memory cells, it is shown that a high ratio of clock frequency to cutoff frequency in the lowpass case, or a high ratio of clock frequency to midband frequency in the bandpass case would introduce high sensitivity. A novel approach for SI ladder filter based on the S2I integrator is also proposed and a canonical realisation for SI filter based on S2I integrator is developed. Examination of SI equaliser design reveals that cascade structure is a better candidate than ladder based structure. Multirate SI filter system design is also studied. Finally, a very brief introduction to the assembly of the design methods in this thesis into a software package XHLT for VLSI analogue filter and equaliser design is given. The user aspects of XFILT have been discussed and various capabilities of XFILT are demonstrated. Several advanced facilities which remove traditional design limitations are illustrated. The philosophy of the system is explained. It is shown that the distinguished features of XFILT are Ease of Use. General Applicability, and Ease of Extension. The system structure is described and the graphics interface which acts both as user friendly interface and a system manager of all the software is outlined. Fabricated SC, transconductor-C, and SI filter and equaliser have been designed by using XFILT. The system is under further enhancement toward a commercial product
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: ⢠Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments⢠Measurements, characterization, and modelling of radio channels beyond 4G networks⢠Key issues in Vehicle (V2X) communication⢠Wireless Body Area Networks, including specific Radio Channel Models for WBANs⢠Energy efficiency and resource management enhancements in Radio Access Networks⢠Definitions and models for the virtualised and cloud RAN architectures⢠Advances on feasible indoor localization and tracking techniques⢠Recent findings and innovations in antenna systems for communications⢠Physical Layer Network Coding for next generation wireless systems⢠Methods and techniques for MIMO Over the Air (OTA) testin
Study, Measurements and Characterisation of a 5G system using a Mobile Network Operator Testbed
The goals for 5G are aggressive. It promises to deliver enhanced end-user experience
by offering new applications and services through gigabit speeds, and significantly
improved performance and reliability. The enhanced mobile broadband (eMBB) 5G use
case, for instance, targets peak data rates as high as 20 Gbps in the downlink (DL) and
10 Gbps in the uplink (UL).
While there are different ways to improve data rates, spectrum is at the core of enabling
higher mobile broadband data rates. 5G New Radio (NR) specifies new frequency
bands below 6 GHz and also extends into mmWave frequencies where more
contiguous bandwidth is available for sending lots of data. However, at mmWave
frequencies, signals are more susceptible to impairments. Hence, extra consideration is
needed to determine test approaches that provide the precision required to accurately
evaluate 5G components and devices.
Therefore, the aim of the thesis is to provide a deep dive into 5G technology, explore its
testing and validation, and thereafter present the OTE (Hellenic Telecommunications
Organisation) 5G testbed, including measurement results obtained and its characterisation based on key performance indicators (KPIs)
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: ⢠Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments⢠Measurements, characterization, and modelling of radio channels beyond 4G networks⢠Key issues in Vehicle (V2X) communication⢠Wireless Body Area Networks, including specific Radio Channel Models for WBANs⢠Energy efficiency and resource management enhancements in Radio Access Networks⢠Definitions and models for the virtualised and cloud RAN architectures⢠Advances on feasible indoor localization and tracking techniques⢠Recent findings and innovations in antenna systems for communications⢠Physical Layer Network Coding for next generation wireless systems⢠Methods and techniques for MIMO Over the Air (OTA) testin
Advances in Batteries, Battery Modeling, Battery Management System, Battery Thermal Management, SOC, SOH, and Charge/Discharge Characteristics in EV Applications
The second-generation hybrid and Electric Vehicles are currently leading the paradigm shift in the automobile industry, replacing conventional diesel and gasoline-powered vehicles. The Battery Management System is crucial in these electric vehicles and also essential for renewable energy storage systems. This review paper focuses on batteries and addresses concerns, difficulties, and solutions associated with them. It explores key technologies of Battery Management System, including battery modeling, state estimation, and battery charging. A thorough analysis of numerous battery models, including electric, thermal, and electro-thermal models, is provided in the article. Additionally, it surveys battery state estimations for a charge and health. Furthermore, the different battery charging approaches and optimization methods are discussed. The Battery Management System performs a wide range of tasks, including as monitoring voltage and current, estimating charge and discharge, equalizing and protecting the battery, managing temperature conditions, and managing battery data. It also looks at various cell balancing circuit types, current and voltage stressors, control reliability, power loss, efficiency, as well as their advantages and disadvantages. The paper also discusses research gaps in battery management systems.publishedVersio
A Photoplethysmography System Optimised for Pervasive Cardiac Monitoring
Photoplethysmography is a non-invasive sensing technique which infers instantaneous
cardiac function from an optical measurement of blood vessels. This
thesis presents a photoplethysmography based sensor system that has been developed
speci fically for the requirements of a pervasive healthcare monitoring
system. Continuous monitoring of patients requires both the size and power
consumption of the chosen sensor solution to be minimised to ensure the patients
will be willing to use the device. Pervasive sensing also requires that
the device be scalable for manufacturing in high volume at a build cost that
healthcare providers are willing to accept. System level choice of both electronic
circuits and signal processing techniques are based on their sensitivity to
cardiac biosignals, robustness against noise inducing artefacts and simplicity
of implementation. Numerical analysis is used to justify the implementation
of a technique in hardware. Circuit prototyping and experimental data collection
is used to validate a technique's application. The entire signal chain
operates in the discrete-time domain which allows all of the signal processing
to be implemented in firmware on an embedded processor which minimised the
number of discrete components while optimising the trade-off between power
and bandwidth in the analogue front-end. Synchronisation of the optical illumination
and detection modules enables high dynamic range rejection of both
AC and DC independent light sources without compromising the biosignal.
Signal delineation is used to reduce the required communication bandwidth as
it preserves both amplitude and temporal resolution of the non-stationary photoplethysmography
signals allowing more complicated analytical techniques to
be performed at the other end of communication channel. The complete sensing
system is implemented on a single PCB using only commercial-off -the-shelf
components and consumes less than 7.5mW of power. The sensor platform
is validated by the successful capture of physiological data in a harsh optical
sensing environment
A Photoplethysmography System Optimised for Pervasive Cardiac Monitoring
Photoplethysmography is a non-invasive sensing technique which infers instantaneous
cardiac function from an optical measurement of blood vessels. This
thesis presents a photoplethysmography based sensor system that has been developed
speci fically for the requirements of a pervasive healthcare monitoring
system. Continuous monitoring of patients requires both the size and power
consumption of the chosen sensor solution to be minimised to ensure the patients
will be willing to use the device. Pervasive sensing also requires that
the device be scalable for manufacturing in high volume at a build cost that
healthcare providers are willing to accept. System level choice of both electronic
circuits and signal processing techniques are based on their sensitivity to
cardiac biosignals, robustness against noise inducing artefacts and simplicity
of implementation. Numerical analysis is used to justify the implementation
of a technique in hardware. Circuit prototyping and experimental data collection
is used to validate a technique's application. The entire signal chain
operates in the discrete-time domain which allows all of the signal processing
to be implemented in firmware on an embedded processor which minimised the
number of discrete components while optimising the trade-off between power
and bandwidth in the analogue front-end. Synchronisation of the optical illumination
and detection modules enables high dynamic range rejection of both
AC and DC independent light sources without compromising the biosignal.
Signal delineation is used to reduce the required communication bandwidth as
it preserves both amplitude and temporal resolution of the non-stationary photoplethysmography
signals allowing more complicated analytical techniques to
be performed at the other end of communication channel. The complete sensing
system is implemented on a single PCB using only commercial-off -the-shelf
components and consumes less than 7.5mW of power. The sensor platform
is validated by the successful capture of physiological data in a harsh optical
sensing environment
Digital signal processing optical receivers for the mitigation of physical layer impairments in dynamic optical networks
IT IS generally believed by the research community that the introduction of complex
network functionsâsuch as routingâin the optical domain will allow a better network
utilisation, lower cost and footprint, and a more efficiency in energy usage. The new optical
components and sub-systems intended for dynamic optical networking introduce
new kinds of physical layer impairments in the optical signal, and it is of paramount
importance to overcome this problem if dynamic optical networks should become a
reality. Thus, the aim of this thesis was to first identify and characterise the physical
layer impairments of dynamic optical networks, and then digital signal processing
techniques were developed to mitigate them.
The initial focus of this work was the design and characterisation of digital optical
receivers for dynamic core optical networks. Digital receiver techniques allow for complex
algorithms to be implemented in the digital domain, which usually outperform
their analogue counterparts in performance and flexibility. An AC-coupled digital receiver
for core networksâconsisting of a standard PIN photodiode and a digitiser that
takes samples at twice the Nyquist rateâwas characterised in terms of both bit-error
rate and packet-error rate, and it is shown that the packet-error rate can be optimised by
appropriately setting the preamble length. Also, a realistic model of a digital receiver
that includes the quantisation impairments was developed. Finally, the influence of
the network load and the traffic sparsity on the packet-error rate performance of the
receiver was investigated.
Digital receiver technologies can be equally applied to optical access networks,
which share many traits with dynamic core networks. A dual-rate digital receiver, capable
of detecting optical packets at 10 and 1.25 Gb/s, was developed and characterised.
The receiver dynamic range was extended by means of DC-coupling and non-linear
signal clipping, and it is shown that the receiver performance is limited by digitiser
noise for low received power and non-linear clipping for high received power