Animal location and distribution control for an improved management system

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e de ComputadoresThis dissertation addresses the problem of animal location management and respective distribution control, with special interest on the virtual fence solution based on GPS. As it is known, animals tend to walk wherever they can find food and safety. This can be a problem since they can interfere with other animals and people in general. To prevent unpleasant encounters physical fences were developed, but since they present high maintenance costs and some questionable efficiency, a new technology was developed: virtual fences. In addition, since cattle and sheep graze over large areas animals are often rotated in order to achieve pasture management limitations. Virtual fences help in this matter due to the ease of changing boundaries. The main goal was to develop a virtual fence system where animal’s behaviour can be managed. To achieve this purpose, were developed a collar prototype (CP) with GPS location and GSM communication, a software application and an energetic study. The collar tests revealed good results from GPS localisation and GSM communication, obtaining signal in open fields, house complex areas and inside constructions with different ceiling types. The collar stimuli were applied as expected, taking in consideration the collar localisation in the defined fence. Also, the system efficiency was tested resulting in the expected attribution of time periods accordingly the collar localisation area and stimulus applied. Furthermore, the speed data achieved from the GPS revealed animal behaviour important to deal with control management. The software application revealed efficiency when designing the fence boundaries. The website was considered user-friendly being easy to use, design the fence limits, register the animals and monitor the cattle

Flexible Receivers in CMOS for Wireless Communication

Consumers are pushing for higher data rates to support more services that are introduced in mobile applications. As an example, a few years ago video-on-demand was only accessed through landlines, but today wireless devices are frequently used to stream video. To support this, more flexible network solutions have merged in 4G, introducing new technical problems to the mobile terminal. New techniques are thus needed, and this dissertation explores five different ideas for receiver front-ends, that are cost-efficient and flexible both in performance and operating frequency. All ideas have been implemented in chips fabricated in 65 nm CMOS technology and verified by measurements. Paper I explores a voltage-mode receiver front-end where sub-threshold positive feedback transistors are introduced to increase the linearity in combination with a bootstrapped passive mixer. Paper II builds on the idea of 8-phase harmonic rejection, but simplifies it to a 6-phase solution that can reject noise and interferers at the 3rd order harmonic of the local oscillator frequency. This provides a good trade-off between the traditional quadrature mixer and the 8- phase harmonic rejection mixer. Furthermore, a very compact inductor-less low noise amplifier is introduced. Paper III investigates the use of global negative feedback in a receiver front-end, and also introduces an auxiliary path that can cancel noise from the main path. In paper IV, another global feedback based receiver front-end is designed, but with positive feedback instead of negative. By introducing global positive feedback, the resistance of the transistors in a passive mixer-first receiver front-end can be reduced to achieve a lower noise figure, while still maintaining input matching. Finally, paper V introduces a full receiver chain with a single-ended to differential LNA, current-mode downconversion mixers, and a baseband circuity that merges the functionalities of the transimpedance amplifier, channel-select filter, and analog-to-digital converter into one single power-efficient block

Journal of Telecommunications and Information Technology, 2018, nr 2

kwartalni

Recent Trends in Communication Networks

In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks