19 research outputs found
Wireless Technologies for IoT in Smart Cities
[EN] As cities continue to grow, numerous initiatives for Smart Cities are being conducted. The
concept of Smart City encompasses several concepts being governance, economy,
management, infrastructure, technology and people. This means that a Smart City can have
different communication needs. Wireless technologies such as WiFi, ZigBee, Bluetooth,
WiMax, 4G or LTE (Long Term Evolution) have presented themselves as solutions to the
communication needs of Smart City initiatives. However, as most of them employ unlicensed
bands, interference and coexistence problems are increasing. In this paper, the wireless
technologies available nowadays for IoT (Internet of Things) in Smart Cities are presented.
Our contribution is a review of wireless technologies, their comparison and the problems that
difficult coexistence among them. In order to do so, the characteristics and adequacy of
wireless technologies to each domain are considered. The problems derived of over-crowded
unlicensed spectrum and coexistence difficulties among each technology are discussed as
well. Finally, power consumption concerns are addressed.García-García, L.; Jimenez, JM.; Abdullah, MTA.; Lloret, J. (2018). Wireless Technologies for IoT in Smart Cities. Network Protocols and Algorithms. 10(1):23-64. doi:10.5296/npa.v10i1.12798S236410
A common European Spectrum policy
This briefing note considers the European Commission\u2019s proposals for a common European spectrum policy through reviewing adopted legislation as well as recent communications and other initiatives. The report was produced against the background of the review of the
regulatory framework for electronic communications and the recent World Radiocommunication Conference
Smart PIN: performance and cost-oriented context-aware personal information network
The next generation of networks will involve interconnection of heterogeneous individual
networks such as WPAN, WLAN, WMAN and Cellular network, adopting the IP as common infrastructural protocol and providing virtually always-connected network. Furthermore,
there are many devices which enable easy acquisition and storage of information as pictures, movies, emails, etc. Therefore, the information overload and divergent content’s
characteristics make it difficult for users to handle their data in manual way. Consequently, there is a need for personalised automatic services which would enable data exchange across heterogeneous network and devices. To support these personalised services, user centric approaches
for data delivery across the heterogeneous network are also required.
In this context, this thesis proposes Smart PIN - a novel performance and cost-oriented context-aware Personal Information Network. Smart PIN's architecture is detailed including its network, service and management components. Within the service component, two novel schemes for efficient delivery of context and content data are proposed:
Multimedia Data Replication Scheme (MDRS) and Quality-oriented Algorithm for Multiple-source Multimedia Delivery (QAMMD).
MDRS supports efficient data accessibility among distributed devices using data replication which is based on a utility function and a minimum data set. QAMMD employs a buffer underflow avoidance scheme for streaming, which achieves high multimedia quality without content adaptation to network conditions. Simulation models for MDRS and
QAMMD were built which are based on various heterogeneous network scenarios. Additionally a multiple-source streaming based on QAMMS was implemented as a prototype and tested in an emulated network environment. Comparative tests show that MDRS and QAMMD perform significantly better than other approaches
Recommended from our members
Operating System Based Perceptual Evaluation of Call Quality in Radio Telecommunications Networks. Development of call quality assessment at mobile terminals using the Symbian operating system, comparison with traditional approaches and proposals for a tariff regime relating call charging to perceived speech quality.
Call quality has been crucial from the inception of telecommunication networks.
Operators need to monitor call quality from the end-user¿s perspective, in order to retain
subscribers and reduce subscriber ¿churn¿. Operators worry not only about call quality and
interconnect revenue loss, but also about network connectivity issues in areas where mobile
network gateways are prevalent. Bandwidth quality as experienced by the end-user is equally
important in helping operators to reduce churn.
The parameters that network operators use to improve call quality are mainly from the
end-user¿s perspective. These parameters are usually ASR (answer seizure ratio), PDD (postdial
delay), NER (network efficiency ratio), the number of calls for which these parameters
have been analyzed and successful calls. Operators use these parameters to evaluate and
optimize the network to meet their quality requirements.
Analysis of speech quality is a major arena for research. Traditionally, users¿ perception
of speech quality has been measured offline using subjective listening tests. Such tests are,
however, slow, tedious and costly. An alternative method is therefore needed; one that can be
automatically computed on the subscriber¿s handset, be available to the operator as well as to
subscribers and, at the same time, provide results that are comparable with conventional
subjective scores. QMeter® ¿ a set of tools for signal and bandwidth measurement that have
been developed bearing in mind all the parameters that influence call and bandwidth quality
experienced by the end-user ¿ addresses these issues and, additionally, facilitates dynamic tariff
propositions which enhance the credibility of the operator.
This research focuses on call quality parameters from the end-user¿s perspective. The
call parameters used in the research are signal strength, successful call rate, normal drop call
rate, and hand-over drop rate. Signal strength is measured for every five milliseconds of an
active call and average signal strength is calculated for each successful call. The successful call
rate, normal drop rate and hand-over drop rate are used to achieve a measurement of the overall
call quality. Call quality with respect to bundles of 10 calls is proposed.
An attempt is made to visualize these parameters for better understanding of where the
quality is bad, good and excellent. This will help operators, as well as user groups, to measure
quality and coverage.
Operators boast about their bandwidth but in reality, to know the locations where speed
has to be improved, they need a tool that can effectively measure speed from the end-user¿s
perspective. BM (bandwidth meter), a tool developed as a part of this research, measures the
average speed of data sessions and stores the information for analysis at different locations.
To address issues of quality in the subscriber segment, this research proposes the
varying of tariffs based on call and bandwidth quality. Call charging based on call quality as
perceived by the end-user is proposed, both to satisfy subscribers and help operators to improve
customer satisfaction and increase average revenue per user. Tariff redemption procedures are
put forward for bundles of 10 calls and 10 data sessions. In addition to the varying of tariffs,
quality escalation processes are proposed. Deploying such tools on selected or random samples
of users will result in substantial improvement in user loyalty which, in turn, will bring
operational and economic advantages
Desenho de antenas para sensores passivos em materiais não convencionais
Doutoramento em Engenharia EletrotécnicaMotivado pela larga expansão dos sistemas RFID e com o desenvolvimento
do conceito de Internet das Coisas, a evolução no desenho e métodos de
produção de antenas em suportes de materiais alternativos tem tido uma
exploração intensiva nos últimos anos. Isto permitiu, não só o desenvolvimento
de produtos no campo da interação homem-máquina, mas também
tornar estes produtos mais pequenos e leves. A procura de novas técnicas
e métodos para produzir eletrónica impressa e antenas em materiais alternativos
e, portanto, uma porta aberta para o aparecimento de novas
tecnologias. Isto aplica-se especialmente no mercado dos sensores, onde
o peso, o tamanho, o consumo energético, e a adaptabilidade a diversos
ambientes, têm grande relevância. Esta tese foca-se no desenvolvimento de
antenas com suporte em materiais não convenvionais, como os já testados
papel e têxteis, mas também na exploração de outros, desconhecidos do
ponto de vista eléctrico, como a cortiça e polímeros biodegradáveis usados
em impressão 3D. Estes materiais são portanto usados como substrato, ou
material de suporte, para diversas antenas e, como tal, as propriedades electromagnéticas destes materiais têm de ser determinadas. Assim, e apresentado
neste documento uma revisão de métodos de caracterização de materiais,
bem como a proposta de um método baseado em linhas de trasmissão
impressas, e a respectiva caracterização electromagnética de diversos materiais.
Além disso, são propostos desenhos de antenas para diversos cenários
e aplicações utilizando os materiais anteriormente mencionados. Com esta
tese concluiu-se que a utilização de materiais alternativos e hoje uma realidade
e os resultados obtidos são muito encorajodares para o desenvolvimento
de um conjunto de sensores para aplicações RFID com uma grande
capacidade de integração.The advancement of the design and fabrication of antennas using textiles
or paper as substrates has rapidly grown motivated by the boom of RFID
systems and the developing concept of the Internet of Things. These advancements
have allowed, not only the development of products for manmachine
interaction, but also to make these products smaller and lighter.
The search for new techniques and methods to produce printed electronics
and antennas in alternative materials is therefore an open door for new
technologies to emerge. Especially in the sensors market, where weight,
size, power consumption and the adaptability to the target application, are
of great importance. This thesis focuses on the development of antenna
design approaches with alternative materials, such as the already tested
paper and textiles, but also others relatively unknown, such as cork and
biodegradable polymers used in 3D printing. These materials are applied to
act as substrates, or support structures for the antennas. Therefore, their
electromagnetic properties need to be determined. Due to that, a review
of electromagnetic characterization methods, as well as the proposal of a
custom method based on printed transmission lines, is presented in this document.
Besides, several antenna designs, for di erent application scenarios,
using the previously mentioned materials, are proposed. With this thesis it
was proved that it is possible to develop passive sensors in di erent alternative
materials for RFID applications and others, which shows great promise
in the use of these materials to achieve higher integration in sensing and
identi cation applications
Mobile Ad Hoc Networks
Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms