518 research outputs found
A Survey of System Architecture Requirements for Health Care-Based Wireless Sensor Networks
Wireless Sensor Networks (WSNs) have emerged as a viable technology for a vast number of applications, including health care applications. To best support these health care applications, WSN technology can be adopted for the design of practical Health Care WSNs (HCWSNs) that support the key system architecture requirements of reliable communication, node mobility support, multicast technology, energy efficiency, and the timely delivery of data. Work in the literature mostly focuses on the physical design of the HCWSNs (e.g., wearable sensors, in vivo embedded sensors, et cetera). However, work towards enhancing the communication layers (i.e., routing, medium access control, et cetera) to improve HCWSN performance is largely lacking. In this paper, the information gleaned from an extensive literature survey is shared in an effort to fortify the knowledge base for the communication aspect of HCWSNs. We highlight the major currently existing prototype HCWSNs and also provide the details of their routing protocol characteristics. We also explore the current state of the art in medium access control (MAC) protocols for WSNs, for the purpose of seeking an energy efficient solution that is robust to mobility and delivers data in a timely fashion. Furthermore, we review a number of reliable transport layer protocols, including a network coding based protocol from the literature, that are potentially suitable for delivering end-to-end reliability of data transmitted in HCWSNs. We identify the advantages and disadvantages of the reviewed MAC, routing, and transport layer protocols as they pertain to the design and implementation of a HCWSN. The findings from this literature survey will serve as a useful foundation for designing a reliable HCWSN and also contribute to the development and evaluation of protocols for improving the performance of future HCWSNs. Open issues that required further investigations are highlighted
Energy aware performance evaluation of WSNs
Distributed sensor networks have been discussed for more than 30 years, but the vision
of Wireless Sensor Networks (WSNs) has been brought into reality only by the rapid advancements
in the areas of sensor design, information technologies, and wireless networks
that have paved the way for the proliferation of WSNs. The unique characteristics of
sensor networks introduce new challenges, amongst which prolonging the sensor lifetime
is the most important. Energy-efficient solutions are required for each aspect of WSN design
to deliver the potential advantages of the WSN phenomenon, hence in both existing
and future solutions for WSNs, energy efficiency is a grand challenge. The main contribution
of this thesis is to present an approach considering the collaborative nature of WSNs
and its correlation characteristics, providing a tool which considers issues from physical
to application layer together as entities to enable the framework which facilitates the
performance evaluation of WSNs. The simulation approach considered provides a clear
separation of concerns amongst software architecture of the applications, the hardware
configuration and the WSN deployment unlike the existing tools for evaluation. The
reuse of models across projects and organizations is also promoted while realistic WSN
lifetime estimations and performance evaluations are possible in attempts of improving
performance and maximizing the lifetime of the network. In this study, simulations are
carried out with careful assumptions for various layers taking into account the real time
characteristics of WSN.
The sensitivity of WSN systems are mainly due to their fragile nature when energy
consumption is considered. The case studies presented demonstrate the importance of
various parameters considered in this study. Simulation-based studies are presented,
taking into account the realistic settings from each layer of the protocol stack. Physical
environment is considered as well. The performance of the layered protocol stack in
realistic settings reveals several important interactions between different layers. These
interactions are especially important for the design of WSNs in terms of maximizing the
lifetime of the network
Design and implementation of a communicating method for WSN
The sensor nodes present in the wireless sensor networks are constrained of energy as they are
powered with the help of battery. Deployment of the sensor nodes in the hostile environment
makes it unfavorable for the people to change the battery of the senor nodes when it is expired.
Due to the energy limitations there is a great need of providing any energy efficient way of
communication for the wireless sensor networks. Several techniques of offering communications
in a sensor network use the classical layered method that results in great overhead of the network
and high energy consumption. It will be very better when a unified technique is present for
converting the functions of common protocol to the cross layer method. A cross layer protocol is
been implemented in this project to provide congestion control, better routing over the cross
layers. This cross layer protocol is designed based on the initiative determination present in cross
layer module. This method offers congestion control forwarding based on initiatives contention
based on receivers and better communication between the sensor nodes of a wireless sensor
network. The implementation of this initiative determination is very easy as it just involves the
comparison with the threshold values. Through this cross layer protocol the functions of each
layer can be combined very easily .The performance of this cross layer protocol is also identified
in this project. Through this cross layer protocol better communications can be provided between
the sensor nodes of a wireless sensor networks and also is far better than the classic layered
protocols with respect to the energy consumption and network performance
Sensor Proxy Mobile IPv6 (SPMIPv6)—A Novel Scheme for Mobility Supported IP-WSNs
IP based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health-care, home automation, environmental monitoring, industrial control, vehicle telematics and agricultural monitoring. In all these applications, mobility in the sensor network with special attention to energy efficiency is a major issue to be addressed. Host-based mobility management protocols are not suitable for IP-WSNs because of their energy inefficiency, so network based mobility management protocols can be an alternative for the mobility supported IP-WSNs. In this paper we propose a network based mobility supported IP-WSN protocol called Sensor Proxy Mobile IPv6 (SPMIPv6). We present its architecture, message formats and also evaluate its performance considering signaling cost, mobility cost and energy consumption. Our analysis shows that with respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 60% and 56%, as well as the mobility cost by 62% and 57%, compared to MIPv6 and PMIPv6, respectively. The simulation results also show that in terms of the number of hops, SPMIPv6 decreases the signaling cost by 56% and 53% as well as mobility cost by 60% and 67% as compared to MIPv6 and PMIPv6 respectively. It also indicates that proposed scheme reduces the level of energy consumption significantly
Low-Power Pıc-Based Sensor Node Devıce Desıgn And Theoretıcal Analysıs Of Energy Consumptıon In Wıreless Sensor Networks
Teknolojinin ilerlemesi, daha enerji verimli ve daha ucuz elektronik bileşenlerinin daha
küçük üretilmesini sağlamıştır. Bu nedenle, daha önce mevcut birçok bilgisayar ve elektronik
bilim-mühendislik fikirleri uygulanabilir hale gelmiştir. Bunlardan birisi de kablosuz sensör
ağları teknolojisidir. Kablosuz algılayıcı ağlar, düşük enerji tüketimi ve gerekli teknik
gereksinimlerin gerçekleşmesi ile uygulanabilir hale gelmiştir. Ayrıca, Kablosuz algılayıcı
ağlarının tasarımında iletişim algoritmaları, enerji tasarruf protokolleri ve yenilenebilir enerji
teknolojileri gibi diğer bilimsel çalışmalar zorunlu hale gelmiştir.
Bu tez, mikroelektronik sistemler, kablosuz iletişim ve dijital elektronik teknolojisinin
ilerlemesiyle uygulanabilir hale gelmiş sensör ağları teknolojisini kapsamaktadır. Birincisi,
algılama görevleri ve potansiyel algılayıcı ağ uygulamaları araştırılmış ve algılayıcı ağlarının
tasarımını etkileyen faktörlerin gözden geçirilmesi sağlanmıştır. Ardından sensör ağları için
iletişim mimarisi ana hatlarıyla belirtilmiştir. Ayrıca, tek bir düğümün WLAN ile iletişim
kurabilmesi için yeni donanım mimarisi tasarlanmış ve düğümlerde yenilenebilir enerji
kaynakları kullanılmıştır.
Bu tezde WSN, analitik bilim ve uygulamalı bilim açısından incelenmiştir. Düşük enerji
tüketimi ve iletişim protokolleri arasındaki ilişki değerlendirilmiş ve bilimsel sonuçlara
varılmıştır. Teorik analizler bilimsel uygulamalarla desteklenmiştir. Çalışmalar, düşük enerji
ve maksimum verimlilik prensibinin gerçekleştirilmesine dayalı kablosuz sensör ağları
üzerinde gerçekleştirilmiştir. Kablosuz sensör ağlari sistemi tasarlandıktan sonra; sensör
düğümlerinin enerji tüketimi ve kablosuz ağdaki davranışları test ve analiz edilmiştir. Düşük
enerji tüketimi ile sensör düğümleri arasındaki ilişki detaylı olarak değerlendirilmiştir.
PIC Tabanlı mikro denetleyiciler sensör düğümlerinin tasarımında kullanılmış ve çok
düşük maliyetli tasarım için ultra düşük güçte, nanoWatt teknolojisi ile desteklenen sensör
düğümleri tasarlanmıştır. İşleme birimi, bellek birimi ve kablosuz iletişim birimi sensör
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düğümlerine entegre edilmiştir. Tasarlanan sensör düğümünün işletim sistemi PIC C dili ile
yazılmıştır ve PIC işletim sistemi nem, sıcaklık, ışığa duyarlılık ve duman sensörü gibi farklı
özelliklerin ölçülmesine izin vermiştir. Sensörlerden gelen verilerin merkezi bir konumdan
kaydedilmesi ve izlenebilmesi için, C# programlama dili ile bilgisayar yazılımı geliştirilmiştir.
Gelişmiş algılayıcı düğümler tarafından alınan kararların uygulanması için yazılım
algoritması ve donanım modüllerini içeren karar verme sistemi tasarlanmıştır. Gelişmiş PIC
Tabanlı sensör düğümleri, enerji üretimi ve enerji tasarrufu için, güneş enerjisi paneli, şarj
edilebilir pil ve süper kapasitör gibi yenilenebilir enerji kaynakları ile benzersiz bir PIC
Kontrollü voltaj birimi ile desteklenmiştir. Geliştirilmiş kablosuz sensör ağları sistemi, endüstri
uygulamaları, akıllı fabrikalar ve akıllı evler gibi günlük hayat uygulamaları için de
kullanılabilecektir. Kablosuz algılayıcı ağlar geniş bir aralıkta kullanılmak üzere tasarlanmıştır.
Tezin sonuçları, özellikle yenilenebilir enerji kaynakları ile WSN'nin geliştirilmesine yardımcı
olmayı amaçlamaktadır
mTOSSIM: A simulator that estimates battery lifetime in wireless sensor networks
Knowledge of the battery lifetime of the wireless sensor network is important for many situations,
such as in evaluation of the location of nodes or the estimation of the connectivity,
along time, between devices. However, experimental evaluation is a very time-consuming
task. It depends on many factors, such as the use of the radio transceiver or the distance
between nodes. Simulations reduce considerably this time. They allow the evaluation of
the network behavior before its deployment. This article presents a simulation tool which
helps developers to obtain information about battery state. This simulator extends the
well-known TOSSIM simulator. Therefore it is possible to evaluate TinyOS applications
using an accurate model of the battery consumption and its relation to the radio power
transmission. Although an specific indoor scenario is used in testing of simulation, the simulator
is not limited to this environment. It is possible to work in outdoor scenarios too.
Experimental results validate the proposed model.Junta de Andalucía P07-TIC-02476Junta de Andalucía TIC-570
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