327 research outputs found

    A Multi-Hop 6LoWPAN Wireless Sensor Network for Waste Management Optimization

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    In the first part of this Thesis several Wireless Sensor Network technologies, including the ones based on the IEEE 802.15.4 Protocol Standard like ZigBee, 6LoWPAN and Ultra Wide Band, as well as other technologies based on other protocol standards like Z-Wave, Bluetooth and Dash7, are analyzed with respect to relevance and suitability with the Waste Management Outsmart European FP7 Project. A particular attention is given to the parameters which characterize a Large Scale WSN for Smart Cities, due to the amount of sensors involved and to the practical application requested by the project. Secondly, a prototype of sensor network is proposed: an Operative System named Contiki is chosen for its portability on different hardware platforms, its Open Source license, for the use of the 6LoW-PAN protocol and for the implementation of the new RPL routing protocol. The Operative System is described in detail, with a special focus on the uIPv6 TCP/IP stack and RPL implementation. With regard to this innovative routing proto col designed specifically for Low Power Lossy Networks, chapter 4 describes in detail how the network topology is organized as a Directed Acyclic Graph, what is an RPL Instance and how downward and upward routes are constructed and maintained. With the use of several AVR Atmel modules mounting the Contiki OS a real WSN is created and, with an Ultrasonic Sensor, the filling level of a waste basket prototype is periodically detected and transmitted through a multi-hop wireless network to a sink nodeope

    Designing and Implimentation of Spatial IP Address Assignment Scheme for a Wireless Network

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    Wireless sensor networks are composed of large numbers up to thousands of tiny radio- equipped sensors. Every sensor has a small microprocessor with enough power to allow the sensors to autonomously form networks through which sensor information is gathered. Wireless sensor networks makes it possible to monitor places like nuclear disaster areas or volcano craters without requiring humans to be immediately present. Many wireless sensor network applications cannot be performed in isolation; the sensor network must somehow be connected to monitoring and controlling entities. This research paper investigates a novel approach for connecting sensor networks to existing networks: by using the TCP/IP protocol suite in the sensor network, the sensors can be directly connected to an outside network without the need for special proxy servers or protocol converters. Bringing TCP/IP to wireless sensor networks is a challenging task, however. First, because of their limited physical size and low cost, sensors are severely constrained in terms of memory and processing power. Traditionally, these constraints have been considered too limiting for a sensor to be able to use the TCP/IP protocols. In this research paper, I show that even tiny sensors can communicate using TCP/IP. Second, the harsh communication conditions make TCP/IP perform poorly in terms of both throughput and energy efficiency. With this research paper, I suggest a number of optimizations that are intended to increase the performance of TCP/IP for sensor networks. The results of the work presented in this research paper have a significant impact on the embedded TCP/IP networking community. The software evolves as part of the research paper has become widely known in the community. The software is mentioned in books on embedded systems and networking, is used in academic courses on embedded systems, is the focus of articles in professional magazines, is incorporated in embedded operating systems, and is used in a

    RESTful Wireless Sensor Networks

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    Sensor networks have diverse structures and generally employ proprietary protocols to gather useful information about the physical world. This diversity generates problems to interact with these sensors since custom APIs are needed which are tedious, error prone and have steep learning curve. In this thesis, I present RESThing, a lightweight REST framework for wireless sensor networks to ease the process of interacting with these sensors by making them accessible over the Web. I evaluate the system and show that it is feasible to support widely used and standard Web protocols in wireless sensor networks. Being able to integrate these tiny devices seamlessly into the global information medium, we can achieve the Web of Things

    A survey on subjecting electronic product code and non-ID objects to IP identification

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    Over the last decade, both research on the Internet of Things (IoT) and real-world IoT applications have grown exponentially. The IoT provides us with smarter cities, intelligent homes, and generally more comfortable lives. However, the introduction of these devices has led to several new challenges that must be addressed. One of the critical challenges facing interacting with IoT devices is to address billions of devices (things) around the world, including computers, tablets, smartphones, wearable devices, sensors, and embedded computers, and so on. This article provides a survey on subjecting Electronic Product Code and non-ID objects to IP identification for IoT devices, including their advantages and disadvantages thereof. Different metrics are here proposed and used for evaluating these methods. In particular, the main methods are evaluated in terms of their: (i) computational overhead, (ii) scalability, (iii) adaptability, (iv) implementation cost, and (v) whether applicable to already ID-based objects and presented in tabular format. Finally, the article proves that this field of research will still be ongoing, but any new technique must favorably offer the mentioned five evaluative parameters.Comment: 112 references, 8 figures, 6 tables, Journal of Engineering Reports, Wiley, 2020 (Open Access

    On the performance of emerging wireless mesh networks

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    Wireless networks are increasingly used within pervasive computing. The recent development of low-cost sensors coupled with the decline in prices of embedded hardware and improvements in low-power low-rate wireless networks has made them ubiquitous. The sensors are becoming smaller and smarter enabling them to be embedded inside tiny hardware. They are already being used in various areas such as health care, industrial automation and environment monitoring. Thus, the data to be communicated can include room temperature, heart beat, user’s activities or seismic events. Such networks have been deployed in wide range areas and various levels of scale. The deployment can include only a couple of sensors inside human body or hundreds of sensors monitoring the environment. The sensors are capable of generating a huge amount of information when data is sensed regularly. The information has to be communicated to a central node in the sensor network or to the Internet. The sensor may be connected directly to the central node but it may also be connected via other sensor nodes acting as intermediate routers/forwarders. The bandwidth of a typical wireless sensor network is already small and the use of forwarders to pass the data to the central node decreases the network capacity even further. Wireless networks consist of high packet loss ratio along with the low network bandwidth. The data transfer time from the sensor nodes to the central node increases with network size. Thus it becomes challenging to regularly communicate the sensed data especially when the network grows in size. Due to this problem, it is very difficult to create a scalable sensor network which can regularly communicate sensor data. The problem can be tackled either by improving the available network bandwidth or by reducing the amount of data communicated in the network. It is not possible to improve the network bandwidth as power limitation on the devices restricts the use of faster network standards. Also it is not acceptable to reduce the quality of the sensed data leading to loss of information before communication. However the data can be modified without losing any information using compression techniques and the processing power of embedded devices are improving to make it possible. In this research, the challenges and impacts of data compression on embedded devices is studied with an aim to improve the network performance and the scalability of sensor networks. In order to evaluate this, firstly messaging protocols which are suitable for embedded devices are studied and a messaging model to communicate sensor data is determined. Then data compression techniques which can be implemented on devices with limited resources and are suitable to compress typical sensor data are studied. Although compression can reduce the amount of data to be communicated over a wireless network, the time and energy costs of the process must be considered to justify the benefits. In other words, the combined compression and data transfer time must also be smaller than the uncompressed data transfer time. Also the compression and data transfer process must consume less energy than the uncompressed data transfer process. The network communication is known to be more expensive than the on-device computation in terms of energy consumption. A data sharing system is created to study the time and energy consumption trade-off of compression techniques. A mathematical model is also used to study the impact of compression on the overall network performance of various scale of sensor networks

    Adaptive header compression techniques for mobile multimedia networks

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    Performance of constrained wireless devices in the Internet of Things

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    The Internet of Things is an emerging concept where every device, regardless of size, have their own connection to the Internet. This thesis examines what possible limitations are imposed on the functionality of resource constrained, wireless devices. Several different technologies are evaluated and compared, before a set of them is chosen for inclusion in an implementation, for example: IEEE 802.15.4, 6LoWPAN and CoAP. The implementation uses the Contiki operating system, and runs on a Texas Instruments CC2530 SoC. We then examine several different performance aspects of our implementation: the amount of data sent, memory usage and energy consumption. The results are discussed together with security aspects applicable to the Internet of things. The memory usage and power consumption were found to be severe issues. Due to the small amount of memory on the chip, all features could not be used at the same time. In addition, the power consumption was found to be too high for battery-powered usage, giving a lifetime of only 27 hours using a button cell battery. The conclusion is that hardware with more memory, and lower power consumption is required. New protocols for radio power-saving should also be developed and implemented in software.Internet of Things – sakernas internet – är ett framväxande koncept där varje enhet, oavsett storlek, har en anslutning till Internet. Detta examensarbete undersöker vilka möjliga begränsningar i funktionalitet detta får på trådlösa enheter med begränsade resurser. Flera olika teknologier undersöks och jämförs, innan ett antal väljs ut för att ingå i en implementation, till exempel: IEEE 802.15.4, 6LoWPAN och CoAP. Implementationen använder operativsystemet Contiki och körs på ett Texas Instruments CC2530 SoC. Flera prestandaaspekter undersöks: mängden skickad data, minnesanvändning och energiförbrukning. Resultaten diskuteras tillsammans med säkerhetsaspekter att ta hänsyn till i Internet of Things. Minnesanvändningen och energiförbrukningen är de mest problematiska områdena. På grund av chippets begränsade mängd minne kan inte all funktionalitet användas samtidigt. Dessutom är energiförbrukningen för hög för längre tids strömförsörjning med batteri, vilket ger en livslängd på enbart 27 timmar med ett knappcellsbatteri. Slutsatsen är att hårdvara med mer minne och lägre energiförbrukning behövs. Nya protokoll för energibesparande radioanvändning behöver också utvecklas och implementeras i mjukvara

    Header Compression and Signal Processing for Wideband Communication Systems.

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    This thesis is dedicated to the investigation, development and practical verification of header compression and signal processing techniques over TErrestrial Trunked RAdio (TETRA), TETRA Enhanced Data Services (TEDS) and Power Line Communication (PLC). TETRA release I is a narrowband private mobile radio technology used by safety and security organizations, while TEDS is a widebandsystem. With the introduction of IP support, TEDS enables multimedia based applications and services to communicate across communication systems. However the IP extension for TEDS comes at a cost of significant header contributions with the payload. With small application payloads and fast rate application traffic profiles, the header contribution in the total size of the packet is considerably more than the actual application payload. This overhead constitutes the considerable slot capacity at the physical layer of TEDS and PLC. Advanced header compression techniques such as Robust Header Compression (RoHC) compress the huge header sizes and offer significant compression gain without compromising quality of service (QoS). Systems can utilize this bandwidth to transmit more information payload than control information. In this study, the objective is to investigate the integration of RoHC in TEDS and design a novel IPv6 enabled protocol stack for PLC with integrated RoHC. The purpose of the study is also to investigate the throughput optimization technique such as RoHC over TEDS and PLC by simulating different traffic profile classes and to illustrate the benefit of using RoHC over TEDS and PLC. The thesis also aims to design and simulate the TEDS physical layer for the purpose of investigating the performance of higher order modulation schemes. Current TEDS, standards are based on the transmission frequencies above 400MHz range, however with delays in the standardization of broadband TETRA, it is important to explore all possible avenues to extend the capacity of the system. The research concludes the finding of the application of RoHC for TEDS and PLC, against different traffic classes and propagation channels. The benefit of using RoHC in terms of saving bandwidth, slot capacity and other QoS parameters is presented along with integration aspects into TEDS and PLC communication stacks. The study also presents the TEDS physical layer simulation results for modulation schemes and transmission frequency other than specified in the standard. The research results presented in this thesis have been published in international symposiums and professional journals. The application of the benefits of using RoHC for TEDS has been proposed to the ETSI TETRA for contribution to the TETRA standard under STF 378. Simulation results for the investigation of characteristics of ?/4 DQPSK performance below 200 MHz have also been also presented to ETSI TETRA as a contribution to the existing TEDS standard. The Results presented for the design of IPv6 enabled stacked with integrated RoHC have been submitted as deliverable under the FP-7 project DLC+VIT4IP. All the results, simulations and investigations presented in the thesis have been carried out through the platform provided by HW Communication Ltd

    6LoWPAN:IPv6 for battery-less building networks

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