141 research outputs found
A Cooja-based tool for coverage and fifetime evaluation in an in-building sensor network.
Contiki’s Cooja is a very popular wireless sensor network (WSN) simulator, but it lacks support for modelling sensing coverage, focusing instead on network connectivity and protocol performance. However, in practice, it is the ability of a sensor network to provide a satisfactory level of coverage that defines its ultimate utility for end-users. We introduce WSN-Maintain, a Cooja-based tool for coverage and network lifetime evaluation in an in-building WSN. To extend the network lifetime, but still maintain the required quality of coverage, the tool finds coverage redundant nodes, puts them to sleep and automatically turns them on when active nodes fail and coverage quality decreases. WSN-Maintain together with Cooja allow us to evaluate different approaches to maintain coverage. As use cases to the tool, we implement two redundant node algorithms: greedy-maintain, a centralised algorithm, and local-maintain, a localised algorithm to configure the initial network and to turn on redundant nodes. Using data from five real deployments, we show that our tool with simple redundant node algorithms and reading correlation can improve energy efficiency by putting more nodes to sleep
Latency Optimization in Smart Meter Networks
In this thesis, we consider the problem of smart meter networks with data collection to a central point within acceptable delay and least consumed energy. In smart metering applications, transferring and collecting data within delay constraints is crucial. IoT devices are usually resource-constrained and need reliable and energy-efficient routing protocol. Furthermore, meters deployed in lossy networks often lead to packet loss and congestion. In smart grid communication, low latency and low energy consumption are usually the main system targets. Considering these constraints, we propose an enhancement in RPL to ensure link reliability and low latency. The proposed new additive composite metric is Delay-Aware RPL (DA-RPL). Moreover, we propose a repeaters’ placement algorithm to meet the latency requirements. The performance of a realistic RF network is simulated and evaluated. On top of the routing solution, new asynchronous ordered transmission algorithms of UDP data packets are proposed to further enhance the overall network latency performance and mitigate the whole system congestion and interference. Experimental results show that the performance of DA-RPL is promising in terms of end-to-end delay and energy consumption. Furthermore, the ordered asynchronous transmission of data packets resulted in significant latency reduction using just a single routing metric
Reducing energy consumption in mobile ad-hoc sensor networks
PhD ThesisRecent rapid development of wireless communication technologies and portable mobile devices such as tablets, smartphones and wireless sensors bring the best out of mobile computing, particularly Mobile Ad-hoc Sensor Networks (MASNETs). MASNETs
are types of Mobile Ad-hoc Networks (MANETs) that are designed to consider energy
in mind because they have severe resource constraints due to their lack of processing power, limited memory, and bandwidth as in Wireless Sensor Networks (WSNs).
Hence, they have the characteristics, requirements, and limitations of both MANETs
and WSNs. There are many potential applications of MASNETs such as a real-time
target tracking and an ocean temperature monitoring. In these applications, mobility
is the fundamental characteristic of the sensor nodes, and it poses many challenges
to the routing algorithm. One of the greatest challenge is to provide a routing algorithm that is capable of dynamically changing its topology in the mobile environment
with minimal consumption of energy. In MASNETs, the main reason of the topology
change is because of the movement of mobile sensor nodes and not the node failure due
to energy depletion. Since these sensor nodes are limited in power supply and have low
radio frequency coverage, they easily lose their connection with neighbours, and face diffi culties in updating their routing tables. The switching process from one coverage
area to another consumes more energy. This network must be able to adaptively alter
the routing paths to minimize the effects of variable wireless link quality, topological
changes, and transmission power levels on energy consumption of the network. Hence,
nodes prefer to use as little transmission power as necessary and transmit control packets as infrequently as possible in energy constrained MASNETs. Therefore, in this
thesis we propose a new dynamic energy-aware routing algorithm based on the trans-
mission power control (TPC). This method effectively decreases the average percentage
of packet loss and reduces the average total energy consumption which indirectly pro-
long the network lifetime of MASNETs. To validate the proposed protocol, we ran
the simulation on the Avrora simulator and varied speed, density, and route update
interval of mobile nodes. Finally, the performance of the proposed routing algorithm
was measured and compared against the basic Ad-hoc On-demand Distance Vector
(AODV) routing algorithm in MASNETs.The Ministry of Education of Malaysia:
The Universiti Malaysia Sarawak
Keberkesanan program simulasi penapis sambutan dedenyut terhingga (FIR) terhadap kefahaman pelajar kejuruteraan elektrik
Kefahaman merupakan aset bagi setiap pelajar. Ini kerana melalui
kefahaman pelajar dapat mengaplikasikan konsep yang dipelajari di dalam dan di
luar kelas. Kajian ini dijalankan bertujuan menilai keberkesanan program simulasi
penapis sambutan dedenyut terhingga (FIR) terhadap kefahaman pelajar kejuruteraan
elektrik FKEE, UTHM dalam mata pelajaran Pemprosesan Isyarat Digital (DSP)
bagi topik penapis FIR. Metodologi kajian ini berbentuk kaedah reka bentuk kuasi�eksperimental ujian pra-pasca bagi kumpulan-kumpulan tidak seimbang. Seramai 40
responden kajian telah dipilih dan dibahagi secara rawak kepada dua kllmpulan iaitu
kumpulan rawatan yang menggunakan program simulasi penapis FIR dan kumpulan
kawalan yang menggunakan kaedah pembelajaran berorientasikan modul
pembelajaran DSP UTHM. Setiap responden menduduki dua ujian pencapaian iaitu
ujian pra dan ujian pasca yang berbentuk kuiz. Analisis data berbentuk deskriptif
dan inferens dilakllkan dengan menggunakan Peri sian Statistical Package for Social
Science (SPSS) versi 11.0. Dapatan kajian menunjukkan kedua-dua kumpulan
pelajar telah mengalami peningkatan dari segi kefahaman iaitu daripada tahap tidak
memuaskan kepada tahap kepujian selepas menggunakan kaedah pembelajaran yang
telah ditetapkan bagi kumpulan masing-masing. Walaubagaimanapun, pelajar
kumpulan rawatan menunjukkan peningkatan yang lebih tinggi sedikit berbanding
pelajar kumpulan kawalan. Namun begitu, dapatan kajian secara ujian statistik
menunjukkan tidak terdapat perbezaan yang signifikan dari segi pencapaian markah
ujian pasca di antara pelajar kumpulan rawatan dengan pelajar kumpulan kawalan.
Sungguhpun begitu, penggunaan program simulasi penapis FIR telah membantu
dalam peningkatan kefahaman pelajar mengenai topik penapis FIR
The Secure and Energy Efficient Data Routing in the IoT based Network
The business applications such as weather forecasting, traffic management, weather forecasting, traffic management, etc., are enormously adopting Internet of Things(IoT). While scaling of these applications are fast, the device/sensor capabilities, particularly in terms of battery life and energy efficiency is limited. Despite of intensive research conducted to address these shortcomings, Wireless IoT Sensor Network(WIoTSN) still cannot assure 100\% efficient network life. Therefore, the core objective of the thesis is to provide an overview of energy efficiency of proactive(OLSR) and reactive(DSR and AODV) data routing protocols by scaling the size of network, i.e. number of sensor nodes, data packet size, data transmission rate and speed of mobile sink node. It also reviews the importance of security in WIoTSN.
The two approaches, such as literature review and simulation testing, are used to achieve the objective of the thesis. The literature review provides information about reactive and proactive protocols and their mechanism for route discovery. Similarly, the network simulator tool NS3 is used for running simulation to evaluate the performance of selected routing protocols for energy efficiency.
The thesis results showed the effect of scaling the parameters selected for experimental purpose on the energy efficiency of proactive and reactive data routing protocols. The simulation results prove that the reactive protocol DSR outperforms another reactive protocol AODV and proactive protocol OLSR in energy efficiency. From the security perspective, the thesis also emphasizes its need in IoT and suggest to minimize wasteful resources in WIoTSN and use them by restructuring the network for secure energy-efficient data routing protocols
Politecast - a new communication primitive for wireless sensor networks
Wireless sensor networks have the potential for becoming a huge market. Ericsson predicts 50 billion devices interconnected to the Internet by the year 2020. Before that, the devices must be made to be able to withstand years of usage without having to change power source as that would be too costly. These devices are typically small, inexpensive and severally resource constrained. Communication is mainly wireless, and the wireless transceiver on the node is typically the most power hungry component. Therefore, reducing the usage of radio is key to long lifetime.
In this thesis I identify four problems with the conventional broadcast primitive. Based on those problems, I implement a new communication primitive. This primitive is called Politecast. I evaluate politecast in three case studies: the Steal the Light toy example, a Neighbor Discovery simulation and a full two-month deployment of the Lega system in the art gallery Liljevalchs. With the evaluations, Politecast is shown to be able to massively reduce the amount of traffic being transmitted and thus reducing congestion and increasing application performance. It also prolongs node lifetime by reducing the overhearing by waking up neighbors
DESIGN OF A MINIMAL OVERHEAD CONTROL TRAFFIC TOPOLOGY DISCOVERY AND DATA FORWARDING PROTOCOL FOR SOFTWARE-DEFINED WIRELESS SENSOR NETWORKS
Software-defined networking is a novel concept that is ported into wireless sensor networks to make them more manageable and customizable. unfortunately, the topology discovery and maintenance processes generate high overhead control packet exchange between the sensor nodes and the central controller leading to a deterioration of the network's performance. In this paper, a novel minimal overhead control traffic topology discovery and data forwarding protocol is proposed and detailed. The proposed protocol requires some changes to the topology discovery protocol implemented in SDN-WISE to improve its performance. The proposed protocol has been implemented within the IT-SDN framework for evaluation. The results show reduced overhead control traffic and increase, of about 20%, data packet delivery rate over the protocol in SDN-WISE
A study into prolonging Wireless Sensor Network lifetime during disaster scenarios
A Wireless Sensor Network (WSN) has wide potential for many applications. It can be employed for normal monitoring applications, for example, the monitoring of environmental conditions such as temperature, humidity, light intensity and pressure. A WSN is deployed in an area to sense these environmental conditions and send information about them to a sink. In certain locations, disasters such as forest fires, floods, volcanic eruptions and earth-quakes can happen in the monitoring area. During the disaster, the events being monitored have the potential to destroy the sensing devices; for example, they can be sunk in a flood, burnt in a fire, damaged in harmful chemicals, and burnt in volcano lava etc. There is an opportunity to exploit the energy of these nodes before they are totally destroyed to save the energy of the other nodes in the safe area. This can prolong WSN lifetime during the critical phase. In order to investigate this idea, this research proposes a new routing protocol called Maximise Unsafe Path (MUP) routing using Ipv6 over Low power Wireless Personal Area Networks (6LoWPAN). The routing protocol aims to exploit the energy of the nodes that are going to be destroyed soon due to the environment, by concentrating packets through these nodes. MUP adapts with the environmental conditions. This is achieved by classifying four different levels of threat based on the sensor reading information and neighbour node condition, and represents this as the node health status, which is included as one parameter in the routing decision. High priority is given to a node in an unsafe condition compared to another node in a safer condition. MUP does not allow packet routing through a node that is almost failed in order to avoid packet loss when the node fails. To avoid the energy wastage caused by selecting a route that requires a higher energy cost to deliver a packet to the sink, MUP always forwards packets through a node that has the minimum total path cost. MUP is designed as an extension of RPL, an Internet Engineering Task Force (IETF) standard routing protocol in a WSN, and is implemented in the Contiki Operating System (OS). The performance of MUP is evaluated using simulations and test-bed experiments. The results demonstrate that MUP provides a longer network lifetime during a critical phase of typically about 20\% when compared to RPL, but with a trade-off lower packet delivery ratio and end-to-end delay performances. This network lifetime improvement is crucial for the WSN to operate for as long as possible to detect and monitor the environment during a critical phase in order to save human life, minimise loss of property and save wildlife
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