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Recent development in the field of Wireless communications and electronics has enabled the deployment of Wireless sensor Networks (WSNs) in an expanding variety of applications. Significantly, wireless communications have demonstrated profound significance in a variety of applications ranging from military to health applications and from home to industry. In WSNs, a major goal is conserving the sensor...
To understand the complex behavior of a mobile ad hoc network, it is often necessary to proceed through the instantiation of a convenient theoretical model which can explain this behavior. The modeling tool we use in this paper is Erdös-Rényi approach. It emanate from random graph theory. Furthermore, since mobile wireless ad hoc and sensor networks are typically limited in memory resources and...
Packet-combining schemes are an attractive improvement to ARQ schemes, since they allow receivers to keep the good parts of an otherwise erroneous packet and use these with good parts from subsequent packets to allow for quicker decoding. In the previous paper a memory-efficient hard-decision packet combining scheme has been described and analysed, which relies on intermediate checksums spread into...
We propose a simple but effective algorithm to formulate growable communication graphs that exhibit (i) fast information dissemination, (ii) high scalability with negligible performance degradation, and (iii) very small diameter and short average path length. In particular, we use Borel Cayley Graphs (BCGs) as base network topologies. Previously, we reported that BCGs are one of the fastest information...
The Link Quality Indicator (LQI) is defined in the 802.15.4 standard, but its context of use is not specified in this standard. Some works on the LQI, few of which are field experiments, have shown that the LQI decreases as the distance increases. In WSN, it is not often desirable to use the GPS technology. Indeed, the use of GPS is expensive and may reduce the overall network performance. Moreover,...
The usage of IPv6 on Wireless Sensor Networks (WSNs) can enable the integration of existing and new sensing applications with the Internet, therefore contributing to a major evolution towards the realization of the internet of things. We believe this vision to be realizable only if security is properly addressed. Although many proposals do exist in the literature to address specific security issues...
Both research and practice have revealed that sensor devices running the 802.15.4 on their MAC layer may be competing for wireless communication on the 2.4 GHz ISM band with Wi-Fi, Bluetooth and other proprietary devices. Building upon a SunSPOT development platform, we evaluate the impact of channel hopping on interference mitigation in the 2.4 GHz ISM band and propose a channel hopping model that...
In highly mobile ad hoc networks the neighbourhood status evolves rapidly. Routing tables which are populated with an “out of date” view of the neighbourhood produce an overhead in the routing process which can affect the QoS of the communication and the stability of the network interconnectivity. To maintain correct network state information, periodic “Hello” messages are often employed. In many...
The behavior of Wireless Sensor Networks (WSN) is nowadays widely analyzed. One of the most important issues is related to their energy consumption, as this has a major impact on the network lifetime. Another important application requirement is to ensure data sensing synchronization, which leads to additional energy consumption as a high number of messages is sent and received at each node. Our proposal...
The following topics are dealt with: ad hoc networks; sensors networks; wireless multimedia; delay tolerant networks; vehicular networks; broadband wireless networks; wireless models; and wireless simulations.
In wireless sensor networks constructed from battery driven nodes, it is difficult to supply electric power to the nodes. Because of this, the power consumption must be reduced. To cope with this problem, clustering techniques have been proposed. EACLE is a method that uses a clustering technique. In EACLE, the route selection is executed independently after the CH (Cluster Head) selection. These...
The use of topological features, more specifically, the importance of an element related to its structural position is a subject widely studied. For instance, complex networks theory provides some general use of centrality measures that have been applied to a large variety of knowledge fields. This work aims to use centrality information in the design of routing algorithms for Wireless Sensor Networks...
In Wireless Visual Sensor Networks (WVSNs), node selection and organization to realize applications is the title of some research fields known as network topology models that can be classified into two main categories of single-tier and multi-tier. According to the literature, only multi-tier topology model is able to provide a balance between WVSNs objectives such as low cost, maximum coverage, minimum...
Gossip-based epidemic protocols are used to aggregate data in distributed systems. This fault-tolerant approach does neither require maintenance of any global network state nor knowledge of network structure. However, although gossip-based aggregation algorithms scale well for graphs with good expansion, their efficiency for sparse graphs is unexamined. In this paper we analyze the feasibility and...
Wireless sensor networks are constituted of a large number of tiny sensor nodes randomly distributed over a geographical region. In order to reduce power consumption, nodes undergo cycles of active-sleep periods that reduce their ability to send/receive data. Aim of this paper is to analyze the reliability of a battery-powered sensor node with active-sleep cycles considering both linear and non linear...
In wireless sensor networks (WSN) the medium access control CSMA/CA uses binary exponential backoff (BEB) algorithm to minimize collision among the contending nodes. The range of backoff exponent is limited to very small values. This causes channel access collision among the nodes resulting in degradation of quality of service. In this paper improved binary exponential backoff (IBEB) algorithm is...
Jamming attacks have been recently studied as wireless security threats disrupting reliable RF communication in a wireless network. By emitting noise-like signals arbitrarily on the shared wireless medium, a jammer can easily disturb the network. Countermeasures such as Frequency-Hopping Spread Spectrum enable nodes to avoid the jamming attacks by hopping over multiple channels. However, these solutions...
Visual Sensor Networks (VSNs) enable enhanced three-dimensional sensing of spaces and objects, and facilitate collaborative reasoning to open up a new realm of vision-based distributed smart applications including security/surveillance, healthcare delivery, traffic monitoring, just to name a few. However, such applications require sensor nodes that can efficiently process large volumes of visual information...
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