378 research outputs found
A COMMUNICATION FRAMEWORK FOR MULTIHOP WIRELESS ACCESS AND SENSOR NETWORKS: ANYCAST ROUTING & SIMULATION TOOLS
The reliance on wireless networks has grown tremendously within a number of varied application domains, prompting an evolution towards the use of heterogeneous multihop network architectures. We propose and analyze two communication frameworks for such networks. A first framework is designed for communications within multihop wireless access networks. The framework supports dynamic algorithms for locating access points using anycast routing with multiple metrics and balancing network load. The evaluation shows significant performance improvement over traditional solutions. A second framework is designed for communication within sensor networks and includes lightweight versions of our algorithms to fit the limitations of sensor networks. Analysis shows that this stripped down version can work almost equally well if tailored to the needs of a sensor network. We have also developed an extensive simulation environment using NS-2 to test realistic situations for the evaluations of our work. Our tools support analysis of realistic scenarios including the spreading of a forest fire within an area, and can easily be ported to other simulation software. Lastly, we us our algorithms and simulation environment to investigate sink movements optimization within sensor networks. Based on these results, we propose strategies, to be addressed in follow-on work, for building topology maps and finding optimal data collection points. Altogether, the communication framework and realistic simulation tools provide a complete communication and evaluation solution for access and sensor networks
A survey on energy efficient techniques in wireless sensor networks
International audienceThe myriad of potential applications supported by wireless sensor networks (WSNs) has generated much interest from the research community. Various applications range from small size low industrial monitoring to large scale energy constrained environmental monitoring. In all cases, an operational network is required to fulfill the application missions. In addition, energy consumption of nodes is a great challenge in order to maximize network lifetime. Unlike other networks, it can be hazardous, very expensive or even impossible to charge or replace exhausted batteries due to the hostile nature of environment. Researchers are invited to design energy efficient protocols while achieving the desired network operations. This paper focuses on different techniques to reduce the consumption of the limited energy budget of sensor nodes. After having identified the reasons of energy waste in WSNs, we classify energy efficient techniques into five classes, namely data reduction, control reduction, energy efficient routing, duty cycling and topology control. We then detail each of them, presenting subdivisions and giving many examples. We conclude by a recapitulative table
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Performance Analysis of Cluster Based Communication Protocols for Energy Efficient Wireless Sensor Networks. Design, Analysis and Performance Evaluation of Communication Protocols under Various Topologies to Enhance the Lifetime of Wireless Sensor Networks.
Sensor nodes are deployed over sensing fields for the purpose of monitoring certain
phenomena of interest. The sensor nodes perform specific measurements, process the
sensed data, and send the data to a base station over a wireless channel. The base station
collects data from the sensor nodes, analyses this data, and reports it to the users.
Wireless sensor networks are different from traditional networks, because of the
following constraints. Typically, a large number of sensor nodes need to be randomly
deployed and, in most cases, they are deployed in unreachable environments; however,
the sensor nodes may fail, and they are subject to power constraints.
Energy is one of the most important design constraints of wireless sensor networks.
Energy consumption, in a sensor node, occurs due to many factors, such as: sensing the
environment, transmitting and receiving data, processing data, and communication
overheads. Since the sensor nodes behave as router nodes for data propagation, of the
other sensor nodes to the base station, network connectivity decreases gradually. This
may result in disconnected sub networks of sensor nodes. In order to prolong the
networkÂżs lifetime, energy efficient protocols should be designed for the characteristics
of the wireless sensor network. Sensor nodes in different regions of the sensing field can
collaborate to aggregate the data that they gathered.
Data aggregation is defined as the process of aggregating the data from sensor nodes to
reduce redundant transmissions. It reduces a large amount of the data traffic on the
network, it requires less energy, and it avoids information overheads by not sending all
of the unprocessed data throughout the sensor network. Grouping sensor nodes into
clusters is useful because it reduces the energy consumption. The clustering technique
can be used to perform data aggregation. The clustering procedure involves the selection
of cluster heads in each of the cluster, in order to coordinate the member nodes. The
cluster head is responsible for: gathering the sensed data from its clusterÂżs nodes,
aggregating the data, and then sending the aggregated data to the base station.
An adaptive clustering protocol was introduced to select the heads in the wireless sensor
network. The proposed clustering protocol will dynamically change the cluster heads to
obtain the best possible performance, based on the remaining energy level of sensor
nodes and the average energy of clusters. The OMNET simulator will be used to present
the design and implementation of the adaptive clustering protocol and then to evaluate
it.
This research has conducted extensive simulation experiments, in order to fully study
and analyse the proposed energy efficient clustering protocol. It is necessary for all of
the sensor nodes to remain alive for as long as possible, since network quality decreases
as soon as a set of sensor nodes die. The goal of the energy efficient clustering protocol
is to increase the lifetime and stability period of the sensor network.
This research also introduces a new bidirectional data gathering protocol. This protocol
aims to form a bidirectional ring structure among the sensor nodes, within the cluster, in
order to reduce the overall energy consumption and enhance the networkÂżs lifetime. A bidirectional data gathering protocol uses a source node to transmit data to the base
station, via one or more multiple intermediate cluster heads. It sends data through
energy efficient paths to ensure the total energy, needed to route the data, is kept to a
minimum. Performance results reveal that the proposed protocol is better in terms of: its
network lifetime, energy dissipation, and communication overheads
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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Named Data Networking in Vehicular Ad hoc Networks: State-of-the-Art and Challenges
International audienceInformation-Centric Networking (ICN) has been proposed as one of the future Internet architectures. It is poised to address the challenges faced by today's Internet that include, but not limited to, scalability, addressing, security, and privacy. Furthermore, it also aims at meeting the requirements for new emerging Internet applications. To realize ICN, Named Data Networking (NDN) is one of the recent implementations of ICN that provides a suitable communication approach due to its clean slate design and simple communication model. There are a plethora of applications realized through ICN in different domains where data is the focal point of communication. One such domain is Intelligent Transportation System (ITS) realized through Vehicular Ad hoc NETwork (VANET) where vehicles exchange information and content with each other and with the infrastructure. To date, excellent research results have been yielded in the VANET domain aiming at safe, reliable, and infotainment-rich driving experience. However, due to the dynamic topologies, host-centric model, and ephemeral nature of vehicular communication, various challenges are faced by VANET that hinder the realization of successful vehicular networks and adversely affect the data dissemination, content delivery, and user experiences. To fill these gaps, NDN has been extensively used as underlying communication paradigm for VANET. Inspired by the extensive research results in NDN-based VANET, in this paper, we provide a detailed and systematic review of NDN-driven VANET. More precisely, we investigate the role of NDN in VANET and discuss the feasibility of NDN architecture in VANET environment. Subsequently, we cover in detail, NDN-based naming, routing and forwarding, caching, mobility, and security mechanism for VANET. Furthermore, we discuss the existing standards, solutions, and simulation tools used in NDN-based VANET. Finally, we also identify open challenges and issues faced by NDN-driven VANET and highlight future research directions that should be addressed by the research community
Unified Role Assignment Framework For Wireless Sensor Networks
Wireless sensor networks are made possible by the continuing improvements in embedded sensor, VLSI, and wireless radio technologies. Currently, one of the important challenges in sensor networks is the design of a systematic network management framework that allows localized and collaborative resource control uniformly across all application services such as sensing, monitoring, tracking, data aggregation, and routing.
The research in wireless sensor networks is currently oriented toward a cross-layer network abstraction that supports appropriate fine or course grained resource controls for energy efficiency. In that regard, we have designed a unified role-based service paradigm for wireless sensor networks. We pursue this by first developing a Role-based Hierarchical Self-Organization (RBSHO) protocol that organizes a connected dominating set (CDS) of nodes called dominators. This is done by hierarchically selecting nodes that possess cumulatively high energy, connectivity, and sensing capabilities in their local neighborhood. The RBHSO protocol then assigns specific tasks such as sensing, coordination, and routing to appropriate dominators that end up playing a certain role in the network.
Roles, though abstract and implicit, expose role-specific resource controls by way of role assignment and scheduling. Based on this concept, we have designed a Unified Role-Assignment Framework (URAF) to model application services as roles played by local in-network sensor nodes with sensor capabilities used as rules for role identification. The URAF abstracts domain specific role attributes by three models: the role energy model, the role execution time model, and the role service utility model. The framework then generalizes resource management for services by providing abstractions for controlling the composition of a service in terms of roles, its assignment, reassignment, and scheduling. To the best of our knowledge, a generic role-based framework that provides a simple and unified network management solution for wireless sensor networks has not been proposed previously
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