Search results for "LESS"
showing 10 items of 2452 documents
A TDMA-Based MAC Protocol Supporting Cooperative Communications in Wireless Mesh Networks
2011
This paper proposes a TDMA-based medium access control protocol which enables cooperative communications in multi-hop wireless mesh networks. According to the proposed scheme, each router at the two-hop neighbourhood of each other is allocated to a specific time slot for accommodating either direct or cooperative transmissions in a coordinated manner, controlled by mini-slots which are part of the time slot. Benefiting from the elaborate mini-slot design, channel resources are fairly and efficiently allocated to each router so that no handshake is needed prior to each packet transmission. By providing access priority to cooperative transmission through an optimal relay which is determined b…
La routine
2015
La pratica dell’insegnamento dovrebbe scaturire sempre da una riflessione sulla pratica stessa, dovrebbe tradursi in un “fare riflessivo”, cioè in un “fare” più consapevole; infatti il racconto della propria esperienza e la riflessione sulle proprie pratiche permette di essere più consapevoli di ciò che viene fatto, del come viene fatto e del perché. Tutto ciò permette all’insegnante di decentrarsi dall’azione, di analizzarla e di sviluppare la capacità di analisi delle situazioni educativo-didattiche. La narrazione attraverso la routine, risulta fondamentale per sviluppare la riflessione metacognitiva e per rintracciare la motivazione profonda che spinge l’insegnante ad operare determinate…
A new Scheme for RPL to handle Mobility in Wireless Sensor Networks
2017
Mobile wireless sensor networks (WSNs) are characterised by dynamic changes in the network topology leading to route breaks and disconnections. The IPv6 routing protocol for low power and lossy networks (RPL), which has become a standard, uses the Trickle timer algorithm to handle changes in the network topology. However, neither RPL nor Trickle timer are well adapted to mobility. This paper investigates the problem of supporting mobility when using RPL. It enhances RPL to fit with sensors' mobility by studying two cases. Firstly, it proposes to modify RPL in order to fit with a dynamic and hybrid topology in the context of medical applications. Secondly, it investigates a more general case…
A self-routing protocol for distributed consensus on logical information
2010
In this paper, we address decision making problems, depending on a set of input events, with networks of dynamic agents that have partial visibility of such events. Previous work by the authors proposed so-called logical consensus approach, by which a network of agents, that can exchange binary values representing their local estimates of the events, is able to reach a unique and consistent decision. The approach therein proposed is based on the construction of an iterative map, whose computation is centralized and guaranteed under suitable conditions on the input visibility and graph connectivity. Under the same conditions, we extend the approach in this work by allowing the construction o…
I-RP: Interference Aware Routing Protocol for WBAN
2018
The Wireless Body Sensor Networks (WBSN) have witnessed tremendous research interest because of their wide range of applications (medical and non-medical) in order to improve the quality of life. The healthcare applications of WBSN demands dissemination of patient’s data, reliably and in a timely manner. For this purpose, medical teams may use real-time applications for disseminating critical data such as blood pressure, ECG, and EEG. The critical data packets are highly delay sensitive that must reach intended destination within time constraints. Due to the exchange of real-time and multi-media data, some nodes or links may experience the significant level of interference in the network. C…
Power-constrained sensor selection and routing for cooperative detection in cognitive radios
2012
Given a spectrum-sensing network, a set of active nodes jointly aggregate sensed data at a preset frequency-band and simultaneously route this information to an arbitrarily chosen querying node through a power-constrained multi-hop path. Locally, each sensor node is assumed to be an energy-based detector. This work focuses on deriving algorithms that jointly optimize sensor selection and cooperative detection from which a power-efficient route to the querying node can be established, and then, a tree routing structure spanning the chosen nodes is constructed under a power budget constraint. Sensor information is sequentially aggregated along this optimized routing structure up to the queryi…
Adaptive live video streaming on low-cost wireless multihop networks for road traffic surveillance in smart cities
2021
Abstract Traffic surveillance is an important issue for Intelligent Transportation Systems (ITS) that helps detect incidents automatically, such as wrong-way drivers, still-standing vehicles and jams. Sometimes these systems require a fast and short-term deployment of video cameras. In these cases, ad-hoc networks could be a low-cost and feasible option, but they have poor performance for video delivery. Thus, we propose a smart live video adaptive streaming technique in order to transport video streams from the cameras to the external road traffic monitoring servers. To achieve this goal, these networks need a thorough study in order to analyze video quality under their inherent constraint…
Assignment of Roles and Channels for a Multichannel MAC in Wireless Mesh Networks
2009
International audience; A multichannel MAC improves throughput in wireless mesh networks by multiplexing transmissions over orthogonal channels. In this paper, we propose an efficient way for constructing the wireless mesh structure associated with Molecular MAC, a multichannel MAC layer designed for efficient packet forwarding. Molecular MAC outperforms other classical approaches, but requires a specific structure for efficient operation. First, we propose a centralized protocol that provides an upper bound for constructing such a molecular structure through a MILP (Mixed Integer Linear Programming) formulation that maximizes network capacity. Then, we present two distributed self-stabiliz…
An intrusion detection system for selective forwarding attack in IPv6-based mobile WSNs
2017
Selective forwarding attack is considered among the most dangerous attack in wireless sensor networks, particularly in mobile environment. The attackers compromise legitimate nodes and selectively drop some packets. In addition to that, the movement of some nodes increases link failures, collisions and packet loss. So, it will be more difficult to detect malicious nodes from legitimates ones. This paper focuses on detecting selective forwarding attackers in IPv6-based mobile wireless sensor networks when the standardized IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) is used. Contrarily to previous works which propose solutions to detect selective forwarding attack in static w…
Performance of H.264 compressed video streams over 802.11b based MANETs
2004
We address the problem of video streams transmission in 802.11b based mobile ad-hoc networks (MANETs). Through the study of the delivery of a live encoded video stream, we expose the characteristics of different routing protocols and the infeasibility to provide QoS. The analysis shows the impact of a MANET on H.264 real-time video flows in terms of packet loss, end-to-end delay, jitter and distortion, and the behavior of H.264 error resilience tools in order to determine their effectiveness on such network scenarios. The results show that video traffic has demands that are hard to be met by a standard MANET, and that improvements are required in terms of routing protocols and QoS provision…