Capacity and interference modeling of CSMA/CA networks using SSI point processes

International audienceThe relative location of simultaneous transmitters, i.e. the set of nodes transmitting a frame at a given time, has a crucial impact on the performance of multi hop wireless networks. Two fundamental aspects of wireless network performances are related to these locations: capacity and interference. Indeed, as interference results from the summation of signals stemmed by concurrent transmitters, it directly depends on the transmitters' location. On the other hand, the network capacity is proportional to the number of simultaneous transmitters. In this paper, we investigate original point processes that can be used to model the location of transmitters that comply with the CSMA/CA policies, i.e. the Medium Access Control protocol used in 802.15.4 and 802.11 families of wireless technologies. We first propose the use of the Simple Sequential Inhibition point process to model CSMA/CA networks where clear channel assessment depends on the strongest emitter only. We then extend this point process to model a busy medium detection based on the strength of all concurrent signals. We finally compare the network capacity obtained through realistic simulations to a theoretical capacity estimated using the intensity of the SSI point process. It turns out that the proposed model is validated by the simulations

Private and Resilient Data Aggregation

Sensors are commonly deployed in hostile environment, and consequently a number of research works have focused on data aggregation schemes designed to be tolerant to attacks on sensor nodes. In parallel, schemes ensuring the confidentiality of sensor data have been proposed to address the emerging privacy concerns. We note that resilience against tampering attacks requires access to the sensor node's data, while in privacy-preserving systems this data must remain confidential. In this work, we aim to reconcile these two seemingly conflicting objectives. We present a novel private and resilient aggregation system, in which an aggregator combines the data collected from sensor nodes and forwards the resulting sum to an analyst. Our scheme protects the privacy of the users from both honest-but-curious aggregator and analyst, while enabling the filtering of fake data values using a Private Range Test protocol.Les réseaux de capteurs peuvent être déployés dans un environnement hostile. Ainsi un nombre de travaux de recherche se sont intéressés à des systèmes d'agrégation de données tolérant aux attaques sur les noeuds. Parallèlement des techniques garantissant la confidentialité des données collectées par les réseaux de capteurs ont été proposées afin de faire face à la problématique de vie privée. La tolérance aux attaques sur les capteurs nécessite un accès aux données retournées par ceux-ci, alors que la protection de la vie privée nécessite justement que ces données restent confidentielles. Le but de ce travail est de réconcilier ces deux objectifs qui apparaissent comme conflictuels. Nous présentons un nouveau système d'agrégation capable de tolérer les attaques sur les noeuds tout en préservant la confidentialité des données des capteurs. Ce système inclut un agrégateur qui collecte et combine les données provenant des capteurs et renvoi le résultat à l'utilisateur final appelé analyste. Ce système protège la vie privée des utilisateurs face à un couple agrégateur/analyste "curieux mais honnête". Il permet également de données les données contrôlées par un attaquant en utilisant un protocole de "Private Range Test" basé sur la théorie du calcul sécurisé multipartie

Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks

This book presents collective works published in the recent Special Issue (SI) entitled "Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks”. These works expose the readership to the latest solutions and techniques for MANETs and VANETs. They cover interesting topics such as power-aware optimization solutions for MANETs, data dissemination in VANETs, adaptive multi-hop broadcast schemes for VANETs, multi-metric routing protocols for VANETs, and incentive mechanisms to encourage the distribution of information in VANETs. The book demonstrates pioneering work in these fields, investigates novel solutions and methods, and discusses future trends in these field

Improving the performance of a dismounted Future Force Warrior by means of C4I2SR

This thesis comprises seven peer-reviewed articles and examines systems and applications suitable for increasing Future Force Warrior performance, minimizing collateral damage, improving situational awareness and Common Operational Picture. Based on a literature study, missing functionalities of Future Force Warrior were identified and new ideas, concepts and solutions were created as part of early stages of Systems of Systems creation. These introduced ideas have not yet been implemented or tested in combat and for this reason benefit analyses are excluded. The main results of this thesis include the following: A new networking concept, Wireless Polling Sensor Network, which is a swarm of a few Unmanned Aerial Vehicles forming an ad-hoc network and polling a large number of fixed sensor nodes. The system is more robust in a military environment than traditional Wireless Sensor Networks. A Business Process approach to Service Oriented Architecture in a tactical setting is a concept for scheduling and sharing limited resources. New components to military Service Oriented Architecture have been introduced in the thesis. Other results of the thesis include an investigation of the use of Free Space Optics in tactical communications, a proposal for tracking neutral forces, a system for upgrading simple collaboration tools for command, control and collaboration purposes, a three-level hierarchy of Future Force Warrior, and methods for reducing incidents of fratricide

Flexible Application-Layer Multicast in Heterogeneous Networks

This work develops a set of peer-to-peer-based protocols and extensions in order to provide Internet-wide group communication. The focus is put to the question how different access technologies can be integrated in order to face the growing traffic load problem. Thereby, protocols are developed that allow autonomous adaptation to the current network situation on the one hand and the integration of WiFi domains where applicable on the other hand