Atika Rivenq

In wireless sensor networks, building energy-efficient systems is one of the major challenges. In such networks, nodes are usually supplied by low power and small batteries. Many factors are involved in the energy consumption, and this issue may be considered as a cross-layer problem, from the hardware architecture to the application layer. This paper aims at presenting a hybrid solution for sensor networks based on two main aspects. The first one is the hardware architecture, where we present a prototype of a sensor node we designed. This node proved its efficiency in terms of energy consumption. The second aspect is related to the topology construction and presents a new topology control algorithm based on graph computing. Thus, our system consists of a real indoor application for temperature and humidity monitoring, applicable to home automation or industrial monitoring. We performed the experiments using a set of sensor nodes deployed over a building and proved the efficiency of the system in terms of energy consumption, network lifetime and data delivery.

Nowadays, in maritime and airway domains, many intelligent systems are used for the localization and to exchange data information. However, in guided transports domain, no system is able to ensure these two functionalities. This paper presents a new system called CODIBT (communication, detection and identification of broken-down trains) allowing multi-user access and combining the two main functionalities: localization and high data flow rate communication. Such systems are developed in order to improve exploitation inside guided transport networks. Our laboratories designed an original radar system that allows inter-vehicle communication. This system is based on the principle of a co-operative radar using a transponder inside targets. It is made of a couple of transmitter/receiver which equips respectively the front and the rear of two successive vehicles. It uses a numerical correlation receiver and has a broad band of about 100 MHz which could be exploited to establish high data flow rate communications. The aim of this paper is to describe the mock-up realized and present some improvements of the coding methods developed using spreading spectrum techniques. Some simulations aimed to evaluate system performance in terms of BER together with main experimental results will be reported