International audienceWireless sensor network (WSN) has emerged as one of the most promising technologies for the future. This has been enabled by advances in technology and availability of small, inexpensive, and smart sensors resulting in cost effective and easily deployable WSNs. However, researchers must address a variety of challenges to facilitate the widespread deployment of WSN technology in real-world domains. In this survey, we give an overview of wireless sensor networks and their application domains including the challenges that should be addressed in order to push the technology further. Then we review the recent technologies and testbeds for WSNs. Finally, we identify several open research issues that need to be investigated in future. Our survey is different from existing surveys in that we focus on recent developments in wireless sensor network technologies. We review the leading research projects, standards and technologies, and platforms. Moreover, we highlight a recent phenomenon in WSN research that is to explore synergy between sensor networks and other technologies and explain how this can help sensor networks achieve their full potential. This paper intends to help new researchers entering the domain of WSNs by providing a comprehensive survey on recent developments

No abstract

This paper presents an optimization of PSM to improve its energy conservation. According to PSM, time is divided into beacon intervals. At the beginning of each beacon interval, all stations must be awake during a specific period called ATIM window to be able to send and receive synchronization messages and announcements of buffered data frames. PSM specifies that a station having sent or received an announcement or having sent a beacon must remain awake during the entire beacon  interval. This may lead to wasting energy specially at light traffic loads where stations should conserve the most. We propose an enhancement called the Traffic Aware Power Saving Mode (TA-PSM) to solve this problem by allowing nodes to enter the doze state when they are no more involved in data delivery even if they have already sent a beacon, an ATIM or an ATIM-ACK. Our objective is to reduce the energy consumption without any throttling to throughput. Extensive simulations based on fixed and dynamic topologies showed that TA-PSM provides a much better energy conservation and a lower power consumption per delivered data frame.

No abstract

No abstract