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Energy efficiency is still a challenging issue in wireless sensor networks (WSNs). Balancing nodes' activities and duty cycling are efficient ways that could enhance WSN's performances. In this paper the authors introduce a new asynchronous power saving mechanism that provides an adaptive duty cycle and a minimum overhead to achieve load balancing and energy saving. This mechanism relies on two basic functions: an asynchronous duty cycling for activity balancing and a lightweight geographic routing. Extensive simulations showed the effectiveness of the proposed approach in terms of residual energy, energy consumption balancing and packet delivery ratio.

International audience ; Unmanned Aerial Systems (UAS) are attracting increasing attention since their introduction in many civil fields and after being solely dedicated to military applications. An UAS is composed of Unmanned Aerial Vehicles (UAV), ground stations and data links. UAVs may form a Flying Ad Hoc Network (FANET), they can communicate with each other or with the ground infrastructure to deliver and exchange information. UAV network topology has a direct impact on the communication scheme, which can be centralized or decentralized. Trajectory and speed variation of UAVs are represented by mobility models. UAVs can move individually or within a group. To meet the requirements of an UAS, which are ensuring high coverage and high speed, new wireless data links are being developed while taking into account the frequency spectrum availability. In this paper we briefly present the general characteristics of UAS, UAV and FANET. We present UAV different current applications, and then we discuss features of their topologies. Next we investigate the different UAV mobility models applied to individuals and to groups. Finally, we present a review of the most important communication protocols proposed for UAS.

International audience ; Unmanned Aerial Systems (UAS) are attracting increasing attention since their introduction in many civil fields and after being solely dedicated to military applications. An UAS is composed of Unmanned Aerial Vehicles (UAV), ground stations and data links. UAVs may form a Flying Ad Hoc Network (FANET), they can communicate with each other or with the ground infrastructure to deliver and exchange information. UAV network topology has a direct impact on the communication scheme, which can be centralized or decentralized. Trajectory and speed variation of UAVs are represented by mobility models. UAVs can move individually or within a group. To meet the requirements of an UAS, which are ensuring high coverage and high speed, new wireless data links are being developed while taking into account the frequency spectrum availability. In this paper we briefly present the general characteristics of UAS, UAV and FANET. We present UAV different current applications, and then we discuss features of their topologies. Next we investigate the different UAV mobility models applied to individuals and to groups. Finally, we present a review of the most important communication protocols proposed for UAS.

International audience ; The tremendous and rapid development in sensors technology allowed their application in various fields requiring monitoring, such as, transportations, rare species surveillance, agriculture, military activities, medical field, etc. Due to their intrinsic constraints and limitations, several dedicated MAC protocols have been designed for wireless sensor networks and whose main objectives are bandwidth optimization while keeping very low energy consumption. One of the newest proposals is ANT which is emerging as a widely used MAC protocol for wellness and sports sensor devices. In this paper, we give a comprehensive overview of ANT/ANT+ and a comparison between ANT and two established standards: Bluetooth Low Energy (BLE) and 802.15.4/4a. We detail also some practical experiments we conducted to evaluate some characteristics of ANT.

The tremendous and rapid development in sensors technology allowed their application in various fields requiring monitoring, such as, transportations, rare species surveillance, agriculture, military activities, medical field, etc. Due to their intrinsic constraints and limitations, several dedicated MAC protocols have been designed for wireless sensor networks and whose main objectives are bandwidth optimization while keeping very low energy consumption. One of the newest proposals is ANT which is emerging as a widely used MAC protocol for wellness and sports sensor devices. In this paper, we give a comprehensive overview of ANT/ANT+ and a comparison between ANT and two established standards: Bluetooth Low Energy (BLE) and 802.15.4/4a. We detail also some practical experiments we conducted to evaluate some characteristics of ANT.

International audience ; The tremendous and rapid development in sensors technology allowed their application in various fields requiring monitoring, such as, transportations, rare species surveillance, agriculture, military activities, medical field, etc. Due to their intrinsic constraints and limitations, several dedicated MAC protocols have been designed for wireless sensor networks and whose main objectives are bandwidth optimization while keeping very low energy consumption. One of the newest proposals is ANT which is emerging as a widely used MAC protocol for wellness and sports sensor devices. In this paper, we give a comprehensive overview of ANT/ANT+ and a comparison between ANT and two established standards: Bluetooth Low Energy (BLE) and 802.15.4/4a. We detail also some practical experiments we conducted to evaluate some characteristics of ANT.