PERSONA - IR3.4.2 - State of the Art of Wireless Sensor Networks Technologies

Recent advances in Micro-electromechanical Systems, microprocessors and low-power radio technologies have enabled the development of low-cost, low-power, multi-functional sensor devices, which can be used to remotely monitor (and possibly alter) physical phenomena in their surrounding environments. Due to their communication capabilities, sensors can interact to form a wireless network of sensors (WSN) [1]. The purpose of this interaction is to improve the monitor activity by combining data sampled by different sensors and to extend the coverage of the monitoring activity to wide areas. Each sensor is a micro-system which comprises a processor, one or more sensing units (transducers), a radio transceiver and an embedded battery. Some of the sensors may also act as sinks. In this case they are equipped with additional interfaces (such as USB ports, Ethernet, IEEE 802.11, etc..) to provide an interface between the sensor network and the rest of the world. When deployed in large quantities in a sensor field, the sensors can automatically organize themselves to form an ad hoc multihop network to communicate with each other and with one or more sink nodes. A remote user can inject commands into the sensor network via the sink nodes to assign data collection, processing and transfer tasks to the sensors, and it can later receive the data sensed by the network through the sink. Use of this technology encompasses different fields including medicine, agriculture, environment, military, inventory monitoring, intrusion detection, motion tracking, machine malfunction, toys and many others. The use of technologies related to wireless sensor networks have also been foreseen as a possible candidate to implement a layer for context information acquisition in PERSONA testbeds. In view of this application this report presents a survey of the available technologies for wireless sensor networks.