Wireless Sensor Networks : Technology, Protocols, and Applications

10
OPERATING SYSTEMS FOR
WIRELESS SENSOR NETWORKS
10.1 INTRODUCTION
WSNs can be used to monitor and/or control physical environment in a space
where it is difficult or impossible to do so manually. A WSN is generally
composed of a centralized station (sink) and tens, hundreds, or perhaps thousands
of tiny sensor nodes such as Mote [10.1] and Mica2 [10.1]. With the integration
of information sensing, computation, and wireless communication, these devices
can sense the physical phenomenon, (pre-)process the raw information, and share
the processed information with their neighboring nodes. The sensor nodes can
form a WSN either ad hoc or with, for example, a cluster-based architecture.
The sink node can query information and sometimes control the behavior of
the sensor nodes. The information is often unidirectional flow from the sensor
nodes to the sink. Since a WSN has a centralized sink and unidirectional
information flow, it acts as a centralized system. But the sensor nodes are distributed
and behave collaboratively. At the same time, a WSN is not only a database
system but also a resource-constrained network with most networking functions,
so they are often used to monitor events and collect data. Therefore, the environment
is event driven and data centric. Therefore, WSNs are a special type of
distributed network system that is similar to database, real-time, and embedded
systems.
Wireless Sensor Networks: Technology, Protocols, and Applications,
and Taieb Znati
Copyright # 2007 John Wiley & Sons, Inc.
by Kazem Sohraby, Daniel Minoli,
273