Although the development originally motivated
by military applications such as battlefield surveillance, they are now used in many civilian application areas, including environment and habitat monitoring, healthcare applications, home automation, traffic control, etc.
All sensors in WSN, normally constitute a wireless ad-hoc network and as such each sensor supports a multi-hop routing algorithm.
Sensor nodes may be imagined as small
micro computers, extremely basic in terms of their interfaces and their components. They usually consist of a processing unit with limited computational power and limited memory, sensors (including specific conditioning
circuitry), a communication device (usually radio
transceivers or alternatively optical), and a power source usually in the form of a battery.
The base stations are the gate ways and they are one or more distinguished components of the WSN with much more computational,
energy and communication resources. The gateway provides connectivity between sensor nodes and the end user.
International Journal of Computer Information Systems and Industrial Management Applications (IJCISIM)
http://www.mirlabs.org/ijcisim