Summary of Sensor Network

　In recent years, due to the rapid development of wireless communication and electronic engineering, it has become possible to develop low-cost, low power, and multi-function sensor nodes. For that reason, a sensor network development is to be expected.
　A sensor network is a system that collects the information that has been detected by the sensor nodes throughout the network. A sensor node is MEMS (Micro Electro Mechanical Systems) or all sort of ultra small sensor which is equipped with data processing and wireless communication capabilities. With the use of wireless communication, sensor nodes can be placed anywhere flexibly, hence, the deployment cost is cheap. In addition, real time information gathering is also possible. Therefore, a variety of applications can be considered such as.

• Disaster relief
  Disaster area monitoring, evacuation routes search, etc
• Disaster prevention
  Buildings vibration measurement, measurement of the degree of obsolescence and durability, etc
• Commerce
  To monitor product quality
• Health
  Monitor and support patients with disability, health support from remote location.
• Military
  Surveillance, reconnaissance, and targeting system.

　Features of sensor networks are as followings:

• Power and resources (processing capablity, memory) may be limited.
• Deployed densely.
• Often malfunctioning.

　The applications of sensor networks require the technology of ad hoc wireless network. Therefore, we consider the use of MAC protocols and routing protocols that have been proposed for the use under ad hoc wireless network. In the research on ad hoc wireless network MAC protocols, the bandwidth efficiency and QoS have been studied intensively. In addition, many studies are also aimed at the reliability and load balancing of the ad hoc network routing protocols. Since the resources of the sensor node in a sensor network are very limited, there is a need to consider power consumption characteristics as described above. Therefore, the technology of traditional ad hoc wireless network cannot be used here. Hence, this research studies the protocol for sensor networks.