Wireless sensor network is composed of a large number of stationary or mobile sensors for self-organization and jump in the way of wireless network, to cooperation to perceive, acquisition, processing and transmission network coverage within the geographical area perceived object information, and finally to send these information to the network owner. In general, the application of wireless sensor network can be classified according to the transmission range and transmission rate:
Home network transmission range is relatively small, but the support of high transmission rate. And its applications include security systems, lighting and air conditioning control and multi-purpose monitoring system at home.
Industrial control and factory automation part of the wireless sensor network, use the medium wireless transmission range of a few kilometers, and the transmission rate as low as.
Metropolitan area network and public construction of wireless sensor network applications, such as monitoring of bridge, railway and traffic lights, etc., all need a wide range of wireless network, usually more than tens of kilometers, with a low transmission rate. Wide-area sensor network also can be used in some special places, such as tracking livestock and induction of forest fires.
Wi-fi has high transmission rate, although is ubiquitous in the environment that occupy the home, but he is a relatively expensive and electricity transmission protocol. Sub - GHz and ZigBee protocol is more suitable for home automation wireless sensor network. For other industry based on 6 lowpan types of IP protocol stack of local area network way to deal with family, also more and more popular.
In the medium transmission range of industrial markets, we will see WirelessHART technology in the sensor network with a 2.4 GHz bandwidth can be used. WirelessHART extremely attractive for industrial control, because he has a self-healing mesh network architecture, can support the "five and nine" reliability standard.
A wide range of wireless sensor network has brought an interesting challenge, the challenge will be overcome by a breakthrough technology, this technology is called "TV white space - in some areas, analog TV spectrum is no longer used, it can be used as empty space for wireless transmission service. TV white space provides excellent transmission range and the transmission rate, rate of up to 16 MBPS, 10 km distance to, so much so that some people called it specifically designed for rural broadband super wi-fi (wi-fi on steroid). Because the TV white space is free frequencies, so the main service provider and the Internet of things technology entrepreneurs, are extremely attractive.
Each kind of wireless sensor network technology will be based on different transmission range, transmission rate and cost requirements, service to different applications. Rapid growth of the wireless sensor network will drive a large amount of data on the network flow, thus requiring greater bandwidth, and expand the cloud computing. Wireless sensor network is an indispensable part of our life. Various IP function of the sensor, is to use wireless technology, connected to each other in a meaningful way. Rapid rise of the convergence of wireless, sensor and signal processing technology, will make things come true.
