In recent years, wireless communications, integrated sensors and a microcomputer system (MEMS) technology for rapid development, and promote low-cost, power consumption and multi-functional wireless sensor mass production. Is a set of sensing functions and drive control, computing communication in one of the resource-constrained embedded devices, and wireless sensor networks (WSN) is a self-organizing wireless sensor network constituted by a large number, the aim of collaboration and awareness, acquisition and processing of network coverage area object information and pass the aim of collaboration and awareness, collection and processing of network coverage area of ??the object information, and the user needs to transfer.
2. with limited computing power and communications, and power supply;

WSN is considered to be the most important technology of the 21st century, it will have a profound impact on the future of human life. In a far-reaching influence students. In February 2003 the US Top profound impact on the future life of mankind yield on the ten emerging technologies, WSN first place. In the same year, the US "Business Week" in his discussion of the future of technology Zhuanban four new, WSN has also been included.

WSN composition and characteristics of the composition and characteristics of the composition and characteristics


Wireless sensors generally by the data acquisition unit, handle input power supply unit generally consists of wireless sensor data acquisition unit, handle input power supply and other components (see Figure 2). It is in the form of monitoring of physical signal determines the sensor type, such as temperature sensors, pressure and other monitoring sound and strong. Treatment is usually used several embedded sensor, monitoring the sound pressure and so strong. Processing usually use embedded data transmission unit mainly by low-power, short-range wireless communication module composition. Miniature operating system used by the data transfer unit mainly low-power, short-range wireless communication module composition. Miniaturization operating systems use embedded operating systems, such as Vximpacts, & mu; peremovedipoetisetytuce-II, & mu; intergpinkpcarveuclothraihumoristergaitx, keepyOS like.


Compared with the conventional sensor network has some unique characteristics, mainly:

1. dense nodes, and each is both a sensor and routing;


3. The unique underlying communication transmission medium;

4. The sensor node between no center, self-organizing, multi-hop communication;

5. You can simultaneously through multiple sources & mdhistriadn; & mdhistriadn; sink routing data transmission;
WSN by a large number of wireless sensors using self-organization structure, which is built by means of a node forms the measurement signal sensors in your environment, in order to detect all kinds of necessary data, and transmitted to where it is needed through the network.

6. Network has a strong robustness and good stretch.

3.WSN applications and overview
Wireless sensor networks have rapidly deployable, self-organized, subtle and strong and high fault tolerance characteristics Watson sensor point, so it is suitable for use in military applications. Using wireless sensor networks can realize the enemy troops and equipment monitoring, real-time monitoring of the battlefield, the target of the battlefield assessment, nuclear attacks and biochemical attack monitoring and search functions. Currently many institutions are subject to the international demand for the background battlefield deployment. For example, the US military carried out as C4KISR plan, Smfavoanuluswesschangeorganisationsorscheme, smart sensor network communication, unattended ground sensor group, the sensor networking systems, mesh sensor system CEC, and so on.

In the military field applications, the vision of the technology are: the use of aircraft or artillery launchers, a large number of low-cost sensor nodes according to a certain density fabric placed in the test area on the surrounding various parameters, such as temperature, humidity , information sound, magnetic, infrared, etc. for the collection, and then build the network by the sensor itself, through the gateway, the Internet, satellite and other channel, return information center.
This technique can be used to monitor the enemy military. The friendly staff, equipment and arms to install the sensor nodes for identification, keep control of your situation. Deploy a variety of sensors through enemy positions, so know ourselves, pre-emptive strike. In addition, the technology can be used to guide smart weapons, cooperate with radar, satellite, etc., using its own close to the characteristics of the environment, can avoid the blind spot, so that greatly enhance the effect of weapons.

Environmental Science

With the growing concern for the environment, the scope of environmental science involved more widely. Raw data collected by conventional means is a difficult task. Sensor Networks for field data acquisition randomness study provides a convenient, for example, track the impact of migration, environmental change migratory birds and insects on crops, monitoring component oceans, atmosphere and soil and so on. clewal systems have several kinds of sensors to monitor rainfall, river levels and soil moisture, and so predict the possibility of the outbreak of flash floods. Similarly, the sensor network for forest fires accurate and timely forecasts should also be helpful.

Agriculture


Wireless sensor networks have a remarkable technological advantage. It can be used to monitor crop irrigation, the soil air change, environmental conditions, as well as livestock and poultry to detect a large surface area. In precision agriculture, to monitor pests, pH and fertilizing the soil condition and other crops.


WSN system usually consists of environmental monitoring nodes, base stations, communications systems, Internet software and hardware system configuration and monitoring. As shown, according to need, it can be placed in the area to be measured and the composition of the different functions of the sensor network, long-term monitoring of large area micro climate change, including temperature, humidity, wind, atmosphere, rainfall, humidity collection relating to land nitrogen enrichment and soil PH value, so as to carry out scientific prediction, help farmers disaster, mitigation, scientific cultivation, to obtain higher crop yields.

Communication wireless sensor networks facilitate ease of deployment advantages, so that in the control of water-saving irrigation can be applied. Meanwhile, the node also has soil parameters, meteorological parameters measurement capability, then, GPS technology with the Internet, it can be more easily implement dynamic management of irrigation, crop water requirement to build information collection and precision control expert system, and thus achieving efficient , low-power, low-input, multi-purpose agricultural water-saving irrigation internet. In the conservatory, courtyard garden green, highway isolation belt, farm wells for irrigation district and other regions, the realization of agricultural and ecological water-saving technology, quantitative, standardized, modeling, integration, and promote the rapid and healthy development of water-saving industry.

Industrial areas and in other areas

Industry, coal, petrochemical, metallurgical industry for staff safety, flammable, explosive, toxic substances monitoring the cost has been high, the wireless sensor network to partially freed from the operator out of high-risk environment while increasing danger of precision and speed response.

In the construction sector, the use of wireless sensor networks, allowing large wireless sensor networks, can make buildings, bridges and other buildings can feel and be aware of their own situation, so that the mounting of the transmission Networks intelligent building move and told to manage their own feeling aware of their situation, making the installation of the transmission network intelligence is telling administration building move their state information, which allows management of regular maintenance work in accordance with the priority.
Home regard, smart home system design goal is to prepare linking various residential up, so they can run automatically, cooperate with each other to provide more convenience and comfort as possible for the occupants.

Medical, wireless sensor networks detect physiological data, the health of elderly hospital wireless sensor networks can play an excellent role in the detection of human physiological data, the health of the elderly and Drug Administration hospital telemedicine and so on. Placed on the patient body temperature acquisition, respiration, blood pressure measurement sensors, physicians can remotely understand the patient's situation. Using the network for a long time to collect human physiological data, which are useful in the process of development of new drugs.