Wireless network

A wireless network is a computer network that uses wireless data connections between network nodes.[1]

Wireless networking is a method by which homes, telecommunications networks and business installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations.[2] Wireless telecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure.[3]

Examples of wireless networks include cell phone networks, wireless local area networks (WLANs), wireless sensor networks, satellite communication networks, and terrestrial microwave networks.[4]

Contents [hide]
1 History
2 Wireless links
3 Types of wireless networks
3.1 Wireless PAN
3.2 Wireless LAN
3.3 Wireless ad hoc network
3.4 Wireless MAN
3.5 Wireless WAN
3.6 Cellular network
3.7 Global area network
3.8 Space network
4 Different uses
5 Properties
5.1 General
5.2 Performance
5.3 Space
5.4 Home
5.5 Wireless Network Elements
5.6 Difficulties
5.6.1 Interferences
5.6.2 Absorption and reflection
5.6.3 Multipath fading
5.6.4 Hidden node problem
5.6.5 Shared resource problem
5.7 Capacity
5.7.1 Channel
5.7.2 Network
6 Safety
7 See also
8 References
9 Further reading
10 External links
History[edit]
The first professional wireless network was developed under the brand ALOHAnet in 1969 at the University of Hawaii and became operational in June 1971. The first commercial wireless network was the WaveLAN product family, developed by NCR in 1986.

1991 2G cell phone network
June 1997 802.11 "WiFi" protocol first release
1999 803.11 VoIP integration
Wireless links[edit]

Computers are very often connected to networks using wireless links, e.g. WLANs
Terrestrial microwave – Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes. Terrestrial microwaves are in the low gigahertz range, which limits all communications to line-of-sight. Relay stations are spaced approximately 48 km (30 mi) apart.
Communications satellites – Satellites communicate via microwave radio waves, which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically in geosynchronous orbit 35,400 km (22,000 mi) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
Cellular and PCS systems use several radio communications technologies. The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
Radio and spread spectrum technologies – Wireless local area networks use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. IEEE 802.11 defines a common flavor of open-standards wireless radio-wave technology known as .
Free-space optical communication uses visible or invisible light for communications. In most cases, line-of-sight propagation is used, which limits the physical positioning of communicating devices.