![]() Intel "My WiFi" and Windows 7 "virtual Wi-Fi" capabilities have made Wi-Fi PANs simpler and easier to set up and configure. Wi-Fi PANs are becoming commonplace (2010) as equipment designers start to integrate Wi-Fi into a variety of consumer electronic devices. For example, both Bluetooth radio and invisible infrared light provides a WPAN for interconnecting a headset to a laptop. Wireless personal area networks (WPANs) connect devices within a relatively small area, that is generally within a person's reach. In most cases, line-of-sight propagation is used, which limits the physical positioning of communicating devices. Free-space optical communication uses visible or invisible light for communications.IEEE 802.11 defines a common flavor of open-standards wireless radio-wave technology known as Wi-Fi. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited 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.Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area. The systems divide the region covered into multiple geographic areas. Cellular and PCS systems use several radio communications technologies.These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals. The satellites are stationed in space, typically in geosynchronous orbit 35,400 km (22,000 mi) above the equator. Communications satellites – Satellites communicate via microwave radio waves, which are not deflected by the Earth's atmosphere.Relay stations are spaced approximately 48 km (30 mi) apart. Terrestrial microwaves are in the low gigahertz range, which limits all communications to line-of-sight. ![]() Terrestrial microwave – Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes.Computers are very often connected to networks using wireless links, e.g.
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