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Broadband Global Area Network
The Broadband Global Area Network (BGAN) is a global satellite internet network with telephony using portable terminals. The terminals are normally used to connect a laptop computer to broadband Internet in remote locations, although as long as line-of-sight to the satellite exists, the terminal can be used anywhere. The value of BGAN terminals is that unlike other satellite Internet services which require bulky and heavy satellite dishes to connect, a BGAN terminal is about the size of a laptop and thus can be carried easily. The network is provided by Inmarsat and uses three geostationary satellites called I-4 to provide almost global coverage.
== Details ==
Downlink speeds of high-end BGAN terminals are up to 492 kbit/s and upload speeds are also up to 492 kbit/s - Best Effort as BGAN Background IP (BIP) is a contended (shared) channel. As with all geosynchronous satellite connections, latency is an issue. Common latency is 1–1.5 seconds round trip for the Background IP service. It is slightly better for the Streaming services at 800 ms – 1 second. This latency is mainly due to the great distance that has to be traveled before a packet can reach the Internet, but is slightly exacerbated by the back-end technology as normal latency over a Very small aperture terminal (VSAT) system is roughly 550ms. BGAN users frequently use PEP software or other TCP packet accelerators to improve performance.
BGAN terminals are made by multiple manufacturers. They all have similar capabilities. The main two that apply to basic BGAN usage are the Standard Background IP (Internet) and Telephone Voice. Data costs from the many ISPs that offer BGAN service averages about per Background Megabyte. Voice calling is on average US$1 per min and varies slightly based on the destination of the call (Land lines, Cell phones, other Satellite phones which are the most expensive).
BGAN is currently the fastest global data link available via a portable terminal. It can be easily set up by anyone, and has excellent voice calling quality. It works on the L band, avoiding rain fade and other issues of traditional larger satellite systems.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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