BGAN - Broadband Global Area Network
Objective of plain BGAN (without the R in front)
The Inmarsat Broadband Global Area Network (BGAN) system has been specified to support point to point telecommunication services on portable and semi fixed land mobile platforms with low to medium gain non-tracking antennas providing bit rates in the range 216 Kbps to 432 Kbps in downlink, and 72 Kbps to 432 Kbps in uplink, depending on type of terminal.
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The BGAN air interface was optimised for a land-portable
environment with directional antennas. To provide email and satellite
internet access direct to laptop sized portable terminals.
Inmarsat, who are running the plain BGAN project, have selected Xantic as one of its suppliers for the interconnection between the terrestrial network carriers and the mobile satellite terminals users for its voice interconnect services networks. BGAN service is planned for start in 2005 and will offer circuit and packet switched data services as well as voice services using the Inmarsat 4 series satellites. Bit rates offered to customer to be up to 432 kbit/s. A total of 3 identical INMARSAT 4 satellites are in construction. The first INMARSAT 4 satellite has been made by EADS Astrium and was shipped from Toulouse on 5 Feb 2005 on its way to the launch site at Cape Canaveral. The first the orbit location intended is 65 deg East geostationary orbit longitude. The satellites use ion beam engines for station keeping propulsion. Other characteristics: 45m long solar array 14kW BOL power. 5940kg BOL mass. Antenna diameter 10m, with 200 spot beams with variable power and bandwidth to each beam. The feed system would appear to be about 4.2m diameter. If you take the earth as a 17 deg diameter circle see how to fit in 200 spot beams, work out the diameter of each beam derive the tx and rx gain and G/T. then try some link budgets. Reference: EADS press release: 2 Feb 2005 |
See here for more details for plain BGAN: http://telecom.esa.int/telecom/www/object/index.cfm?fobjectid=11369
Try not to get confused, as I did, it is not the same thing as
Navigation link out of this BGAN page:Page started 12 October 2004, amended 13th Mar 2005 |