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I-4 Satellite
Three I-4 satellites make up the INMARSAT BGAN, FleetBroadband and SwiftBroadband communications network. They provide Internet and telephony connections anywhere on Earth, except in polar regions. Data services Two general types of data service are currently provided: #Streaming #Background Streaming Streaming is a guaranteed delivery style of service. A terminal requests a context of X bandwidth (currently 8, 16, 32, 64, 128, or 256 kbit/s) and, if the current spot beam has enough resources available, it is allocated a guaranteed chunk of the available bandwidth. So if a request is made 8k streaming context, the terminal will, at all times, be able to send data at 8 kbit/s. As a result, streaming is billed based on time usage. Background Background is a best-effort style of service. Each spot beam provides a certain amount of usable bandwidth. The bandwidth which is not in use by Streaming contexts is used for Background contexts. This means that the actual a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadband Global Area Network
The Broadband Global Area Network (BGAN) is a global satellite network with telephony owned by Inmarsat 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 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. Typical latency is 0.6–1.5 seconds round trip for the Backg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FleetBroadband
FleetBroadband is maritime satellite internet, telephony, SMS texting, and ISDN network for ocean-going vessels using portable domed terminal antennas. These antennas, and corresponding indoor controllers, are used to connect phones and laptop computers from sailing vessels with the rest of the world. All FleetBroadband antennas require line-of-sight to one of three geosynchronous orbit satellites thus allowing the terminal to be used anywhere, including on land. Details The FleetBroadband network was developed by Inmarsat and is composed of three geosynchronous orbiting satellites called I-4s that allow contiguous global coverage, except for the poles. FleetBroadband systems installed on vessels may travel from ocean to ocean without human interaction. Line-of-sight to the ''I-4'' satellites is required for connectivity, which can be achieved even in rough rolling seas. Since the FleetBroadband network uses the L band, rain fade is much less of an issue than VSAT or C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure In general, every telecommunications network conce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and Web application, applications of the World Wide Web (WWW), email, electronic mail, internet telephony, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone. Telephony is commonly referred to as the construction or operation of telephones and telephonic systems and as a system of telecommunications in which telephonic equipment is employed in the transmission of speech or other sound between points, with or without the use of wires. The term is also used frequently to refer to computer hardware, software, and computer network systems, that perform functions traditionally performed by telephone equipment. In this context the technology is specifically referred to as Internet telephony, or voice over Internet Protocol (VoIP). Overview The first telephones were connected directly in pairs. Each user had a separate telephone wired ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Regions Of Earth
The polar regions, also called the frigid zones or polar zones, of Earth are the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floating sea ice covering much of the Arctic Ocean in the north, and by the Antarctic ice sheet on the continent of Antarctica and the Southern Ocean in the south. Definitions The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or just the region north of 60° north latitude, or the region from the North Pole north to the timberline. The Antarctic is usually defined simply as south of 60° south latitude, or the continent of Antarctica. The 1959 Antarctic Treaty uses the former definition. The two polar regions are distinguished from the other two climatic and biometric belts of Earth, a tropics belt near the equator, and two middle latitude regions located between t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (computing)
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth. This definition of ''bandwidth'' is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which ''bandwidth'' is used to refer to analog signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel. Network capacity The term ''bandwidth'' sometimes defines the net bit rate 'peak bit rate', 'information rate,' or physical layer 'useful bit rate', channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwidth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data-rate Units
In telecommunications, data-transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of bits per second (bit/s) and bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s). Standards for unit symbols and prefixes Unit symbol The ISQ symbols for the bit and byte are ''bit'' and ''B'', respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit octet. The abbreviation bps is often used to mean bit/s, so that when a ''1 Mbps'' connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s ( megabyte per second), or about 0.1192 MiB/s ( mebibyte per second). The Ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Beam
A spot beam, in telecommunications parlance, is a satellite signal that is specially concentrated in power (i.e. sent by a high-gain antenna) so that it will cover only a limited geographic area on Earth. Spot beams are used so that only Earth stations in a particular intended reception area can properly receive the satellite signal.{{cite book, first=Michael Olorunfunmi, last= Kolawole, title=Satellite Communication Engineering, Second Edition, publisher =CRC Press , year=2013 , page=43 , isbn=9781138075351 One notable example of the use of spot beams is on direct broadcast satellite systems such as DirecTV and Dish Network that deliver local broadcast television via satellite only to viewers in the part of North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ... from which t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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