Satellite Internet access
Encyclopedia
Satellite Internet access is Internet access
provided through satellite
s. The service can be provided to users world-wide through low Earth orbit
(LEO) satellites. Geostationary
satellites can offer higher data speeds, but their signals can not reach some polar region
s of the world. Different types of satellite systems have a wide range of different features and technical limitations, which can greatly affect their usefulness and performance in specific applications.
Latency is the delay between requesting data and the receipt of a response, or in the case of one-way communication, between the actual moment of a signal's broadcast and the time it is received at its destination. Compared to ground-based communication, all geostationary satellite communications experience high latency due to the signal having to travel 35786 km (22,236 mi)
to a satellite in geostationary orbit
and back to Earth again. Even at the speed of light
(about 300,000 km/s or 186,000 miles per second), this delay can be significant. If all other signaling delays could be eliminated, it still takes a radio signal about 250 milliseconds (ms), or about a quarter of a second, to travel to the satellite and back to the ground. For an internet packet, that delay is doubled before a reply is received. That is the theoretical minimum. Factoring in other normal delays from network sources gives a typical one-way connection latency of 500–700 ms from the user to the ISP, or about 1,000–1,400 ms latency for the total round-trip time (RTT) back to the user. This is much more than most dial-up users experience at typically 150–200 ms total latency.
The internet latency mentioned above makes satellite Internet service problematic for applications requiring real-time user input, such as online game
s or remote surgery
. This delay can also be irritating and debilitating with interactive applications, such as VoIP, videoconferencing
, or other person-to-person communication. It will cause most general market applications (such as Skype
) to behave unpredictably and fail, as these are not designed for the difficult compensation required for the high-latency connections. Some people find that the delays inserted into conversation over a high-latency connection make communication difficult and may lead to a feeling of mistrust or hesitation, even when both sides are aware of the lag.
Latency also impacts the initiation of secure Internet connections such as SSL which require the exchange of numerous pieces of data between web server and web client. Although these pieces of data are small, the multiple round trips involved in the handshake produce long delays compared to other forms of Internet connectivity, as documented by Stephen T. Cobb
in a 2011 report published by the Rural Mobile and Broadband Alliance. This annoyance extends to entering and editing data using some Software as a Service or SaaS
applications as well as other forms of online work.
The functionality of live interactive access to a distant computer can be impaired by high latency. While these problems may be tolerable for basic email access and web browsing, the use of character-by-character command shell or virtual private network
s (which typically involve several round trips using layered protocols) is almost impossible through geostationary connections. For this reason, the two largest satellite Internet providers in North America, HughesNet and WildBlue, do not recommend their services be used for VPNs. The HughesNet FAQ states: "Virtual Private Networks do not work well over satellite…HughesNet Technical Support does not provide help with…problems associated with VPN clients."
features that shorten the round trip time (RTT) per packet by splitting the feedback loop between the sender and the receiver. Such acceleration features are usually present in recent technology developments embedded in new satellite Internet services.
Medium Earth orbit (MEO) and low Earth orbit (LEO) satellites do not have such great delays. The current LEO constellations of Globalstar
and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude. The proposed O3b Networks
MEO constellation scheduled for deployment in 2010 would orbit at 8,062 km, with RTT latency of approximately 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s (Gigabits per second). The planned COMMStellation™
, scheduled for launch in 2015, will orbit the earth at 1,000 km with a latency of approximately 7 ms. This polar orbiting constellation of 78 microsatellites will provide global backhaul with throughput in excess of 1.2 Gbit/s.
Satellite communications are affected by moisture and various forms of precipitation (such as rain or snow) in the signal path between end users or ground stations and the satellite being utilized. This interference with the signal is known as rain fade. The effects are less pronounced on the lower frequency 'L' and 'C' bands, but can become quite severe on the higher frequency 'Ku' and 'Ka' band. For satellite Internet services in tropical areas with heavy rain, use of the C band (4/6 GHz) with a circular polarisation satellite is popular. Satellite communications on the Ka band (19/29 GHz) can use special techniques such as large rain margins, adaptive uplink power control and reduced bit rates during precipitation.
Rain margins are the extra communication link requirements needed to account for signal degradations due to moisture and precipitation, and are of acute importance on all systems operating at frequencies over 10 GHz.
The amount of time during which service is lost can be reduced by increasing the size of the satellite communication dish
so as to gather more of the satellite signal on the downlink and also to provide a stronger signal on the uplink.
Modern consumer-grade dish antennas tend to be fairly small, which reduces the rain margin or increases the required satellite downlink power and cost.
Large commercial dishes of 3.7 m to 13 m diameter are used to achieve large rain margins and also to reduce the cost per bit by requiring far less power from the satellite.
Modern download DVB-S2
carriers, with RCS feedback, are intended to allow the modulation method to be dynamically altered, in response to rain problems at a receive site. This allows the bit rates to be increased substantially during normal clear sky conditions, thus reducing overall costs per bit.
Typically a completely clear line of sight between the dish and the satellite is required for the system to work. In addition to the signal being susceptible to absorption and scattering by moisture, the signal is similarly impacted by the presence of trees and other vegetation in the path of the signal. As the radio frequency decreases, to below 900 MHz, penetration through vegetation increases, but most satellite communications operate above 2 GHz making them sensitive to even minor obstructions such as tree foliage. A dish installation in the winter must factor in plant foliage growth that will appear in the spring and summer.
(named for physicist Augustin-Jean Fresnel
), and limits the usefulness of satellite dish antennas in locations where there is extremely limited open sky for signal reception. The signal path through space must be clear not only for direct line of sight, but also for the expanding Fresnel zone, which may be several meters larger in diameter than the ground-based satellite dish.
Two-way satellite Internet service involves both sending and receiving data from the remote VSAT site via satellite to a hub teleport, which then relays data via the terrestrial Internet. The satellite dish at each location must be precisely pointed to avoid interference with other satellites. The two way satellite market can be divided into those systems that support professional applications, such as banking, retail etc. and those built to provide home or small business users with access. The key difference between these systems can be seen in their ability to support advanced quality of service controls. While systems for professionals such as those from iDirect will allow the operator to define and meet strict service level agreements - those used for consumer access provide a 'best effort' service level.
Some providers oblige the customer to pay for a member of the provider's staff to install the system and correctly align the dish—although the European ASTRA2Connect
system encourages user-installation and provides detailed instructions for this. Many customers in the Middle East and Africa are also encouraged to do self installs. At each VSAT site the uplink frequency, bit rate and power must be accurately set, under control of the service provider hub.
There are several types of two way satellite Internet services, including time division multiple access
(TDMA) and single channel per carrier
(SCPC). Two-way systems can be simple VSAT terminals with a 60–100 cm dish and output power of only a few watts intended for consumers and small business or larger systems which provide more bandwidth. Such systems are frequently marketed as "satellite broadband" and can cost two to three times as much per month as land-based systems such as ADSL. The modems
required for this service are often proprietary, but some are compatible with several different providers. They are also expensive, costing in the range of US$
600 to $2000.
The two-way "iLNB" used on the ASTRA2Connect
terminal dish has a transmitter and single-polarity receive LNB, both operating in the Ku band
. Pricing for Astra2Connect modems range from €299 to €350. These types of system are generally unsuitable for use on moving vehicles, although some dishes may be fitted to an automatic pan and tilt mechanism to continuously re-align the dish—but these are more expensive. The technology for ASTRA2Connect was delivered by a Belgian company called Newtec.
Home users tend to use shared satellite capacity to reduce the cost, while still allowing high peak bit rates when congestion is absent. There are usually restrictive time-based bandwidth allowances so that each user gets their fair share, according to their payment. When a user exceeds their allowance, the company may slow down their access, deprioritise their traffic or charge for the excess bandwidth used. For consumer satellite internet, the allowance can typically range from 200 MB
per day to 17,000 MB per month. A shared download carrier may have a bit rate of 1 to 40 Mbit/s and be shared by up to 100 to 4,000 end users.
The uplink direction for shared user customers is normally time division multiple access
(TDMA), which involves transmitting occasional short packet bursts in between other users (similar to how a cellular phone shares a cell tower)
Each remote location may also be equipped with a telephone modem; the connections for this are as with a conventional dial-up ISP. Two-way satellite systems may sometimes use the modem channel in both directions for data where latency is more important than bandwidth, reserving the satellite channel for download data where bandwidth is more important than latency, such as for file transfer
s.
In 2006, the European Commission
sponsored the UNIC
project which aims at developing an end-to-end scientific test bed for the distribution of new broadband interactive TV-centric services delivered over low-cost two-way satellite to actual end-users in the home. The UNIC architecture employs DVB-S2
standard for downlink and DVB-RCS
standard for uplink.
Normal VSAT dishes (1.2–2.4 m diameter) are widely used for VoIP phone services. A voice call is sent by means of packets via the satellite and internet. Using coding and compression techniques the bit rate needed per call is only 10.8 kbit/s each way.
or Universal serial bus
. Some also have an integrated Bluetooth
transceiver and double as a satellite phone. The modems also tend to have their own batteries so they can be connected to a laptop
without draining its battery. The most common such system is INMARSAT
's BGAN
—these terminals are about the size of a briefcase
and have near-symmetric connection speeds of around 350–500 kbit/s. Smaller modems exist like those offered by Thuraya
but only connect at 444 kbit/s in a limited coverage area.
Using such a modem is extremely expensive—bandwidth costs between $5 and $7 per megabyte
. The modems themselves are also expensive, usually costing between $1,000 and $5,000.
s have been able to connect to the internet. Bandwidth varies from about 2400 bit/s for Iridium network satellites and ACeS
based phones to 15 kbit/s upstream
and 60 kbit/s downstream for Thuraya
handsets. Globalstar also provides internet access at 9600 bit/s—like Iridium and ACeS a dial-up connection is required and is billed per minute, however both Globalstar
and Iridium are planning to launch new satellites offering always-on data services at higher rates. With Thuraya phones the 9,600 bit/s dial-up connection is also possible, the 60 kbit/s service is always-on and the user is billed for data transferred (about $5 per megabyte
). The phones can be connected to a laptop or other computer using a USB or RS-232
interface. Due to the low bandwidths involved it is extremely slow to browse the web with such a connection, but useful for sending email, Secure Shell
data and using other low-bandwidth protocols. Since satellite phones tend to have omnidirectional antenna
s no alignment is required as long as there is a line of sight between the phone and the satellite.
) data traveling through a telephone modem
, but downstream data sent via satellite at a higher rate. In the U.S., an FCC license is required for the uplink station only; no license is required for the users.
Another type of 1-way satellite Internet system uses General Packet Radio Service
(GPRS) for the back-channel. Using standard GPRS or Enhanced Data Rates for GSM Evolution
(EDGE), if the upload volume is very low and since this service is not per-time charged, but charged by volume uploaded, costs are reduced for higher effective rates. GPRS as return improves mobility when the service is provided by a satellite that transmits in the field of 50–53 dBW. Using a 33 cm wide satellite dish, a notebook and a normal GPRS equipped GSM phone
, users can get mobile satellite broadband.
At the remote location (Earth station) the setup consists of:
Often, non-standard IP stacks
are used to address the latency
and asymmetry problems of the satellite connection. Data sent over the satellite link is generally also encrypted, as otherwise it would be accessible to anyone with a satellite receiver.
Many IP-over-satellite implementations use paired proxy servers at both endpoints so that certain communications between clients and servers [ftp://ftp.rfc-editor.org/in-notes/rfc2488.txt] do not need to accept the latency inherent in a satellite connection. For similar reasons, there exist special Virtual private network
(VPN) implementations designed for use over satellite links because standard VPN software cannot handle the long packet travel times.
Upload speeds are limited by the user's dial-up modem, and latency is high, as it is for any satellite based Internet (minimum of 240 ms one-way, resulting in a minimum round-trip time of almost 500 ms). Download speeds can be very fast compared to dial-up.
or(and) Virtual private network
servers at the earth station
(teleport), which is configured to route all outbound traffic to the QoS server, which makes sure no user exceeds their allotted bandwidth or monthly traffic limits. Traffic is then sent to the encapsulator, which puts the IP packets inside of DVB packets. The DVB packets are then sent to the DVB modem and then to the transmitter (BUC)
(IP) multicast
-based data, audio and video distribution. In the U.S.
, a Federal Communications Commission
(FCC) license is required only for the uplink station and no license is required for users. Note that most Internet protocols will not work correctly over one-way access, since they require a return channel. However, Internet content such as web page
s can still be distributed over a one-way system by "pushing" them out to local storage at end user sites, though full interactivity is not possible. This is much like TV or radio content which offers little user interface.
for squawk box applications. An Internet connection is not required, but many applications include a File Transfer Protocol
(FTP) server to queue data for broadcast.
, HTTP
pre-fetching and DNS
caching.
for Firefox is exceptionally beneficial for satellite Internet, as most Internet advertising websites use cache
busting in order to render the browser and ISP's cache useless, by displaying advertisements (for the purpose of maximizing the number of ad views seen by the affiliate marketing
company's server).
On December 26, 2010, Eutelsat's KA-SAT
was successfully launched by an ILS Proton Breeze M vehicle at the Baïkonour Cosmodrome Kazakhstan
. The last satellite was due in service in mid 2011. It covers the European continent with 80 spot beams—focused signals that cover an area a few hundred kilometers across Europe and the Mediterranean. Spot beams allow for frequencies to be effectively reused in multiple regions without interference. The result is increased capacity. Each of the spot beams will have an overall capacity of 900 Mbit/s and the entire satellite will have a capacity of 70 Gbit/s.
Internet access
Many technologies and service plans for Internet access allow customers to connect to the Internet.Consumer use first became popular through dial-up connections in the 20th century....
provided through satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s. The service can be provided to users world-wide through low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
(LEO) satellites. Geostationary
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
satellites can offer higher data speeds, but their signals can not reach some polar region
Polar region
Earth's polar regions are the areas of the globe surrounding the poles also known as frigid zones. The North Pole and South Pole being the centers, these regions are dominated by the polar ice caps, resting respectively on the Arctic Ocean and the continent of Antarctica...
s of the world. Different types of satellite systems have a wide range of different features and technical limitations, which can greatly affect their usefulness and performance in specific applications.
Signal latency
1 E7 m
To help compare different orders of magnitude, this page lists lengths starting at 107 metres .Distances shorter than 107 metres- Conversions :10 megametres is* 6,215 miles....
to a satellite in geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
and back to Earth again. Even at the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
(about 300,000 km/s or 186,000 miles per second), this delay can be significant. If all other signaling delays could be eliminated, it still takes a radio signal about 250 milliseconds (ms), or about a quarter of a second, to travel to the satellite and back to the ground. For an internet packet, that delay is doubled before a reply is received. That is the theoretical minimum. Factoring in other normal delays from network sources gives a typical one-way connection latency of 500–700 ms from the user to the ISP, or about 1,000–1,400 ms latency for the total round-trip time (RTT) back to the user. This is much more than most dial-up users experience at typically 150–200 ms total latency.
Geostationary unsuitable for low-latency applications
A geostationary orbit (or geostationary Earth orbit/GEO) is a geosynchronous orbit directly above the Earth's equator (0° latitude), with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers. Communications satellites and weather satellites are often given geostationary orbits, so that the satellite antennas that communicate with them do not have to move to track them, but can be pointed permanently at the position in the sky where they stay. Due to the constant 0° latitude and circularity of geostationary orbits, satellites in GEO differ in location by longitude only.The internet latency mentioned above makes satellite Internet service problematic for applications requiring real-time user input, such as online game
Online game
An online game is a game played over some form of computer network. This almost always means the Internet or equivalent technology, but games have always used whatever technology was current: modems before the Internet, and hard wired terminals before modems...
s or remote surgery
Remote surgery
Remote surgery is the ability for a doctor to perform surgery on a patient even though they are not physically in the same location. It is a form of telepresence. Remote surgery combines elements of robotics, cutting edge communication technology such as high-speed data connections and elements...
. This delay can also be irritating and debilitating with interactive applications, such as VoIP, videoconferencing
Videoconferencing
Videoconferencing is the conduct of a videoconference by a set of telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously...
, or other person-to-person communication. It will cause most general market applications (such as Skype
Skype
Skype is a software application that allows users to make voice and video calls and chat over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system...
) to behave unpredictably and fail, as these are not designed for the difficult compensation required for the high-latency connections. Some people find that the delays inserted into conversation over a high-latency connection make communication difficult and may lead to a feeling of mistrust or hesitation, even when both sides are aware of the lag.
Latency also impacts the initiation of secure Internet connections such as SSL which require the exchange of numerous pieces of data between web server and web client. Although these pieces of data are small, the multiple round trips involved in the handshake produce long delays compared to other forms of Internet connectivity, as documented by Stephen T. Cobb
Stephen T. Cobb
Stephen Cobb is an English American author, entrepreneur, film producer, and subject matter expert in the field of computer security and data privacy. He is currently Security Evangelist for ESET, an international company on the forefront of Internet security. Cobb's books are published under the...
in a 2011 report published by the Rural Mobile and Broadband Alliance. This annoyance extends to entering and editing data using some Software as a Service or SaaS
Saas
SAAS is an abbreviation for* Social Accountability Accreditation Services* Software as a service * Student Awards Agency for Scotland* Seattle Academy of Arts and Sciences* South Australian Ambulance Service...
applications as well as other forms of online work.
The functionality of live interactive access to a distant computer can be impaired by high latency. While these problems may be tolerable for basic email access and web browsing, the use of character-by-character command shell or virtual private network
Virtual private network
A virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
s (which typically involve several round trips using layered protocols) is almost impossible through geostationary connections. For this reason, the two largest satellite Internet providers in North America, HughesNet and WildBlue, do not recommend their services be used for VPNs. The HughesNet FAQ states: "Virtual Private Networks do not work well over satellite…HughesNet Technical Support does not provide help with…problems associated with VPN clients."
Acceptable latencies, but lower speeds, of lower orbits
For geostationary satellites, there is no way to eliminate latency, but the problem can be somewhat mitigated in Internet communications with TCP accelerationTCP Acceleration
TCP acceleration is the name of a series of techniques for achieving better throughput on an Internet connection than standard TCP achieves, without modifying the end applications...
features that shorten the round trip time (RTT) per packet by splitting the feedback loop between the sender and the receiver. Such acceleration features are usually present in recent technology developments embedded in new satellite Internet services.
Medium Earth orbit (MEO) and low Earth orbit (LEO) satellites do not have such great delays. The current LEO constellations of Globalstar
Globalstar
Globalstar is a low Earth orbit satellite constellation for satellite phone and low-speed data communications, somewhat similar to the Iridium satellite constellation and Orbcomm satellite systems.-History:...
and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude. The proposed O3b Networks
O3b Networks, Ltd.
O3b Networks, Ltd. is a next generation network service provider building the world’s first Medium Earth Orbit satellite constellation. The network will combine the ubiquitous reach of satellite with the speed of fiber to deliver satellite Internet services and mobile backhaul services to emerging...
MEO constellation scheduled for deployment in 2010 would orbit at 8,062 km, with RTT latency of approximately 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s (Gigabits per second). The planned COMMStellation™
COMMStellation
COMMStellation is a network of 78 microsatellites with an additional six microsatellites to be used as spares. The constellation will be situated in a low Earth orbit and the satellites will travel on 6 orbital planes separated by 30 degrees of longitude. Each plane will contain 14 satellites which...
, scheduled for launch in 2015, will orbit the earth at 1,000 km with a latency of approximately 7 ms. This polar orbiting constellation of 78 microsatellites will provide global backhaul with throughput in excess of 1.2 Gbit/s.
Ultralight atmospheric aircraft as satellites
A proposed alternative to geostationary relay satellites is a special-purpose solar-powered ultralight aircraft, which would fly along a circular path above a fixed ground location, operating under autonomous computer control at a height of approximately 20,000 meters. Onboard batteries would be charged during daylight hours by solar panels covering the wings, and would provide power to the plane during night. Ground-based satellite dishes would relay signals to and from the aircraft, resulting in a greatly reduced round-trip signal latency of only 0.25 milliseconds. The planes could potentially run for long periods without refueling. Several such schemes involving various types of aircraft have been proposed in the past.Rain fade
Rain margins are the extra communication link requirements needed to account for signal degradations due to moisture and precipitation, and are of acute importance on all systems operating at frequencies over 10 GHz.
The amount of time during which service is lost can be reduced by increasing the size of the satellite communication dish
Satellite dish
A satellite dish is a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television.-Principle of operation:...
so as to gather more of the satellite signal on the downlink and also to provide a stronger signal on the uplink.
Modern consumer-grade dish antennas tend to be fairly small, which reduces the rain margin or increases the required satellite downlink power and cost.
Large commercial dishes of 3.7 m to 13 m diameter are used to achieve large rain margins and also to reduce the cost per bit by requiring far less power from the satellite.
Modern download DVB-S2
DVB-S2
Digital Video Broadcasting - Satellite - Second Generation is a digital television broadcast standard that has been designed as a successor for the popular DVB-S system. It was developed in 2003 by the , an international industry consortium, and ratified by ETSI in March 2005...
carriers, with RCS feedback, are intended to allow the modulation method to be dynamically altered, in response to rain problems at a receive site. This allows the bit rates to be increased substantially during normal clear sky conditions, thus reducing overall costs per bit.
Line of sight
Fresnel zone
The radio signal width between any two antennas is not perfectly straight and uniform, as if it were a beam of light. Instead as the signal propagates away from the transmitting antenna, it widens towards the centerpoint between the two antennas and then narrows again as it approaches the receiving antenna. This is known as the Fresnel zoneFresnel zone
In optics and radio communications , a Fresnel zone , named for physicist Augustin-Jean Fresnel, is one of a number of concentric ellipsoids which define volumes in the radiation pattern of a circular aperture...
(named for physicist Augustin-Jean Fresnel
Augustin-Jean Fresnel
Augustin-Jean Fresnel , was a French engineer who contributed significantly to the establishment of the theory of wave optics. Fresnel studied the behaviour of light both theoretically and experimentally....
), and limits the usefulness of satellite dish antennas in locations where there is extremely limited open sky for signal reception. The signal path through space must be clear not only for direct line of sight, but also for the expanding Fresnel zone, which may be several meters larger in diameter than the ground-based satellite dish.
Two-way satellite-only communication
Some providers oblige the customer to pay for a member of the provider's staff to install the system and correctly align the dish—although the European ASTRA2Connect
ASTRA2Connect
ASTRA2Connect is a two-way satellite broadband Internet service available across Europe, which launched in March 2007, and uses the ASTRA series of geostationary satellites...
system encourages user-installation and provides detailed instructions for this. Many customers in the Middle East and Africa are also encouraged to do self installs. At each VSAT site the uplink frequency, bit rate and power must be accurately set, under control of the service provider hub.
There are several types of two way satellite Internet services, including time division multiple access
Time division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
(TDMA) and single channel per carrier
Single channel per carrier
Single channel per carrier refers to using a single signal at a given frequency and bandwidth. Most often, this is used on broadcast satellites to indicate that radio stations are not multiplexed as subcarriers onto a single video carrier, but instead independently share a transponder...
(SCPC). Two-way systems can be simple VSAT terminals with a 60–100 cm dish and output power of only a few watts intended for consumers and small business or larger systems which provide more bandwidth. Such systems are frequently marketed as "satellite broadband" and can cost two to three times as much per month as land-based systems such as ADSL. The modems
Satellite modem
A satellite modem or sat modem is a modem used to establish data transfers using a communications satellite as a relay.There is a wide range of satellite modems from cheap devices for home internet access to expensive multifunctional equipment for enterprise use.A "modem" stands for...
required for this service are often proprietary, but some are compatible with several different providers. They are also expensive, costing in the range of US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
600 to $2000.
ASTRA2Connect
ASTRA2Connect is a two-way satellite broadband Internet service available across Europe, which launched in March 2007, and uses the ASTRA series of geostationary satellites...
terminal dish has a transmitter and single-polarity receive LNB, both operating in the Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
. Pricing for Astra2Connect modems range from €299 to €350. These types of system are generally unsuitable for use on moving vehicles, although some dishes may be fitted to an automatic pan and tilt mechanism to continuously re-align the dish—but these are more expensive. The technology for ASTRA2Connect was delivered by a Belgian company called Newtec.
Bandwidth
Satellite internet customers range from individual home users with one PC to large remote business sites with several hundred PCs.Home users tend to use shared satellite capacity to reduce the cost, while still allowing high peak bit rates when congestion is absent. There are usually restrictive time-based bandwidth allowances so that each user gets their fair share, according to their payment. When a user exceeds their allowance, the company may slow down their access, deprioritise their traffic or charge for the excess bandwidth used. For consumer satellite internet, the allowance can typically range from 200 MB
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
per day to 17,000 MB per month. A shared download carrier may have a bit rate of 1 to 40 Mbit/s and be shared by up to 100 to 4,000 end users.
The uplink direction for shared user customers is normally time division multiple access
Time division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
(TDMA), which involves transmitting occasional short packet bursts in between other users (similar to how a cellular phone shares a cell tower)
Each remote location may also be equipped with a telephone modem; the connections for this are as with a conventional dial-up ISP. Two-way satellite systems may sometimes use the modem channel in both directions for data where latency is more important than bandwidth, reserving the satellite channel for download data where bandwidth is more important than latency, such as for file transfer
File transfer
File transfer is a generic term for the act of transmitting files over a computer network or the Internet. There are numerous ways and protocols to transfer files over a network. Computers which provide a file transfer service are often called file servers. Depending on the client's perspective the...
s.
In 2006, the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
sponsored the UNIC
Unic
Unic was a French car manufacturer firm founded by Georges Richard in 1906 after having left Richard-Brasier. Société anonyme des automobiles UNIC was established in Puteaux with two-cylinder and four-cylinder models. The 1943 cc 12 CV four-cylinder model was extremely successful and...
project which aims at developing an end-to-end scientific test bed for the distribution of new broadband interactive TV-centric services delivered over low-cost two-way satellite to actual end-users in the home. The UNIC architecture employs DVB-S2
DVB-S2
Digital Video Broadcasting - Satellite - Second Generation is a digital television broadcast standard that has been designed as a successor for the popular DVB-S system. It was developed in 2003 by the , an international industry consortium, and ratified by ETSI in March 2005...
standard for downlink and DVB-RCS
DVB-RCS
DVB-RCS is an acronym for Digital Video Broadcasting - Return Channel via Satellite or . It is a specification for an interactive on-demand multimedia satellite communication system formulated in 1999 by the DVB consortium....
standard for uplink.
Normal VSAT dishes (1.2–2.4 m diameter) are widely used for VoIP phone services. A voice call is sent by means of packets via the satellite and internet. Using coding and compression techniques the bit rate needed per call is only 10.8 kbit/s each way.
Portable satellite modem
These usually come in the shape of a self-contained flat rectangular box that needs to be pointed in the general direction of the satellite—unlike VSAT the alignment need not be very precise and the modems have built in signal strength meters to help the user align the device properly. The modems have commonly used connectors such as EthernetEthernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
or Universal serial bus
Universal Serial Bus
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
. Some also have an integrated Bluetooth
Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
transceiver and double as a satellite phone. The modems also tend to have their own batteries so they can be connected to a laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...
without draining its battery. The most common such system is INMARSAT
Inmarsat
Inmarsat plc is a British satellite telecommunications company, offering global, mobile services. It provides telephony and data services to users worldwide, via portable or mobile terminals which communicate to ground stations through eleven geostationary telecommunications satellites...
's BGAN
BGAN
The Broadband Global Area Network 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...
—these terminals are about the size of a briefcase
Briefcase
A briefcase is a narrow box-shaped bag or case used mainly for carrying papers and other documents and equipped with a handle. Lawyers commonly use briefcases to carry briefs to present to a court, hence the name...
and have near-symmetric connection speeds of around 350–500 kbit/s. Smaller modems exist like those offered by Thuraya
Thuraya
Thuraya , the Arabic name of the Pleiades, is a regional satellite phone provider. Its coverage area is most of Europe, the Middle East, North, Central and East Africa, Asia and Australia....
but only connect at 444 kbit/s in a limited coverage area.
Using such a modem is extremely expensive—bandwidth costs between $5 and $7 per megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
. The modems themselves are also expensive, usually costing between $1,000 and $5,000.
Internet via satellite phone
For many years satellite phoneSatellite phone
A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites...
s have been able to connect to the internet. Bandwidth varies from about 2400 bit/s for Iridium network satellites and ACeS
ACeS
ACeS is a regional satellite telecommunications company based in Jakarta, Indonesia. It offers GSM-like satellite telephony services to Asian market. The coverage area includes Indonesia, Malaysia, Thailand, Philippines, Sri Lanka, Vietnam, China and India. The company operates the Garuda 1...
based phones to 15 kbit/s upstream
Upstream (networking)
In computer networking, upstream refers to the direction in which data can be transferred from the client to the server . This differs greatly from downstream not only in theory and usage, but also in that upstream speeds are usually at a premium...
and 60 kbit/s downstream for Thuraya
Thuraya
Thuraya , the Arabic name of the Pleiades, is a regional satellite phone provider. Its coverage area is most of Europe, the Middle East, North, Central and East Africa, Asia and Australia....
handsets. Globalstar also provides internet access at 9600 bit/s—like Iridium and ACeS a dial-up connection is required and is billed per minute, however both Globalstar
Globalstar
Globalstar is a low Earth orbit satellite constellation for satellite phone and low-speed data communications, somewhat similar to the Iridium satellite constellation and Orbcomm satellite systems.-History:...
and Iridium are planning to launch new satellites offering always-on data services at higher rates. With Thuraya phones the 9,600 bit/s dial-up connection is also possible, the 60 kbit/s service is always-on and the user is billed for data transferred (about $5 per megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
). The phones can be connected to a laptop or other computer using a USB or RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
interface. Due to the low bandwidths involved it is extremely slow to browse the web with such a connection, but useful for sending email, Secure Shell
Secure Shell
Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...
data and using other low-bandwidth protocols. Since satellite phones tend to have omnidirectional antenna
Omnidirectional antenna
In radio communication, an omnidirectional antenna is an antenna which radiates radio wave power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna's axis. This radiation pattern is often...
s no alignment is required as long as there is a line of sight between the phone and the satellite.
One-way receive, with terrestrial transmit
One-way terrestrial return satellite Internet systems are used with conventional dial-up Internet access, with outbound (upstreamUpstream (networking)
In computer networking, upstream refers to the direction in which data can be transferred from the client to the server . This differs greatly from downstream not only in theory and usage, but also in that upstream speeds are usually at a premium...
) data traveling through a telephone modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
, but downstream data sent via satellite at a higher rate. In the U.S., an FCC license is required for the uplink station only; no license is required for the users.
Another type of 1-way satellite Internet system uses General Packet Radio Service
General Packet Radio Service
General packet radio service is a packet oriented mobile data service on the 2G and 3G cellular communication system's global system for mobile communications . GPRS was originally standardized by European Telecommunications Standards Institute in response to the earlier CDPD and i-mode...
(GPRS) for the back-channel. Using standard GPRS or Enhanced Data Rates for GSM Evolution
Enhanced Data Rates for GSM Evolution
Enhanced Data rates for GSM Evolution is a digital mobile phone technology that allows improved data transmission rates as a backward-compatible extension of GSM...
(EDGE), if the upload volume is very low and since this service is not per-time charged, but charged by volume uploaded, costs are reduced for higher effective rates. GPRS as return improves mobility when the service is provided by a satellite that transmits in the field of 50–53 dBW. Using a 33 cm wide satellite dish, a notebook and a normal GPRS equipped GSM phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
, users can get mobile satellite broadband.
System hardware components
The transmitting station (also called "teleport", "head end", "uplink facility", or "hub") has two components:- Internet connection: The ISP's routers connect to proxy serverProxy serverIn computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
s which can enforce quality of serviceQuality of serviceThe quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...
(QoS) bandwidth limits and guarantees for user traffic. These are then connected to a DVB encapsulator which is then connected to a DVB-SDVB-SDVB-S is an abbreviation for Digital Video Broadcasting — Satellite; it is the original Digital Video Broadcasting forward error coding and demodulation standard for satellite television and dates from 1994, in its first release, while development lasted from 1993 to 1997...
modulator. The radio frequencyRadio frequencyRadio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
(RF) signal from the DVB-S modulator is connected to an up converter which is connected via feed lineFeed lineIn a radio antenna, the feed line is the cable or other transmission line that connects the antenna with the radio transmitter or receiver. In a transmitter, it feeds the radio frequency current from the transmitter to the antenna, where it is radiated as radio waves. In a receiver it transfers...
to the outdoor unit. - Satellite uplink: The block upconverterBlock upconverterA block upconverter is used in the transmission of satellite signals. It converts a band of frequencies from a lower frequency to a higher frequency. Modern BUCs convert from the L band to Ku band, C band and Ka band...
(BUC) and optional low-noise block converterLow-noise block converterA low-noise block downconverter is the receiving device of a parabolic satellite dish antenna of the type commonly used for satellite TV reception...
(LNB), which may use a waveguideWaveguideA waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
to connect to the optional orthomode transducerOrthomode transducerAn orthomode transducer is a microwave duct component of the class of microwave circulators. It is commonly referred to as an OMT, and commonly referred as a polarisation duplexer. Such device may be part of a VSAT antenna feed Orthomode transducers serve either to combine or to separate two...
(OMT) which is bolted to the feed hornFeed hornIn satellite dish and antenna design, a feedhorn is a small horn antenna used to convey radio waves between the transmitter and/or receiver and the reflector, particularly in parabolic antennas...
which is connected by metal supports to the satellite dishSatellite dishA satellite dish is a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television.-Principle of operation:...
and mount.
At the remote location (Earth station) the setup consists of:
- Outdoor unit
- Satellite dish with mount
- Feedhorn
- Universal LNB, for Ku-band.
- Feed line
- Indoor unit
- DVB-S Peripheral Component InterconnectPeripheral Component InterconnectConventional PCI is a computer bus for attaching hardware devices in a computer...
(PCI) card internal to a computer. - or, DVB external modem where an 8P8C (RJ-45) EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
port or a Universal Serial BusUniversal Serial BusUSB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
(USB) port connects the modem to the computer
- DVB-S Peripheral Component Interconnect
System software components
Remote sites require a minimum of programming to provide authentication and set proxy server settings. Filtering is usually provided by the DVB card driver.Often, non-standard IP stacks
Internet protocol suite
The Internet protocol suite is the set of communications protocols used for the Internet and other similar networks. It is commonly known as TCP/IP from its most important protocols: Transmission Control Protocol and Internet Protocol , which were the first networking protocols defined in this...
are used to address the latency
Lag
Lag is a common word meaning to fail to keep up or to fall behind. In real-time applications, the term is used when the application fails to respond in a timely fashion to inputs...
and asymmetry problems of the satellite connection. Data sent over the satellite link is generally also encrypted, as otherwise it would be accessible to anyone with a satellite receiver.
Many IP-over-satellite implementations use paired proxy servers at both endpoints so that certain communications between clients and servers [ftp://ftp.rfc-editor.org/in-notes/rfc2488.txt] do not need to accept the latency inherent in a satellite connection. For similar reasons, there exist special Virtual private network
Virtual private network
A virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
(VPN) implementations designed for use over satellite links because standard VPN software cannot handle the long packet travel times.
Upload speeds are limited by the user's dial-up modem, and latency is high, as it is for any satellite based Internet (minimum of 240 ms one-way, resulting in a minimum round-trip time of almost 500 ms). Download speeds can be very fast compared to dial-up.
Theory of operation
Remote sites use proxy serverProxy server
In computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
or(and) Virtual private network
Virtual private network
A virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
servers at the earth station
Earth station
A ground station, earth station, or earth terminal is a terrestrial terminal station designed for extraplanetary telecommunication with spacecraft, and/or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth, or within Earth's...
(teleport), which is configured to route all outbound traffic to the QoS server, which makes sure no user exceeds their allotted bandwidth or monthly traffic limits. Traffic is then sent to the encapsulator, which puts the IP packets inside of DVB packets. The DVB packets are then sent to the DVB modem and then to the transmitter (BUC)
One-way multicast, receive only
One-way multicast satellite Internet systems are used for Internet ProtocolInternet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
(IP) multicast
Multicast
In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires...
-based data, audio and video distribution. In the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, a Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC) license is required only for the uplink station and no license is required for users. Note that most Internet protocols will not work correctly over one-way access, since they require a return channel. However, Internet content such as web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...
s can still be distributed over a one-way system by "pushing" them out to local storage at end user sites, though full interactivity is not possible. This is much like TV or radio content which offers little user interface.
System hardware components
Similar to one-way terrestrial return, satellite Internet access may include interfaces to the public switched telephone networkPublic switched telephone network
The public switched telephone network is the network of the world's public circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all inter-connected by...
for squawk box applications. An Internet connection is not required, but many applications include a File Transfer Protocol
File Transfer Protocol
File Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...
(FTP) server to queue data for broadcast.
System software components
Most one-way multicast applications require custom programming at the remote sites. The software at the remote site must filter, store, present a selection interface to and display the data. The software at the transmitting station must provide access control, priority queuing, sending, and encapsulating of the data.Reducing satellite latency
Much of the slowdown associated with satellite Internet is that for each request, many roundtrips must be completed before any useful data can be received by the requester. Special IP stacks and proxies can also reduce latency through lessening the number of roundtrips, or simplifying and reducing the length of protocol headers. These types of technologies are generally referred to as TCP accelerationTCP Acceleration
TCP acceleration is the name of a series of techniques for achieving better throughput on an Internet connection than standard TCP achieves, without modifying the end applications...
, HTTP
Hypertext Transfer Protocol
The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....
pre-fetching and DNS
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
caching.
Elimination of advertising
While also effective for terrestrial communications, the use of ad-blocking software such as AdblockAdblock
Adblock Plus is a content-filtering extension for Mozilla Firefox and Google Chrome web browsers. ABP, a forked version of Adblock, allows users to prevent page elements, such as advertisements, from being downloaded and displayed.-How it works:Like Mozilla's built-in image blocker, Adblock...
for Firefox is exceptionally beneficial for satellite Internet, as most Internet advertising websites use cache
Cache
In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...
busting in order to render the browser and ISP's cache useless, by displaying advertisements (for the purpose of maximizing the number of ad views seen by the affiliate marketing
Affiliate marketing
Affiliate marketing is a marketing practice in which a business rewards one or more affiliates for each visitor or customer brought about by the affiliate's own marketing efforts...
company's server).
Satellites launched
SkyTerra-1 was launched in mid-November 2010 and will provide service across North America while Hylas-1 was launched at the end of November 2010 and will target Europe.On December 26, 2010, Eutelsat's KA-SAT
KA-SAT
KA-SAT is a telecommunications satellite owned by Eutelsat. The satellite will provide broadband Internet access services across Europe and also a small area of the Middle East. It is positioned at 9°E, joining Eurobird 9A Ku band satellite. KA-SAT was manufactured by EADS Astrium, based on the...
was successfully launched by an ILS Proton Breeze M vehicle at the Baïkonour Cosmodrome Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
. The last satellite was due in service in mid 2011. It covers the European continent with 80 spot beams—focused signals that cover an area a few hundred kilometers across Europe and the Mediterranean. Spot beams allow for frequencies to be effectively reused in multiple regions without interference. The result is increased capacity. Each of the spot beams will have an overall capacity of 900 Mbit/s and the entire satellite will have a capacity of 70 Gbit/s.
See also
- ASTRA2ConnectASTRA2ConnectASTRA2Connect is a two-way satellite broadband Internet service available across Europe, which launched in March 2007, and uses the ASTRA series of geostationary satellites...
(Satellite Internet Access in Europe) - Back-channelBack-channel-In telecommunications:A back-channel is typically a low-speed, or less-than-optimal, transmission channel in the opposite direction to the main channel.-In IT Security:...
and return channelReturn channelIn communications systems that use star topologies, the return channel is the transmission link from a user terminal to the central hub.... - HughesNet (formerly DIRECWAY)
- IP over DVBIP over DVBIP over DVB or IP over MPEG implies that Internet Protocol datagrams are transferred over the MPEG transport stream, and are distributed using some digital television system, for example DVB-H, DVB-T, DVB-S or DVB-C.-Application examples:...
- ITC Global Career CertificationsITC Global Career CertificationsITC Global Career Certifications are VSAT professional certifications for satellite based telecommunication systems. There are currently two levels of certification: Installer, and Professional...
- Thaicom 4Thaicom 4Thaicom 4, also known as IPSTAR, is a broadband satellite built by Space Systems/Loral for Thaicom Public Company Limited and was the heaviest commercial satellite launched as of August 2005. It was launched on August 11, 2005 from the European Space Agency's spaceport in French Guiana on board...
- Lamit CompanyLamit CompanyLamit Company is an independent satellite operator company in Europe, operating worldwide. The company provides satellite internet and telephony to primary schools and high schools from five continents. Lamit also helps companies extend their activities all over the world, by using satellite...
- List of device bit rates
- StarBandStarBandStarBand is a two-way satellite broadband Internet service available in the U.S.. StarBand Communications Inc. was initially a joint venture between Gilat Satellite Networks, EchoStar and Microsoft, and the StarBand service was launched in 2000. StarBand Communications filed for Chapter 11...
- TeledesicTeledesicTeledesic was a company founded in the 1990s to build a commercial broadband satellite constellation for Internet services. Using low-earth orbiting satellites small antennas could be used to provide uplinks of as much as 100 Mbit/second and downlinks of up to 720 Mbit/second...
- ToowayToowayTooway is a bi-directional satellite broadband Internet service available across Europe. The service was launched in 2007 via two Eutelsat geostationary satellites, Hot Bird 6 and Eurobird 3, respectively at the 13° and 33° East orbital positions....
- Ts 2Ts 2TS 2 is an Internet Provider for US Army soldiers in Iraq and Afghanistan. Most of all active customers are Polish and US Army soldiers, but TS 2 solutions have been implemented also for private companies and organizations. TS 2' network in Iraq and Afghanistan has over 15 thousand military users...
- Very small aperture terminalVery small aperture terminalA very-small-aperture terminal , is a two-way satellite ground station or a stabilized maritime Vsat antenna with a dish antenna that is smaller than 3 meters. The majority of VSAT antennas range from 75 cm to 1.2 m. Data rates typically range from 56 kbps up to 4 Mbps...
- Virtual private networkVirtual private networkA virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
- Voice over Internet Protocol
- WildBlueViaSatViaSat is a communication company based in Carlsbad, California, that provides equipment and services for military and commercial communications, primarily in satellite related technologies...
- Wireless Internet Service Provider