Satellite Internet

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Satellite Internet services are used in locations where Terrestrial Internet is not available and in locations which move frequently. Internet access via Satellite is available globally, including vessels at sea. There are three types of Satellite Internet Service: One-Way (Mulitcast), One-Way (Terrestrial return) and two-way.

One-Way (Multicast)

One-Way (Multicast) Satellite Internet systems are used for IP multicast-based data, audio and video distribution. In the US, a FCC license is only required for the uplink station, no license is required for the users.

System Hardware Components

Usually similar to One-Way (Terrestrial return), but may include interfaces to the Public Switched Telephone Network for Squawk box applications. An Internet connection is not required, but many applications include an 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 Teleport must provide access control, priority queueing, sending, and encapsulating of the data.

One-Way (Terrestrial return)

One-Way (Terrestrial return) Satellite Internet systems are used with traditional Dial-up access to the internet, with outbound data travelling through a telephone modem, but downloads are sent via satellite at a speed near that of Broadband Internet access. In the US, a FCC license is only required for the uplink station, no license is required for the users.

System Hardware Components

• Teleport (also called "Head End", "Uplink Facility", or "Hub")

• • Internet Connection

Physical Internet Connection (Fiber optic or copper) is connected to CSU/DSU which uses V.35 to connect to the Router which uses Ethernet to connect to the Firewall which uses Ethernet to connect to the Network switch which uses Ethernet to connect to the Proxy servers which uses Ethernet to connect to the QoS (Quality of Service) Server which uses Ethernet to connect to the

• • DVB Encapsulation (Indoor Unit)

Encapsulator which uses Coaxial cable to connect to the DVB-S modem which uses Coaxial cable to connect to the which Upconverter (optional) which Feedline, a type of Coaxial cable to connect to the

• • Outdoor Unit

Block Up Converter (BUC) and Low Noise Block (LNB) connects to the Splitter which uses a Wave guide (optional) to connect to the OMT which is bolted to the which Feedhorn which is connected by metal "arms" to the which Satellite Dish and Mount

• Remote Locations (Earth Stations)
  • Outdoor Unit
    • Satellite dish w/mount
    • Feedhorn
    • Low Noise Block (LNB)
    • Feedline
  • Indoor Unit
    • DVB-S PCI Card (in a computer)

System Software Components

Remote sites require a minimum of programming to provide authenication and set Proxy server settings. Filtering is usually provided by the DVB card driver.

Theory of Operation

Remote sites use the Proxy server at the 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).

Two-Way

Two-Way Satellite Internet sends data from remote sites via satellite to a Hub, which then sends the data to the internet. In the US, each location requires a license from the FCC to operate. The satellite dish at each location must be precisely positioned to avoid interference with other satellites. The oscillators in some radar detectors can cause interference with these systems. Also, each location must use power management to adjust the amount of transmit power to compensate for things like rain fade. There are several types of two way Satellite Internet services TDMA including SCPC.