Terms

8PSK / 8 Phase Shift Keying

A method of modulating a carrier in eight distinct phase states each representing three binary digits.

16QAM / 16 Quadrature Ampliture Modulation

A method of modulating a carrier in eight distinct phase states each with two possible amplitude states. The sixteen resultant states each representing four binary digits.

A collection of routers forming a network which is interconnected to at least two other AS so as to become part of the fabric of the Internet.

Transmit and receive routes in a duplex service which are not of equal bandwidth.

Azimuth

The angle of rotation (horizontal) that a ground based parabolic antenna must be rotated through to point to a specific satellite in a geosynchronous orbit. The azimuth angle for any particular satellite can be determined for any point on the surface of the earth giver the latitude and longitude of that point. It is defined with respect to due north as a matter of easy convenience.

That part of the network at the core of a larger network, typically interconnecting POPs and running at the highest data rates in the network.

The protocol used to communicate between AS’s, the current interconnectivity of the whole Internet.

Data transmission rate when data is transmitted faster than usually.

Provider of B2C and B2C services via terrestrial cable or fiber typically including television, radio and interactive services such as gaming and Internet.

Carrier

Central freqiency of transmitting signal.

Carrier to Noise Ratio C/N

Carrier-to-noise ratio measured either at the Radio Frequency (RF) or Intermediate Frequency (IF).

C band

RF frequency range of 4GHz to 6GHz which is resistant to rain outages but requires larger antennas because of the longer wavelengths.

CIR / Committed Information Rate

The committed information rate (CIR) is the rate at which the network supports data transfer under normal operations.

Coverage area

Satellite's defined service area. In many cases, the EOC is defined as being 3 dB down from the signal level at beam center. However, reception may still be possible beyond the -3dB point.

Dial-Up

Dial-Up is simply the application of the Public Switched Telephone Network to carry data on behalf of the end user.

DSL / Digital Subscriber Line

Digital Subscriber Line technology is a modem technology that uses existing twisted-pair telephone lines to transport high-bandwidth data, such as multimedia and video, to service subscribers.

Data can flow in both directions simultaneously.

DVB / Digital Video Broadcasting

Common international standard of digital multimedia broadcasting.

DVB-RCS / Return Channel over Satellite

DVB/RCS is a standard that specifies a satellite terminal that supports a two-way DVB satellite system.

Earth station

An antenna and its associated sub-systems used for reception and/or for transmission to/from a satellite. While the term applies to all antennas regardless of size, it tends to be only used in the context of 3.7m antennas and larger.

EB/N0

Eb/No is the ratio of Energy per Bit (Eb) to the Spectral Noise Density (No). This value is used to specify the lower limit of operation in most digital communications systems and is also used to measure radio channel performance.

Encapsulation

Taking data formatted for one protocol and enclosing it within another protocol in order to transmit the data successfully accross a type of network the original protocol was not designed for.

FEC / Forward Error Correction

FEC is a process in which a transmitter of digital data adds extra information known as check bits to the data stream. The receiver analyzes the check bit information to locate and correct errors.

GPRS / General Packet Radio Service

General Packet Radio Service is a new service designed for digital cellular networks (GSM, DCS, PCS). It utilises a packet radio principle and can be used for carrying end user’s packet data protocol (such as IP and X.25) information from/to a GPRS terminals to/from other GPRS terminals and/or external packet data networks.

HSSI / High Speed Serial Interface

Network standard for high speed (up to 52Mbps) serial communications over wide area network links.

Intelsat

International satellite organisation owned and operated by the major PTTs.

IP - Internet Protocol(s)

The collection of protocols defined in the RFCs which together are used for networking

IP-address

In TCP/IP message transmissions, packets/datagrams are routed within a network via the IP address; consists of a network identifier and host identifier.

ISDN / Integrated Services Digital Network

A set of communications standards allowing a single wire or optical fiber to carry voice, digital network services and video. ISDN was intended to eventually replace the plain old telephone system (POTS).

ISP / Internet Service Provider

Business providing access for its clients to the Internet and other value added services via leased lines or dial-up.

Ku band

RF frequency range of 12GHz to 14GHz typically used for DTH and VSAT applications.

L-band

Frequency range from 0.5 to 1.5 GHz.

MPEG / Moving Picture Experts Group

Group of standards for compressing and transmitting audio and video signals (MPEG-1, MPEG-2, MPEG-3, MPEG-4, MPEG-7).

NAT / Network Address Translation

Network Address Translation is a method by which IP addresses are mapped from one group to another, transparent to end users. Mostly used for connecting multiple computers to the Internet (or any other IP network) using one IP address.

NOC

Network Operations Center.

A connection agreement between ISPs for the exchange of Internet traffic.

Packet Identifier. In digital DVB stream information is being transmitted by packet streams which differ by packet Identifier. The receiver analyzes which stream to get and decapsulates by packet Identifier.

Polarization

A technique used by the satellite designer to increase the capacity of the satellite transmission channels by reusing the satellite transponder frequencies. In linear cross polarization schemes, half of the transponders beam their signals to earth in a vertically polarized mode; the other half horizontally polarize their down links. Although the two sets of frequencies overlap, they are 90 degree out of phase, and will not interfere with each other. To successfully receive and decode these signals on earth, the earth station must be outfitted with a properly polarized feedhorn to select the vertically or horizontally polarized signals as desired.

Strategic location for the secure deployment of equipment providing access to or from the network.

SCPC / Single Channel Per Carrier

A method used to transmit a large number of signals over a single satellite transponder.

Signal to Noise Ratio S/N

The ratio of the signal power and noise power. A video S/N of 54 to 56 dB is considered to be an excellent S/N, that is, of broadcast quality. A video S/N of 48 to 52 dB is considered to be a good S/N at the headend for Cable TV.

SR / Simbol Rate

Parameter indicationg information stream symbol speed value.

Connection to SatGate Internet service using IP-address from SatGate's delegated range is possible only if you're connectied through ISP that has anti-spoofing service turned off.

Sun interference

Solar outages occur when an antenna is looking at a satellite, and the sun passes behind or near the satellite and within the field of view of the antenna. This field of view is usually wider than the beamwidth. Solar outages can be exactly predicted as to the timing for each site.

Simplex

Data flows in one direction only, from transmitter to receiver. For satellite Internet, a simplex service requires an alternative path to provide the capability for interactive services.

The Réseaux IP Européens is one of 3 Regional Internet Registries (RIR) which exist in the world today, providing allocation and registration services which support the operation of the Internet globally.

TDMA / Time Division Multiple Access

Time division multiple access. Refers to a form of multiple access where a single carrier is the shared by many users. Signals from earth stations reaching the satellite consecutively are processed in time segments without overlapping.

Transponder

The device on a spacecraft that amplifies a signal received by the satellite so that it can be re-transmitted over a very wide geographic region. Transponders have a fixed bandwidth and power capability, which varies from satellite to satellite.

Tunnel,  Tunneling

Encapsulating data from one application/protocol to another - used for transporting multiple protocols over single connections, also used in network security applications.

VoIP / Voice (Video) Over Internet Protocols

The transmission of telephony and / or video services with the necessary QOS parameters using an IP based network.

VPN / Virtual Private Network

A VPN is an encrypted tunnel between two endpoints. VPN tunnels are created using a tunneling protocol such as L2TP and secured using a protocol such as PPTP and IPsec.