Advanced Encryption Standard – an encryption algorithm that secures data before it is transmitted over a network. Typically used by US Government Agencies. More on AES can be found on Search Security.
Adaptive Coding and Modulation – an algorithm to dynamically change the coding and modulation scheme to reach to atmospheric conditions and network configurations (Dish size, modem characteristics, BUC size, Satellite power, etc)
Amplitude and phase-shift keying or asymmetric phase-shift keying – a digital modulation scheme that changes the amplitude and phase of the carrier wave. See APSK for more info.
A transmission method using a continuous signal for transmitting voice, data, image, signal or video information. This signal varies in amplitude, phase, or some other property in proportion to that of a variable. Further information on Wikipedia.
Equipment that typically transmits and receives electromagnetic waves, usually referred to as the satellite dish
Code Division Multiple Access (CDMA) is a radio communication technology that allows for several transmitters to send information simultaneously over a single communications channel. This shared communications technology often uses spread-spectrum and a special codeing scheme to prevent interference between users.
The ratio of the received carrier power and the noise power in a given bandwidth, expressed in dB. This figure is directly related to G/T and S/N. Typically in a signal, the higher the C/N, the better the quality.
Frequency band with uplink 5.925‐6.425 GHz, downlink 3.7‐4.2 GHz. The C band is primarily used for voice and data communications.
Transmission of cellular voice and data signals, typically from a base station to a remote site. Includes 3g and LTE.
Refers to a method of transmitting signals from a satellite. On some satellites, both right‐hand rotating and left-hand rotating signals can be transmitted simultaneously on the same frequency; thereby doubling the capacity of the satellite to carry communications channels.
Footprint or the area on the earth’s surface that is covered by a satellite’s transmission beam.
Geostationary Earth Orbit (GEO) satellites orbit at 35,786 km (22,282 mi) above the equator in the same direction and speed as the earth rotates on its axis, making them appear as fixed in the sky.
Global System for Mobile (GSM) communications is a standard for digital wireless communications to mobile phones.
A figure of merit of an antenna and low noise amplifier combination expressed in dB. “G” is the gain of the system and “T” is the noise temperature. The higher the G/T, the better the system.
A measure of amplification expressed in dB.
Ground Station in the Cloud
A ground station in the cloud is a satellite gateway using virtual and cloud-based architectures to create a flexible, scalable, and cost-effective satellite gateway infrastructure.
Transmission carriers are separated on a transponder by spacing them several kilohertz (kHz) apart. This unused space serves to prevent the adjacent transmission carriers from interfering with each other.
Border Gateway Protocol – a routing protocol for exchanging route information between gateway hosts in a network of autonomous systems. See BGP on Wikipedia.
Binary Phase Key Shifting – a modulation scheme that uses a change in the phase of a signal to transmit information. The most simple form of PSK, BPSK has only two phases, 180 degrees apart.
A block upconverter (BUC) converts from a lower frequency transmitted by a modem to a higher frequency used by satellites. Most satellite modems output 70-Mhz or L-Band frequencies which must be upconverted to Ku, C, or Ka band frequencies.
The ratio of the power to one Watt expressed in decibels. Typically the E.I.R.P of satellite beams are measured in dBW.
Deterministic Time Division Multiple Access (D-TDMA) is iDirect’s patented access technology that provides simultaneous access to shared upstream channels using dynamically assigned time slots.
Digital Video Broadcasting – Satellite – Second Generation (DVB-S2) is the enhanced version of the DVB‐S satellite broadband transmission standard and has forward error correction and modulation specifications.
The time it takes for a signal to go from the sending station through the satellite to the receiving station. This transmission delay for a single hop satellite connection is very close to 240 ms.
Digital IF is the concept of digitizing RF signals into IP.
Digital Satellite Gateway
Satellite gateways typically use an L-Band transport infrastructure to move RF signals between the satellite antenna (outside) and the modem (inside). Modems convert the RF to an IP data stream as well as the opposite. A digital gateway digitizes the RF signal into an IP data stream at the antenna, and the gateway uses standard internetworking (routers and switches) as the transport infrastructure. They are specific to an end-user application while an RF digitizer creates an industry-standard IP data stream (e.g., VITA-49).
Transmission of information from one terminal to another terminal in two stages, first from a remote site VSAT up to the satellite to the network hub or from the network hub up to the satellite then to another remote site.
Transmission of a signal from the satellite to the earth. In a network it is typically referred to the link between a network hub over the satellite to a remote site.
Low Earth Orbit (LEO) is a satellite orbit from 160‐2000km above the earth. These satellites orbit the earth and take about 127 minutes to make a full orbit.
Frequency band from 1 to 2 GHz, this band is the result of the down‐conversion of the received downlink satellite signal from the LNB.
Low Noise Amplifier (LNA)
This is the preamplifier between the antenna and the earth station receiver. For maximum effectiveness, it must be located as near the antenna as possible, and is usually attached directly to the antenna receive port.
Low Noise Block Downconverter (LNB)
A combination Low Noise Amplifier and downconverter built into one device attached to the feed. It is used for the downlink satellite transmission by converting a band from a higher frequency to a lower frequency.
Paired Carrier Multiple Access (PCMA) is a satellite signal canceller that maximizes the capacity of satellite networks by using ViaSat’s patented PCMA technology to reduce satellite bandwidth as much as 50 percent.
Phase Shift Key (PSK) is a digital modulation scheme that changes the phase of the carrier wave.
A technique used by satellite operators to reuse the satellite transponder frequencies when transmitting these signals to Earth. Two methods are possible: linear and circular. To successfully receive and decode these signals on earth, the antenna must be outfitted with a properly polarized linear or circular feedhorn to select the signals as desired
Wide Area Network (WAN) is a computer network that covers a broad area that connects multiple remote locations.
Transmission of a signal from the remote router to a satellite to a hub.
Virtual LAN (VLAN) is a group of hosts that simulates a LAN although they are not located locally on the same network switch.
The VmE bus International trade Association created VITA-49 to create a standard method for packaging digitized RF signals into an IP packet. VITA-49 created the ability to deploy IP based, digital gateway architectures.
Very Small Aperture Terminal (VSAT) is an antenna that is typically less than 3 meters in diameter.
Wideband Global Satcom (WGS) a satellite communication system used by the U.S. Department of Defense.
Frequency band with uplink 7.9‐ 8.4 GHz, downlink 7.25 – 7.75 GHz, this band is primarily used for military communications and Wideband Global Satcom (WGS) systems.