Satellite Communications Industry Terminology

Adaptive Coding and Modulation (ACM)

Technique where the modem dynamically changes error-correction coding and modulation to match link conditions, maximizing throughput while maintaining availability.

Adjusted from 16APSK to QPSK via ACM during a rain fade to keep the link up; Enabling ACM improved cell-backhaul efficiency by 20 percent; The DVB-S2X hub uses ACM to exploit higher C/N during clear-sky periods.

Adjacent Satellite Interference (ASI)

Interference caused by signals from neighboring satellites or poor antenna pointing, often in tightly spaced GEO orbital slots.

The teleport saw degraded C/N due to ASI from a satellite 2 degrees away; We tightened antenna pointing to reduce ASI; The regulator issued a notice after our uplink exceeded ASI limits.

Antenna Gain

Measure of how well an antenna directs radio energy in a particular direction, expressed in dBi; key factor in EIRP and G/T.

Upgrading to a 1.2 m dish increased antenna gain by 3 dB; The link budget assumes 35 dBi receive antenna gain; Electronically steered arrays trade size and scan angle for gain.

ARPU (Average Revenue Per User)

Business metric indicating average monthly revenue per customer or terminal; used to track pricing power and product mix.

Mobility ARPU rose after introducing premium plans; The investor deck shows ARPU by verticals like maritime and aero; Price competition in backhaul pressured ARPU this quarter.

Backhaul

Use of satellite capacity to connect remote cell sites, enterprise branches, or edge nodes to the core network.

We use GEO backhaul to extend 4G into rural areas; LEO backhaul lowered latency for edge offload; The contract is priced per Mbps with a committed information rate for backhaul.

Beamforming

Shaping and steering of radio beams using phased arrays or digital processors to focus energy and reduce interference.

Digital beamforming lets us steer multiple spot beams simultaneously; The ship terminal uses beamforming to track LEO satellites; Beamforming reduces interference into restricted zones.

Broadcasting-Satellite Service (BSS)

ITU service category for broadcasting directly to the public (e.g., DTH TV) using space stations.

The platform operates under BSS for national TV; BSS orbital-slot coordination took three years; New HD channels launched over the BSS Ku-band payload.

C-band

Satellite frequencies around 3.4–4.2 GHz downlink and 5.85–6.725 GHz uplink; robust against rain but subject to 5G re-farming in some markets.

Video distribution still relies on C-band for reliability; Tropical climates favor C-band over Ku for uptime; The C-band clearing program required dish repointing.

CAPEX (Capital Expenditure)

Upfront investment in satellites, launch, payloads, ground gateways, and teleports.

HTS projects are CAPEX-heavy before revenue ramps; Rideshare launches reduced our CAPEX; We shifted from ownership to leasing capacity to lower CAPEX.

Carrier-to-Noise Ratio (C/N)

Ratio of carrier power to noise power at the receiver, in dB; determines achievable modulation and coding. Sometimes expressed as C/N0 for spectral density.

ACM maintains operation down to a C/N of 7 dB; C/N fluctuated during rain fade events; Increasing EIRP improved C/N by 2 dB.

Constellation

A set of satellites working together to provide global or regional coverage, often in LEO or MEO.

The LEO constellation needs 48 planes for full coverage; Constellation phasing affects handover frequency; Financing a constellation requires staged launches and service ramp.

Direct-to-Device (D2D)

Satellite service connecting directly to standard handsets or IoT devices, typically under 3GPP NTN specifications.

We trialed D2D texting using Release 17 NTN; Coexistence with terrestrial networks is key for D2D; Chip vendors announced NTN-capable modems for D2D.

Doppler Shift

Frequency shift due to relative motion between satellite and terminal; prominent in LEO and MEO links.

The terminal compensates Doppler up to ±40 kHz; Doppler tracking is essential for LEO OFDM; Guard bands account for Doppler uncertainty on the uplink.

Downlink

The satellite-to-ground transmission path.

The Ku-band downlink uses vertical polarization; EIRP contours define downlink beam strength; Rain fade mostly impacts the Ka-band downlink.

Earth Station In Motion (ESIM)

Mobile satellite terminals on aircraft, ships, and land vehicles operating under specific regulatory frameworks.

Airline Wi‑Fi uses Ka-band ESIM terminals; Regulators updated rules to authorize ESIM at sea; ESIMs require rapid beam steering for LEO tracking.

Earth Station

Ground facility with antennas and RF/baseband equipment that communicates with satellites; includes teleports and gateways.

The teleport hosts multiple 9 m earth stations; Licensing an earth station requires coordination; The controller automates antenna switching across satellites.

EIRP (Effective Isotropic Radiated Power)

Equivalent power radiated by an isotropic antenna, combining transmitter power and antenna gain; used to assess coverage and interference.

The link budget assumes 52 dBW EIRP at beam center; Masks cap EIRP toward the horizon; A larger HPA increased EIRP by 1.5 dB.

Footprint

Geographic area covered by a satellite beam, often shown with EIRP contours.

The HTS spot-beam footprint covers the North Sea; We published 50 dBW contours across the footprint; Moving beam footprints enable surge capacity.

Frequency Reuse

Reusing the same frequencies across multiple beams or polarizations to increase total system capacity.

Four-color reuse doubled capacity versus two-color; High-gain spot beams enable aggressive reuse; Cross-polar isolation is critical for frequency reuse.

Fixed-Satellite Service (FSS)

ITU service category for communications between fixed earth stations via satellites.

Corporate VSATs fall under FSS; FSS licensing differs from MSS and BSS; FSS video revenue declined while data grew.

Gateway

Ground station that connects the satellite network to terrestrial networks and the internet; includes RF, baseband, and backhaul.

LEO gateways are distributed to minimize latency; Cloud-hosted gateways virtualize baseband; Weather diversity across gateways boosts availability.

GEO (Geostationary Earth Orbit)

Circular equatorial orbit at about 35,786 km where satellites appear stationary relative to Earth.

GEO simplifies terminal pointing; Round-trip latency is roughly 600 ms; We leased a GEO transponder for TV distribution.

G/T (Receive Antenna Gain-to-Noise-Temperature)

Receiver figure of merit combining antenna gain and system noise temperature, expressed in dB/K.

The modem requires minimum G/T of 16 dB/K; Rain increases system temperature, lowering G/T; A lower-noise LNA improved site G/T.

Ground Segment

All non-space elements of the system: gateways, teleports, terminals, NOC, and network management.

We outsourced ground-segment operations; The virtualized ground segment runs on COTS servers; The NMS orchestrates the ground segment end-to-end.

High Power Amplifier (HPA)

Amplifier such as a TWTA or SSPA that boosts RF power for transmission.

SSPAs replaced TWTAs in our gateways; Output backoff prevents HPA saturation; HPA redundancy improves availability.

High-Throughput Satellite (HTS)

Satellite with many high-gain spot beams and extensive frequency reuse, delivering high aggregate capacity.

Our HTS offers 500 Gbps; Beam hopping adapts HTS capacity to demand; HTS economics favor broadband and mobility.

Interference Mitigation

Techniques to detect, locate, and reduce unwanted signals that degrade link performance.

Carrier ID aids interference mitigation for video carriers; Adaptive filtering and nulling reduce interference; Geo-location tools found a mispointed uplink.

Internet of Things via Satellite (Sat-IoT)

Low-power, low-data-rate connectivity for sensors and assets outside terrestrial coverage.

Sat-IoT enables asset tracking across oceans; LPWAN waveforms are optimized for Sat-IoT; Pricing is often per message or kilobyte.

ITU (International Telecommunication Union)

UN agency that manages global spectrum, orbital slots, and radio regulations.

ITU filings secure orbital positions; We coordinated under ITU Radio Regulations Article 9; The team attended WRC-23 to advocate NTN bands.

Jamming

Intentional interference that disrupts communications, often via high-power uplinks.

The GEO uplink suffered from targeted jamming; We deployed spread spectrum to mitigate jamming; Geolocation identified the jammer's location.

Ka-band

Satellite frequencies roughly 26.5–40 GHz (commonly 27.5–31 uplink, 17.7–21.2 downlink); high capacity but rain sensitive.

Ka-band HTS delivers broadband to aircraft; Site diversity mitigates Ka-band rain fade; Terminals require better calibration at Ka.

Key Performance Indicator (KPI)

Quantifiable metric to track technical or business performance.

SLA KPIs include latency and availability; Sales KPIs track ARPU and churn; NOC dashboards display RF KPIs like C/N and BER.

Ku-band

Satellite frequencies roughly 12–18 GHz (commonly 14/12 GHz links); widely used for TV and VSAT.

Maritime VSAT commonly uses Ku-band; Ku-band is less rain-sensitive than Ka; We migrated TV feeds from C-band to Ku.

L-band

Frequencies around 1–2 GHz used by MSS and GNSS; high availability and small antennas.

L-band supports satellite phones and safety services; We use L-band for control channels; Compact L-band terminals suit IoT.

Latency

End-to-end delay in data transmission; affected by propagation time, routing, and processing.

LEO reduces latency for real-time apps; TCP acceleration mitigates GEO latency; The SLA guarantees sub-100 ms latency on LEO routes.

LEO (Low Earth Orbit)

Orbit from roughly 160 to 2,000 km altitude; enables low latency but requires many satellites and frequent handovers.

LEO handovers occur every few minutes; Doppler and tracking are significant in LEO; LEO backhaul complements GEO for resilience.

Link Budget

Calculation of all gains and losses from transmitter to receiver to predict performance and margins.

The link budget shows 2 dB of rain margin; We adjusted coding rate based on the link budget; A higher G/T improved the downlink budget.

Medium Earth Orbit (MEO)

Orbit between about 2,000 and 20,000 km; fewer satellites than LEO, lower latency than GEO.

MEO latency is around 120–180 ms one-way; Tracking antennas support MEO links; OISLs can reduce MEO gateway dependence.

Modulation (QPSK, 8PSK, 16APSK)

Method of mapping bits onto RF waveforms; higher-order modulation increases spectral efficiency at higher C/N.

We fell back to QPSK during a storm; DVB-S2X supports up to 64APSK in high C/N; Modulation choice impacts required SNR.

Mobile-Satellite Service (MSS)

ITU service category for communications with mobile earth stations, including ESIMs and handhelds.

L-band supports MSS safety services; ESIMs on ships operate under MSS; MSS licensing differs from FSS requirements.

Network Operations Center (NOC)

Central facility that monitors and manages the satellite network and services.

The NOC monitors gateways 24x7; Escalations follow ITIL processes; AI anomaly detection alerts the NOC to RF issues.

NGSO (Non-Geostationary Orbit)

Collective term for LEO and MEO systems that move relative to Earth; subject to EPFD limits and coordination.

NGSO filings face spectrum coexistence rules; NGSO terminals need tracking antennas; EPFD compliance is central to NGSO licensing.

Non-Terrestrial Networks (NTN)

3GPP term for integrating satellites and HAPS with cellular networks for standardized service to devices.

Release 17 defined NTN waveforms and timing; MNOs plan roaming agreements for NTN; NTN enables D2D messaging in remote areas.

OPEX (Operating Expenditure)

Ongoing costs to run the business and network, such as leases, power, staffing, and maintenance.

Gateway leases are a major OPEX line; Virtualization reduced OPEX per Mbps; Power-saving modes cut OPEX at teleports.

Optical Inter-Satellite Link (OISL)

Laser communication links between satellites that create space-based mesh networks with high throughput and low latency.

OISLs reduce reliance on ground gateways; Precise pointing is critical for OISL acquisition; OISLs enable global routing across planes.

Path Loss

Signal attenuation over distance due to free-space spreading and atmospheric effects; increases with frequency and range.

Path loss at Ka-band exceeds that at C-band; The GEO path includes ~196 dB free-space loss; Rain and fog add to path loss.

Payload

Onboard communications subsystem, including transponders, processors, antennas, and switching.

The payload includes a digital transparent processor; Regenerative payloads demodulate on-board; Payload power constraints limit beam count.

Phased Array Antenna

Antenna composed of many elements whose phases are controlled to steer beams electronically without moving parts.

ESAs use phased arrays to track multiple LEOs; Phased arrays enable beam hopping; Thermal design is critical for phased arrays.

Polarization

Orientation of an electromagnetic wave, such as horizontal, vertical, or circular; dual-polarization doubles capacity with reuse.

We switched to RHCP to match the satellite; Cross-pol isolation of 30 dB minimizes interference; Dual-polarization increased throughput.

Quality of Service (QoS)

Traffic management policies that prioritize and guarantee performance for different applications and users.

QoS ensures VoIP gets priority over bulk data; SLAs specify QoS metrics like jitter and loss; We configure QoS profiles per customer plan.