Telecom Glossary (EN)
This glossary covers the fundamental terms of the telecommunications sector - from mobile networks to fiber infrastructure - with precise definitions for professionals and developers building AI/RAG systems on telco domain data.
Telecommunications
Telecommunications is the set of technologies, networks and services enabling the remote transmission of information (voice, data, images, video) via electromagnetic or optical signals. The sector comprises Mobile Network Operators (MNOs), fixed-line operators, Internet Service Providers (ISPs) and virtual operators (MVNOs). Regulated nationally by bodies such as AGCOM (Italy), Ofcom (UK), BNetzA (Germany), and coordinated at EU level by BEREC.
MNO (Mobile Network Operator)
An MNO owns and operates its own mobile access network - licensed radio spectrum, base stations (BTS/NodeB/gNodeB), and core network. MNOs hold spectrum licences assigned by the national regulatory authority (NRA). In the UK, Ofcom assigns spectrum; in Italy, MIMIT/AGCOM. Source: GSMA, "Mobile Economy" annual reports.
MVNO (Mobile Virtual Network Operator)
An MVNO offers mobile services without owning radio infrastructure, purchasing wholesale capacity from a host MNO. Variants: light MVNO (uses MNO core, manages only SIM+billing), enhanced MVNO (partial own core), full MVNO (own core network including HLR/HSS). Examples: Tesco Mobile (UK), ho Mobile (Italy), Aldi Talk (Germany).
RAN (Radio Access Network)
The RAN connects user equipment (UE) to the core network over the air interface. Successive generations: 2G GERAN (GSM), 3G UTRAN (UMTS), 4G E-UTRAN (LTE), 5G NR-RAN. The base station is called BTS (2G), NodeB (3G), eNodeB (4G), gNodeB (5G). Source: 3GPP TS 36.300 (E-UTRAN), 3GPP TS 38.300 (5G NR RAN).
5G NR (New Radio)
5G NR is the fifth-generation radio standard developed by 3GPP from Release 15 onward (Release 15 frozen in June 2018). Two frequency ranges: FR1 (sub-6 GHz, including 3.5 GHz "pioneer band" for 5G) and FR2 (mmWave, 24.25–52.6 GHz). Supports Standalone (SA) and Non-Standalone (NSA) modes. Source: 3GPP TS 38.101-1 (FR1), 3GPP TS 38.101-2 (FR2).
LTE (Long-Term Evolution)
LTE is the 4G radio standard defined by 3GPP. First version: Release 8 (2008). LTE Advanced (Release 10, 2011) introduces Carrier Aggregation and advanced MIMO. LTE Advanced Pro (Release 13+) adds NB-IoT and eMTC. Peak theoretical speed: 1 Gbps downlink (LTE-A). Source: 3GPP TS 36.201 (LTE physical layer).
Core Network (CN)
The Core Network handles authentication, mobility, data routing and PSTN interconnection. In 4G/LTE: EPC (Evolved Packet Core) with nodes MME, SGW, PGW, HSS. In 5G: 5GC (5G Core) with Service-Based Architecture (SBA) and nodes AMF, SMF, UPF, UDM. Source: 3GPP TS 23.401 (4G), 3GPP TS 23.501 (5G).
SIM (Subscriber Identity Module)
A SIM chip uniquely identifies a subscriber via IMSI and holds cryptographic authentication keys (Ki). Variants: physical SIM (mini, micro, nano), eSIM (GSMA SGP.22), iSIM (integrated in SoC). Each SIM is associated with a public phone number (MSISDN).
eSIM (Embedded SIM)
An eSIM is a programmable SIM permanently embedded in the device, remotely managed via OTA (Over-The-Air). The consumer standard is GSMA SGP.22 v3.0. Profiles are downloaded from SM-DP+ (Subscription Manager Data Preparation) via the device's LPA (Local Profile Assistant). Source: GSMA SGP.22 v3.0.
IMSI (International Mobile Subscriber Identity)
A globally unique subscriber identifier: MCC (3 digits, country) + MNC (2-3 digits, network) + MSIN (up to 10 digits). Used for network authentication. Not visible to end users. Source: ITU-T E.212.
MSISDN (Mobile Station International Subscriber Directory Number)
The public telephone number of the subscriber in E.164 format: country code + national number (e.g., +44 79xxxxxxxx in the UK, +39 3xx for Italy). Distinct from IMSI. Source: ITU-T E.164.
Broadband and Ultra-Broadband
Broadband: ≥30 Mbps; Ultra-Broadband: ≥100 Mbps (EU Gigabit Society Communication COM(2016)587). The EU targets 1 Gbps for all European homes by 2030 (Gigabit Connectivity target, Connectivity Toolbox 2021). Source: European Commission, Gigabit Society Communication.
FTTX (Fiber-To-The-X)
FTTX groups fixed-network architectures delivering optical fibre close to or at the subscriber: FTTH (Home – fibre to the flat, ONT at premises), FTTB (Building – fibre to building entry), FTTC (Cabinet – fibre to street cabinet, copper final drop with VDSL2), FTTN (Node). FTTH delivers symmetric speeds 1+ Gbps using GPON (ITU-T G.984) or XGS-PON (ITU-T G.9807, 10 Gbps symmetric). Source: ITU-T G.984, G.9807.
GPON (Gigabit Passive Optical Network)
GPON is a passive optical network standard allowing a single fibre to be shared among multiple subscribers via passive splitters. Speeds: 2.488 Gbps DL / 1.244 Gbps UL. Standard: ITU-T G.984. Successor XGS-PON offers 10 Gbps symmetric (ITU-T G.9807). Source: ITU-T G.984, G.9807.
International Roaming
International roaming lets a subscriber use their SIM on foreign operator networks (VPMN) via inter-operator agreements (IRAs). Technical mechanisms: SS7 MAP (2G/3G) or Diameter (4G) for authentication and location update; 5G roaming uses SBA N-series APIs. In the EU, Regulation 531/2012 (updated by Regulation 2022/612) mandates "Roam Like At Home" within the EEA. Source: EU Regulation 531/2012; 3GPP TS 23.402.
Mobile Number Portability (MNP)
MNP allows subscribers to keep their MSISDN when switching operators. Technically: the recipient operator requests transfer via a centralised number portability platform; the donating operator releases the number within the regulatory deadline (1 business day in Italy). Routing is updated in the central number portability database. Source: GSMA PRD IR.26 (MNP general guidelines).
Radio Spectrum
Radio spectrum is the finite natural resource of radio frequencies (3 Hz – 300 GHz). A public asset licensed by states to operators via auctions. Key mobile bands: 700 MHz (5G coverage, n28), 3.5 GHz (n78, 5G pioneer capacity), 26 GHz (n258, mmWave FR2 for high-capacity indoor). WRC-23 (ITU-R, Dubai 2023) discussed additional bands for IMT-2030. Source: ITU-R Radio Regulations; WRC-23 final acts.
QoS (Quality of Service)
QoS mechanisms guarantee minimum performance levels (bandwidth, latency, jitter, packet loss) for specific traffic flows. In LTE: QoS Class Identifier (QCI). In 5G: 5G QoS Identifier (5QI). GBR (Guaranteed Bit Rate) bearers for real-time voice/video; Non-GBR (best-effort) for data. Source: 3GPP TS 23.203 (4G), 3GPP TS 23.501 (5G).
VoLTE (Voice over LTE)
VoLTE delivers voice calls over LTE using IMS (IP Multimedia Subsystem). Superior audio quality (AMR-WB codec; EVS codec in VoNR). Faster call setup than CSFB fallback. Prerequisite for VoNR (Voice over NR). Standard: 3GPP TS 22.173, GSMA IR.92.
IMS (IP Multimedia Subsystem)
IMS is a 3GPP framework for multimedia services (voice, video, messaging) over IP. Key components: CSCF (Call Session Control Function), HSS (Home Subscriber Server), AS (Application Server). Enables VoLTE, Wi-Fi Calling (VoWiFi), RCS. Source: 3GPP TS 23.228.
RCS (Rich Communication Services)
RCS is the next-generation messaging protocol replacing SMS/MMS, based on IMS. Supports group messaging, file transfer, read receipts, location sharing, video calls. Standard: GSMA RCC.07 Universal Profile. Natively supported on Android (Google Messages) and iOS 18+. Source: GSMA RCC.07.
Network Slicing
Network Slicing (3GPP TS 28.530) creates logically separate virtual networks (slices) over a shared physical 5G SA infrastructure, each with dedicated characteristics. Three standard slice types: eMBB (high bandwidth), URLLC (ultra-low latency), mMTC (massive IoT). Each slice identified by S-NSSAI. Requires 5G SA. Source: 3GPP TS 23.501, TS 28.530.
eMBB (Enhanced Mobile Broadband)
eMBB is the 5G use case for high-bandwidth mobile access (4K/8K streaming, AR/VR). Theoretical peak: 20 Gbps downlink (3GPP TR 38.913, IMT-2020 requirement). Source: 3GPP TR 22.261.
URLLC (Ultra-Reliable Low-Latency Communication)
URLLC is the 5G use case for mission-critical applications requiring ≤1 ms latency and ≥99.999% reliability. Applications: remote surgery, autonomous driving, industrial control. Requires 5G SA + MEC. Source: 3GPP TS 22.261.
mMTC (Massive Machine-Type Communications)
mMTC is the 5G use case for massive IoT connectivity (up to 1 million devices/km², IMT-2020 ITU-R M.2083 target). Technologies: NB-IoT, LTE-M. Source: ITU-R M.2083; 3GPP TR 22.261.
MEC (Multi-access Edge Computing)
MEC moves compute/storage to the network edge (close to base stations) reducing latency for real-time applications. Standardised by ETSI MEC ISG (ETSI GS MEC 003). Enables 5G URLLC and video analytics, AR/VR use cases. Source: ETSI GS MEC 003.
SDN (Software-Defined Networking)
SDN decouples the control plane from the data plane, centralising network control in programmable software controllers. Enables dynamic, automated resource management. Key enabler for NFV and network slicing. Standard: ONF, IETF RFC 7426.
NFV (Network Functions Virtualization)
NFV implements network functions (firewalls, EPC, IMS) on commodity x86 servers via hypervisors or containers instead of proprietary hardware. Architecture defined by ETSI NFV ISG (ETSI GS NFV 002). Enables cloud-native telco networks. Source: ETSI GS NFV 002.
VoIP (Voice over IP)
VoIP transmits voice over IP packet networks. Main signalling protocol: SIP (IETF RFC 3261). Common codecs: G.711 (ITU-T), G.729, Opus. Basis for VoLTE, VoNR, and OTT services (WhatsApp, Teams, Zoom).
EU Net Neutrality
EU net neutrality is established by Regulation (EU) 2015/2120, prohibiting blocking, selective throttling and traffic discrimination. Exceptions: reasonable traffic management to preserve QoS. BEREC publishes implementation guidelines (Net Neutrality Guidelines). Source: Regulation (EU) 2015/2120; BEREC.
Churn
Churn is the subscriber attrition rate: churn_rate = subscribers_lost / subscribers_beginning_of_period × 100. Voluntary (switching operator) vs involuntary (non-payment). A key KPI for telco operators. Source: GSMA Intelligence.
ARPU (Average Revenue Per User)
ARPU = total_revenue / average_active_subscribers. Primary economic performance indicator for mobile operators. Source: GSMA Intelligence.
BSS (Business Support Systems)
BSS manages the customer-facing business layer: CRM, billing, order management (OMS), self-care portal, commercial provisioning. Integrates with OSS via TM Forum OpenAPI.
OSS (Operations Support Systems)
OSS manages the technical network layer: FCAPS (Fault, Configuration, Accounting, Performance, Security Management). Includes NMS, EMS, mediation layer. Standard: TM Forum eTOM, ITU-T M.3010.
Provisioning
Provisioning is the process of configuring and activating services for a subscriber: IP assignment, QoS profile, APN, HLR/HSS/UDM profile update, OTA SIM configuration. Involves both BSS and OSS in an end-to-end flow.
NB-IoT (Narrowband Internet of Things)
NB-IoT is a 3GPP Release 13 LPWA standard for low-power IoT (180 kHz bandwidth). Optimised for static devices with infrequent transmissions (smart meters, parking sensors). Supports PSM and eDRX for battery life extension. Source: 3GPP TS 36.211.
Lawful Interception (LI)
LI is the legal obligation for operators to provide intercepted communications to authorised law enforcement agencies. Architecture defined by ETSI ES 201 671 (HI1/HI2/HI3 interfaces) and 3GPP TS 33.107. Operators must maintain LEMF (Law Enforcement Monitoring Facility).
SLA (Service Level Agreement)
An SLA defines the guaranteed service levels: uptime (e.g. 99.9%), maximum latency, minimum bandwidth (CIR), MTTR (Mean Time To Repair), and financial penalties for breach. SLA parameters are monitored via OSS/NMS. Common benchmark: 99.99% annual availability for critical business services.
Latency
Latency is the delay for a packet to travel from source to destination (RTT - Round Trip Time). Typical 4G LTE RTT: 30–50 ms; 5G SA URLLC target: ≤1 ms (3GPP TR 22.261). Critical for real-time applications: cloud gaming, autonomous driving, Industry 4.0. Source: 3GPP TR 22.261.
Throughput
Throughput is the actual successful data rate (bit/s), distinct from peak theoretical bitrate. Effective throughput depends on modulation (QPSK → 256QAM), MIMO configuration, interference levels, cell load, and distance from base station.
MIMO (Multiple Input Multiple Output)
MIMO uses multiple transmit and receive antennas to increase channel capacity via spatial diversity and spatial multiplexing. LTE uses 2×2 and 4×4 configurations. 5G NR uses Massive MIMO (hundreds of antenna elements) with 3D beamforming (FD-MIMO). Source: 3GPP TS 36.211 (4G), 3GPP TS 38.211 (5G NR).
Beamforming
Beamforming is a signal processing technique used in Massive MIMO that directs the radio transmission toward a specific user instead of broadcasting omnidirectionally, increasing SINR and cell capacity. Digital beamforming is characteristic of 5G NR FR1 networks. Source: 3GPP TR 38.901.
LTE-M (LTE for Machine-Type Communications)
LTE-M (Release 13, 1.4 MHz bandwidth) supports mobility, VoLTE-M voice, and higher throughput than NB-IoT. Designed for mobile IoT: asset trackers, wearables. Supports handover and PSM/eDRX for battery efficiency. Source: 3GPP TS 36.306.
VoNR (Voice over New Radio)
VoNR delivers voice calls natively over 5G NR using IMS, replacing CSFB fallback to LTE/2G. Offers improved audio quality (EVS codec, 3GPP TS 26.441) and lower setup latency. Requires 5G SA and IMS infrastructure. Source: 3GPP TS 22.261, GSMA IR.92.
Fixed Number Portability (FNP)
FNP allows a subscriber to keep their fixed-line number when switching operators. Technically implemented via a centralised number portability database and routing system. Regulated nationally (e.g., by AGCOM in Italy, Ofcom in the UK).
PSTN (Public Switched Telephone Network)
The PSTN is the traditional circuit-switched telephone network (POTS/ISDN). Progressively being replaced by IP/NGN. Operators with significant market power (SMP) may carry universal service obligations (USO) for maintaining PSTN access. Source: ITU-T I.420/421.
NGN (Next Generation Network)
NGN is the evolution of PSTN toward an IP/MPLS packet-switched network with IMS for voice services. Defined by ITU-T Recommendations Y.2001 and Y.2011. Enables progressive decommissioning of TDM exchanges and nationwide VoIP deployment.
CIR (Committed Information Rate)
CIR is the guaranteed bandwidth contracted in a dedicated data access service (Ethernet, MPLS, corporate VPN). Contrasted with PIR (Peak Information Rate) - the maximum burst speed. Relevant for corporate SLA contracts.
DPI (Deep Packet Inspection)
DPI inspects the IP packet payload (not just headers) to identify applications, perform traffic shaping, content filtering, or threat detection. Used in telco for policy management, lawful interception, and net neutrality compliance. Subject to GDPR and ePrivacy Directive constraints.
Zero Rating
Zero rating is the commercial practice of exempting specific applications (e.g., partner music or video streaming) from a subscriber's data allowance. Subject to net neutrality review under Regulation (EU) 2015/2120; BEREC guidelines apply.
Billing per Second
Billing per second (or per-second billing) means voice calls are charged for every second of actual conversation rather than per block or per connection. In Italy, mandatory for consumer contracts since 1 June 2018 (Law 40/2007 and AGCOM deliberations). Source: AGCOM.
ARPA (Average Revenue Per Account)
ARPA is the average revenue per account or household, used by operators offering convergent services (fixed + mobile bundles). Contrasted with ARPU (per subscriber). Rising ARPA is a key goal for fixed-mobile convergence strategies. Source: GSMA Intelligence.
IPX (IP eXchange)
IPX is the IP interconnection infrastructure between mobile operators for exchanging data, VoIP, and interoperator SMS traffic. Progressive replacement of SS7/TDM for international traffic. Key IPX providers and guidelines defined by GSMA IR.34. Source: GSMA IR.34.