Telecom FAQ (EN)
Frequently asked questions about the telecommunications sector, oriented to the search intent of developers, product managers and analysts building AI/RAG applications on telco domain data.
What is the difference between an MNO and an MVNO?
An MNO (Mobile Network Operator) owns physical radio network infrastructure - licensed spectrum, antennas (BTS/NodeB/gNodeB), and a core network - allowing it to serve end users directly. An MVNO (Mobile Virtual Network Operator) offers mobile services without owning radio infrastructure; it purchases wholesale capacity from a host MNO. MVNOs range from light (using the MNO's core, managing only SIM and billing) to full MVNO (own core network including HLR/HSS). Examples include: Tesco Mobile (light MVNO on O2 UK), ho Mobile (enhanced MVNO on WINDTRE Italy). The distinction matters for AI systems because MNOs and MVNOs have different data architectures, OSS/BSS stacks and regulatory obligations.
How does 5G NR differ from 4G LTE technically?
5G NR (3GPP Release 15+) introduces several key improvements over 4G LTE. Frequency ranges: FR1 (sub-6 GHz, same range as 4G) and FR2 (mmWave, 24.25–52.6 GHz, new for 5G). Radio: wider channel bandwidths (up to 400 MHz in FR2 vs 20 MHz for LTE), Massive MIMO with beamforming, flexible numerology (scalable subcarrier spacing). Architecture: 5G SA introduces a cloud-native Service-Based Architecture (SBA) core (AMF, SMF, UPF instead of MME, PGW, SGW). Key new capabilities: Network Slicing, MEC, URLLC (≤1 ms latency), enhanced mMTC. Source: 3GPP TS 38.300; 3GPP TS 23.501.
What is spectrum and how is it allocated globally?
Radio spectrum is the finite natural resource of radio frequencies (3 Hz – 300 GHz) used for wireless communications. It is a public resource managed by states and internationally coordinated by ITU-R. Allocation happens through: 1) ITU-R World Radiocommunication Conferences (WRC) that assign frequency bands to service categories (mobile, satellite, etc.) in the Radio Regulations; 2) national auctions or beauty contests by the NRA (e.g., Ofcom in the UK, MIMIT/AGCOM in Italy). Key 5G frequency bands globally: 3.5 GHz (n78, main 5G capacity band), 700 MHz (n28, 5G coverage), 26 GHz (n258, FR2 mmWave for dense urban capacity). WRC-23 (Dubai 2023) discussed additional bands for IMT-2030 (6G). Source: ITU-R Radio Regulations; GSMA Spectrum.
How does international roaming work technically?
International roaming allows a subscriber to use their SIM on a foreign operator's network (VPMN - Visited PLMN). Technical flow: 1) UE attaches to VPMN, sending IMSI/SUCI; 2) VPMN MME/AMF queries the subscriber's HPLMN via SS7 MAP (2G/3G) or Diameter (4G) or SBA APIs (5G) to authenticate and get service profile; 3) data traffic is routed either Home-Routed (via HPLMN PGW/UPF) or via Local Breakout (VPMN PGW/UPF). IPX networks (GSMA IR.34) carry the inter-operator traffic. In the EU EEA, Regulation 531/2012 mandates Roam Like At Home (RLAH). Source: 3GPP TS 23.402; Regulation (EU) 531/2012.
What is the difference between 5G NSA and 5G SA?
5G NSA (Non-Standalone, 3GPP Release 15 Option 3): uses an LTE eNodeB as signalling anchor (control plane) while 5G NR carries data (EN-DC dual connectivity). Core remains 4G EPC. Faster to deploy (reuses existing LTE core infrastructure) but cannot enable advanced 5G features like full Network Slicing, URLLC, or cloud-native 5GC. 5G SA (Standalone, Release 15 Option 2): both 5G NR radio and 5G Core (AMF, SMF, UPF). Enables all advanced 5G features. Requires larger investment but unlocks industrial 5G use cases (Industry 4.0, private networks). Most operators launched 5G NSA first for coverage, migrating to 5G SA over 2023-2026. Source: 3GPP TS 38.300.
How does FTTX compare to other fixed broadband technologies?
FTTX variants: FTTH brings fibre to the apartment ONT (symmetric 1 Gbps+ using GPON ITU-T G.984 or XGS-PON ITU-T G.9807); FTTB to the building entry, copper distribution inside; FTTC to the street cabinet (typically within 300m), copper final drop with VDSL2 (up to 200 Mbps). Older alternatives: ADSL/ADSL2+ (copper pair, asymmetric, 8–24 Mbps), HFC (fibre+coaxial cable, cable TV networks, DOCSIS 3.1 up to 10 Gbps). FTTH is the gold standard for ultrabroadband but requires the highest capex (duct and last-mile fibre installation). Source: ITU-T G.984, G.9807.
What are NB-IoT and LTE-M, and when should you use each?
Both are 3GPP Release 13 LPWA (Low-Power Wide-Area) IoT standards. NB-IoT (180 kHz band): optimised for static devices with infrequent, small-payload transmissions (smart meters, parking sensors, utility monitoring). Best deep-indoor coverage (MCL ~164 dB). Does not support voice or fast handover. LTE-M (1.4 MHz band): supports mobility (handover), voice (VoLTE on LTE-M), and higher throughput. Better for moving devices (asset tracking, wearables, elderly care trackers). Both support PSM (Power Saving Mode) for battery life extension of years. NB-IoT generally has lower module cost; LTE-M has higher mobility. Source: 3GPP TS 36.211 (NB-IoT), 3GPP TS 36.306 (LTE-M).
How does Network Slicing work in 5G?
Network Slicing (3GPP TS 28.530) creates logically isolated virtual networks (slices) over a shared physical 5G SA infrastructure, each with dedicated performance characteristics. Each slice is identified by an S-NSSAI (Single-Network Slice Selection Assistance Information) containing SST (Slice/Service Type) and SD (Slice Differentiator). The three standardised SST values: 1=eMBB, 2=URLLC, 3=mMTC. Slicing applies both to the RAN (differentiated radio resource scheduling) and the core (separate AMF/SMF/UPF instances per slice). The UE requests slice(s) during registration; AMF decides admission. Enables operators to offer guaranteed SLA to enterprise customers (e.g., private 5G for a factory on a dedicated URLLC slice). Source: 3GPP TS 23.501; 3GPP TS 28.530.
How does MEC (Multi-access Edge Computing) reduce latency?
Traditional mobile architecture routes all data traffic from the UE through the core network and back to a central data centre - adding 50–100+ ms round-trip latency. MEC deploys compute and storage infrastructure at the network edge (co-located with gNodeB or at the aggregation node), so data can be processed locally without traversing the full core. The 5G SA UPF can be positioned at the edge and configured for local breakout. This reduces end-to-end latency to <5 ms for applications co-located at the edge. Key use cases: video analytics, gaming, AR/VR, autonomous robotics. Standard: ETSI GS MEC 003. Source: ETSI GS MEC 003.
What is Lawful Interception (LI) and what are the technical obligations for operators?
LI is the legal obligation for telco operators to provide, upon authorised court order, the intercepted communications of a target subscriber to law enforcement agencies (LEA). Operators must maintain dedicated LI infrastructure (LEMF - Law Enforcement Monitoring Facility). The technical architecture is defined by ETSI ES 201 671 (for circuit-switched and packet) and 3GPP TS 33.107. Three interfaces: HI1 (administrative/authorisation), HI2 (intercept-related information/signalling), HI3 (content of communication). The intercept is set up without the target's knowledge. LI systems must be logically separated from operational monitoring. Source: ETSI ES 201 671; 3GPP TS 33.107.
What is SIM authentication (AKA) and how does 5G improve privacy?
SIM authentication uses AKA (Authentication and Key Agreement). In 4G: the UE sends its IMSI; the MME requests authentication vectors from HSS; the UE verifies the network (AUTN) and responds with RES; the MME compares RES with XRES. In 5G, AKA is preserved (5G-AKA and EAP-AKA' methods) but privacy is enhanced: the UE sends SUCI (Subscription Concealed Identifier) instead of IMSI. SUCI is the IMSI encrypted with the operator's public key using ECIES (Elliptic Curve Integrated Encryption Scheme), preventing IMSI catchers from harvesting the permanent identity over the air. The operator's UDM decrypts SUCI to obtain the SUPI (Subscription Permanent Identifier = the IMSI). Source: 3GPP TS 33.501.
What is EU Net Neutrality and how does it affect operators?
EU Regulation 2015/2120 establishes open internet obligations: ISPs and MNOs must treat all internet traffic equally, prohibiting blocking of lawful services, selective throttling, and paid prioritisation for internet access services. Exceptions: reasonable traffic management (for network integrity/congestion), quality of service for specialised services (VoLTE, IPTV) provided they do not degrade general internet quality. Zero-rating (excluding specific apps from data counting) is permitted if non-discriminatory; selective zero-rating that distorts competition may infringe net neutrality. BEREC publishes binding guidelines (Net Neutrality Guidelines). National NRAs (AGCOM, Ofcom, etc.) enforce. Source: Regulation (EU) 2015/2120; BEREC Net Neutrality Guidelines.
How do BSS and OSS integrate in a telco?
BSS (Business Support Systems) covers the customer-facing layer: CRM, billing/invoicing, order management (OMS), self-care portal, commercial provisioning. OSS (Operations Support Systems) covers the technical layer: network element management (NMS/EMS), FCAPS (Fault/Configuration/Accounting/Performance/Security), inventory, technical provisioning. Integration happens via middleware: a customer order in the BSS triggers a provisioning workflow in the OSS, which configures the network. The TM Forum eTOM (Business Process Framework) defines the reference process model. OpenAPI (TM Forum OpenAPI) standardises the interfaces. Tight coupling between BSS and OSS is an anti-pattern: changes to the core network should not require CRM changes.
How is mobile call billing calculated?
Mobile calls are billed per second (since June 2018 in Italy, as mandated by Law 40/2007; per-second billing is common in most EU markets). The Call Detail Record (CDR) captures: calling MSISDN, called MSISDN, call duration, start/end timestamp, originating cell (CGI/E-UTRAN Cell ID), service type. CDRs are generated by the MSC (circuit-switched voice) or PGW/SMF (VoLTE/data). Billing systems (BSS/mediation) aggregate CDRs, apply the tariff plan (including in-bundle allowances), and generate invoices. Prepaid balances are decremented in real-time via OCS (Online Charging System).
What are Mobile Termination Rates (MTR) and why are they regulated?
MTRs are the wholesale prices an operator charges another operator to terminate a call on its mobile network. Without regulation, dominant operators could use high MTRs to raise costs for competitors. In the EU, NRAs regulate MTRs using the BU-LRIC+ (Bottom-Up Long-Run Incremental Cost) methodology to set rates reflecting efficient network costs. BEREC issues common positions on MTR calculation. Rates have declined significantly across the EU over 2010-2024. Source: BEREC Common Position on Mobile Termination Rates.
What is VoLTE and how does it differ from OTT VoIP?
VoLTE (Voice over LTE) is operator-managed voice over LTE using IMS. Quality is guaranteed (GBR bearer QCI=1, AMR-WB codec; EVS for VoNR). Supports seamless handover between LTE and 2G/3G (SRVCC). Emergency calls (112) always use VoLTE/CSFB paths. OTT (Over-The-Top) VoIP (WhatsApp, Teams, FaceTime, Zoom) runs as a data application over the internet connection without IMS integration. No dedicated QoS (best-effort, QCI=9), no guaranteed handover continuity. VoLTE quality is generally superior under network congestion. Source: 3GPP TS 22.173; GSMA IR.92.