Why the 3G Shutdown Matters For MVNO Lawful Interception
Most European operators have already switched off 3G (in Germany, for example, during 2021), and 2G networks are next: Telekom Deutschland plans to switch off 2G by 30 June 2028. For most subscribers, this means faster data and better coverage on 4G and 5G. For Mobile Virtual Network Operators (MVNOs) that run their own voice core, or that move to their own IMS as 3G (and later 2G) networks close, lawful interception has to move to the IMS as well. Light MVNOs that use their host’s VoLTE service usually remain covered by the host’s LI.
Under 3G, most light MVNOs relied on their host MNO’s circuit-switched core, so the host carried out the interception; depending on national law, the MVNO still had its own duties, such as making sure the host could implement orders. Full MVNOs that ran their own switching already operated their own LI.
For MVNOs that take voice into their own hands, that model changes when circuit-switched voice disappears.
From Circuit-Switched To IMS: The Technical Shift
With 3G decommissioned, voice services migrate to VoLTE (Voice over LTE) and VoNR (Voice over New Radio for 5G). Both technologies deliver voice as IP packets over the data network, using the IP Multimedia Subsystem (IMS) architecture.
Some host MNOs do not offer VoLTE to their MVNOs, and many full MVNOs choose to run their own IMS for control over features and billing. Running its own IMS gives an MVNO more control over service features, billing and customer experience. But it also means the MVNO now controls voice call signalling and, through its IMS media functions, the voice media, and with that it takes on lawful interception duties of its own.
When the MVNO operates the IMS core that processes voice calls, it becomes an obliged operator for that voice service. The host MNO usually keeps obligations for the radio and packet core it operates, so the two parties must agree who delivers what to avoid gaps and duplicate content.
What MVNOs Must Implement
MVNOs transitioning to their own IMS infrastructure need a complete MVNO lawful interception solution that covers:
Warrant Management
A system to receive, validate and track lawful interception requests from law enforcement agencies. This includes managing target identities (for IMS voice, for example the IMPU/TEL URI, IMPI, MSISDN or IMEI), warrant timelines and authorized agency access.
IMS Interception Points
Integration with the IMS core to collect Intercept Related Information (IRI) and Content of Communication (CC) for VoLTE and VoNR calls. This requires interception of signalling (IRI) at the P-CSCF/S-CSCF and of media (CC) at the media-plane functions such as the IMS-AGW, TrGW or MRF (3GPP TS 33.127).
Mediation And Formatting
A mediation platform that receives the X2/X3 output of the IMS points of interception and delivers it in the handover format required nationally, for example ETSI TS 102 232-5 for IP multimedia, used with the TS 102 232-1 PS-PDU (as in Germany), or 3GPP TS 33.108/33.128.
Secure Handover
Encrypted delivery channels (HI2 for IRI, HI3 for CC) to law enforcement monitoring facilities, with mutual authentication, delivery confirmation and audit logging.
Compliance Reporting
Documentation and reporting capabilities to demonstrate compliance during regulatory audits and respond to agency inquiries about interception status.
Building this infrastructure in-house requires specialized expertise in 3GPP standards, ETSI LI specifications, IMS architecture and law enforcement interface requirements – expertise most MVNOs don’t have on staff.
Three Paths Forward For MVNOs
MVNOs facing this challenge have three main options:
Option 1: Build In-House
Hire LI specialists, purchase mediation software, integrate with IMS elements and establish LEA connections. This gives maximum control but requires significant capital investment, ongoing operational costs and the ability to keep up with evolving standards.
Option 2: Managed LI Service
Outsource the entire LI operation to a specialist provider like ICS. The provider operates the mediation platform, manages warrant lifecycles, handles LEA handover and runs day-to-day compliance on your behalf. The legal obligation stays with you. The MVNO maintains oversight but avoids building specialized infrastructure and hiring dedicated staff.
Option 3: Software Platform With Support
License LI management and mediation software and run it on your own infrastructure, with implementation support, training and ongoing consulting from an LI specialist. This middle path gives you control while leveraging external expertise for setup and maintenance.
Most MVNOs find that managed services or supported software platforms offer the best balance of compliance assurance, cost control and operational simplicity. The business case for building in-house only makes sense at significant scale – typically two to three million subscribers or more in one market.
Don’t Wait Until The Last Minute
Shutdown timelines vary by country, but the trend is clear: circuit-switched voice is ending, IMS is the future, and MVNOs that operate their own IMS need their own lawful interception solutions. Regulators expect compliance from day one of IMS operation – there’s no grace period for MVNOs to “figure it out later.”
ICS helps MVNOs navigate this transition with flexible solutions that fit your timeline, budget and technical environment. Whether you need a complete managed service, integration support for IMS interception or consulting to understand your obligations, we provide the expertise to ensure you remain compliant as your voice infrastructure evolves.
The 3G shutdown is forcing a change. Make sure MVNO lawful interception doesn’t become the surprise roadblock in your IMS migration plan.
Contact ICS to discuss your MVNO lawful interception requirements and explore the right solution for your IMS deployment.
Further Reading on IMS Lawful Interception for MVNOs
For further reading on related topics, explore these articles:
- The MVNO LI Checklist: Everything You Need Before Going Live
- MVNO vs MNO: Who Is Legally Responsible for Lawful Interception?
External Resources
The following external resources provide additional context and official documentation:
