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.
从电路交换到 IMS：技术转变
随着 3G 停止使用，语音服务将迁移到 VoLTE（LTE 语音）和 VoNR（5G 新无线电语音）。这两种技术都采用 IP 多媒体子系统（IMS）架构，通过数据网络以 IP 数据包的形式传输语音。.
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.
MVNO 必须实施的内容
正在向自有 IMS 基础设施过渡的 MVNO 需要一套完整的 MVNO 解决方案 合法截获解决方案 涵盖以下内容：
权证管理
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 拦截点
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).
调解和格式化
A 调解平台 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.
安全移交
加密传输通道（IRI 采用 HI2，CC 采用 HI3）至 执法监控设施, ，并具备相互认证、送达确认和审计日志功能。.
合规报告
文档和报告功能可在监管审计期间证明合规性，并回复机构关于截获状态的查询。.
在公司内部建立这种基础设施需要 3GPP 标准、ETSI LI 规范、IMS 架构和执法接口要求方面的专业知识，而大多数 MVNO 都不具备这些专业知识。.
MVNO 的三条出路
面临这一挑战的 MVNO 有三种主要选择：
方案 1：内部建造
聘请 LI 专家、购买调解软件、与 IMS 元件集成并建立 LEA 连接。这样可以实现最大程度的控制，但需要大量资金投入、持续运营成本以及跟上不断发展的标准的能力。.
选项 2： 托管型 LI 服务
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.
方案 3：提供支持的软件平台
授权使用 LI 管理和调解软件，并在自己的基础设施上运行，由 LI 专家提供实施支持、培训和持续咨询。这种中间途径既能让您进行控制，又能利用外部专家进行设置和维护。.
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.
不要等到最后一刻
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 帮助 MVNO 实现这一转变 灵活的解决方案 我们可以根据您的时间表、预算和技术环境提供最适合您的服务。无论您是需要完整的托管服务、IMS 拦截集成支持，还是需要咨询以了解您的义务，我们都能提供专业技术，确保您的语音基础设施在发展过程中始终合规。.
3G 关停迫使我们做出改变。确保 MVNO 合法拦截不会成为您 IMS 迁移计划中的意外障碍。.
请联系 ICS，讨论您的 MVNO 合法拦截要求，并探索适合您的 IMS 部署的解决方案。.
Further Reading on IMS Lawful Interception for MVNOs
如需进一步了解相关主题，请浏览这些文章：
外部资源
以下外部资源提供了更多背景资料和官方文件：
