VoNR has the same SIM requirements as VoLTE. A SIM must carry an ISIM application on the UICC with IMS Private Identity (IMPI) and Public Identity (IMPU) provisioned by the operator. If a SIM supports VoLTE, the same SIM can support VoNR when the device and network upgrade to 5G SA – no new SIM required.
The IMS authentication and identity credentials required for VoNR are identical to those required for VoLTE:
These are the same requirements as VoLTE. A SIM provisioned for VoLTE by the operator already has these credentials. When the operator deploys VoNR on its 5G SA network, the same SIM can be used for VoNR calls without replacement.
The SIM does not change. What changes is the network (5G SA instead of 4G LTE), the device (5G SA modem instead of LTE modem), and the operator’s IMS configuration (enabling VoNR on the 5G SA core). The ISIM credentials on the SIM remain the same across VoLTE and VoNR.
This is one of the design virtues of the IMS architecture: the subscriber identity and authentication layer is network-generation agnostic. The same IMS handles VoLTE, VoWiFi, and VoNR calls for the same subscriber using the same SIM.
eSIM (embedded SIM) using eUICC technology is increasingly common in smartphones and industrial devices. An eSIM profile can contain the ISIM application in exactly the same way as a physical SIM card. VoNR on an eSIM-equipped device works the same way as on a physical SIM, provided the downloaded profile includes IMS credentials provisioned for voice services. For the full eUICC and eSIM technical reference, see euicc.co.uk.
Need a SIM specifically provisioned for IMS voice – for VoLTE now and VoNR when 5G SA coverage reaches your site? The VoLTE SIM sourcing guide at voltesim.co.uk covers what to ask for and how to verify provisioning.