3GPP has specified that 5G uses the 4G voice/video communication architecture and still provides voice/ video communication services based on the IMS. The 4G radio access technology is LTE, and the voice/video over the LTE network is called VoLTE. The 5G radio access technology is NR, and the voice/video over the 5G network is called voice/video over NR (VoNR). VoLTE and VoNR are different access modes for IMS voice/video communication services.