nding a NAS message (PDU session ID, N1 SM container (PDU session modification command ACK)). Step 13: The gNB transfers the NAS message to the AMF. Step 14: The AMF forwards the N1 SM container (PDU session modification command ACK) and user location information received from the (R) AN to the SMF via the Nsmf_PDUSession_Update SMContext service operation. path/nsmf -pdusession v1/sm-contexts/imsi- - 123xxxx : 1/modify Step 15: The SMF acknowledges with 204 No Content. Packet Core Procedures Step 16: The SMF sends an HTTP POST request ( / nchf - convergedcharging/v/ chargingdata/acdsddsdd-988739-1466329180645 - - SBI/update) to the CHF. The SMF sends ChargingDataUpdateReq by including Multi - Uni - Usage with Rating- Group-1d which is received as part of Charging_Description of Sm_Policy Control UpdateNotify_Request to install PCCRules. Step 17: The CHF responds with 200 OK with triggers and PDU session charging information. Step 18: The SMF updates the N4 session of the UPF(s) that are involved in the PDU session modification by sending an N4 session modification request (N4 Session ID) message. Step 19: The UPF acknowledges the request and responds with "cause" accepted. This marks the end of the VoNR procedure. The VoNR procedure is key to establishing voice calls with NR. The IMS PDU session establishment along with a VoNR call flow completes the requirement needed to make a voice call or a video call over NR. One key thing to keep in mind, however, is that the IMS PDU session is established when the phone is turned on, but the VoNR call flow is executed when we dial a number for voice or video calls. In the next section, we will study the integration of Wi-Fi with 5G networks. Wi-Fi attach One of the prime features of the 5G core network is its capability to inter-work with different types of access networks, both 3GPP-based and non-3GPP-based. One such network is Wi-Fi. The 5G radio can coexist with Wi-Fi access to cover coverage gaps. Hence, denser access can be planned with complementing radio access tec