Patent ID: 11765211

Abstract:
In a cellular system having both 4th-Generation (4G) and 5th-Generation (5G) cellular networks, cellular device sends a Session Initiation Protocol (SIP) INVITE message to initiate a voice call. The message is received and acted upon by a Proxy-Call Session Control Function (P-CSCF) of an IP Multimedia Subsystem (IMS). Cellular devices that support 5G services are configured to include an information element (IE) in the SIP INVITE message to indicate support for 5G services. When responding to a SIP INVITE message, the P-CSCF determines whether the SIP INVITE message includes such an IE. If the SIP INVITE message contains an IE indicating 5G support, the P-CSCF sends an Authorization Authentication Request (AAR) message to a 5G Policy Control Function (PCF) to initiate a 5G dedicated bearer. Otherwise, the P-CSCF sends the AAR to a 4G Policy and Charging Rules Function (PCRF) to initiate a 4G dedicated bearer.