PCRF Session Identification Using Subscription Identifier Binding

The patent introduces a subscription identifier (IMSI or MSISDN) as an intermediary element to resolve the ambiguity of IP address reuse. Instead of directly using the IP address to identify UE sessions, the system first maps the IP address to a subscription identifier, which then serves as the reliable key for session identification. This intermediary layer eliminates conflicts when multiple UEs share the same IP address while maintaining the simplicity of the identification process.

The patent applies preliminary action by establishing the binding between subscription identifier and IP address during the initial IP-CAN session setup phase. The PCRF binds these identifiers together when the PDN-GW establishes the session, so that the mapping is pre-configured and stored. When session identification is needed later, the system simply retrieves the pre-bound subscription identifier without performing complex real-time matching, thus reducing operational complexity while maintaining high accuracy.

The patent changes the identification parameter from IP address to subscription identifier. When PDN-GWs assign the same IP address to different UEs to improve pool utilization, the system compensates by using the unique subscription identifier (IMSI or MSISDN) as the primary identification parameter. This parameter change allows aggressive IP address reuse while maintaining reliable network connection identification through the subscription identifier, which remains unique to each subscriber.