Inter-System Mobility Using Network Slice Information for 5G Handover

The patent applies preliminary action by obtaining network slice information from the second network system before the user equipment actually moves to the 5G system. The first network system retrieves subscription data including network slice identifiers in advance, stores this information locally, and provides it to the user equipment during the PDN connection establishment phase. This ensures that when mobility to 5G occurs, the transition can proceed smoothly without service disruption, as all necessary slice information is already available.

The patent uses the first network system as an intermediary that manages network slice information between the second network system and the user equipment. Instead of requiring direct complex interactions between the user equipment and multiple network systems, the first network system acts as a local intermediary that obtains, stores, and provides network slice information. This intermediary approach simplifies information management by centralizing the handling of slice data at the PDN gateway level, reducing the burden on both the user equipment and the broader network infrastructure.

The patent merges the network slice information management function with the existing PDN gateway (first network system) infrastructure. Rather than creating separate dedicated systems for slice information management, the solution combines these functions within the existing PDN gateway that already handles PDN connection establishment and mobility management. This merging approach increases transition success rates by ensuring slice information availability while avoiding the need for entirely new complex apparatus, as the existing infrastructure is enhanced with additional information management capabilities.