CSIPTO Handover PDN Connection Establishment
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Solution Overview
Problem
In 3GPP LTE systems, the reassignment of Packet Data Network (PDN) gateways for user equipment (UE) mobility leads to service breaks due to IP address changes, particularly when traffic offloading is done close to the network edge, causing suboptimal traffic routing and increased frequency of service disruptions.
Innovation Solution
The implementation of Coordinated Selected Internet Protocol Traffic Offloading (CSIPTO) allows for a make-before-break operation, enabling the establishment of a new PDN connection before releasing the old one, ensuring continuous service by maintaining at least one PDN connection at all times and enabling seamless traffic migration, even when the UE moves between different network cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PDN gateway reassignment is performed during UE mobility, then traffic routing is optimized, but service breaks occur due to IP address changes
Solution Approach 1:
The patent applies preliminary action by establishing a new PDN connection with the target PDN gateway before releasing the old connection. The source eNB includes a request to create a new PDN connection in the handover request message to the target eNB, and the target eNB establishes this connection before the handover is completed. This ensures that the UE maintains continuous connectivity throughout the mobility process, eliminating service breaks while still optimizing traffic routing.
2Loss of time
If traffic offloading is done close to the network edge, then latency is reduced, but service disruptions increase in frequency
Solution Approach 1:
The patent resolves this contradiction by performing preliminary establishment of the new PDN connection at the target eNB before the handover occurs. The target eNB creates the PDN connection with the target PDN gateway in advance, so when traffic offloading is performed close to the network edge during handover, the connection is already in place and ready to immediately handle traffic. This eliminates service disruptions while maintaining the latency benefits of edge-based offloading.
3Speed
If handover procedure is completed quickly, then mobility is optimized, but PDN connection establishment may be interrupted
Solution Approach 1:
The patent applies preliminary action by having the target eNB establish the new PDN connection before the handover is finalized. The source eNB includes a request to create a new PDN connection in the handover request, the target eNB processes this request and establishes the connection in advance, and only then is the handover completed. This sequence ensures that even though the handover procedure is completed quickly, the PDN connection establishment is not interrupted because the connection is already in place and ready to immediately handle traffic.
Data Source
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AI summary
Technology for user equipment (UE) operable to establish a new packet data network (PDN) connection during handover is disclosed. The UE can receive a radio resource control (RRC) connection reconfiguration message from a source radio base station during a handover procedure. The RRC connection reconfiguration message can include a request for establishment of the new PDN connection between the UE and a target PDN gateway (PGW). The UE can establish the new PDN connection with the target PGW using one or more parameters included in the RRC connection reconfiguration message. The UE can send, to a target radio base station, an RRC connection reconfiguration complete message during the handover procedure that includes an acknowledgement of the establishment of the new PDN connection.