Local Gateway Tunnel for Seamless UE Handover
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Solution Overview
Problem
In packet data networks, when user equipment (UE) hands over from one local gateway (LGW) to another, the uplink and downlink packets of a local service are interrupted or take a roundabout path, causing service disruptions due to the lack of a tunnel between the original and new LGWs.
Innovation Solution
The remote gateway (RGW) sends request messages to both the source-LGW (S-LGW) and target-LGW (T-LGW) to establish a tunnel between them, ensuring continuous packet transmission of the local service by using the tunnel for uplink and downlink packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE hands over from S-LGW to T-LGW, then UE mobility is achieved, but packet transmission continuity is interrupted
Solution Approach 1:
The patent applies preliminary action by establishing a tunnel between S-LGW and T-LGW before the UE actually hands over. The network detects the handover condition (UE moving out of T-LGW's coverage) and proactively sets up the tunnel in advance, so that when handover occurs, packet transmission continuity is already ensured without interruption.
Solution Approach 2:
The patent introduces an intermediary tunnel mechanism between S-LGW and T-LGW. This tunnel acts as a mediator that carries user packets between the source and target local gateways during handover, ensuring continuous packet delivery without requiring direct connection between UE and application server through the new gateway alone.
2Reliability
If tunnel is established between RGW and S-LGW, then uplink packet transmission is maintained, but roundabout path problem occurs
Solution Approach 1:
The patent segments the packet transmission path into two distinct segments: one for uplink packets (UE→T-LGW→S-LGW→Application Server) and one for downlink packets (Application Server→S-LGW→T-LGW→UE). This segmentation allows each direction to have optimized routing, preventing the roundabout path problem while maintaining transmission reliability.
Solution Approach 2:
The patent applies inversion by treating uplink and downlink packets differently in terms of routing paths. Instead of using the same path for both directions, the patent inverts the routing logic: uplink packets go through the tunnel to S-LGW while downlink packets are forwarded directly through T-LGW, eliminating the roundabout path issue.
3Productivity
If local offload policy is executed, then packet processing efficiency is improved, but service continuity during handover is compromised
Solution Approach 1:
The patent applies preliminary action by establishing the tunnel between S-LGW and T-LGW before handover occurs. This proactive tunnel setup ensures that when local offload policy needs to be executed during handover, the necessary routing path is already in place, maintaining both packet processing efficiency and service continuity.
Data Source
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AI summary
A method for establishing a tunnel between local gateways, and a gateway are disclosed, to resolve a prior-art problem that after UE is handed over from an S-LGW to a T-LGW, a same local service accessed by the UE before and after the UE is handed over is interrupted, or a roundabout packet path of a same local service accessed by the UE before and after handover occurs. The method of the present invention includes: determining, by an RGW, that UE is handed over from an S-LGW to a T-LGW, where before the UE is handed over, a packet of a local service of the UE is forwarded by the S-LGW between the UE and an application server of the local service, and the local service includes a same service that is deployed on the S-LGW and that is accessed by the UE before and after the UE is handed over; sending, by the RGW to the S-LGW and the T-LGW respectively, a first request message and a second request message to request to establish a tunnel, where the tunnel is used to transmit the packet of the local service between the S-LGW and the T-LGW; and establishing the tunnel between the S-LGW and the T-LGW.