Local Gateway Migration for Cellular Handover Latency
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Solution Overview
Problem
Conventional cellular packet-access systems face latency issues due to triangular routing problems when mobile devices handover between access points, particularly when using centralized anchor nodes, which also compromise mobility support.
Innovation Solution
Implementing a system that allows user equipment (UE) to migrate a packet data network (PDN) connectivity session from a source access node to a target access node without tearing down the session, by establishing a new data radio link and updating the data path to route packets directly through the target access node, thereby avoiding centralized routing and maintaining mobility support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized anchor nodes (PDN gateways) are used to enable session continuity during handover, then mobility support is maintained, but triangular routing causes increased latency
Solution Approach 1:
The patent segments the routing function by separating the control plane (centralized PDN gateway for session management) from the user plane (local gateway for data forwarding). This allows session continuity to be maintained through centralized control while data packets are routed locally through the target access node, eliminating triangular routing latency.
Solution Approach 2:
The patent introduces a local gateway function at the target access node that acts as an intermediary between the UE and the centralized PDN gateway. This local gateway receives session continuity information from the source access node and establishes direct data paths, serving as a mediator that enables both centralized session management and localized efficient routing.
2Loss of time
If local gateways are introduced to optimize routing path and reduce latency, then triangular routing problem is solved, but mobility support is sacrificed
Solution Approach 1:
The patent makes the target access node universal by equipping it with both local gateway functionality (for optimized routing) and mobility management capabilities (for session continuity). This multi-functional design allows the same node to perform both efficient local data forwarding and mobile session management, eliminating the trade-off between latency optimization and mobility support.
Solution Approach 2:
The patent performs preliminary actions by having the target access node receive session continuity information from the source access node before the handover is complete. This allows the target node to pre-establish the necessary data paths and gateway functions, ensuring that when the UE actually hands over, both optimized routing and mobility support are immediately available without conflict.
3Adaptability or versatility
If handover is performed between access nodes, then mobility is maintained, but triangular routing through centralized gateway increases end-to-end latency
Solution Approach 1:
The patent adds a new dimension to the routing architecture by introducing local gateway functions at multiple access nodes simultaneously. Instead of a single centralized routing path, this creates a multi-dimensional routing structure where data can flow directly through the target access node while control plane functions remain centralized, enabling both mobility and low latency.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may establish a packet data network (PDN)-connectivity session to a PDN using a cellular radio access technology (RAT) and migrate the PDN-connectivity session from a source access node (AN) to a target AN. Migration may initiate when a decision to perform a handover is made. The target AN may receive a network address and information about a first data radio link established between the UE and source AN. The target AN may establish a second data radio link with the UE based at least in part on the first data radio link information, and may transmit, to the PDN, a path update including the network address and an updated path via the target AN. In some cases, the target AN may forward packets between the UE and the PDN via the second data radio link.