Path Switching Using User Text Information for RAN Node Resume
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the LTE and 5G systems, there is a challenge in obtaining user text information across RAN nodes when a UE moves, which can lead to user resume failures and cache data forwarding failures due to the lack of existing interfaces like X2, especially in scenarios where the core network is unaware of the user's state changes.
Innovation Solution
A path switching method and apparatus that involves sending a user text obtain request message to a source base station or RAN node, receiving user text information, and establishing a data transmission channel to forward cached data, using identifiers like user text IDs, MME IDs, and data forwarding addresses to ensure seamless user text resume across RAN nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE moves between RAN nodes in inactive state, then the UE can maintain low power consumption and rapid resume capability, but the target RAN node cannot obtain user text information from the source RAN node due to lack of direct interface
Solution Approach 1:
The patent introduces the core network (specifically the MME) as an intermediary to facilitate information exchange between RAN nodes. When a UE moves from source to target RAN node, the target RAN node queries the MME for user text information, which the MME retrieves from the source RAN node via the S1 interface. This mediator approach enables information transfer without requiring direct X2 interfaces between RAN nodes, resolving the contradiction between maintaining simple RAN node architecture and ensuring reliable user resume.
Solution Approach 2:
The patent extends the existing S1 interface functionality to serve dual purposes: its original function for connected state signaling and an additional function for obtaining user text information during inactive state transitions. By making the S1 interface multi-functional, the system avoids adding new dedicated interfaces while still enabling the target RAN node to acquire necessary user information from the source RAN node through the core network.
2Speed
If direct X2 interface is used between RAN nodes for user text information transfer, then the information transfer speed is fast, but the network architecture becomes more complex and requires additional interface maintenance
Solution Approach 1:
The patent makes the existing S1 interface multi-functional by enabling it to carry user text information transfer in addition to its original signaling functions. The MME utilizes the established S1 interface connection with RAN nodes to retrieve and forward user text information, eliminating the need for separate dedicated interfaces while maintaining efficient information transfer through the core network's existing infrastructure.
Solution Approach 2:
The patent creates a logical copy of the direct RAN node-to-RAN node information transfer path by routing it through the core network. Instead of implementing a physical X2 interface, the system replicates the information exchange function using existing S1 interfaces and MME processing, achieving the same functional outcome without the physical complexity of additional direct connections between RAN nodes.
3Reliability
If the core network is made aware of all user state changes, then the user text information can be properly managed, but the signaling overhead between RAN and core network increases
Solution Approach 1:
The patent implements a selective information management approach where the core network (MME) is made aware only of specific critical state changes (suspend and resume) that require user text information management, rather than being notified of all user state transitions. This localized awareness approach allows the MME to maintain necessary user text information for inactive state transitions while minimizing unnecessary signaling overhead for other state changes that do not require core network involvement.
Data Source
AI summary
Disclosed is a path switching method and apparatus based on user text information, including that: (401) when a UE is switched into an inactive state on a source random access network (RAN) node and paging of the UE is initiated by the source RAN node, a target RAN node receives a resume request message sent by the UE, and sends a user text obtain request message to the source RAN node; (402) the target RAN node receives a user text obtain response message sent by the source RAN node, where the user text obtain response message carries user text information on the source RAN node; (403) after a data transmission channel is established between the source RAN node and the target RAN node according to information carried in the user text obtain request message, the target RAN node receives data cached locally and forwarded by the source RAN node.