Base Station UE Context Retrieval via MME
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Solution Overview
Problem
In wireless communication systems, user equipment (UE) handover failures often occur due to the lack of valid context information at the new cell's base station, leading to delayed and unsuccessful re-establishment of RRC connections, especially when there is no X2 network interface between the original and new cells.
Innovation Solution
A method where the first base station determines if it meets the condition for requesting UE context information by checking connectivity with the UE's MME and the original base station, and if not, it sends a context information request to the MME, which then retrieves and responds with the necessary context information to facilitate RRC connection re-establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the UE uses DRX to reduce power consumption, then power consumption is reduced, but handover reliability deteriorates due to low listening frequency
Solution Approach 1:
The patent applies preliminary action by having the base station proactively determine and prepare context information retrieval conditions before handover occurs. The base station checks whether it meets the conditions for requesting UE context information (such as having an X2 interface with the original cell or being connected to the same MME) in advance, and initiates context fetch procedures before the actual handover failure can occur, thereby ensuring handover reliability while maintaining DRX power savings.
2Loss of information
If the base station uses context fetch procedure from original cell, then UE context information can be obtained, but connection re-establishment time increases due to additional signaling
Solution Approach 1:
The base station performs preliminary determination of context retrieval conditions and initiates context information requests in advance. By checking whether the base station meets the conditions (having X2 interface or same MME connection) before handover failure occurs, and proactively fetching context information when conditions are met, the system reduces the time needed during actual connection re-establishment operations.
Solution Approach 2:
The patent introduces the MME (Mobility Management Entity) as an intermediary when the direct X2 interface between base stations is unavailable. The base station requests context information through the MME as an intermediate node, which then retrieves the context from the original cell and forwards it back, enabling context transfer without requiring direct base station-to-base station connectivity.
3Adaptability or versatility
If there is no X2 network interface between new cell and original cell, then cell reselection flexibility is improved, but context fetch procedure fails
Solution Approach 1:
The patent employs the MME as an intermediary to bridge the gap when direct X2 interface is absent. The base station sends context information requests through the MME, which acts as a mediator to retrieve context from the original cell and deliver it to the new cell, thus maintaining context fetch reliability while preserving cell reselection flexibility.
Solution Approach 2:
The system achieves universality by supporting multiple context retrieval paths: direct X2 interface when available, and MME-mediated retrieval when X2 interface is unavailable. This multi-functional approach ensures that context fetch procedure remains reliable regardless of network topology or cell reselection scenarios.
4Adaptability or versatility
If the base station requests UE context information through MME, then context information can be obtained without X2 interface, but signaling complexity increases
Solution Approach 1:
The MME serves as a standardized intermediary with predefined signaling protocols, which simplifies the overall process compared to implementing custom direct base station communication. By using the existing MME infrastructure for context retrieval when X2 interface is unavailable, the system avoids adding complex custom signaling mechanisms while maintaining extended context retrieval capability.
Data Source
AI summary
The invention discloses a method of obtaining user equipment context information that includes: receiving, by a first base station, a first radio resource control (RRC) connection establishment request sent by a user equipment (UE), where the first RRC connection establishment request carries connection status information before the UE sends the first RRC connection establishment request; determining, by the first base station according to the connection status information, whether the first base station meets a condition for requesting the UE context information; if the first base station determines that the first base station does not meet the condition for requesting the UE context information, sending, by the first base station, the UE context information establishment request to a mobility management entity (MME); and receiving, by the first base station, a response message sent by the MME for responding to the UE context information establishment request, where the response message carries the UE context information.