UE Capability Acquisition During Inter-System Handover
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Solution Overview
Problem
In the process of inter-system handover from a GERAN system to an LTE system, the UE capability information exceeds the transmission limit of the GERAN system, leading to incomplete information transfer and unnecessary signaling overheads, as the GERAN system can only transmit up to 255 bytes, causing the target base station to uncertain about the completeness of the received UE capability information.
Innovation Solution
A method where the target base station determines if the received UE capability information is complete by receiving first UE capability information and, if incomplete, acquires the complete capability information by sending a capability enquiry request to the UE, ensuring accurate resource allocation and reducing signaling overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE capability information is transmitted through GERAN system during handover, then handover process can be completed, but the UE capability information becomes incomplete due to 255-byte transmission limit
Solution Approach 1:
The patent segments the UE capability information transmission into two parts: first UE capability information transmitted through GERAN system (within 255-byte limit) and second UE capability information transmitted directly from UE to target base station after handover. This segmentation allows complete capability information to be delivered despite GERAN's transmission limitations.
Solution Approach 2:
The patent performs preliminary transmission of first UE capability information through GERAN system before handover completion, then follows up with second UE capability information transmission after handover. This preliminary action ensures that at least partial capability information is available to the target base station in time for handover processing.
2Measurement precision
If target base station requests complete UE capability information after handover, then accurate resource allocation can be achieved, but signaling overhead increases
Solution Approach 1:
The patent applies partial action by transmitting only the necessary first UE capability information through GERAN system during handover, then conditionally transmitting the second UE capability information directly from UE to target base station. This avoids unnecessary complete capability requests and responses, reducing signaling overhead while ensuring accuracy when needed.
Solution Approach 2:
The patent implements a feedback mechanism where the target base station evaluates the received first UE capability information and determines whether to request additional second UE capability information from the UE. This feedback-based approach optimizes signaling by requesting complete information only when necessary, balancing accuracy requirements with overhead reduction.
Data Source
AI summary
Embodiments of the present invention provide a method for acquiring a UE capability, a terminal, and a base station. A method for acquiring a UE capability includes: receiving, by a target base station, a handover request sent by a core network device or a source base station, where the handover request carries first UE capability information; and if the first UE capability information indicates an incomplete capability of a UE, after the UE is handed over to the target base station, the target base station determines, according to the first UE capability information, whether to acquire a complete capability of the UE.