CSFB Handover Strategy Selection for LTE-to-2G3G Fallback
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Solution Overview
Problem
Existing CSFB handover methods fail when a UE is outside the overlapping coverage area of an LTE and a 2G/3G cell, leading to handover failures and inability to use CS services.
Innovation Solution
An eNB sends a measurement control message to a UE to assess signal quality and select either blind or measurement-based handover to a 2G/3G neighboring cell, ensuring successful CSFB handover by choosing the best available cell based on signal quality reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If blind handover is used to reduce voice service setup delay, then handover speed is improved, but handover reliability deteriorates when UE is located beyond 2G/3G cell coverage
Solution Approach 1:
The patent implements dynamic handover strategy selection based on real-time measurement report conditions. The eNB dynamically determines whether to use blind handover or measurement-based handover according to the UE's location and signal quality, transforming a static handover approach into a dynamic adaptive one that optimizes both speed and reliability
Solution Approach 2:
The patent introduces measurement reports as feedback mechanisms where UEs report their measurement data to eNBs. The eNB uses this feedback information to determine the appropriate handover manner, creating a closed-loop control system that improves handover reliability while maintaining speed through informed decision-making
2Reliability
If measurement-based handover is used to improve handover reliability, then handover success rate is improved, but handover time increases
Solution Approach 1:
The patent applies partial measurement action by only performing detailed measurements when necessary (when blind handover conditions are not met). This selective measurement approach reduces unnecessary measurement time while ensuring reliable handovers are performed when needed, balancing speed and reliability
3Ease of manufacture
If preconfigured GSM/UMTS cells are used for CSFB, then voice service setup is simplified, but service availability deteriorates in non-overlapping coverage areas
Solution Approach 1:
The patent changes the handover parameter selection based on measurement conditions. Instead of using a fixed preconfigured cell, the system dynamically selects handover parameters (target cell, handover type) based on real-time measurement reports and UE location, enabling service availability across both overlapping and non-overlapping coverage areas
Data Source
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AI summary
The present invention discloses a CSFB handover method and apparatus, and a system, and belongs to the communications field. The method includes: receiving, by an eNB, a CSFB indication; sending, by the base station after receiving the CSFB indication, a measurement control message to user equipment, where the measurement control message is used to instruct the user equipment to measure cell signal quality and send a corresponding event measurement report; and according to a receiving status of the event measurement report sent by the user equipment, selecting, by the base station, to complete CSFB handover by using blind handover, or selecting to complete CSFB handover by using measurement-based handover. The apparatus includes a first receiving module, a sending module, a second receiving module, and a handover module. In the present invention, according to a receiving status of an event measurement report sent by user equipment, blind handover is selected or measurement-based handover is selected to complete CSFB handover, thereby increasing a CSFB handover success probability.