Path-Aware Conditional Handover for Blocked Cellular Links
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Solution Overview
Problem
In LTE and NR systems, handover messages often fail due to fast channel quality attenuation, terminal movement, object blocking, or prolonged measurement and preparation times, leading to handover failures and reduced success rates.
Innovation Solution
A handover method using conditional handover (CHO) configuration information, where a terminal device sends path information to a network device, receives CHO configuration information, and determines a target cell based on this information to improve handover reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional handover mechanism is used, then network device controls mobility management, but handover message may fail to be sent due to fast attenuation of channel quality, fast movement of UE, blocking of an object, or long duration of measurement or handover preparation, causing handover failure and reducing handover success rate
Solution Approach 1:
The patent applies preliminary action by sending conditional handover configuration information in advance before the actual handover is needed. The terminal device receives and stores handover configuration information for multiple candidate target cells beforehand, including path information and resource allocation. When handover conditions are met, the terminal can immediately execute the pre-prepared configuration without waiting for real-time handover messages, thus overcoming channel quality attenuation and object blocking issues.
2Reliability
If conditional handover mechanism is used, then handover reliability is improved, but current protocol does not specify how to use the CHO mechanism in an unmanned aerial vehicle scenario
Solution Approach 1:
The patent applies local quality by introducing height information as a specific parameter for unmanned aerial vehicle scenarios. The terminal device sends its height information to the network device, and the network device determines path information based on this height. This allows the handover mechanism to be adapted to the specific characteristics of UAV scenarios where height affects signal propagation and cell selection, while maintaining the overall CHO framework.
3Reliability
If terminal device sends path information to network device, then network device can provide suitable candidate cell, but requires additional information exchange and processing
Solution Approach 1:
The patent applies preliminary action by having the terminal device send path information and receive conditional handover configuration information in advance, during periods when channel conditions are good. This preliminary information exchange allows the network to prepare handover configurations before they are actually needed, reducing the complexity and time pressure of real-time handover decision-making and execution.
Data Source
AI summary
This application provides a handover method and apparatus. The handover method includes: A terminal device sends path information used to determine a first cell to a network device; and the terminal device receives conditional handover CHO configuration information that is corresponding to the first cell and that is sent by the network device, and determines a target cell based on the CHO configuration information corresponding to the first cell. According to the technical solutions provided in this application, a handover success rate can be improved when the terminal device performs cell handover.