Cell Change Decision for Micro Cells Using Mobility State
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Solution Overview
Problem
Frequent cell changes in wireless communication systems, especially for high-speed user equipment, lead to increased system signaling burden, throughput, and power consumption, as well as higher failure rates due to unnecessary handovers and reselections between micro and macro cells.
Innovation Solution
A method and device that determine a user equipment's mobility state or moving speed to make informed cell change decisions, using scaled decision parameters based on whether the target cell is a micro or macro cell, thereby reducing unnecessary cell changes by setting specific offsets to invalid when high mobility is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE frequently changes cells based on signal quality comparison, then the UE can maintain connection to the highest quality cell, but the system signaling burden and UE power consumption increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the reselection timer value (Treselection) based on the UE's mobility state. When high mobility is detected, a shorter timer is used to prevent excessive cell reselections, while in low mobility scenarios, a longer timer maintains optimal connection quality. This parameter adaptation resolves the contradiction by reducing power consumption during high mobility without sacrificing connection quality during low mobility.
Solution Approach 2:
The patent implements dynamics by making the cell reselection behavior adaptive to the UE's mobility conditions. The system transitions from static cell reselection parameters to dynamic parameters that change based on detected mobility state, allowing the UE to optimize between connection quality and power consumption according to real-time movement conditions.
2Reliability
If the UE performs cell reselection based on signal quality, then the UE maintains optimal network service, but the system signaling burden increases
Solution Approach 1:
The patent reduces system signaling burden by changing the reselection timer parameter based on mobility state. During high mobility, the shortened timer prevents frequent cell reselection attempts that would generate excessive signaling, while maintaining the capability to reselect when appropriate. This parameter adaptation resolves the contradiction between maintaining service quality and reducing signaling overhead.
3Speed
If the UE changes cells frequently during high speed movement, then the UE tracks signal quality, but the cell change failure rate increases
Solution Approach 1:
The patent addresses high-speed movement by dynamically adjusting the reselection timer to a shorter duration when high mobility is detected. This parameter change prevents the UE from attempting cell reselection too frequently during high-speed movement, thereby reducing the cell change failure rate while still allowing timely reselection when signal conditions warrant it.
Data Source
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AI summary
Embodiments of the present invention provide a cell change method and device. The method includes: determining that a target cell of cell change is a micro cell, where the cell change includes cell reselection or cell handover; determining a mobility state or a moving speed of a user equipment; and making a cell change decision for the target cell according to the mobility state or the moving speed of the user equipment. In a process of making a cell change decision for a micro cell in the embodiments of the present invention, the mobility state or the moving speed of the user equipment is taken into account, to reduce unnecessary cell changes for the micro cell, thereby reducing the system burden and user equipment power consumption caused by frequent cell change.