Adaptive Time-to-Trigger Handling for Wireless Handovers
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Solution Overview
Problem
The fixed time-to-trigger (TtT) parameter in wireless communication systems leads to a trade-off between system stability and response time, causing either delayed handovers or frequent ping-ponging, which results in suboptimal performance, especially in scenarios where a user equipment (UE) is moving between cells.
Innovation Solution
Adapting the TtT parameter based on signal quality measurements by setting quality thresholds and scaling the TtT value using quality scaling factors (QSF) to dynamically adjust the waiting period for state transitions, ensuring timely handovers without flooding the network with unnecessary reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed time-to-trigger (TtT) parameter is used to delay state transitions, then system stability is improved and ping-ponging between states is prevented, but response time deteriorates and handovers are delayed
Solution Approach 1:
The patent applies dynamics by making the TtT parameter variable rather than fixed. The TtT value is dynamically adjusted based on signal quality measurements and scaling factors, allowing the system to adapt the waiting period to current conditions. This resolves the contradiction by enabling short TtT when signal quality is good (improving response time) while maintaining longer TtT when signal quality is poor (maintaining stability).
Solution Approach 2:
The patent implements parameter changes by modifying the TtT parameter based on signal quality measurements. Quality scaling factors (QSF) are applied to adjust the TtT value dynamically. This allows the system to change the TtT parameter according to environmental conditions, resolving the contradiction between stability and response time by optimizing the parameter for current signal conditions.
2Loss of time
If a short TtT parameter is used to improve response time, then handovers occur more quickly, but system stability deteriorates and ping-ponging between states increases
Solution Approach 1:
The dynamic adjustment mechanism allows the system to use short TtT values only when signal quality measurements indicate stable conditions. The quality scaling factors ensure that short TtT values are applied selectively rather than universally, preventing ping-ponging while maintaining quick response when appropriate.
Solution Approach 2:
The system uses feedback from signal quality measurements to determine the appropriate TtT value. By continuously monitoring signal quality and adjusting TtT based on these measurements, the system can quickly respond to genuine handover opportunities while filtering out transient fluctuations that would cause ping-ponging.
3Ease of operation
If a fixed TtT parameter is used, then device complexity is reduced and operation is simpler, but adaptability to different conditions deteriorates
Solution Approach 1:
The system performs self-service by automatically adjusting the TtT parameter based on its own signal quality measurements. The UE autonomously calculates quality scaling factors and applies them to determine the appropriate TtT value without requiring external configuration or complex manual tuning, maintaining ease of operation while improving adaptability.
Solution Approach 2:
The system automatically changes the TtT parameter based on measured signal conditions. Quality scaling factors are computed and applied to adjust TtT dynamically, allowing the system to adapt to different environmental conditions without increasing operational complexity or requiring manual intervention.
Data Source
AI summary
Time-to-trigger (TtT) time periods are usually fixed. A better TtT parameter is adapted based on the signal quality that a receiver perceives from its surrounding area. For example, the lower the value of a first signal quality at the same time that the value of a second signal quality is greater than a trigger threshold, the shorter the TtT parameter becomes.