Conditional Handover Control for NES Mode Cell Transitions
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Solution Overview
Problem
Existing handover procedures in cellular networks fail to effectively manage the transition to a power saving mode (NES mode) without compromising quality of service, leading to potential degradation in user experience and increased signaling complexity.
Innovation Solution
A terminal apparatus and base station apparatus implement conditional handover control by evaluating multiple event conditions, including time-based and quality-based criteria, to proactively manage handovers before entering the NES mode, reducing the need for complex signaling and ensuring seamless transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing handover procedures are used without conditional handover control, then the handover process is simpler, but the robustness and success probability of handover during NES mode transitions deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-configuring handover parameters and candidate target cells before the NES mode transition occurs. The terminal apparatus evaluates event conditions and prepares handover in advance, which ensures handover success during the actual transition while avoiding complex real-time decision-making during the mode change.
2Reliability
If conditional handover control with multiple event conditions is implemented, then the robustness of handover processes is improved, but the signaling overhead and complexity increase
Solution Approach 1:
The patent extracts and separates the handover control logic into distinct event conditions (first event condition for normal operation, second event condition for NES mode transition). By taking out the NES-specific handover control as a separate evaluable condition, the system maintains robustness while organizing signaling efficiently, reducing redundant information transmission.
3Loss of information
If the terminal apparatus evaluates only the first event condition, then the signaling overhead is reduced, but the ability to maintain quality of service during NES mode transitions deteriorates
Solution Approach 1:
The patent implements dynamic evaluation of event conditions based on the current cell state. The terminal apparatus dynamically switches between evaluating only the first event condition (during normal operation) and evaluating both first and second event conditions (when NES mode transition is detected). This dynamic approach maintains quality of service during transitions while minimizing signaling overhead during stable operation.
4Speed
If handover is performed without evaluating NES mode-specific conditions, then the handover procedure is faster, but the quality of service during power saving mode transitions deteriorates
Solution Approach 1:
The patent applies preliminary action by having the terminal apparatus pre-evaluate the second event condition related to NES mode transition before actually executing handover. This allows the system to prepare and decide on handover necessity in advance, maintaining quality of service during transitions while enabling relatively fast execution since the decision logic is already evaluated.
Data Source
AI summary
A terminal apparatus includes: a controller configured to perform control corresponding to a first cell state that is a first mode and a second cell state that is a second mode different from the first mode; and a receiver configured to receive information regarding a second condition that is a condition indicating that a third event condition is no longer fulfilled in a case of a second time at which a predetermined duration has elapsed from a first time from the base station apparatus, wherein the receiver receives a PDCCH notifying of validation of the third event condition from the base station apparatus, and the controller controls to perform evaluation of a first event condition of conditional handover corresponding to the first cell state until a first condition that the PDCCH is received is fulfilled.