UE Handover GNSS Measurement Reporting for Guard Timer Control
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Solution Overview
Problem
In non-terrestrial networks, user equipment (UE) may face challenges in determining the need for global navigation satellite system (GNSS) measurements during handover, leading to potential handover failures and resource wastage due to incorrect configuration of guard timers and resource reservation by the network side, as the network is unaware of the UE's GNSS acquisition requirements.
Innovation Solution
The UE determines the need for location measurements and reports this requirement to the network, allowing the network to adjust guard timers and resource reservation based on the UE's measurement validity duration and conditions, thereby optimizing handover processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network side reserves target BS resources earlier before UE accesses to target BS, then handover reliability is improved, but network resource waste increases
Solution Approach 1:
The network side performs preliminary resource reservation at the target base station based on handover prediction information from the source base station. This allows resources to be prepared in advance for UEs that are likely to handover, improving handover reliability while avoiding reservation for all UEs, thus reducing resource waste.
Solution Approach 2:
The source base station provides feedback to the network side about UE GNSS acquisition status and handover requirements. This feedback enables the network to make informed decisions about resource reservation timing and duration, ensuring resources are reserved only when necessary and for the appropriate duration, balancing reliability with resource efficiency.
2Device complexity
If the network side configures guard timer T304 without knowledge of UE GNSS measurement requirement, then device complexity is reduced, but handover failure rate increases
Solution Approach 1:
The source base station provides feedback to the network side about UE GNSS acquisition status and handover requirements. This feedback enables the network to make informed decisions about resource reservation timing and duration, ensuring resources are reserved only when necessary and for the appropriate duration, balancing reliability with resource efficiency.
Solution Approach 2:
The guard timer T304 configuration is dynamically adjusted based on UE-specific parameters such as GNSS acquisition status and measurement requirements. Instead of using a fixed timer value for all UEs, the network adapts the timer duration to match each UE's actual needs, preventing premature timer expiration and handover failures.
3Measurement precision
If UE performs GNSS (re)acquisition before accessing target BS, then positioning accuracy is improved, but handover time delay increases
Solution Approach 1:
The source base station identifies UEs that have already acquired valid GNSS position information before handover and provides this information to the network side. This allows these UEs to skip GNSS (re)acquisition at the target base station, reducing handover time delay while maintaining positioning accuracy through the use of pre-acquired valid GNSS data.
Solution Approach 2:
The requirement for GNSS (re)acquisition is extracted and removed for UEs that already possess valid GNSS position information. By identifying and excluding these UEs from the mandatory (re)acquisition process, the system reduces unnecessary time delays while still ensuring accurate positioning for UEs that need to perform (re)acquisition.
Data Source
AI summary
Disclosed are devices, methods, apparatuses, and computer readable media for handover. An example terminal device may include at least one processor and at least one memory. The at least one memory may store instructions that, when executed by the at least one processor, may cause the terminal device at least to perform: determining a measurement for at least location information is to be required or unrequired during a handover from a source network device to a target network device; determining a requirement to complete the measurement; and reporting to the source network device, the requirement to complete the measurement in a case where the measurement is determined to be required.