User Equipment PLMN Search Optimization for NTN Terrestrial Handover
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Solution Overview
Problem
Current wireless communication systems face challenges in optimizing terrestrial network acquisition time and user equipment (UE) power consumption when transitioning from non-terrestrial networks (NTNs) to terrestrial networks (TNs), leading to prolonged connection times and high power consumption.
Innovation Solution
Implementing a method for power management at UE, which includes establishing an RRC connection with an NTN-based PLMN, determining the current location, and performing a PLMN search only if the distance exceeds a threshold, or skipping the search if close, and activating a sleep state when no uplink data is required, to optimize power usage and reduce unnecessary scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE performs frequent PLMN searches to quickly acquire terrestrial network coverage, then the terrestrial network acquisition time is reduced, but the UE power consumption increases
Solution Approach 1:
The patent dynamically adjusts the PLMN search timer value based on UE mobility state. When the UE is in idle mode and determines it is stationary or moving slowly, it extends the PLMN search timer to reduce the frequency of PLMN searches, thereby saving battery power. When the UE detects high mobility, it reduces the timer value to enable faster PLMN acquisition. This adaptive parameter adjustment resolves the contradiction by optimizing the balance between acquisition speed and power consumption based on actual mobility conditions.
Solution Approach 2:
The UE autonomously determines its own mobility state by monitoring location changes and signal quality metrics, and self-adjusts the PLMN search timer without requiring network intervention. The device performs self-service by evaluating its own operational context (idle vs. connected mode, mobility state) and independently optimizing its PLMN search behavior accordingly, reducing unnecessary searches when stationary and enabling rapid acquisition when moving.
2Reliability
If the UE continuously monitors for higher priority PLMNs while connected to NTN, then the network priority optimization is improved, but the power consumption and resource wastage increase
Solution Approach 1:
The patent implements partial monitoring by introducing a conditional approach to PLMN searches. Instead of continuously monitoring for higher priority PLMNs, the UE performs partial searches based on triggering conditions such as timer expiration, location changes, or signal quality degradation. This partial action approach maintains adequate network priority optimization while significantly reducing power consumption and resource wastage compared to continuous monitoring.
Solution Approach 2:
The UE performs PLMN searches periodically based on a configurable timer rather than continuously. The periodic search mechanism allows the system to balance between detecting higher priority networks and conserving energy. The timer can be adjusted based on mobility state and network conditions, enabling the UE to perform searches at appropriate intervals without wasting resources on excessive monitoring.
3Speed
If the UE performs PLMN search immediately upon completing data transmission, then the network switching speed is improved, but the power consumption increases due to unnecessary scanning
Solution Approach 1:
The patent prepares for potential network switching by pre-configuring PLMN search parameters and maintaining readiness states without immediately initiating full PLMN searches upon data transmission completion. The system performs preliminary checks such as evaluating whether the current NTN connection is still adequate, checking for pending higher priority network indications, and preparing search configurations in advance. This preliminary action allows the UE to quickly switch networks when necessary while avoiding unnecessary full-scale scans that would consume excessive power.
Data Source
AI summary
A method and a system for optimizing acquisition time and power consumption at a user equipment (UE) are provided. The method includes establishing, by the UE located at an initial location, a radio resource control (RRC) connection with a non-terrestrial network (NTN)-based public land mobile network (PLMN), determining a current location of the UE based on one or more predetermined parameters, determining whether to perform a PLMN search for identifying a PLMN with a higher priority than connected NTN-based PLMN based at least on the initial location and the current location of the UE; and performing one of performing the PLMN search upon determining that a distance between the initial location and the current location of the UE is greater than a predetermined threshold distance value, or skipping the PLMN search upon determining that the distance between the initial location and the current location of the UE is less than the predetermined threshold distance value.