UE Cell Selection by Service KPI for Call Drop Prevention
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Solution Overview
Problem
Existing cellular communication systems face challenges in selecting optimal cells for UE camping, particularly in 5G Stand Alone (SA) mode, leading to call drops due to low uplink link budgets during time-critical services, and there is a need for cell selection/reselection based on service-specific parameters like battery level, transmit power, and connectivity.
Innovation Solution
A method for UE to identify triggers for service initiation, check availability of frequency bands, and connect to optimal cells based on Key Performance Indicators (KPIs) such as data volume, transmitter power, battery level, and network connection, prioritizing Sub6 or mmWave cells in 5G and E-UTRAN New Radio-Dual Connectivity (ENDC) systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE camps on a cell with higher frequency band for data service, then data speed is improved, but uplink link budget deteriorates causing call drops during voice calls
Solution Approach 1:
The system dynamically changes the frequency band parameter based on the type of service being performed. When voice call service is detected, the UE switches from higher frequency bands (mmWave/Sub6) to lower frequency bands (LTE bands) to improve uplink link budget and prevent call drops. This parameter adaptation resolves the contradiction by optimizing the frequency band selection according to service requirements.
2Reliability
If the UE performs cell reselection to optimize link budget, then call reliability is improved, but service delay increases
Solution Approach 1:
The system performs preliminary actions by pre-configuring cell priority information and frequency band availability data before service initiation. When a voice call is triggered, the UE can immediately select an appropriate cell based on pre-evaluated link budget information, avoiding time-consuming cell search and reselection procedures. This preliminary preparation reduces service delay while maintaining call reliability.
3Adaptability or versatility
If the UE checks multiple frequency bands for service availability, then service compatibility is improved, but device complexity increases
Solution Approach 1:
The system implements feedback mechanisms where the network provides cell priority information and frequency band availability data to the UE. The UE uses this feedback to simplify its cell selection process, checking only the prioritized frequency bands first. This feedback-driven approach maintains service compatibility across multiple bands while reducing device complexity by avoiding exhaustive searches of all possible frequency bands.
Data Source
AI summary
A method for an optimal cell selection for a UE in a wireless network, may include receiving a plurality of KPIs associated with the UE, determining whether at least one KPI from the plurality of KPIs meets at least one KPI criteria; and performing, one of: prioritizing a sub6 cell over a mmWave cell and selecting the sub6cell cell or prioritizing a LTE cell over a sub6 cell and selecting the LTE cell or, prioritizing the LTE cell over the mmWave cell and selecting the LTE cell, and prioritizing the mmWave cell over the sub6 cell and selecting the mmWave cell in response to determining that the at least one KPI from the plurality of KPIs does not meets the at least one KPI criteria.