Cell Selection Parameters for REDCAP Uplink Capability Gaps
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Solution Overview
Problem
Reduced capability terminal devices (REDCAP UE) face communication failures due to insufficient uplink transmit power, despite being within the downlink coverage area, as existing cell selection criteria do not account for varying uplink enhancement capabilities among devices.
Innovation Solution
A cell selection method that adjusts cell selection parameters (Srxlev and Squal) based on uplink capability information, using different offsets for devices that can and cannot perform uplink enhancement, ensuring proper cell selection and reselection to maintain communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a terminal device uses a common cell selection criterion without considering uplink enhancement capability, then the cell selection process is simple and unified, but terminal devices with low uplink transmit power (reduced capability UEs) cannot establish normal wireless communication even when within downlink coverage
Solution Approach 1:
The patent applies local quality by differentiating cell selection parameters based on terminal device characteristics. Specifically, terminal devices with uplink enhancement capability use one cell selection parameter set (e.g., SrxlevOffsetQqual), while devices without this capability use another set (e.g., SrxlevOffsetQqual-REDCAP). This allows the system to treat different terminal types differently, ensuring that reduced capability UEs can successfully establish communication by using parameters optimized for their lower transmit power, thereby resolving the contradiction between operational simplicity and communication reliability.
2Reliability
If uplink enhancement is implemented to increase transmit power for reduced capability terminals, then communication reliability improves, but the system becomes more complex as uplink enhancement capability becomes an optional feature that not all terminals support
Solution Approach 1:
The patent applies parameter changes by modifying cell selection parameters (SrxlevOffsetQqual and SrxlevOffsetQqual-REDCAP) based on the terminal device's uplink enhancement capability. Instead of changing the physical uplink transmit power through complex enhancement techniques, the system changes the selection parameters to accommodate different terminal capabilities. This approach maintains communication reliability for reduced capability UEs while avoiding the complexity of implementing optional uplink enhancement features across the entire system.
3Reliability
If different cell selection parameters are used for terminals with and without uplink enhancement capability, then communication reliability for all terminal types is ensured, but the cell selection process becomes more complex requiring terminals to determine their capability and select appropriate parameters
Solution Approach 1:
The patent applies self-service by enabling terminal devices to autonomously determine their own uplink enhancement capability and automatically select the appropriate cell selection parameters based on this determination. The terminal device itself performs the capability assessment and parameter selection without requiring complex network-side configuration or manual intervention. This self-service approach ensures communication reliability through differentiated parameters while keeping the implementation simple at the terminal side, as the device only needs to follow a straightforward capability-check-and-select process.
Data Source
AI summary
This application provides a cell selection method and apparatus, to resolve abnormal wireless communication between a terminal device and a selected cell. The method includes: A terminal device may obtain a first offset of at least one first to-be-selected cell. The first offset is used to determine a cell selection parameter of the at least one first to-be-selected cell. The cell selection parameter includes a cell selection receive level value Srxlev and/or a cell selection receive quality value Squal. Next, the terminal device may determine, based on uplink capability as to whether the terminal device can perform uplink enhancement, the cell selection parameter of the at least one first to-be-selected cell by using the first offset. Then, the terminal device may determine a first cell from the at least one first to-be-selected cell based on the cell selection parameter.