Dynamic CQI Threshold Adjustment for URLLC Reliability
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Solution Overview
Problem
Current methods for determining Channel Quality Indicators (CQI) in 5G networks, especially for URLLC services, face challenges due to the stochastic nature of wireless channels and the outdated CQI issue, leading to inefficiencies in adapting thresholds for low target BLERs like 0.001%, which results in slow response to changes and reliability issues.
Innovation Solution
A method that calculates a variation quantification parameter (αi) to assess channel changes and uses a reliability index to apply a correction margin, adjusting CQI thresholds dynamically to ensure target BLERs are met, thereby improving the precision and reliability of CQI estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CQI threshold methods are used for URLLC services, then the system maintains compatibility with existing 4G standards, but the response to channel changes is slow and reliability is insufficient for low target BLERs like 0.001%
Solution Approach 1:
The patent implements dynamic adaptation of CQI thresholds by introducing a variation quantification parameter (αi) that captures channel changes between measurements. The threshold is no longer static but adapts dynamically based on the measured channel variation, allowing the system to respond quickly to channel conditions while maintaining reliability for URLLC services with target BLER of 0.001%.
Solution Approach 2:
The patent changes the parameter of CQI threshold from a fixed value to a variable that depends on the measured channel variation αi. By modifying the threshold parameter dynamically based on actual channel conditions, the system achieves both fast response to channel changes and high reliability, resolving the contradiction between response time and reliability.
2Measurement precision
If CQI is calculated based on outdated measurements, then the calculation process is simple, but the precision of CQI estimation deteriorates due to channel variations
Solution Approach 1:
The patent performs preliminary measurement of the channel variation parameter αi between CQI measurement instant and data reception instant. By pre-quantifying the channel variation, the system can later compensate for outdated CQI measurements without requiring complex real-time re-measurement, thus improving precision while keeping calculation complexity manageable.
Solution Approach 2:
The patent introduces the channel variation parameter αi as an intermediary that bridges the gap between outdated CQI measurements and current channel conditions. This intermediary parameter allows the system to correct outdated measurements without directly measuring current conditions, achieving high precision with moderate computational complexity.
3Adaptability or versatility
If the system uses fixed CQI thresholds for all conditions, then the device complexity is low, but the adaptability to different channel conditions and services is insufficient
Solution Approach 1:
The patent applies local quality by making CQI thresholds specific to local channel conditions rather than using a universal fixed threshold. The threshold is locally adapted based on the measured channel variation αi and the specific service requirements (e.g., URLLC with BLER=0.001%), allowing each transmission to be optimized for its specific conditions without requiring complex global optimization.
Data Source
AI summary
The present invention relates to a communications channel adaptation method for URLLC services which is configured for ensuring reliability when implementing said URLLC services and executed in a communications system with at least one transmitter node (eNode) and a receiver or mobile terminal, wherein the receiver or mobile terminal measures the desired signal-to-interference ratio (SIR) from the reference signal received in instant t=i−1 and saves this SIR value (SIRi-1) in a memory; wherein based on this SIR value in instant t=i−1 (SIRi-1), a CQI value (CQIi-1) is determined and sent to the transmitter node (eNode), which selects the modulation and coding format in the subsequent transmission (MCSi) in the downlink according to that CQI measured in instant t=i-1 (CQIi-1); and wherein upon receiving in instant t=i the data packet sent by the transmitter node (eNode), the receiver terminal measures the SIR (SIRi) and saves it in a memory.