Dynamic BLER Target Selection for Link Adaptation
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Solution Overview
Problem
Conventional link adaptation methods in wireless communication technologies face challenges in rapidly varying channel conditions due to inaccurate channel quality reports, leading to suboptimal transmission performance and decreased spectral efficiency, especially in scenarios with inter-cell interference.
Innovation Solution
A dynamic Block Error Rate (BLER) target is selected using a contextual bandit algorithm and machine learning model, which considers current channel conditions and neighbor cell interference, allowing for continuous adaptation and optimal policy mapping based on reconstructed information from additional measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed common BLER target is used for all UEs, then implementation is simple and consistent, but transmission performance deteriorates in rapidly varying channel conditions with inter-cell interference
Solution Approach 1:
The patent transforms the fixed BLER target into a dynamic one that adapts to current channel conditions. The base station determines a dynamic BLER target based on reported channel quality indicators and detected inter-cell interference levels, allowing the system to switch between conservative and aggressive transmission strategies according to real-time conditions rather than using a static value for all UEs
Solution Approach 2:
The patent changes the BLER target parameter dynamically based on interference conditions. When inter-cell interference is detected, the system adjusts the BLER target to be more conservative (higher allowed error rate), while in good conditions it uses a more aggressive target (lower allowed error rate), thereby optimizing spectral efficiency across varying network conditions
2Reliability
If a high value fixed BLER target is used to compensate for inaccurate channel quality reports, then transmission reliability improves for UEs experiencing interference, but spectral efficiency deteriorates for all UEs
Solution Approach 1:
The patent applies different BLER target values to different UEs based on their local channel conditions and interference exposure. Instead of using a uniformly high BLER target for all UEs, the system determines individual dynamic BLER targets based on each UE's reported channel quality and the base station's detection of interference affecting that specific UE, thereby maintaining reliability where needed while preserving spectral efficiency elsewhere
3Quantity of substance
If channel quality reports are systematically filtered by terminals to reduce reporting overhead, then signaling overhead is reduced, but measurement precision deteriorates due to loss of fast channel variations
Solution Approach 1:
The patent introduces an intermediary mechanism where the base station performs additional measurements and interference detection to compensate for the filtering applied at the terminal. The base station uses its own measurements of channel conditions and interference levels to determine the dynamic BLER target, effectively mediating between the filtered terminal reports and the actual channel conditions to restore measurement precision without increasing terminal reporting overhead
Data Source
AI summary
Methods and systems for dynamically selecting a link adaptation policy, LAP. In some embodiments, the method includes using channel quality information, additional information, and a machine learning, ML, model to select a LAP from a set of predefined LAPs, the set of predefined LAPs comprising a first LAP and a second LAP. In some embodiments, the additional information comprises: neighbor cell information about a second cell served by a second TRP, distance information indicating a distance between a UE and a first TRP, and/or gain information indicating a radio propagation gain between the UE and the serving node. The method further includes the first TRP transmitting data to the UE using the selected LAP.