Downlink Reference Signal Grouping for Uplink Timing
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Solution Overview
Problem
In wireless communication systems, particularly in multi-Transmit Receive Point (TRP) scenarios, the handling of Timing Advance (TA) for uplink transmissions is inefficient, leading to performance degradation due to varying propagation delays and complex beam management, as existing methods require UEs to track multiple downlink reference signals for accurate timing alignment.
Innovation Solution
The system introduces a method where a base station groups downlink reference signals into interchangeable groups based on similar propagation delays, allowing user equipment (UE) to track a subset of signals for uplink timing, using Quasi Co-Location (QCL) TypeA and TypeE associations, and dynamically adjusts groupings in response to performance degradation or time expiry, reducing the overhead of RRC reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UEs track multiple downlink reference signals for accurate timing alignment in multi-TRP scenarios, then uplink timing alignment accuracy is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent segments downlink reference signals into multiple groups, where each group contains reference signals with similar propagation delays. The UE tracks one reference signal per group, reducing the total number of tracked signals while maintaining timing alignment accuracy for multi-TRP scenarios.
Solution Approach 2:
The patent introduces dynamic grouping where the base station can reconfigure reference signal groups based on changing channel conditions, UE mobility, and performance requirements. This allows the system to adaptively adjust the number of tracked reference signals, balancing accuracy and complexity in real-time.
2Reliability
If the base station reconfigures reference signal groups dynamically to adapt to channel changes, then uplink performance is improved, but RRC reconfiguration overhead increases
Solution Approach 1:
The patent implements periodic evaluation of reference signal group configurations based on predefined criteria such as time expiry, performance degradation thresholds, or channel condition changes. This periodic approach allows dynamic adaptation when needed while avoiding unnecessary reconfigurations during stable conditions, reducing overall overhead.
Solution Approach 2:
The system uses feedback mechanisms where the base station monitors uplink performance metrics and channel conditions, then triggers reconfiguration only when performance degradation is detected or predefined thresholds are exceeded. This feedback-driven approach optimizes performance while minimizing unnecessary RRC reconfigurations.
3Loss of information
If UEs track all downlink reference signals from multiple TRPs, then comprehensive timing information is obtained, but processing overhead and power consumption increase
Solution Approach 1:
The patent extracts and groups reference signals with similar propagation delay characteristics, allowing the UE to selectively track only one representative signal from each group. This extraction approach maintains comprehensive timing information for multi-TRP scenarios while significantly reducing the number of signals the UE must process, thereby lowering power consumption.
4Ease of manufacture
If the system uses fixed reference signal groupings, then configuration simplicity is maintained, but adaptability to changing channel conditions deteriorates
Solution Approach 1:
The patent implements dynamic reference signal grouping where the base station can reconfigure groups based on UE feedback, channel conditions, and performance metrics. The system maintains simple initial configuration but enables adaptive reconfiguration when needed, balancing ease of deployment with flexibility to handle varying channel conditions in multi-TRP environments.
Data Source
AI summary
An apparatus includes means for receiving, from a base station, an indication of at least one group of downlink reference signals for tracking, by the apparatus, downlink reception time to use for uplink transmissions at the apparatus; means for tracking, for uplink transmissions at the apparatus, at least one downlink reference signal within each of the at least one group of downlink reference signals.