Doppler-Aware Beam Measurement and Reporting in High-Speed Mobility
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Solution Overview
Problem
Existing wireless communication systems face challenges in high-speed mobility scenarios due to rapid variations in channel conditions, leading to outdated CSI and increased feedback overhead, which affect user perceived throughput.
Innovation Solution
Incorporating Doppler spread and coherence time measurements into beam management by the UE, allowing for the reporting of these metrics alongside traditional L1-RSRP, L3-RSRP, and L1-SINR, to enhance beam management in high-speed mobility scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI reporting frequency is increased to track rapid channel variations in high-speed mobility, then channel state accuracy is improved, but feedback overhead increases and user perceived throughput decreases
Solution Approach 1:
The patent applies dynamics by making the CSI reporting frequency adaptive rather than fixed. The UE determines its mobility state based on beam changes detected over time, and adjusts reporting frequency accordingly. High mobility scenarios trigger higher reporting frequencies while low mobility scenarios use lower frequencies, resolving the contradiction between tracking accuracy and feedback overhead
Solution Approach 2:
The patent changes the parameter of reporting frequency based on detected mobility conditions. By monitoring beam changes and determining mobility states, the system dynamically adjusts the CSI reporting frequency parameter to match channel variation rates, achieving accurate channel tracking only when necessary and reducing overhead during stable conditions
2Measurement precision
If CSI reporting frequency is increased to maintain accurate channel state information, then channel tracking quality is improved, but user perceived throughput deteriorates
Solution Approach 1:
The patent makes throughput protection dynamic by adjusting reporting frequency based on actual mobility needs. When channel conditions are stable, reporting frequency is reduced to preserve throughput. When rapid changes are detected, frequency increases to maintain tracking quality, thus dynamically balancing these competing objectives
Solution Approach 2:
The UE autonomously determines its own mobility state by monitoring beam changes and self-adjusts the CSI reporting frequency without network intervention. This self-service mechanism ensures that throughput is protected by reducing unnecessary reporting while maintaining tracking quality when the UE itself detects channel variations
3Device complexity
If traditional beam management metrics (L1-RSRP, L3-RSRP, L1-SINR) are used without Doppler spread information, then reporting complexity is reduced, but beam management accuracy in high-speed scenarios deteriorates
Solution Approach 1:
The patent applies preliminary action by having the UE determine mobility state and select appropriate reporting configurations before actual CSI reporting occurs. By pre-determining the reporting frequency and format based on detected beam changes, the system prepares the optimal reporting strategy in advance, achieving accurate beam management without adding complex real-time decision-making
Solution Approach 2:
The patent segments the beam management process into distinct phases: mobility state determination based on beam changes, and conditional CSI reporting based on that state. This segmentation allows traditional metrics to be used for basic beam selection while Doppler-aware reporting is activated only when mobility is detected, maintaining simplicity for stationary users while improving accuracy for mobile users
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of beam management by accounting for changing channel conditions, reducing feedback overhead, and maintaining effective communication in high-speed environments.
Implementation Method 1
Doppler spread at a given time instance determines how long the estimated/tracked Doppler shift for that instance is valid... The largest possible spread (Δf_Max) and the channel coherence time (Tc) may be defined as follows: The largest possible spread (Δf_Max) 1200 Hz
Implementation Method 2
channel coherence time is based on the Doppler spread of the channel which is due to the multipath propagation... the channel coherence time (Tc)≈1/(Δf_Max)=830 μs
Data Source
AI summary
A terminal is disclosed including a processor that measures for beam management: a Doppler spread or a coherence time associated with a beam and one or more reporting quantities. The terminal also includes a transceiver that reports the Doppler spread or the coherence time. In other aspects, a method for a terminal and a base station are also disclosed.