Frequency Offset Configuration for Doppler Shift Compensation in 5G NTN
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Solution Overview
Problem
In 5G/NR communication systems, high frequency offsets due to Doppler shift pose challenges in aligning signals from different transmission-reception points (TRPs), especially for UEs with high mobility or in non-terrestrial networks (NTN).
Innovation Solution
The system configures multiple timing adjustments or frequency offsets to compensate for Doppler shift, which are applied to resource element mapping, CSI-RS configuration, BWP configuration, or CORESET configuration. These adjustments are dynamically indicated to user equipment (UE) for proper alignment of signals from different TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple timing adjustments or frequency offsets are configured to compensate for Doppler shift, then signal alignment and reception quality are improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting timing adjustments and frequency offsets based on Doppler shift conditions. Multiple configurations with different parameter sets are prepared in advance, and the appropriate parameters are selected and applied according to the current channel conditions, thereby improving signal alignment without permanently increasing system complexity
Solution Approach 2:
The patent implements dynamics by making timing adjustments and frequency offsets adaptable rather than fixed. The system dynamically selects among multiple pre-configured parameter sets based on real-time conditions, allowing the system to respond to changing Doppler shift effects while maintaining manageable complexity through pre-computation of multiple scenarios
2Reliability
If multiple TRPs perform joint transmission with full subcarrier alignment, then reception quality is improved, but frequency resource utilization efficiency deteriorates
Solution Approach 1:
The patent applies partial action by implementing partial subcarrier alignment rather than requiring full alignment across all subcarriers. This allows joint transmission from multiple TRPs to proceed with sufficient alignment to maintain reception quality, while accepting that not all frequency resources achieve perfect alignment, thereby improving overall resource utilization efficiency
Solution Approach 2:
The patent implements local quality by applying different alignment requirements to different subcarrier groups. Critical subcarriers carrying essential control information receive full alignment treatment, while other subcarriers can operate with relaxed alignment requirements, optimizing the balance between reception quality and resource efficiency
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 enhances signal alignment and reception quality for UEs, particularly in scenarios with high mobility or in NTN systems, by effectively managing frequency offsets and improving overall system performance.
Implementation Method 1
Multiple Timing adjustments or frequency offsets that each at least partially compensate for Doppler shift (e.g., due to distance of a satellite transmitter or relative speed of a terrestrial receiver) of a signal, physical channel, or resource during wireless transmission are configured
Data Source
AI summary
Timing adjustments or frequency offsets that at least partially compensate for Doppler shift (e.g., due to distance of a satellite transmitter or relative speed of a terrestrial receiver) of a signal, physical channel, or resource during wireless transmission are configured. The characteristics compensated comprise one of resource element (RE) mapping, channel state information reference signal (CSI-RS) configuration, bandwidth part (BWP) configuration, or control resource set (CORESET) configuration. Information indicating the multiple configurations is transmitted from a base station (BS) to at least one user equipment (UE). The timing adjustments or frequency offsets are specifically configured for one UE, a group of UEs, or the UEs served by a single serving cell. Joint transmission from multiple cells/TRPs/spotbeams may involve partial/full subcarrier alignment.