5G NR Timing Advance Quantization Across Subcarrier Spacings
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Solution Overview
Problem
The challenge in 5G New Radio (NR) is the need for flexible timing advance (TA) quantization units due to varying subcarrier spacings, which affect uplink synchronization and orthogonality among user equipment (UEs) with different cell radii and channel configurations.
Innovation Solution
A method for determining timing advance groups based on subcarrier spacing configurations, using predefined bit values and quantization units to adjust TA for different subcarrier spacings, ensuring uplink synchronization and orthogonality across varying cell radii.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed TA quantization unit (16 Ts) is used for all subcarrier spacings, then the signaling format remains simple, but the uplink timing alignment accuracy deteriorates for larger subcarrier spacings
Solution Approach 1:
The patent applies dynamics by making the TA quantization unit variable rather than fixed. The quantization unit is dynamically adjusted based on the subcarrier spacing configuration, where larger subcarrier spacings use finer quantization units (e.g., 16 Ts for 15 kHz, 8 Ts for 30 kHz, 4 Ts for 60 kHz) to maintain timing alignment accuracy across different numerologies
Solution Approach 2:
The patent changes the parameter of TA quantization unit size according to subcarrier spacing. By linking the quantization unit size to the subcarrier spacing parameter, the system adapts the timing precision to match the frequency domain granularity, ensuring that timing accuracy scales appropriately with the chosen numerology
2Length of stationary object
If the TA time range is extended to support larger cell radii, then the coverage area increases, but the TA quantization resolution decreases
Solution Approach 1:
The patent segments the TA parameter space by creating separate TA fields for different subcarrier spacing configurations. Each TA field is optimized for its specific subcarrier spacing, with appropriate quantization units and ranges. This segmentation allows the system to maintain high resolution for each segment while supporting a wide overall range through the use of multiple segments corresponding to different numerologies
Solution Approach 2:
The patent changes the TA field parameters (quantization unit size and bit width) based on the subcarrier spacing configuration. For example, when using 15 kHz subcarrier spacing with a specific cell radius, the system configures an appropriate TA field size and quantization unit, and adjusts these parameters when switching to different subcarrier spacings to maintain optimal resolution for each configuration
3Measurement precision
If different TA quantization units are used for different subcarrier spacings, then the timing alignment accuracy improves, but the signaling overhead increases
Solution Approach 1:
The patent creates a universal TA indication mechanism that works across all subcarrier spacing configurations. By defining a standardized relationship between subcarrier spacing and TA quantization units, and by using a common RA-RNTI calculation method that incorporates the SCS index, the system achieves multi-functionality where a single signaling framework supports multiple numerologies without requiring separate dedicated signaling for each configuration
Solution Approach 2:
The patent changes the interpretation of TA parameters based on the subcarrier spacing context rather than transmitting separate TA values for each configuration. The UE determines the appropriate quantization unit by referencing the configured subcarrier spacing, allowing the same TA field to convey different levels of precision depending on the active numerology, thereby reducing signaling overhead while maintaining accuracy
Data Source
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AI summary
A timing advance indication method, a base station, a terminal and a device are provided. The method includes: transmitting subcarrier spacing configuration information of a physical uplink shared channel and/or a physical uplink control channel to a terminal; receiving a preamble fed back by the terminal based on subcarrier spacing configuration information; obtaining a quantized value of a timing advance corresponding to a tracking area based on the preamble; and transmitting the quantized value of the timing advance to the terminal.