Uplink Timing Adjustment Granularity in Mobile Communication
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Solution Overview
Problem
The conventional mobile communication systems, such as LTE and NR, face a challenge in achieving precise uplink synchronization due to the discrete TA step (16 Ts), resulting in a TA granularity error of 260 ns, which can lead to maximized uplink synchronization errors.
Innovation Solution
The proposed solution involves a timing adjustment (TA) method that improves granularity by allowing terminals to acquire TA granularity-related information from the base station, which includes cell size, application information, TA command bit-width, and TA step, enabling terminals to determine an optimized TA step for uplink frame transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a discrete TA step of 16 Ts is used for timing adjustment, then the system can maintain simple timing control, but the TA granularity error increases to 260 ns
Solution Approach 1:
The patent applies dynamics by making the TA step configurable rather than fixed. The base station can dynamically adjust the TA step size based on propagation delay characteristics, allowing the system to adapt between coarse timing control (larger TA steps) and fine timing adjustment (smaller TA steps), thereby resolving the contradiction between simplicity and precision
Solution Approach 2:
The patent changes the parameter of TA step size from a fixed value (16 Ts) to a configurable parameter that can be adjusted based on system conditions. By allowing the TA step to vary according to propagation delay and synchronization requirements, the system achieves both simple control mechanisms and high measurement precision when needed
2Device complexity
If the TA step is increased to reduce the number of adjustment levels, then the device complexity is reduced, but the uplink synchronization precision deteriorates
Solution Approach 1:
The system dynamically adjusts the TA step size based on propagation delay characteristics. For distant terminals with large propagation delays, larger TA steps are used to reduce the number of adjustment levels. For nearby terminals, smaller TA steps provide finer granularity, thereby maintaining high synchronization reliability without uniformly increasing device complexity
3Device complexity
If a fixed TA granularity is used for all terminals, then the system configuration is simplified, but terminals in different locations experience different synchronization errors
Solution Approach 1:
The patent applies local quality by tailoring the TA step size to specific terminal locations and propagation delay characteristics. Different terminals or terminal groups can be assigned different TA step sizes according to their distance from the base station, ensuring that each terminal receives appropriate timing adjustment granularity for its specific conditions, thereby reducing synchronization errors without requiring a completely custom configuration for each terminal
Data Source
AI summary
A timing adjustment method performed by a terminal may include: acquiring downlink synchronization with a base station; obtaining, from the base station, TA granularity-related information; transmitting, to the base station, a preamble and/or an SRS; receiving, from the base station, a TA command generated based on the preamble and/or SRS; determining a timing for uplink frame transmission by interpreting the TA command based on a TA granularity determined based on the TA granularity-related information; and performing the uplink frame transmission based on the determined timing.