Terminal Timing Adjustment in Non-Terrestrial Networks
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Solution Overview
Problem
Conventional TA control in non-terrestrial networks (NTN) relies on terminals having a positioning function, which is not feasible for devices without GNSS, leading to inadequate timing adjustment calculations for uplink transmissions.
Innovation Solution
A terminal is designed to receive a command for a first timing adjustment value from a base station and calculate a second timing adjustment value using the received information, enabling appropriate timing alignment in NTN even without a positioning function, by utilizing a reference point and orbital information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TA control is used in NTN, then timing adjustment can be performed, but it requires the terminal to have a positioning function which increases device complexity and power consumption
Solution Approach 1:
The patent extracts the positioning function requirement from the TA control process by introducing a network-provided reference timing value that replaces the need for terminal-based positioning. The terminal no longer needs to independently determine its position or calculate timing adjustments based on positioning data, as this information is now provided by the network through the TAC field in downlink messages.
Solution Approach 2:
The patent introduces an intermediary reference timing value (first timing adjustment value) provided by the base station that mediates between the network's timing requirements and the terminal's transmission timing. This reference value acts as a mediator that eliminates the need for direct terminal positioning while still enabling accurate timing adjustment.
2Reliability
If conventional TA control is used in NTN, then timing adjustment can be performed, but it increases power consumption due to GNSS positioning requirements
Solution Approach 1:
The patent removes the power-consuming GNSS positioning operation from the terminal by providing timing adjustment information directly from the network. The terminal no longer needs to activate positioning hardware or process positioning signals, as the first timing adjustment value is received passively through downlink communication.
Solution Approach 2:
The network performs the timing adjustment calculation service that previously required terminal-based positioning. The base station calculates and provides the first timing adjustment value, effectively self-serving the timing synchronization function that would otherwise require terminal resources.
3Use of energy by moving object
If a terminal without positioning function is used in NTN, then power consumption is reduced, but timing adjustment cannot be appropriately performed
Solution Approach 1:
The patent creates a universal timing adjustment mechanism that works for all terminals regardless of positioning capability. By providing the first timing adjustment value through network signaling, the system enables both terminals with and without positioning functions to perform timing adjustment appropriately, making the solution universally applicable to all terminal types.
Solution Approach 2:
The network-provided first timing adjustment value serves as an intermediary that enables timing adjustment for terminals without positioning functions. This mediator bridges the gap between terminals lacking positioning capability and the timing synchronization requirements of NTN.
4Measurement precision
If terminal calculates timing adjustment independently, then positioning accuracy is maintained, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the timing adjustment calculation function from the terminal and relocates it to the network. Instead of the terminal independently calculating timing adjustments based on positioning data, the base station performs this calculation and provides the result through the TAC field, eliminating the need for terminal positioning functionality.
Data Source
AI summary
A terminal includes: a reception unit configured to receive a command that designates a first timing adjustment value and information from a base station; and a control unit configured to calculate a second timing adjustment value that is used for uplink transmission in a non-terrestrial network using the information and the first timing adjustment value.