NTN Terminal Timer Control for Uplink Synchronization
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Solution Overview
Problem
In non-terrestrial network (NTN) systems, there is a lack of clarity on how a terminal device determines uplink synchronization or out-of-synchronization after closed-loop frequency domain offset adjustment is introduced.
Innovation Solution
A communication method and apparatus that utilize timers to determine uplink synchronization or out-of-synchronization by running a timer upon receiving a message for frequency domain offset and/or timing advance (TA) adjustment, based on the timer's state, and optionally using separate or combined timers for frequency and TA adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop frequency domain offset adjustment is introduced in NTN system, then frequency offset correction capability is improved, but uplink synchronization determination becomes unclear
Solution Approach 1:
The network device pre-configures a timer for the terminal device before frequency domain offset adjustment is performed. This timer is activated when the terminal receives the adjustment message, and its expiration indicates uplink out-of-synchronization state, providing a clear synchronization determination mechanism in advance.
Solution Approach 2:
A timer is introduced as an intermediary mechanism between frequency domain offset adjustment and uplink synchronization determination. The timer translates the abstract synchronization state into a concrete, measurable time-based indicator, making synchronization status detectable and manageable.
2Reliability
If timer mechanism is implemented for synchronization determination, then uplink synchronization control is improved, but device complexity increases
Solution Approach 1:
The timer mechanism serves multiple functions: it determines uplink synchronization status, indicates out-of-synchronization state upon expiration, and works with both frequency domain offset adjustment and timing advance adjustment. This multi-functionality reduces the need for separate mechanisms for different adjustment types.
Solution Approach 2:
The terminal device autonomously manages the timer based on received adjustment messages without requiring continuous network intervention. The device itself determines synchronization status by monitoring timer state, reducing overall system complexity while maintaining reliability.
Data Source
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AI summary
Provided are a communication method and a communication apparatus. The method comprises: after receiving a first message sent by a network device, a terminal device runs a timer, wherein the first message is used for the terminal device to perform frequency domain offset adjustment and/or timing advance (TA) adjustment; and the terminal device determines, according to the running state of the timer, whether uplink out-of-synchronization has occurred. In the method of embodiments of the present application, after introducing closed-loop frequency domain offset adjustment, the terminal device can determine whether uplink out-of-synchronization has occurred.