SR Triggering for NTN Timing Advance Reporting
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Solution Overview
Problem
In Non Terrestrial Networks (NTN), the large propagation delay causes timing issues with uplink transmission, leading to a mismatch between the Timing Advance (TA) value used by terminals and the offset parameter koffset configured by the network, resulting in failed uplink transmissions due to unavailable uplink resources.
Innovation Solution
A method and device that trigger a Scheduling Request (SR) when a Timing Advance report is needed, allowing the terminal to report its TA to the network, enabling the network to configure a suitable koffset for the terminal, ensuring timely and accurate uplink resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal uses TA pre-compensation based on location information and ephemeris information, then the uplink transmission timing can be compensated, but the network device cannot obtain the terminal's location and TA pre-compensation value, leading to mismatch between terminal TA and network koffset
Solution Approach 1:
The patent implements a feedback mechanism where the terminal reports its TA value to the network device through SR triggering and uplink transmission. The network device receives this TA information and uses it to configure the koffset parameter, creating a closed-loop feedback system that resolves the information asymmetry between terminal and network.
Solution Approach 2:
The patent introduces an intermediary reporting mechanism where the terminal's TA value is transmitted to the network through scheduled uplink resources. This intermediary process allows the TA information to be conveyed from terminal to network, enabling the network to configure appropriate koffset values based on actual terminal conditions.
2Reliability
If the terminal reports TA to the network device, then the network can configure suitable koffset, but the terminal needs available uplink resources which may not be available in NTN scenarios with large propagation delay
Solution Approach 1:
The patent implements preliminary action by triggering SR immediately when TA reporting is needed, before uplink resources become available. The SR is triggered in advance based on TA reporting conditions, and the terminal waits for network scheduling response, allowing the reporting process to start early rather than delaying until resources are available.
Solution Approach 2:
The patent introduces dynamic resource allocation where the network device dynamically assigns uplink resources for TA reporting based on terminal requests. The SR triggering mechanism dynamically activates when TA reporting conditions are met, and the network responds by dynamically allocating appropriate uplink resources, making the system adaptive to changing conditions.
3Stability of the object's composition
If the terminal waits for available uplink resources to report TA, then resource conflicts are avoided, but uplink transmission may fail due to timeout before TA can be reported
Solution Approach 1:
The patent uses feedback mechanism where the terminal monitors whether uplink resources become available after SR triggering. If resources become available before timeout, the terminal reports TA successfully. If timeout occurs, the terminal triggers random access procedure as fallback, creating a feedback loop that ensures TA reporting eventually succeeds through alternative paths.
Solution Approach 2:
The patent implements beforehand cushioning by preparing alternative TA reporting paths in advance. When the primary uplink resource allocation fails or times out, the system has pre-configured random access procedure as a backup path for TA reporting, cushioning against the failure of the primary path and ensuring reliability.
Data Source
AI summary
A method for triggering an SR triggering and a terminal are provided. The method is applied to a terminal in a RRC connected state, and includes the following operation. An SR is triggered when a Timing Advance (TA) report is triggered and an uplink resource satisfies an unavailable condition. The uplink resource is a Physical Uplink Shared Channel (PUSCH) resource used for a new uplink transmission.