Timing Advance Exchange Using TA Margin in NTN Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Non-Terrestrial Networks (NTNs) with NB-IoT/eMTC, the large and varying round-trip propagation times cause challenges in uplink/downlink scheduling synchronization due to unknown Timing Advance (TA) at User Equipment (UE), leading to inefficiencies and increased signaling overhead.
Innovation Solution
UE determines a reference TA based on its location and an actual TA based on its actual location, comparing the difference with a provided TA margin to decide when to update its reference location, thereby optimizing signaling and reducing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE frequently updates reference location to maintain accurate TA, then uplink/downlink scheduling synchronization is improved, but signaling overhead increases
Solution Approach 1:
The network pre-configures a TA margin threshold that determines when location updates are necessary. UE compares its calculated TA difference against this pre-set threshold, performing updates only when the difference exceeds the margin, thereby avoiding unnecessary signaling while maintaining synchronization reliability
Solution Approach 2:
The system dynamically adjusts the TA margin parameter based on network conditions and UE mobility characteristics. By changing this threshold parameter, the system optimizes the balance between synchronization accuracy and signaling overhead, allowing larger margins for stationary UEs and smaller margins for mobile U
2Measurement precision
If UE transmits updated reference location frequently, then TA accuracy is improved, but power consumption increases
Solution Approach 1:
UE continuously monitors its TA difference and compares it against the TA margin threshold, creating a feedback mechanism that triggers location updates only when necessary. This feedback-based approach maintains TA accuracy by updating whenever the difference exceeds the margin while avoiding unnecessary power consumption from frequent updates
Solution Approach 2:
The network provides preliminary configuration of the TA margin threshold, enabling UE to make autonomous decisions about when to update its location. This preliminary setup allows UE to maintain accuracy by updating only when the pre-defined condition (TA difference exceeding margin) is met, reducing unnecessary power consumption
Data Source
AI summary
Embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media of signalling enabling Timing Advance (TA) exchange between User Equipment (UE) and Radio Access Network (RAN). The method comprises receiving, at a first device, a TA margin from a second device; transmitting, to the second device, information associated with a reference location of the first device at a first time point; determining a reference TA of the first device at least based on the reference location of the first device; determining an actual TA of the first device at least based on an actual location of the first device at a second time point; and determining, based on a comparison of a TA margin with a difference between the reference TA and the actual TA, whether to transmit an updated reference location of the first device to the second device. In this way, the control for uplink overhead from TA/location updates and probability of impacting downlink scheduling become flexible. Furthermore, the downlink delay can be optimised and meanwhile overhead in case of very few small packets transmitted can be minimized. As a result, the network can optimize its own performance and the battery savings of the users.