NTN Uplink Timing Offsets for Large-Cell Synchronization
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Solution Overview
Problem
In non-terrestrial networks (NTNs), the long propagation delays and large cell sizes necessitate accurate timing adjustments for uplink transmissions, particularly in preconfigured resources, as a single cell-specific timing offset is often inaccurate due to varying delays among UEs, leading to synchronization challenges.
Innovation Solution
A user equipment (UE) determines a timing offset by summing a first and second time offset received via system information block and medium access control element, respectively, to accurately adjust uplink transmissions in preconfigured resources, and a base station determines a similar offset for downlink receptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single cell-specific timing offset is used for uplink transmissions in large NTN cells, then the system complexity is reduced and ease of operation is improved, but the synchronization precision deteriorates due to varying propagation delays among UEs
Solution Approach 1:
The patent divides the single cell-specific timing offset into two separate components: a common timing offset applicable to all UEs in the cell, and a UE-specific timing offset tailored to individual propagation delays. This segmentation allows the system to maintain simplicity in configuring the common offset while achieving precise synchronization through the UE-specific component.
Solution Approach 2:
The patent applies local quality by making the timing offset UE-specific rather than uniform across all UEs. Each UE receives a customized timing offset based on its individual propagation delay characteristics, allowing optimal synchronization precision for each local condition while the common timing offset maintains overall system coordination.
2Measurement precision
If UE-specific timing offsets are implemented to improve synchronization precision, then the measurement precision is improved, but the device complexity and signaling overhead increase
Solution Approach 1:
The patent implements preliminary action by having the network pre-configure the common timing offset for all UEs before uplink transmissions begin. This advance configuration establishes a baseline synchronization reference that simplifies subsequent UE-specific timing adjustments, reducing the complexity of real-time timing management.
Solution Approach 2:
The patent introduces a two-component timing offset structure where the common timing offset acts as an intermediary that handles the bulk of synchronization requirements for all UEs. This intermediary layer simplifies the UE-specific timing adjustments needed, as UEs only need to apply relatively small corrections to the pre-established common offset rather than calculating complete timing values independently.
Data Source
AI summary
Apparatuses and methods for uplink transmission timing in non-terrestrial networks (NTNs). A method for operating a user equipment includes receiving: first information, by a system information block, indicating a value of a first time offset; second information, by a medium access control (MAC) control element (CE), indicating a value of a second time offset; and a first channel in a first time unit associated with a transmission of a second channel in a second time unit. The method includes determining: a value of a third time offset based on a sum of the first and second time offsets and the second time unit based on the first time unit and the value of the third time offset and transmitting the second channel in the second time unit.