Sidelink Time Synchronization for Low-Latency Multi-Link UEs
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Solution Overview
Problem
Existing synchronization methods for UEs in cellular networks introduce significant latency and interference in sidelink communication, particularly for ultra-reliable low-latency applications, due to varying connectivity and timing conditions among UEs.
Innovation Solution
A selective action process is employed by network infrastructure apparatuses to synchronize UEs based on their connectivity state, using distributed iterative synchronization procedures and external time references to expedite timing convergence, reducing latency and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distributed iterative synchronization procedures are used, then timing synchronization accuracy is improved, but synchronization latency increases
Solution Approach 1:
The patent implements dynamic synchronization procedures that adapt the level of iterative synchronization based on UE connectivity state. For UEs in coverage, full iterative synchronization is performed to achieve high accuracy. For out-of-coverage UEs, a simplified procedure is used that reduces latency while maintaining adequate synchronization. This dynamic adaptation resolves the contradiction by adjusting the synchronization depth according to actual network conditions.
Solution Approach 2:
The patent changes the synchronization parameter set based on UE connectivity state. Different synchronization parameter configurations are applied: one set for in-coverage UEs that prioritizes accuracy through multiple iterations, and another set for out-of-coverage UEs that prioritizes faster synchronization with fewer iterations. This parameter adaptation allows the system to optimize between accuracy and latency for different operational scenarios.
2Object-affected harmful factors
If selective action process is employed based on connectivity state, then interference is reduced, but device complexity increases
Solution Approach 1:
The patent enables UEs to autonomously determine their connectivity state and select appropriate synchronization actions without requiring complex centralized control. Each UE independently evaluates its own connectivity status and applies the corresponding synchronization procedure, thereby reducing overall system complexity while still achieving interference reduction through state-appropriate synchronization behavior.
Solution Approach 2:
The patent segments the synchronization process into distinct procedures based on UE connectivity state. By dividing the synchronization mechanism into separate pathways (one for in-coverage UEs, another for out-of-coverage UEs), the system can apply simpler rules within each segment rather than managing a single complex unified process, thereby reducing overall device complexity while maintaining interference reduction benefits.
Data Source
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AI summary
A network apparatus of a cellular network for synchronizing at least one user equipment (UE) for a sidelink, comprising a processor adapted to receive from a first UE which is connected to the cellular network a request to establish a sidelink with at least a second UE, receive from the first UE a connectivity state information, in particular on channel quality, connectivity and/or timing, of the first UE and/or of at least the second UE and instruct the first UE to establish or decline the sidelink after synchronizing according to an action selected by the network apparatus from a plurality of action based on at least one of: the connectivity state and at least one operational condition of the cellular network.