Uplink Timing Adjustment via Synchronous Coordination
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Solution Overview
Problem
In LTE communication systems, uplink time alignment is necessary to prevent signal interference between terminals with different propagation delays, but existing methods require reinitializing random access procedures when synchronization is lost, leading to resource overhead and potential disruptions in multi-connection scenarios.
Innovation Solution
A method where a terminal requests and receives a Timing Advance Command (TAC) from a synchronous connection to adjust the uplink timing of a serving cell that has lost synchronization, thereby avoiding the need for a random access procedure and conserving resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal reinitializes random access procedure to obtain uplink synchronization, then uplink time alignment can be restored, but communication disruption occurs and time is lost
Solution Approach 1:
The network side device pre-configures multiple TAGs (Timing Advance Groups) for the terminal, where each TAG is associated with a different uplink timing. This preliminary configuration allows the terminal to switch between different timing groups without performing random access procedure, thus avoiding communication disruption and time loss while maintaining uplink synchronization.
2Reliability
If a terminal reinitializes random access procedure to obtain uplink synchronization, then uplink time alignment can be restored, but resource overhead increases
Solution Approach 1:
The network side device pre-configures multiple TAGs with different uplink timings before the terminal needs synchronization. When synchronization is needed, the terminal simply switches to a pre-configured TAG instead of initiating random access, thereby avoiding additional resource consumption for random access procedures while ensuring uplink synchronization is restored.
3Device complexity
If the terminal uses a single TAG for uplink timing, then the system is simple to manage, but adaptability is reduced when one connection loses synchronization
Solution Approach 1:
The uplink timing management is segmented into multiple independent TAGs (Timing Advance Groups), where each TAG can be independently configured and managed. This segmentation allows the terminal to have different uplink timings for different connections or carriers, enabling the system to handle multiple synchronization states simultaneously while maintaining relatively simple management through the TAG framework.
Data Source
AI summary
Embodiments of an uplink timing adjustment method and a terminal are disclosed. The method includes: when a Time Alignment Timer TAT corresponding to a first Timing Advance adjustment Group TAG fails, requesting, by a terminal, a serving cell corresponding to a second TAG to coordinate uplink timing of a serving cell corresponding to the first TAG; receiving, by the terminal, a Timing Advance Command TAC corresponding to the first TAG; and adjusting, by the terminal, the uplink timing of the serving cell corresponding to the failed first TAG according to the TAC corresponding to the first TAG.