Dual Timing Advance Groups for Multi-TRP Uplink Transmission
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Solution Overview
Problem
In mobile communication systems with multiple TRPs, the ambiguity in defining uplink timings for two timing advance groups (TAGs) within a serving cell leads to unclear criteria for configuring downlink timings, affecting the reliability of M-DCI-based M-TRP uplink transmission and reception.
Innovation Solution
The method involves configuring and determining first and second uplink timings based on first and second timing advance offsets and downlink timings, using distinct control resource sets and TCI states for each TAG, with clear criteria defined for each uplink channel or signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single timing advance value is supported for a timing advance group in existing LTE and NR standards, then the system complexity is low, but the reliability of uplink transmission in multi-TRP environments deteriorates due to inability to compensate for timing differences between TRPs
Solution Approach 1:
The patent segments the single timing advance group into multiple timing advance groups (first TAG and second TAG), each associated with a specific TRP. This allows independent timing advance configuration for each TRP, enabling accurate compensation of timing differences while maintaining manageable complexity through structured organization.
Solution Approach 2:
The patent applies local quality by configuring TRP-specific timing advance values (first TA and second TA) for different geographical locations (different TRPs). Each TRP receives customized timing advance configuration based on its specific propagation characteristics, improving local transmission reliability without affecting other TRPs.
2Reliability
If two TAGs are configured within one serving cell to support TRP-specific TA, then the reliability of M-DCI based M-TRP operation is improved, but the ambiguity in defining downlink timings increases
Solution Approach 1:
The patent segments the downlink timing definition by associating each TAG with a specific downlink timing (first downlink timing for first TAG, second downlink timing for second TAG). This segmentation eliminates ambiguity by clearly defining which downlink timing corresponds to which TAG, preventing confusion in multi-TRP operations.
Solution Approach 2:
The patent introduces downlink timing as an intermediary that mediates between the multiple TRPs and the UE. By using downlink timing as a reference point for determining uplink timing in each TAG, the system establishes a clear causal relationship that resolves the ambiguity in timing definition.
3Ease of operation
If downlink timing is utilized to determine uplink timing for TAG, then the synchronization is simplified, but the accuracy of uplink timing determination deteriorates when reference cell definition is ambiguous
Solution Approach 1:
The patent applies local quality by defining reference cell-specific timing advance offsets (N_TA,offset) for each TAG. Instead of using a generic reference cell definition, the system configures specific reference cells (first reference cell for first TAG, second reference cell for second TAG) that are locally optimized for each TRP's characteristics, improving timing accuracy while maintaining operational simplicity.
Data Source
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AI summary
A method performed by a terminal in a wireless communication system, according to an embodiment of the present disclosure, comprises the steps of: receiving first configuration information; receiving second configuration information; determining a first uplink timing and a second uplink timing; transmitting a first uplink channel/signal on the basis of the first uplink timing; and transmitting a second uplink channel/signal on the basis of the second uplink timing.