Secondary Cell Synchronization via Preliminary Time Reference
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Solution Overview
Problem
Current methods for secondary cell activation in carrier aggregation scenarios face challenges in meeting latency requirements for channel state information (CSI) reporting, particularly during blind activation, due to the need for time synchronization and cell detection processes that prolong the activation time.
Innovation Solution
The method involves setting a preliminary time reference for the secondary cell based on the primary cell's time reference, performing synchronization signal-based detection, and conducting preliminary channel state measurements to transmit a channel quality indicator (CQI) report, allowing for earlier activation and meeting latency requirements by overlapping measurement processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time synchronization and cell detection processes are performed before secondary cell activation, then synchronization accuracy is improved, but activation latency increases
Solution Approach 1:
The patent applies preliminary action by performing channel state measurements and preparing CSI reports based on primary cell timing before actual synchronization to the secondary cell is achieved. This allows the UE to prepare measurement results in advance using the preliminary time reference from the PCell, so that when synchronization is completed, the CSI report can be transmitted immediately without waiting for post-synchronization measurements, thus reducing activation latency while maintaining measurement accuracy
Solution Approach 2:
The patent implements continuity of useful action by overlapping the channel state measurement process with the synchronization process. Instead of sequentially performing synchronization first and then measurements, the UE continuously performs measurements based on the preliminary time reference during the synchronization period, ensuring that measurement activities never stop and useful work continues throughout the activation process, thereby reducing overall activation time
2Productivity
If secondary cell activation is performed before detection, then activation speed is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by having the UE perform channel state measurements and prepare CSI reports based on the primary cell's time reference before actually detecting and synchronizing to the secondary cell. This allows activation to proceed rapidly while measurements are prepared in advance using the available PCell timing information, thus achieving both fast activation and maintained measurement quality
Solution Approach 2:
The patent uses the primary cell time reference as an intermediary to enable measurements on the secondary cell before direct synchronization is achieved. The PCell timing serves as a mediator that allows the UE to perform measurements and prepare CSI reports without requiring precise SCell synchronization yet, thus enabling early activation while maintaining measurement accuracy through the intermediary reference
Data Source
Figure 1(a)~1(e)
Figure 2
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AI summary
A carrier aggregation application method is provided of attaining time synchronization to a secondary cell for a wireless communication device usable in a cellular communication network. The method comprises, if a time reference of the secondary cell is unknown to the wireless communication device: setting a preliminary time reference of the secondary cell to equal a time reference of a primary cell of the carrier aggregation application; performing a synchronization signal based detection of the time reference of the secondary cell based on the preliminary time reference and one or more synchronization signals transmitted in the secondary cell; performing preliminary time reference based channel state measurements of the secondary cell based on the preliminary time reference and one or more reference signals transmitted in the secondary cell; setting, based on the synchronization signal based detection, a value of a channel quality indicator to either a nominal value or a value based on the preliminary time reference based channel state measurements; and transmitting a channel state information report comprising the channel quality indicator to the cellular communication network. An arrangement for a wireless communication device usable in a cellular communication network, adapted to attain time synchronization to a secondary cell of a carrier aggregation application is also disclosed. A modem comprising the arrangement and wireless communication device comprising the arrangement are also disclosed.