Aperiodic TRS for Reducing SCell Activation Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 5G New Radio (NR) systems experience significant secondary cell (SCell) activation delays due to the alignment requirements with periodic synchronization signal blocks (SSBs) and tracking reference signals (TRSs), which hinder efficient time and frequency tracking by user equipment (UE).
Innovation Solution
The method involves the UE receiving an activation command on a primary cell, initiating an RF chain during an interruption period, and receiving aperiodic TRSs prior to the initial periodic SSB or TRS, allowing for time and frequency tracking based on these signals, thereby reducing activation delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE waits for initial periodic SSB or TRS to perform time and frequency tracking on SCell, then tracking accuracy is ensured, but activation delay increases
Solution Approach 1:
The base station transmits aperiodic TRS signals before the initial periodic SSB or TRS, allowing the UE to perform time and frequency tracking in advance during the interruption period. This preliminary action enables the UE to complete tracking operations before the standard periodic signals arrive, thereby reducing activation delay while maintaining tracking accuracy
Solution Approach 2:
Aperiodic TRS signals serve as an intermediary mechanism between the activation command and the initial periodic SSB/TRS. These intermediate signals provide the necessary tracking reference before the regular periodic signals are available, bridging the time gap and enabling earlier tracking operations
2Speed
If the UE initiates RF chain during interruption period, then activation speed improves, but signal reception capability deteriorates due to RF chain being inactive
Solution Approach 1:
The UE initiates the RF chain during the interruption period before actual signal reception begins. This preliminary activation ensures the RF chain is ready and operational when the aperiodic TRS signals arrive, allowing immediate processing without waiting for periodic SSB/TRS
Solution Approach 2:
The RF chain transition from inactive to active state is dynamically controlled based on the activation timeline. The UE activates the RF chain during the interruption period, maintaining it in an active state to receive aperiodic TRS, then continues it for periodic signal reception, optimizing both speed and reliability
3Adaptability or versatility
If the system uses only periodic SSB and TRS for tracking, then signal structure simplicity is maintained, but tracking timing flexibility is reduced
Solution Approach 1:
The system dynamically switches between periodic and aperiodic TRS signaling modes. Aperiodic TRS is used during SCell activation to provide timing flexibility, while periodic TRS continues for normal operation, allowing the system to adapt to different operational states without permanent structural changes
Solution Approach 2:
The base station changes the temporal parameters of TRS transmission by introducing aperiodic instances with specific offsets relative to the activation command. This parameter change allows precise control over when tracking signals are available, enabling flexible activation timing without altering the fundamental periodic signal structure
Data Source
AI summary
A method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE receives, on a primary cell, an activation command from a base station for activating a secondary cell between the UE and the base station. The UE receives scheduling information of a set of aperiodic TRSs. The UE receives a trigger indicating transmission of the set of aperiodic TRSs. The UE initiates a RF chain of the UE configured for the secondary cell in an interruption period. The UE receives, in response to receiving the trigger and in accordance with the scheduling information, the set of aperiodic TRSs on the secondary cell prior to receiving an initial SSB or an initial periodic TRS after the interruption period. The UE performs time and frequency tracking on the secondary cell based on the set of aperiodic TRSs.