Fast SCell Activation Using Preconfigured CSI-RS Tracking
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Solution Overview
Problem
SCell activation latency in current new radio (NR) systems is excessively slow, often taking tens to hundreds of milliseconds, which is even longer than in LTE systems, necessitating improvements for faster activation.
Innovation Solution
A UE receives configurations for channel state information reference signals (CSI-RS) and reference signals (RS) from a base station, including a medium access control element (MAC CE) message for SCell activation, enabling fast SCell activation by performing automatic gain control and time/frequency synchronization based on these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional SCell activation procedures are used in NR systems, then the activation process is reliable and follows standard protocols, but the activation latency becomes excessively slow (tens to hundreds of milliseconds)
Solution Approach 1:
The patent applies preliminary action by pre-configuring CSI-RS resources and parameters before SCell activation is needed. The UE receives and stores CSI-RS configurations, resource allocations, and measurement parameters in advance, so that when activation is triggered, the UE can immediately perform measurements and reporting without waiting for configuration messages, thereby reducing activation latency
Solution Approach 2:
The patent extracts the SCell activation procedure from the conventional multi-step RRC configuration process. By separating the activation trigger (MAC CE) from the detailed configuration (pre-stored CSI-RS parameters), the patent enables faster activation while maintaining measurement accuracy and network control
2Loss of time
If faster SCell activation is implemented by reducing signaling overhead, then activation latency decreases, but measurement precision and channel state information accuracy may be compromised
Solution Approach 1:
The patent performs preliminary configuration of CSI-RS resources, measurement parameters, and reporting configurations before activation. This ensures that when the SCell is activated, the UE can immediately perform accurate measurements using pre-configured parameters without needing additional signaling, thus maintaining measurement precision while reducing latency
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports CSI measurements back to the network using pre-configured reporting formats and resources. This feedback loop ensures that the network receives accurate channel state information while the pre-configured nature of the feedback resources eliminates additional signaling delay
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3B
AI summary
According to embodiments, a UE receives a first signaling including a first configuration of a first CSI-RS for tracking for an SCell. The first configuration is associated with a first ID. The UE receives a second signaling including a second configuration of an RS for fast SCell activation of the SCell. The second configuration is associated with a second ID. The second configuration includes the first ID. The UE receives a MAC CE message including an SCell activation command indicating to activate the SCell and the second ID. The UE receives the RS for the fast SCell activation of the SCell. The RS includes a first burst of the first CSI-RS for tracking. The UE performs SCell activation for activating the SCell based at least on the RS upon receiving the SCell activation command. The UE sends a report indicating that the SCell is activated for the UE.