Carrier Aggregation QCL Sourcing for SSB-Less Reference Signals
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Solution Overview
Problem
Wireless communications systems face high power consumption due to increased signaling and throughput, particularly in carrier aggregation deployments with SSB-less carriers, necessitating efficient methods to identify quasi-colocation (QCL) sources for reference signal reception.
Innovation Solution
Network nodes receive a synchronization signal on a primary cell to determine QCL parameters, using it as a source for receiving reference signals on secondary cells without synchronization signal blocks (SSBs), thereby establishing QCL relationships for power-efficient communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronization signaling is transmitted on all carriers in carrier aggregation, then reliable QCL relationship establishment is achieved, but power consumption and signaling overhead increase
Solution Approach 1:
The patent extracts the synchronization signal transmission function from all carriers and concentrates it only on the primary cell. Secondary cells that do not require independent synchronization signal transmission are identified and have this function removed, thereby reducing overall power consumption while maintaining necessary QCL relationship establishment through alternative means.
Solution Approach 2:
The patent makes the primary cell's synchronization signal serve multiple functions: it provides synchronization for the primary cell itself and also serves as a QCL source for secondary cells. This multi-functionality allows secondary cells to establish QCL relationships without requiring their own synchronization signals, reducing total signaling overhead and power consumption.
2Reliability
If synchronization signals are transmitted on all cells, then QCL sources are available for all cells, but signaling overhead and resource usage increase
Solution Approach 1:
The patent merges the QCL source function for multiple cells into a single synchronization signal transmitted on the primary cell. Instead of having separate synchronization signals on each cell, the primary cell's synchronization signal is combined to serve as the QCL source for both the primary cell and secondary cells, reducing signaling overhead.
Solution Approach 2:
The patent introduces configuration signaling as an intermediary that informs the network node about QCL relationships. This configuration message acts as a mediator that establishes QCL associations between the primary cell's synchronization signal and secondary cells without requiring additional synchronization signal transmissions on those secondary cells.
3Use of energy by moving object
If SSB-less carriers are used to reduce power consumption, then signaling costs decrease, but QCL source identification becomes more difficult
Solution Approach 1:
The patent implements feedback through configuration signaling that explicitly informs the network node about QCL relationships. The network node receives configuration messages that provide feedback information about which synchronization signals serve as QCL sources for which cells, making QCL source identification straightforward even when synchronization signals are not transmitted on all carriers.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a first message that includes information indicative of an inter-band carrier aggregation configuration that identifies a set of cells for communication by the network node. The UE may receive a synchronization signal on a first cell of the set of cells via a wireless channel having a first set of channel properties. Based on a first set of quasi-colocation (QCL) parameters including the first set of channel properties, the UE may then receive one or more reference signals on the second cell of the set of cells. The UE may receive the one or more reference signals on the second cell based on the synchronization signal of the first cell being a first QCL source indicating use of the first set of QCL parameters to receive the one or more reference signals.