User Apparatus QCL Parameter Determination for Non-Contention Random Access
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Solution Overview
Problem
In the radio communication system of NR, the quasi-co-location (QCL) assumption for control signals is often inappropriate, leading to inefficient monitoring of control signals by user apparatuses from base station apparatuses.
Innovation Solution
A user apparatus is equipped with a control unit that determines spatial reception parameters based on QCL information for synchronization signals or reference signals, allowing appropriate monitoring during non-contention based random access procedures by applying the determined parameters to receive control channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam forming is applied to improve received power in high frequency bands, then propagation loss is compensated, but the assumed QCL of control signals becomes inappropriate
Solution Approach 1:
The patent applies dynamic QCL assumption adjustment by changing the QCL reference from a fixed SSB to a dynamic CSI-RS based on beam forming configuration. This allows the QCL assumption to adapt to the actual beam forming state, resolving the contradiction between improving received power through beam forming and maintaining accurate QCL assumptions for control signal monitoring.
2Reliability
If narrow beam width is used to compensate propagation loss, then received power is improved, but control signal monitoring becomes inefficient
Solution Approach 1:
The patent introduces CSI-RS as an intermediary element that bridges the gap between beam forming configuration and QCL assumptions. The CSI-RS serves as a mediator that carries beam forming information, allowing the control signal monitoring to efficiently adapt to narrow beam conditions without direct coupling between beam forming and QCL assumption mechanisms.
3Ease of operation
If QCL information from SSB is used for control channel reception, then monitoring is simplified, but accuracy deteriorates in beam forming scenarios
Solution Approach 1:
The patent changes the fundamental parameter used for QCL assumptions from SSB-based to CSI-RS-based. This parameter change enables accurate QCL assumptions in beam forming scenarios while maintaining monitoring efficiency through standardized procedures. The transformation involves updating the QCL information source and adjusting the associated monitoring configurations.
Data Source
AI summary
A user apparatus includes a control unit configured to determine a spatial reception parameter of a control channel based on QCL (Quasi-co-location) information pertaining to a synchronization signal or a reference signal, and a receiver configured to receive the control channel based on the determined spatial reception parameter, wherein, in a case where a first search space is received during a non-contention based random access procedure, the control unit determines the spatial reception parameter of the first search space based on the QCL information applied when receiving an instruction by the control channel, the instruction triggering the non-contention based random access procedure.