User Terminal TCI State Switching via Spatial Domain Filter
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Solution Overview
Problem
In next-generation mobile communication systems, the existing method for changing the transmission configuration indicator (TCI) state in Rel-15 NR requires a long time, leading to reduced communication throughput due to high communication overhead, especially when frequent changes are needed.
Innovation Solution
A user terminal is equipped with a transmitting section for measuring reference signals using a spatial domain filter and a control section that assumes a stable TCI state based on low latency beam selection configured by higher layer signaling, allowing for rapid switching of TCI states, channel quasi-co-location assumptions, or beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing TCI-state control method is used in Rel-15 NR, then the TCI-state can be changed with proper signaling, but the switching time is relatively long and communication overhead increases
Solution Approach 1:
The patent applies preliminary action by having the user terminal pre-measure and report reference signal qualities (RSRP/RSRQ) for multiple beams in advance. The base station stores these measurement results and uses them for rapid TCI-state switching without requiring new measurement reports, thus reducing switching time while maintaining control accuracy.
Solution Approach 2:
The patent implements dynamics by enabling flexible TCI-state switching between different beams based on stored measurement results. The system can dynamically select between multiple pre-measured beams (e.g., switching from first beam to second beam) without fixed timing constraints, allowing adaptive response to changing channel conditions.
2Reliability
If the existing TCI-state control method is used in Rel-15 NR, then the TCI-state can be changed with proper signaling, but communication overhead increases
Solution Approach 1:
The patent reduces communication overhead by performing reference signal measurements and reporting in advance. The base station stores these measurement results locally and reuses them for multiple TCI-state switching decisions, eliminating the need for repeated measurement report transmissions and reducing uplink signaling overhead.
Solution Approach 2:
The patent uses copying by having the user terminal report reference signal qualities for multiple candidate beams in advance. The base station stores these copies of measurement results and references them during TCI-state switching, avoiding the need to transmit new measurement data each time a switch is needed.
3Adaptability or versatility
If frequent TCI-state changes are needed, then beam adaptability improves, but communication throughput may be reduced due to long switching time
Solution Approach 1:
The patent enables frequent TCI-state changes by pre-measuring and storing reference signal qualities for multiple beams. When switching is needed, the base station can immediately select from pre-evaluated beams without waiting for new measurement reports, thus maintaining high beam adaptability while avoiding throughput degradation from repeated signaling exchanges.
Data Source
AI summary
A user terminal according to an aspect of the present disclosure includes: a transmitting section that transmits a measurement result of a reference signal measured by applying a spatial domain filter; and a control section that assumes, when having low latency beam selection configured by higher layer signaling and receiving confirmation information regarding the measurement result at time T, that a spatial domain filter of a given channel after a time when a second time has elapsed from the time T is the same as a spatial domain filter corresponding to the latest measurement result transmitted before a time going back by a first time from the time T. According to an aspect of the present disclosure, a TCI-state of a channel, QCL assumption, or a beam can be switched at high speed.