User Terminal COT End Timing Determination
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Solution Overview
Problem
Current radio communication systems face challenges in determining the end of a channel occupancy time (COT) in next-generation mobile communication systems, particularly in unlicensed bands where sudden changes in the channel environment can lead to reduced throughput due to inflexible slot format control.
Innovation Solution
A user terminal and radio communication method that allows for flexible modification of slot formats based on newly detected DCI within a period corresponding to a slot format combination index, enabling appropriate determination of the COT end timing and adapting to sudden environmental changes in unlicensed channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the base station reports the start of COT using DCI format 2_0, then the UE can acquire channel occupancy information, but the method for reporting the end of COT is not clearly defined
Solution Approach 1:
The patent reuses the existing DCI format 2_0 structure, which was originally designed for slot format indication, to also convey COT end timing information. This multi-functional use of the DCI format eliminates the need for a separate signaling mechanism, thereby reducing overall system complexity while ensuring complete information transmission about COT boundaries
Solution Approach 2:
The patent introduces a new parameter (a 2-bit field) within the existing DCI format 2-0 to indicate COT end timing. By adding this parameter to the existing control structure rather than creating a entirely new message format, the solution provides clear end timing information while minimizing increases in device complexity
2Adaptability or versatility
If the slot format is fixed based on initial DCI, then the control structure is simple, but the system cannot adapt to sudden changes in unlicensed channel environment
Solution Approach 1:
The patent enables dynamic modification of slot formats by allowing the UE to monitor for new DCI format 2-0 messages that can override previously indicated slot formats. This dynamic control mechanism allows the system to adapt to sudden changes in unlicensed channel environment while maintaining a relatively simple control structure that builds upon the existing DCI framework
Solution Approach 2:
The patent implements a feedback mechanism where the UE monitors for updated DCI format 2-0 messages that provide current slot format information. This continuous feedback loop allows the system to adapt slot formats in response to changing channel conditions while using the existing DCI signaling infrastructure, thereby achieving adaptability without proportionally increasing control complexity
3Reliability
If the UE monitors DCI with periodicity longer than the slot format combination period, then the monitoring overhead is reduced, but the UE cannot detect sudden slot format changes
Solution Approach 1:
The patent applies partial monitoring action by allowing the UE to monitor DCI format 2-0 at periodic intervals rather than continuously. This partial monitoring approach provides sufficient slot format detection accuracy for adaptive control while significantly reducing the energy consumption associated with continuous DCI monitoring, achieving a practical balance between reliability and energy efficiency
Data Source
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AI summary
A user terminal includes a receiving section that receives downlink control information including information indicating a combination of one or more slot formats, and a control section that assumes that a channel occupancy time (COT) ends at an end of a period corresponding to the one or more slot formats. This allows the user terminal to appropriately determine the end of the COT.