User Terminal Dynamic TDD Fallback UL Signal Control
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Solution Overview
Problem
In Dynamic TDD-based communication, user terminals sometimes fail to recognize dynamically changed UL-DL configurations, leading to incorrect transmission of UL signals in subframes other than UL subframes during fallback operations, resulting in intra-cell interference.
Innovation Solution
A user terminal with a reception section for receiving control information and a control section that stops transmission of sounding reference signals in subframes without uplink allocation, applying specific resource transmission rules to prevent UL signal transmission in non-UL subframes, such as the first rule inhibiting transmission in flexible subframes or the second rule using a defined table for fixed subframes only.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user terminal performs fallback operation using UL-DL configuration from SIB1, then the terminal can maintain basic communication functionality, but the terminal may transmit UL signals in wrong subframes causing intra-cell interference
Solution Approach 1:
The patent applies preliminary action by configuring the user terminal with reference UL-DL configurations in advance through higher layer signaling (RRC connection release message). When fallback operation is needed, the terminal can determine which pre-configured reference configuration to use based on the actual UL-DL configuration detected from downlink subframes, preventing wrong UL signal transmission before it occurs.
Solution Approach 2:
The patent introduces reference UL-DL configurations as an intermediary between the SIB1 configuration and the actual dynamic UL-DL configuration. This intermediary provides a set of predefined configurations that the terminal can select from, serving as a bridge that prevents direct conflicts between fallback operation and actual network configuration.
2Adaptability or versatility
If the user terminal dynamically switches UL-DL configurations in Dynamic TDD, then the system can adapt to traffic changes, but the terminal may fail to recognize the actual configuration leading to transmission errors
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple reference UL-DL configurations through higher layer signaling before the terminal needs to perform fallback operation. These reference configurations are prepared in advance based on possible dynamic TDD scenarios, enabling the terminal to quickly determine the correct configuration without real-time detection errors.
Solution Approach 2:
The patent applies partial action by providing a subset of reference UL-DL configurations (e.g., configurations #0 to #6 with specific patterns) that cover the most likely dynamic TDD scenarios. Rather than providing all possible configurations, the patent supplies enough reference configurations to handle typical traffic adaptation needs while reducing terminal complexity.
Data Source
AI summary
For the purpose of preventing transmission of UL signals in a subframe other than a UL subframe during the fallback operation in Dynamic TDD communication, the present invention provides a user terminal for communicating in Dynamic TDD, the user terminal having: a reception section that receives control information including an indication to dynamically change a subframe configuration of a Dynamic TDD cell and a control section that controls not to perform specific resource transmission in flexible subframes in the fallback operation based on the subframe configuration of Dynamic TDD cell signaled by higher layers or SIB1.