Terminal Device Aperiodic CSI Reporting via Dynamic UL-DL Configuration
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Solution Overview
Problem
The radio communication system lacks efficient technologies for utilizing channel state information, leading to suboptimal communication performance.
Innovation Solution
A terminal device and radio communication method that receive and transmit channel state information using specific uplink-downlink configurations, allowing for periodic and aperiodic reporting of channel quality indicators, enabling efficient communication by defining valid subframes for reporting based on uplink-downlink configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel state information is reported using fixed uplink-downlink configurations, then reporting timing is simplified, but communication efficiency deteriorates due to inability to adapt to dynamic traffic conditions
Solution Approach 1:
The patent applies dynamics by enabling the uplink-downlink configuration to change over time based on traffic conditions. The base station can dynamically switch between different uplink-downlink configurations (e.g., configuration 0-6) to adapt to varying traffic demands, making the system flexible rather than static. This resolves the contradiction by allowing communication efficiency to improve through adaptation while the complexity is managed through predefined configuration sets.
Solution Approach 2:
The patent changes the parameter of uplink-downlink configuration dynamically. By allowing the configuration parameter to vary based on traffic conditions and subframe types (flexible subframes, special subframes), the system optimizes communication efficiency. The complexity is reduced by establishing clear rules for parameter selection based on subframe characteristics and traffic adaptation needs.
2Adaptability or versatility
If flexible subframes are used for traffic adaptation, then traffic flexibility improves, but interference management becomes more difficult due to dynamic uplink-downlink switching
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple uplink-downlink configurations (configuration 0-6) before dynamic adaptation begins. The base station and terminal device agree on these configurations in advance, so when traffic adaptation is needed, the system can quickly switch between predefined configurations without real-time negotiation. This reduces interference by ensuring both parties are synchronized on the configuration being used at any given time.
Solution Approach 2:
The patent implements feedback mechanisms where the base station monitors traffic conditions and channel state information, then adjusts the uplink-downlink configuration accordingly. The system uses feedback from channel quality indicators and traffic patterns to determine when to switch configurations, allowing the system to adapt to traffic conditions while managing interference through informed decision-making about when to switch between uplink and downlink modes.
3Measurement precision
If channel state information reporting is triggered in every subframe, then reporting accuracy improves, but uplink resource consumption increases
Solution Approach 1:
The patent applies periodic action by triggering channel state information reporting at specific intervals and under specific conditions rather than in every subframe. The system uses periodic triggering mechanisms based on subframe type (e.g., triggering in downlink subframes but not in uplink subframes) and configuration patterns. This reduces uplink resource consumption while maintaining adequate reporting accuracy by reporting at strategically selected moments when channel conditions are most relevant.
Solution Approach 2:
The patent implements partial action by reporting channel state information selectively rather than continuously. The system determines which subframes require reporting based on traffic adaptation needs, flexible subframe configurations, and channel conditions. This partial reporting approach maintains sufficient measurement precision for traffic adaptation decisions while significantly reducing uplink resource consumption compared to reporting in every subframe.
Data Source
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AI summary
For aperiodic reporting of CSI, nCQI ref is four, and a subframe n - nCQI ref corresponds to a valid subframe. A subframe that satisfies a criteria including at least a criterion (i) is regarded as being valid. In the criterion (i), in a case where third information for a radio frame is detected, an UL-DL configuration for the radio frame is given by the third information for the radio frame, and in a case where the third information for the radio frame is not detected, the UL-DL configuration for the radio frame is given by first information. The criterion (i) stipulates that the subframe is a subframe indicated as a DL subframe or a special subframe by the UL-DL configuration for the radio frame. In a case where a subframe n - 4 is not a valid subframe for aperiodic reporting of channel state information, the reporting of the CSI is omitted in the subframe n.