Reference Subframe Determination for CQI Reporting
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Solution Overview
Problem
Current wireless communication systems face challenges in determining a suitable reference subframe for Channel Quality Indicator (CQI) reporting, leading to potential degradation in communication quality due to interference and subframe validity issues, particularly in scenarios like half-duplex relays and cross-subframe scheduling.
Innovation Solution
A wireless communication device and base station system that determines a reference subframe based on specific limits and criteria, such as subframe type, triggering mode, and reference signal presence, to ensure accurate CQI reporting and improve communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reference subframe is selected based on a fixed limit (e.g., n_CQI_ref >= 4), then the CQI reporting timing is standardized, but the reference subframe may fall on an invalid downlink subframe or experience interference in certain scenarios (e.g., half-duplex relays, cross-subframe scheduling)
Solution Approach 1:
The patent introduces dynamic adaptation of the reference subframe selection by allowing the limit value to be adjusted based on subframe configuration types. Instead of a fixed limit of 4, the system dynamically determines the appropriate limit based on whether the subframe configuration is type 1 or type 2, and whether a reference signal is present in the current subframe. This dynamic approach resolves the contradiction by making the reference subframe selection adaptable to different scenarios while maintaining reliability.
Solution Approach 2:
The patent changes the parameter of the reference subframe limit from a fixed value to a variable that depends on subframe configuration type and reference signal presence. Specifically, the limit is set to 4 for type 1 configurations and 3 for type 2 configurations, with additional adjustments based on whether the current subframe contains a reference signal. This parameter change enables the system to adapt to different deployment scenarios while ensuring reliable CQI reporting.
2Productivity
If the reference subframe is determined with a minimum limit of 4, then aperiodic CQI reporting timing is standardized, but periodic CQI reporting may use subframes that are not optimal or valid
Solution Approach 1:
The patent applies parameter changes by introducing different limit values for periodic and aperiodic CQI reporting based on subframe configuration type. For type 1 configurations, the limit remains 4, while for type 2 configurations, the limit is reduced to 3. Additionally, the system checks whether the current subframe contains a reference signal and adjusts the limit accordingly. This enables both periodic and aperiodic reporting to use valid subframes while maintaining high efficiency.
Solution Approach 2:
The patent performs preliminary determination of the reference subframe limit based on the subframe configuration type before actual CQI reporting. The system预先 (in advance) identifies whether the configuration is type 1 or type 2 and sets the appropriate limit accordingly, ensuring that the selected reference subframe will be valid for both periodic and aperiodic reporting scenarios.
3Productivity
If cross-subframe scheduling is used to improve resource allocation flexibility, then scheduling efficiency increases, but determining a valid reference subframe becomes more complex
Solution Approach 1:
The patent simplifies the reference subframe determination process by introducing clear parameter-based rules that account for cross-subframe scheduling. The system determines the reference subframe limit based on the subframe configuration type (1 or 2) and reference signal presence, providing a straightforward methodology that works seamlessly with cross-subframe scheduling without adding significant complexity.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a reference signal presence check that mediates between the cross-subframe scheduling requirements and the reference subframe selection. By using the reference signal as an intermediary indicator, the system can determine valid reference subframes in cross-subframe scheduling scenarios without complex calculations or additional overhead.
4Adaptability or versatility
If the reference subframe limit is reduced to improve adaptability, then more subframes become valid candidates, but the timing accuracy for CQI reporting may deteriorate
Solution Approach 1:
The patent applies parameter changes by setting different limit values for different subframe configuration types rather than using a single reduced limit for all cases. For type 1 configurations, the limit remains at 4 to maintain timing accuracy, while for type 2 configurations, the limit is reduced to 3 to improve adaptability. This differentiated approach ensures that timing accuracy is preserved where possible while gaining adaptability where needed.
Solution Approach 2:
The patent applies local quality by tailoring the reference subframe limit to the specific characteristics of each subframe configuration type. Instead of applying a uniform limit reduction across all configurations, the system applies different limits locally based on whether the configuration is type 1 or type 2, and whether reference signals are present. This ensures that timing accuracy is maintained in configurations where it is critical while gaining adaptability in configurations where it is less critical.
Data Source
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AI summary
A wireless communication device for determining a reference subframe is described. The wireless communication device includes a processor and instructions stored in memory that is in electronic communication with the processor. The wireless communication device determines a reporting subframe n. The wireless communication device also determines a reference subframe based on a limit and at least one limiting criterion. The wireless communication device further generates a report based on the reference subframe if the reference subframe is determined. The wireless communication device additionally sends the report during the reporting subframe if the reference subframe is determined.