CSI Reporting Overhead Reduction via Compressed Format
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Solution Overview
Problem
Current CSI reporting formats in MIMO systems are inefficient as they cannot support compressed-type CSI reports, leading to high overheads due to the need to report uncompressed combination coefficient sets for each frequency-domain subband.
Innovation Solution
A communication method that allows for the reporting of a compressed-format combination coefficient set by using a CSI report with CSI part 1 to indicate the number of bits and type of CSI part 2, which includes wideband PMI information to indicate an oversampling factor or index of a preset orthogonal beam vector, enabling autonomous selection between compressed and uncompressed reporting formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uncompressed combination coefficient sets are reported for each frequency-domain subband, then transmission reliability is improved, but reporting overheads increase
Solution Approach 1:
The patent segments the combination coefficient set into multiple parts: wideband PMI information (CSI part 2) and subband-specific information (CSI part 1). This segmentation allows the system to report essential precoding matrix indicator information at wideband level while reducing subband reporting requirements, thereby lowering overall reporting overheads while maintaining transmission reliability.
Solution Approach 2:
The patent extracts the most critical precoding information (wideband PMI) and reports it separately at a higher level, while only reporting differential or compressed subband information. This extraction approach removes the need to report complete uncompressed combination coefficient sets for every subband, significantly reducing reporting overhead while preserving the essential information needed for reliable transmission.
2Quantity of substance
If compressed-type CSI reports are used, then reporting overheads are reduced, but compatibility with existing CSI reporting formats is lost
Solution Approach 1:
The patent designs a universal CSI reporting framework that can accommodate both traditional uncompressed reporting and new compressed reporting formats. The reporting structure uses standardized fields (CSI part 1 and CSI part 2) that can carry different types of information depending on configuration, allowing the same reporting mechanism to serve multiple purposes and maintain compatibility across different deployment scenarios.
Solution Approach 2:
The patent introduces dynamic switching capability between compressed and uncompressed reporting modes. The system can adaptively select the appropriate reporting format based on channel conditions, traffic requirements, and network configuration, making the CSI reporting mechanism flexible and compatible with both legacy and advanced scenarios.
3Measurement precision
If more combination coefficients are reported, then precoding accuracy is improved, but system complexity increases
Solution Approach 1:
The patent performs preliminary processing of combination coefficients by deriving wideband PMI information first, which captures the dominant precoding characteristics. This preliminary action allows the system to establish a baseline precoding matrix that can be refined with minimal subband-specific information, thereby maintaining precoding accuracy while avoiding the need to report all detailed coefficients.
Solution Approach 2:
The patent applies different reporting granularities to different parts of the frequency spectrum. Instead of uniformly reporting all combination coefficients across all subbands, the system reports detailed information only where necessary (local areas with significant channel variations) and uses compressed or differential reporting in other areas, optimizing the balance between precoding accuracy and system complexity.
Data Source
AI summary
Example communication methods and devices are provided. One example method includes a first device determines a first channel state information CSI report based on a precoding matrix type, where the precoding matrix type is a compressed type or an uncompressed type. The first device sends the first CSI report to a second device, where the first CSI report includes a CSI part 1 and a CSI part 2, the CSI part 1 indicates a number of bits of the CSI part 2 and the precoding matrix type, the CSI part 2 indicates wideband precoding matrix indicator (PMI) information, the wideband PMI information indicates an oversampling factor of a preset orthogonal beam vector and/or an index of the preset orthogonal beam vector, and the preset orthogonal beam vector is a spatial-domain orthogonal basis vector selected by the first device from a spatial-domain basis vector set.