Hybrid CSI Feedback via Two-Stage Reporting
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Solution Overview
Problem
The existing hybrid CSI reporting mechanism does not provide a method for feeding back hybrid CSI based on different beamformed CSI-RS resources, resulting in high information overheads and inflexible configuration, leading to inaccuracy in reported information.
Innovation Solution
A method for reporting hybrid CSI in two stages using either the same or different codebooks, where the first stage includes a CRI, RI, and/or PMI for multiple CSI-RS resources, and the second stage includes a CRI, CQI, and/or PMI for a single CSI-RS resource, with configurable reporting periods and codebook dimensions to reduce overheads and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the existing hybrid CSI reporting mechanism is used, then CSI information can be reported, but information overheads are high and configuration is inflexible
Solution Approach 1:
The patent segments the CSI reporting process into two distinct stages: a first stage that reports wideband CSI parameters (RI, PMI, CQI) and a second stage that reports subband CSI parameters. This segmentation allows different levels of detail to be reported at appropriate granularities, reducing overall information overhead while maintaining configuration flexibility for each stage independently.
Solution Approach 2:
The patent introduces a two-dimensional reporting structure where the first dimension is the reporting stage (first stage/second stage) and the second dimension is the frequency granularity (wideband/subband). This dimensional approach enables flexible configuration of when and what to report without increasing overall overhead, as the base station can selectively request information from either or both stages.
2Measurement precision
If hybrid CSI reporting is implemented without supporting multiple beamformed CSI-RS resources, then reporting complexity is reduced, but reporting accuracy decreases
Solution Approach 1:
The patent implements dynamic reporting where the terminal device adaptively selects which CSI parameters to report in each stage based on channel conditions and configuration. The first stage reports wideband parameters that are relatively stable, while the second stage reports subband parameters that capture finer channel variations. This dynamic approach improves accuracy without requiring all parameters to be reported at maximum detail simultaneously, thus managing complexity.
Solution Approach 2:
The first stage of reporting performs preliminary action by reporting wideband CSI parameters (RI, PMI, CQI) that provide a coarse but essential characterization of the channel. This preliminary information allows the base station to make initial scheduling decisions while the terminal prepares more detailed subband information for the second stage, improving overall accuracy without requiring all detailed information to be processed simultaneously.
3Loss of information
If all CSI parameters are reported in a single stage, then reporting process is simplified, but information overheads increase and accuracy decreases
Solution Approach 1:
The patent divides the CSI reporting into two stages with distinct parameter sets. The first stage reports wideband parameters (RI, PMI, CQI) that apply across broader frequency ranges, while the second stage reports subband parameters that provide finer frequency resolution. This segmentation reduces total overhead compared to reporting all parameters at full detail in a single stage, as the wideband parameters serve as a foundation that reduces the information needed in the second stage.
Solution Approach 2:
The patent applies local quality by reporting different levels of detail at different frequency granularities. Wideband parameters are reported with coarser detail suitable for overall channel characterization, while subband parameters are reported with finer detail only where needed. This localized approach to information quality reduces overall overhead while maintaining accuracy where it matters most, without requiring uniformly high-detail reporting across all parameters.
Data Source
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AI summary
Embodiments of the present invention relate to a method for feeding back hybrid channel state information, a terminal device, and a base station. The method includes: reporting, by a terminal device, channel state information CSI to a base station, where the CSI is reported in two stages, CSI used when a quantity of beamformed channel state information reference signal CSI-RS resources is greater than 1 is reported in a first stage, CSI used when the quantity of beamformed CSI-RS resources is equal to 1 is reported in a second stage, and reporting the CSI in the two stages occupies one CSI reporting process. In the method for feeding back hybrid CSI provided in the embodiments of the present invention, hybrid CSI is reported based on a beamformed CSI-RS. Therefore, CSI reporting overheads can be reduced, and CSI reporting accuracy can be improved, so that a cell throughput can be increased.