Terminal CSI Feedback via Delay Domain Precoding
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Solution Overview
Problem
In future radio communication systems, the wideband channel state information (CSI) reporting accuracy deteriorates when the subband size exceeds the coherence bandwidth, while making the uplink overhead increase if the subband size is kept smaller than the coherence bandwidth.
Innovation Solution
A terminal that receives configuration information for CSI reporting and controls the transmission of wideband information, including delay and coefficient information, to maintain reporting accuracy while minimizing uplink overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the subband size is made smaller than the coherence bandwidth to improve CSI reporting accuracy, then the reporting accuracy is improved, but the uplink overhead increases
Solution Approach 1:
The patent segments the CSI reporting into two parts: wideband CSI information (amplitude and phase) and subband CSI information (amplitude only). This segmentation allows the system to maintain accurate CSI reporting while reducing uplink overhead by not transmitting redundant phase information at subband level.
Solution Approach 2:
The patent extracts the phase information from subband CSI reports, keeping only amplitude information at subband level while maintaining wideband phase information. This extraction removes redundant data from subband reports, reducing uplink overhead while preserving necessary accuracy.
2Quantity of substance
If the subband size is made larger to reduce uplink overhead, then the uplink overhead is reduced, but the CSI reporting accuracy deteriorates
Solution Approach 1:
The patent segments the frequency band into wideband and subband components, with different reporting granularities. The wideband component provides coarse-grained amplitude and phase information, while subband provides fine-grained amplitude information, achieving a balance between overhead and accuracy.
Solution Approach 2:
The patent applies different quality levels of CSI information to different frequency regions. Wideband regions use full CSI (amplitude and phase), while subband regions use reduced CSI (amplitude only), optimizing the trade-off between overhead and accuracy for each region.
3Area of stationary object
If the wideband becomes broadband in future radio communication systems, then the coverage area is expanded, but the subband size exceeds the coherence bandwidth causing CSI reporting accuracy to deteriorate
Solution Approach 1:
The patent segments the broadband wideband into multiple subbands with different reporting configurations. By transmitting wideband amplitude and phase information along with subband amplitude information, the system maintains accurate CSI representation across the entire broadband coverage despite individual subbands exceeding coherence bandwidth.
Solution Approach 2:
The patent adds a dimensional structure to CSI reporting by separating wideband and subband components with different information types. This dimensional approach allows the system to handle broadband coverage while maintaining accuracy through multi-level information representation.
Data Source
AI summary
A terminal according to the present disclosure includes: a receiving section that receives configuration information related to channel state information (CSI) reporting; and a control section that controls transmission of a plurality of pieces of wideband information each including at least one of information related to a plurality of delays and information related to a plurality of coefficients corresponding to the delays, based on the configuration information. Thereby, it is possible to prevent degradation of the reporting accuracy of CSI while suppressing the increment of the UL overhead.