Codebook Feedback Method Reducing Signaling Overhead
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Solution Overview
Problem
The existing New Radio (NR) type II codebook feedback mechanism experiences high signaling overhead due to the reporting of Channel State Information (CSI) by terminal devices, particularly when the number of frequency domain DFT vectors is large, which affects communication efficiency.
Innovation Solution
The proposed method involves selecting and indicating a subset of frequency domain Discrete Fourier Transform (DFT) vectors and their positions within a DFT array, using cyclic shift relationships to reduce the number of bits required for feedback, thereby minimizing signaling overhead. This includes determining a first frequency domain DFT vector indication set and sending an indication message to the network device, which recovers the downlink channel using equivalent DFT vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal device reports all M frequency domain DFT vectors using traditional indication methods, then the channel state information accuracy is improved, but the signaling overhead increases significantly
Solution Approach 1:
The patent extracts and reports only the positions of the strongest L coefficients in each frequency domain DFT vector rather than reporting all M frequency domain DFT vectors. This selective extraction of critical information (strongest coefficients) maintains channel state information accuracy while significantly reducing the number of bits required for feedback.
Solution Approach 2:
The patent segments the frequency domain DFT vectors into groups based on the positions of strongest coefficients. Instead of treating all M vectors uniformly, it divides them into subsets where only the dominant characteristics (strongest L coefficients) are explicitly indicated, reducing overall feedback complexity.
2Measurement precision
If the number of frequency domain DFT vectors M is increased to improve feedback granularity, then the codebook accuracy is improved, but the feedback complexity increases
Solution Approach 1:
The patent extracts only the essential characteristics (positions of strongest L coefficients) from each frequency domain DFT vector. This extraction approach allows the system to work with larger M values for improved accuracy without proportionally increasing feedback complexity, as only the dominant features are reported.
Solution Approach 2:
The patent applies partial action by reporting only the most significant L coefficients out of M total frequency domain DFT vectors. This partial reporting strategy provides sufficient codebook accuracy for practical purposes while avoiding the excessive complexity that would result from reporting all M vectors in full detail.
Data Source
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AI summary
Disclosed in the embodiments of the present application are a codebook feedback method, a terminal device and a network device. The method comprises: a terminal device selecting from a discrete Fourier transform (DFT) array a number M of frequency-domain DFT vectors; the terminal device, according to indicators of the M frequency-domain DFT vectors, determining a first frequency-domain DFT vector indicator set from among multiple frequency-domain DFT vector indicator sets, indicators of the M frequency-domain DFT vectors and the first frequency-domain DFT vector indicators in the first frequency-domain DFT vector indicator set being equivalent, and M being a positive integer; the terminal device sending an indicator message to a network device, the indicator message being used to indicate the first frequency-domain DFT vector indicator set. The method of the embodiment of the present application is helpful for lowering signaling overhead of a terminal device during codebook feedback.