CSI-RS Feedback Scheme Selection for Channel State Reporting
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Solution Overview
Problem
In LTE-A systems, User Equipment (UE) cannot report channel state information based on CSI-RS due to the absence of a CSI-RS feedback scheme, as it cannot determine the transmission scheme adopted by the eNB for PDSCH.
Innovation Solution
A method and apparatus for a UE to detect CSI-RS configuration information, determine the number of ports required, and select a corresponding Precoding Matrix Indicator (PMI) feedback scheme, using a codebook-based precoding scheme represented by the formula y0 … yP-1 = W ⋅ s, to report channel state information, where W is a codebook of precoding matrices and S represents PDSCH data layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CSI-RS is introduced to support higher-order MIMO transmission, then the system capacity and transmission efficiency are improved, but the UE cannot determine the transmission scheme adopted by eNB for PDSCH, making channel state reporting impossible
Solution Approach 1:
The patent applies preliminary action by having the UE detect and store CSI-RS configuration information in advance, including the number of ports and feedback scheme correspondence relationships. This pre-prepared information enables the UE to subsequently determine the appropriate feedback scheme without ambiguity when channel state reporting is required, resolving the information loss problem while maintaining high system capacity
2Adaptability or versatility
If a codebook-based precoding scheme is used with multiple CSI-RS ports, then the transmission flexibility and adaptability are improved, but the complexity of determining the appropriate feedback scheme increases
Solution Approach 1:
The patent applies parameter changes by establishing a correspondence relationship between the number of CSI-RS ports and specific feedback schemes. When the eNB configures a particular number of ports, the UE automatically selects the corresponding feedback scheme from predefined options. This parameter-based mapping simplifies the determination process while maintaining transmission flexibility across different port configurations
Data Source
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AI summary
There is disclosed method for reporting channel state so as to report channel state based upon CSI-RS. The method includes: a UE detecting configuration information of Channel State Information-Reference Signal (CSI-RS), determining according to detection result the number of ports required to report channel state based upon CSI-RS, the UE determining CSI-RS based PMI feedback scheme to be adopted in preset corresponding relationship between the number of ports and feedback scheme upon determining that the eNB is to map data of Physical Downlink Shared Channel (PDSCH) onto P (number) CSI-RS ports for transmission in a codebook-based precoding scheme, wherein the codebook-based precoding scheme is a scheme as represented in the formula of y0⋮yP-1=W⋅s, wherein W represents a codebook consisted of a precoding matrix, S is PDSCH data consisted of data layers whose quantity is equal to value of Rank Indication (RI) and y0⋮yP-1 represents a vector consisted of data on P (number) CSI-RS ports; and the UE calculating and reporting channel state information according to the determination result. The invention further discloses apparatus for performing the method.