Dual-Polarized MIMO CSI Feedback Using a Universal Codebook
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Solution Overview
Problem
Current codebook designs for channel state information quantization feedback in MIMO systems are inadequate for dual-polarized channels, particularly when the number of antennae is greater than or equal to 4, as they fail to match well with the channel features of dual-polarized antennae, leading to poor performance.
Innovation Solution
A method for constructing a universal codebook space at both the transmitting and receiving ends, using orthogonal and 8PSK feature-based codewords extracted from existing LTE codebooks, with specific models for different Rank values, to create a codebook that can handle multiple Ranks and adapt to dual-polarized channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If codebook-based channel state information quantization feedback is used, then feedback overhead is reduced, but quantization error increases leading to poor pre-coding performance
Solution Approach 1:
The patent changes the structural parameters of the codebook by introducing a universal codebook design with specific models for different Rank values. The codebook structure is optimized to match dual-polarized channel features, using orthogonal and 8PSK feature-based codewords. This parameter change in codebook structure reduces quantization error while maintaining feedback overhead constraints.
Solution Approach 2:
The patent applies local quality by designing different codebook models for different Rank values (Rank=1, Rank=2, etc.). Each Rank has its specific codebook model tailored to the channel characteristics at that Rank, providing localized optimization rather than a one-size-fits-all approach. This improves quantization accuracy for each specific channel condition.
2Ease of manufacture
If existing LTE codebook designs are used, then implementation is simple, but performance is poor for dual-polarized channels with 4 or more antennae
Solution Approach 1:
The patent creates a universal codebook design that works for multiple Rank values and dual-polarized channel configurations. The same codebook structure and selection methodology can be applied across different scenarios (Rank=1, Rank=2, etc.), providing multi-functionality while maintaining implementation simplicity through standardized procedures.
Solution Approach 2:
The patent modifies key parameters of the codebook design including the use of orthogonal features, 8PSK constellation points, and specific mathematical models for codeword generation. These parameter changes improve performance for dual-polarized channels while keeping the implementation approach systematic and manageable.
3Measurement precision
If codebook size is increased to reduce quantization error, then feedback capacity is consumed, but feedback overhead increases
Solution Approach 1:
The patent applies partial action by using a subset of carefully selected codewords from the codebook space that are most relevant to dual-polarized channel characteristics. Rather than using all possible codewords, the patent selects and optimizes a specific set that provides the best performance for the target channel type, reducing feedback overhead while maintaining quantization accuracy.
Data Source
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AI summary
The present invention discloses a method for feeding back channel information, which includes: configuring a same codebook space at a data transmitting end and a data receiving end (101); the data receiving end selecting, from the codebook space, a codeword matched with a channel, and transmitting a sequence number corresponding to the codeword to the data transmitting end (102); and the data transmitting end extracting, according to the sequence number, a corresponding codeword from a locally-configured codebook space to obtain channel state information (103). The present invention also discloses a system for feeding back channel information, which includes a data transmitting end and a data receiving end. The method and system for feeding back channel information solve the problem that there is no channel information feedback method for dual-polarized channels.