Channel State Information Feedback Compression via Codebook Segmentation
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Solution Overview
Problem
In CoMP systems, the large amount of channel state information (CSI) feedback required for multiple point transmission leads to high overhead, with existing compression methods having low compression ratios and inefficient bit usage.
Innovation Solution
The method involves converting CSI into a current channel parameter frame, performing frequency domain quantization and coding, and using differential quantization and coding techniques to reduce the number of feedback bits while maintaining accuracy, by employing direct and differential quantization methods on the channel parameter frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple base stations transmit reference signals for CoMP, then transmission diversity and reliability are improved, but the amount of channel state information feedback required increases dramatically
Solution Approach 1:
The patent segments the channel state information feedback into two parts: a first codebook index indicating the selected codebook from a set of codebooks, and a second codebook index indicating the specific codeword within the selected codebook. This segmentation allows the terminal to feedback channel state information for multiple base stations without transmitting the complete channel matrix, thereby reducing feedback overhead while maintaining the ability to support CoMP transmission diversity.
Solution Approach 2:
The patent extracts only the essential channel state information needed for CoMP operation - specifically the codebook indices that represent the most significant channel characteristics - rather than feedback the complete channel state matrix. This extraction approach captures the critical information for transmission scheduling and precoding selection while eliminating redundant data, thus resolving the contradiction between reliable multi-point transmission and feedback overhead.
2Productivity
If the terminal feeds back channel state information for multiple antenna ports, then MIMO performance is improved, but the feedback overhead increases due to the large number of antenna ports
Solution Approach 1:
The patent merges the feedback of channel state information for multiple antenna ports into a unified codebook structure. Instead of separately feedback information for each antenna port, the terminal uses a single codebook that captures the joint channel characteristics across all antenna ports. This merging approach maintains MIMO performance by preserving the spatial correlation information while significantly reducing feedback overhead compared to individual port feedback.
Solution Approach 2:
The patent transforms the channel state information from the spatial domain (individual antenna ports) to a codebook index domain. By mapping the multi-dimensional channel state information across multiple antenna ports into a compact codebook representation, the patent reduces the feedback dimensionality while preserving the essential MIMO channel characteristics needed for high throughput performance.
3Device complexity
If conventional quantization methods are used for CSI compression, then implementation simplicity is maintained, but compression ratio is low and bit efficiency is poor
Solution Approach 1:
The patent introduces dynamic codebook selection where the terminal can choose from multiple codebooks based on the actual channel conditions. The first codebook index dynamically indicates which codebook from the set should be used, allowing the system to adapt to different channel scenarios (e.g., different spatial correlations, different antenna configurations). This dynamic approach improves compression efficiency and bit efficiency compared to fixed conventional quantization methods while maintaining reasonable implementation complexity through standardized codebook structures.
Data Source
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AI summary
Embodiments of the present invention relate to a channel state information processing method, a terminal and a base station. The channel state information processing method includes: converting current channel state information into a current channel parameter frame; obtaining feedback information after performing frequency domain quantization and coding on the current channel parameter frame; and sending the feedback information to a base station.