Channel Information Feedback Using Trellis-Extended Codebook
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Solution Overview
Problem
In 5G wireless communication systems, acquiring channel state information (CSI) in Frequency Division Duplexing (FDD) is challenging due to different frequency bands, leading to increased complexity and overhead in channel information feedback, particularly in massive MIMO systems where exhaustive search methods are impractical for large codebooks.
Innovation Solution
The implementation of a method that includes block-wise quantization of channel information, trellis-coded quantization, and phase adjustment, using a Trellis-Extended Codebook (TEC) and Trellis-Extended Successive Phase Adjustment (TE-SPA) to reduce feedback overhead by selectively feeding back quantized and phase-adjusted channel information based on preferred domains, allowing for efficient CSI feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaustive search methods are used for channel information feedback in massive MIMO systems, then beamforming gain is improved, but computational complexity and feedback overhead increase significantly
Solution Approach 1:
The patent segments the channel information feedback process into two stages: first, block-wise quantization of channel coefficients using Trellis-Extended Codebook (TEC) to reduce dimensionality; second, phase adjustment using Trellis-Extended Successive Phase Adjustment (TE-SPA) to refine accuracy. This segmentation allows achieving near-optimal beamforming gain without exhaustive search computational complexity.
Solution Approach 2:
The patent changes the parameter representation from full complex channel coefficients to quantized magnitude indices combined with phase adjustment values. By representing channel information as H = |H|·e^(jφ) where |H| is quantized using TEC and φ is adjusted using TE-SPA, the system reduces feedback overhead while maintaining beamforming performance.
2Measurement precision
If full channel information is fed back in massive MIMO systems, then channel accuracy is improved, but feedback overhead increases
Solution Approach 1:
The patent extracts only the essential components of channel information for feedback: magnitude values are quantized using TEC and phase values are adjusted using TE-SPA. By separating magnitude and phase processing and selectively feeding back quantized magnitude indices with compact phase adjustment information, the system maintains channel accuracy while significantly reducing feedback overhead compared to full channel coefficient feedback.
3Quantity of substance
If channel information is quantized to reduce overhead, then feedback overhead is reduced, but quantization error increases
Solution Approach 1:
The patent applies preliminary block-wise quantization using TEC to compress channel coefficients before phase adjustment. This preliminary quantization reduces the dimensionality of the problem, making subsequent phase adjustment more efficient. The two-stage process (TEC quantization followed by TE-SPA phase adjustment) progressively refines the channel representation, minimizing quantization error while controlling feedback overhead.
Data Source
AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A channel information feedback in a wireless communication system and a method of a receiving node of a wireless communication system are provided. The method includes transmitting an indication representing an indexing rule for channel values and block-wise quantized channel information, and receiving beamformed signals mapped to an antenna based on the indexing rule.