Sub-Codebook TCQ for CSI Feedback Under Bandwidth Constraints
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Solution Overview
Problem
Current channel state information (CSI) feedback schemes in wireless communication systems suffer from information loss and inefficiencies due to bandwidth constraints, limiting the precision of channel knowledge and thus the effectiveness of transmission beamforming.
Innovation Solution
The implementation of a trellis coded quantization (TCQ) scheme that estimates channel parameters, converts phase and magnitude information, and applies Viterbi algorithms to maximize the distance between sub-codebooks, enabling more accurate CSI feedback without information loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If current channel feedback schemes are used, then bandwidth requirements are reduced, but channel information loss increases and measurement precision deteriorates
Solution Approach 1:
The codebook is divided into multiple sub-codebooks, each handling a specific portion of the channel state information. This segmentation allows for more granular and efficient quantization of CSI, reducing information loss while optimizing bandwidth usage through selective feedback of sub-codebook indices.
Solution Approach 2:
The patent transforms the channel state information from the complex domain to the polar domain (magnitude and phase), and further applies trellis-coded quantization in a structured dimension. This dimensional transformation enables more efficient representation and feedback of channel information, reducing both information loss and bandwidth requirements.
2Quantity of substance
If quantization of full CSI feedback is applied, then bandwidth efficiency improves, but measurement precision and channel knowledge accuracy deteriorate
Solution Approach 1:
The patent introduces trellis-coded quantization as an intermediary process between channel estimation and feedback transmission. This intermediary technique provides a structured mapping from continuous channel values to discrete feedback values, minimizing quantization error and preserving measurement precision while achieving bandwidth efficiency through compact representation.
Solution Approach 2:
The patent changes the quantization parameters by using trellis-coded quantization with specific code rates and sub-codebook structures. This parameter optimization allows for efficient bandwidth utilization while maintaining high measurement precision through carefully designed quantization levels and feedback mechanisms.
3Measurement precision
If more precise channel knowledge is obtained, then transmission effectiveness improves, but bandwidth consumption increases
Solution Approach 1:
By segmenting the channel state information into magnitude and phase components, and further dividing the codebook into sub-codebooks, the patent enables selective and efficient feedback transmission. This segmentation allows for high precision channel knowledge to be conveyed using optimized bandwidth through targeted feedback of only the most critical parameters.
Data Source
AI summary
Aspects of the disclosure provide for methods and systems for Sub-codebook based Trellis Coded Quantization for CSI Feedback. An aspect of the disclosure provides method executed by a receiver. The method includes receiving a signal from a transmitter, via a communication channel between the receiver and the transmitter. The method further includes estimating parameters associated with the channel based on the received signal. The method further includes obtaining phase information from the estimated parameters. The method further includes applying a trellis coded quantization (TCQ) scheme to the obtained phase information by mapping each sub-codebook index of a set of sub-codebook indices to output bits of each trellis branch making the distance between sub-codebooks maximally equal. The method further includes transmitting a channel state information (CSI) measurement feedback to the transmitter, the CSI measurement feedback based on the TCQ scheme and comprising one or more of: a beginning state, input bits to the TCQ scheme, and a sub-codebook index.