High-Resolution Multi-TRP PMI Feedback with Reduced CSI Overhead
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Solution Overview
Problem
The overhead associated with transmitting high-resolution channel state information (CSI) feedback for multiple transmission-reception points (TRPs) in wireless communication systems is significant, leading to increased processing complexity and bandwidth utilization.
Innovation Solution
Implement mechanisms to control the quantity of spatial and frequency domain bases, precoding matrix coefficients, and per-coefficient quantization bits for efficient multi-TRP CSI reporting, allowing UEs to report high-resolution PMI with minimal payload overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution CSI feedback is transmitted for multiple TRPs, then beam formation quality is improved, but overhead and bandwidth utilization increase
Solution Approach 1:
The patent segments the multi-TRP CSI feedback into multiple codebook types (first codebook for TRP identification, second codebook for precoding matrix selection, third codebook for spatial domain filtering). This segmentation allows the feedback to be structured efficiently, reducing overall overhead while maintaining high resolution for beam formation by separating identification functions from precision measurement functions.
Solution Approach 2:
The patent introduces spatial domain basis vectors as an additional dimension for representing channel state information. By projecting the channel response onto a set of spatial basis vectors and reporting only the dominant coefficients, the system achieves high-resolution CSI feedback with reduced payload size, effectively adding a spatial dimension to compress the feedback information.
2Reliability
If high-resolution PMI feedback is reported for multiple TRPs, then communication reliability is enhanced, but processing complexity increases
Solution Approach 1:
The patent applies partial action by reporting only the most significant spatial domain coefficients above a threshold value, rather than reporting all coefficients. This partial reporting approach maintains sufficient reliability for beam formation while significantly reducing the processing complexity at both the UE and network side.
Solution Approach 2:
The patent changes the representation parameters of CSI feedback by transforming the traditional precoding matrix indication into a spatial domain basis representation with configurable precision. The network can adjust the number of bits allocated for spatial coefficients, allowing dynamic trade-off between reliability and processing complexity based on channel conditions and service requirements.
3Measurement precision
If detailed precoding matrix coefficients are reported for each TRP, then beam quality is improved, but bandwidth utilization increases
Solution Approach 1:
The patent extracts only the essential components for beam formation by separating TRP identification information from precoding matrix details. The first codebook extracts TRP identification with minimal overhead, while the second and third codebooks extract only the dominant spatial coefficients needed for beamforming, discarding redundant information and reducing bandwidth utilization.
Solution Approach 2:
The patent performs preliminary spatial domain decomposition at the UE side before feedback transmission, pre-identifying the dominant spatial basis vectors and their coefficients. This preliminary processing allows the network to receive pre-compressed high-resolution precoding information, reducing the bandwidth required for feedback transmission while maintaining beam quality.
Data Source
AI summary
Wireless communications systems and methods related to multi-transmission-reception point (multi-TRP) precoding matrix indication (PMI) operations are provided. A user equipment (UE) receives a configuration indicating a precoder size parameter for a plurality of transmission-reception points (TRPs). The UE receives, from a first TRP of the plurality of TRPs, a first reference signal. The UE receives, from a second TRP of the plurality of TRPs, a second reference signal, the second TRP being different from first TRP. The UE transmits, to the first TRP or the second TRP, a channel state information (CSI) report including a first feedback component based on the first reference signal and a second feedback component based on the second reference signal, where a combined payload size of the first feedback component and the second feedback component is based on the precoder size parameter.