Precoding Matrix Indicator Reporting for 5G Polarization Efficiency
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Solution Overview
Problem
The current precoding matrix indicator (PMI) reporting in 5G networks faces challenges due to limited channel state information at the transmitter, especially with multiple polarizations, leading to complications in feedback and quantization, particularly in identifying the reference amplitude of the weaker polarization, which affects the reconstruction of amplitudes and phases in the precoding matrix.
Innovation Solution
Incorporating indicators for the position of the strongest coefficient of the weaker polarization in the uplink control information (UCI) to facilitate efficient reporting and reduce signaling overhead, allowing the network node to derive the reference amplitude and reconstruct the precoding matrix accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PMI reporting is performed with multiple polarizations, then precoding accuracy is improved, but feedback complexity and quantization difficulty increase
Solution Approach 1:
The feedback information is segmented into distinct components: a first indicator for the position of the strongest coefficient and a second indicator for the reference amplitude. This segmentation allows the receiver to process and reconstruct the precoding matrix more efficiently by handling each component separately, reducing overall feedback complexity while maintaining precoding accuracy for multiple polarizations.
Solution Approach 2:
The patent performs preliminary identification and reporting of the strongest coefficient's position and its reference amplitude before the actual precoding matrix reconstruction. By providing these reference values in advance through the UCI, the system enables the transmitter to accurately reconstruct the precoding matrix without requiring complex real-time quantization and feedback of all matrix elements.
2Measurement precision
If reference amplitude of weaker polarization is explicitly reported, then amplitude reconstruction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the essential reference amplitude information of the strongest coefficient in the weaker polarization and reports it separately through a second indicator in the UCI. This extraction approach provides the necessary reference for amplitude reconstruction without transmitting the entire amplitude matrix, thereby improving reconstruction accuracy while minimizing signaling overhead by reporting only the critical reference value.
3Productivity
If PMI feedback includes detailed coefficient information, then precoding performance is improved, but uplink control information size increases
Solution Approach 1:
Instead of transmitting the complete precoding matrix or all coefficient details, the patent transmits a compact representation consisting of a first indicator (position of strongest coefficient) and a second indicator (reference amplitude). These indicators serve as a compressed copy that enables the transmitter to reconstruct the full precoding matrix at the receiver side, thereby maintaining precoding performance while significantly reducing the size of uplink control information.
Data Source
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AI summary
There is provided a method at a user equipment, comprising: receiving transmission on two different polarizations over a wireless channel from network (300); determining a plurality of coefficients associated with a precoding matrix based on channel measurements of the reception, wherein the coefficients at least partially define a combination matrix (302); selecting a coefficient among the coefficients of the weaker polarization, the selected coefficient being a reference coefficient for the weaker polarization (304); determining a first indicator and a second indicator for the reference coefficient, wherein the first indicator indicates a position of the reference coefficient in the combination matrix and the second indicator comprises an amplitude value associated with the reference coefficient (306); reporting the first and second indicators to the network (308).