Precoding Matrix Design for ULA Spatial Resolution
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Solution Overview
Problem
The existing two-stage feedback approach for precoding in multi-antenna technology, particularly for uniform linear array (ULA) antennas, results in high overhead and unsatisfactory performance due to limited co-phasing factor choices, leading to inadequate spatial resolution and phase distribution.
Innovation Solution
A new precoding scheme is proposed that involves an optimized first matrix W1 with a diagonal structure to increase the number of DFT beams and a co-phasing adjustment in the second matrix W2 to ensure even phase distribution across the phase space, improving spatial resolution and performance by increasing the number of DFT beams and adjusting phases for each beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the existing two-stage feedback approach with limited co-phasing factor choices is used, then the feedback overhead is reduced, but the spatial resolution and performance are insufficient
Solution Approach 1:
The patent changes the parameter of co-phasing factor choices from limited discrete values to continuously adjustable phases. Specifically, the second matrix W2 introduces adjustable phase shifts that can be optimized to achieve even phase distribution across the phase space, thereby increasing the number of DFT beams from 16 to 32 and improving spatial resolution without proportionally increasing feedback overhead
Solution Approach 2:
The patent adds a phase adjustment dimension to the existing two-stage feedback structure. By introducing phase adjustment parameters in the second matrix W2, the system extends the solution space from limited co-phasing factors to a continuous phase space, enabling more beams to be formed while maintaining efficient feedback through selective parameter reporting
2Measurement precision
If the amount of DFT beams is increased to improve spatial resolution, then the performance is improved, but the complexity of the precoding scheme increases
Solution Approach 1:
The patent segments the precoding matrix into two distinct matrices: W1 for wideband/long-term channel properties and W2 for frequency-selective/short-term properties. This segmentation allows the system to increase DFT beams by enhancing W2 with phase adjustments while keeping W1 relatively simple, thereby improving spatial resolution without proportionally increasing overall system complexity
Solution Approach 2:
The patent introduces dynamic phase adjustment capabilities in the second matrix W2, allowing the phase of each beam to be adaptively optimized based on channel conditions. This dynamic adjustment enables the system to achieve higher spatial resolution with 32 beams while maintaining manageable complexity through structured codebook design and selective feedback
Data Source
AI summary
A method for determining precoding matrix for the sub-band precoding in a transmitter with M transmitting antennas. The method includes determining an optimized first matrix W1 according to wideband and/or long-term channel properties, multiplying the optimized first matrix W1, with each second matrix W2, in a second codebook, to obtain a plurality of candidate precoding matrices, the second matrix W2 corresponds to frequency-selective and/or short-term channel properties; selecting an optimized one from the plurality of candidate preceding matrices for precoding the data to be transmitted, according to a frequency selection and/or a short-term channel state information. The amount of DFT beams may be increased to improve the spatial resolution; a diagonal matrix is involved in the first matrix W1; and phase adjustment is involved in the second matrix W2, so as to guarantee the adjusted phase is evenly distributed among the whole phase space.