Analog Precoder Matrix Acquisition for Millimeter Wave Massive MIMO
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Solution Overview
Problem
Conventional analog precoders in hybrid beamforming systems face performance degradation in frequency selective fading environments due to design limitations, particularly in achieving high frequency spectrum efficiency while maintaining low complexity.
Innovation Solution
An analog precoding matrix acquisition method that sets an objective form to maximize frequency spectrum efficiency, approximates it using a digital precoding matrix, generates an analog precoding matrix, and iteratively optimizes it to minimize errors within a predetermined range, effectively updating the initial matrix to achieve optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional analog precoders are used in hybrid beamforming systems, then device complexity is reduced by using fewer RF chains, but frequency spectrum efficiency deteriorates in frequency selective fading environments
Solution Approach 1:
The patent applies dynamics by making the analog precoding matrix adaptive through iterative optimization. Instead of using a fixed precoding matrix, the system dynamically updates the analog precoder based on channel state information and frequency selective fading characteristics, allowing it to adapt to changing environmental conditions while maintaining low complexity
Solution Approach 2:
The patent changes parameters by optimizing the analog precoding matrix elements through iterative algorithms. The system adjusts precoding parameters based on channel conditions and frequency selectivity, transforming the fixed parameter approach into a dynamic parameter optimization process that improves frequency spectrum efficiency without increasing RF chain count
2Device complexity
If the same analog precoding matrix is applied to all sub-carriers, then device complexity is maintained at low levels, but frequency spectrum efficiency deteriorates due to severe channel changes in frequency selective fading environments
Solution Approach 1:
The patent makes the precoding approach dynamic by iteratively optimizing the analog precoding matrix for each sub-carrier based on its specific channel conditions. This allows different precoding matrices to be used for different sub-carriers while maintaining manageable complexity through systematic optimization rather than complete redesign
Solution Approach 2:
The patent segments the frequency spectrum into individual sub-carriers and applies optimized precoding to each segment separately. By dividing the overall precoding problem into sub-carrier-specific optimizations, the system achieves frequency-selective optimization without requiring a completely new complex architecture
3Productivity
If digital beamforming is used to achieve high channel capacity, then frequency spectrum efficiency is improved, but device complexity and power consumption increase due to requiring RF chains for each antenna
Solution Approach 1:
The patent merges digital and analog beamforming into a hybrid system that combines the advantages of both approaches. The analog precoder handles the bulk of the beamforming operation to reduce RF chain requirements, while the digital precoder provides fine-grained control for capacity optimization, achieving high channel capacity with fewer RF chains than full digital beamforming
Solution Approach 2:
The patent applies partial action by using a reduced number of RF chains compared to the total number of antennas. Instead of requiring full digital beamforming with RF chains for each antenna, the system uses a partial RF chain configuration combined with analog precoding to achieve sufficient performance for high channel capacity
Data Source
AI summary
The present inventive concept relates to a method for designing an optimal analog precoder for improving frequency spectrum efficiency in a millimeter wave-based multi-user massive MIMO-based hybrid beamforming system and a hybrid beamforming system applying the same, and more specifically, to a method for designing an optimal analog precoder using an approximation technique and an iterative optimization algorithm, and a hybrid beamforming system to which the same is applied.