Hybrid Beamforming Precoding via Linear SVD Decomposition
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Solution Overview
Problem
Current hybrid beamforming systems face high precoding complexity and performance limitations, especially in multi-user OFDMA systems, due to the need for nonlinear iteration optimizations or exhaustive searches, which are computationally expensive and do not guarantee convergence.
Innovation Solution
A method using a linear algorithm for hybrid beamforming precoding, where user equipment spatial channel vectors are aggregated and decomposed via singular value decomposition (SVD) to generate wideband sub-spatial channel vectors, allowing for the selection of the best vectors for channel truncation, which in turn enables the generation of linear analog and digital beamforming, thus reducing complexity while maintaining high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonlinear iteration optimizations or exhaustive search are used for hybrid precoding design, then system performance is improved, but precoding complexity becomes extremely high
Solution Approach 1:
The patent segments the precoding design into two distinct parts: analog beamforming (using fixed down-tilt based patterns) and digital beamforming (using iterative optimization). This segmentation allows the complex digital part to be optimized separately while keeping the analog part simple and fixed, thereby reducing overall computational complexity while maintaining system performance.
Solution Approach 2:
The patent applies preliminary action by pre-determining the analog beamforming component based on fixed down-tilt angles before the digital beamforming optimization. This preliminary setup constrains the search space for the digital precoder, significantly reducing the computational burden of the iterative optimization process while still achieving high system performance.
2Device complexity
If fixed analog beamforming is used, then precoding complexity is reduced, but system performance deteriorates
Solution Approach 1:
The patent segments the precoding into analog and digital components, where the analog part uses simple fixed patterns and the digital part handles performance optimization. This segmentation allows the system to benefit from low-complexity analog beamforming while compensating for performance limitations through sophisticated digital beamforming.
Solution Approach 2:
The patent changes the parameter representation by using down-tilt angles as the primary control parameter for analog beamforming. This parameterization allows the system to explore a reduced-dimensional search space while maintaining the ability to achieve high system performance through the digital layer.
3Reliability
If iteration optimization-based hybrid precoding techniques are used for multi-user OFDMA systems, then system performance is improved, but computational complexity becomes unacceptably high
Solution Approach 1:
The patent segments the multi-user precoding problem into user-specific digital beamforming vectors and common analog beamforming patterns. This segmentation allows independent optimization of digital components for each user while sharing the simple analog structure across all users, dramatically reducing the computational complexity for multi-user OFDMA systems.
Solution Approach 2:
The patent applies preliminary action by pre-defining the analog beamforming patterns based on down-tilt angles before user-specific digital optimization. This preliminary structure reduces the dimensionality of the optimization problem for each user, enabling efficient computation even in multi-user OFDMA scenarios while maintaining high system performance.
Data Source
AI summary
A method and a communication device adapted for designing a hybrid beamforming (HB) precoding used in a mobile communication system with an antenna array, the method including aggregating spatial channel vectors received by the antenna array; performing a linear factorization of the aggregation; truncating the linear factorization to generate truncated channels; and designing the HB precoding based on the truncated channels, wherein the HB precoding includes a linearly generated analog beamforming component and a linearly generated digital beamforming component.