Precoding Apparatus Quadrant Search Complex Plane
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nonlinear precoding techniques, such as QRM-VP, face limitations in reducing the amount of operation while maintaining transmission performance, especially as the number of multiplex terminal apparatuses increases, which restricts the improvement of spectral efficiency in wireless communication systems.
Innovation Solution
A precoding apparatus that generates a linear filter based on channel information, expands perturbation term candidates in a complex plane, and searches for an optimal perturbation vector to reduce the amount of operation by using a perturbation vector with complex numbers and channel matrix transformations like QR decomposition, QL decomposition, and Cholesky decomposition, while optimizing the number of candidates and metric calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vector perturbation (VP) is used to achieve optimal transmission performance, then transmission performance is improved, but the amount of operation exponentially increases relative to the number of multiplex terminals
Solution Approach 1:
The patent segments the search space by dividing the complex plane into quadrants and further dividing each quadrant into regions. This segmentation allows the system to focus search efforts on specific regions where optimal perturbation vectors are more likely to be found, reducing the overall search complexity from exponential to polynomial while maintaining transmission performance.
Solution Approach 2:
The patent applies local quality by treating different regions of the complex plane differently. By identifying and prioritizing search in specific quadrants and regions based on channel conditions and reference signal positions, the system optimizes the search process locally rather than uniformly across the entire space, significantly reducing computational operations.
2Device complexity
If sphere encoding (SE) is used to reduce the amount of operation, then the amount of operation is reduced, but the increase in operation relative to the number of multiplex terminals remains exponential
Solution Approach 1:
The patent divides the complex plane into quadrants and further segments each quadrant into regions. This hierarchical segmentation transforms the search problem from a global exponential search to a localized polynomial search within specific regions, enabling the system to handle a polynomial increase in multiplex terminals rather than exponential growth in operations.
Solution Approach 2:
The patent performs partial action by searching only in specific quadrants and regions of the complex plane rather than exhaustively searching the entire space. This selective search approach achieves sufficient transmission performance with polynomial operations instead of requiring complete exponential search.
3Device complexity
If QRM-VP is used to suppress the amount of operation, then the amount of operation is suppressed, but the degree of suppression is limited due to operations needed to determine relevance
Solution Approach 1:
The patent segments the complex plane into quadrants and regions, allowing the system to determine relevance by checking which segment contains the reference signal rather than performing complex relevance calculations for all candidate points. This segmentation approach significantly reduces operations while maintaining effective suppression.
Solution Approach 2:
The patent performs preliminary action by pre-dividing the complex plane into quadrants and regions before the search process. This preliminary segmentation structure enables rapid determination of relevant search areas without requiring complex runtime calculations to assess relevance of each candidate point.
Data Source
AI summary
More reduction of the amount of operation than in QRM-VP is realized while maintaining transmission performance that can be achieved by VP. A precoding apparatus 109 that performs preliminary processing on transmission data transmitted from a wireless transmission apparatus including a plurality of antennas to a wireless reception apparatus includes a linear filter generation section 301 that generates a linear filter on the basis of a result of estimation of a channel between an antenna unit 111 and the wireless reception apparatus, a signal conversion section 303 that expands perturbation term candidates of a perturbation vector to be added to a transmission data vector and a reference signal associated with the transmission data in a complex plane, and a perturbation vector search section 305 that searches for the perturbation vector to be added to the transmission data vector by performing a quadrant search on the basis of the perturbation term candidates and the reference signal expanded in the complex plane. A transmission signal vector is calculated by adding a found perturbation vector to the transmission data vector and multiplying the transmission data vector by the linear filter.