Backscatter Signal Separation Using Phase Angle Projector Matrix
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Solution Overview
Problem
Existing radio communication systems face challenges in efficiently separating multiple backscatter signals from tag devices using a single reception antenna, requiring complex signal processing and high computational resources, while also needing to improve signal-to-noise ratio and reduce system size.
Innovation Solution
A radio communication apparatus that converts mixed backscatter signals into complex data, calculates phase angles of carrier waves to form a projector matrix, and separates signals using an inverse matrix, allowing for signal separation with fewer antennas and reduced computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional signal separation methods using propagation coefficients are used, then signal separation can be achieved, but communication capacity is reduced and signal processing complexity increases
Solution Approach 1:
The patent extracts only the necessary phase angle information from the mixed signal to construct the projector matrix, rather than processing the entire complex signal. This extraction approach maintains signal separation accuracy while significantly reducing computational complexity and processing requirements.
Solution Approach 2:
The patent creates a simplified mathematical model (projector matrix) that copies only the essential phase relationships between signals. This model allows signal separation to be achieved through simpler matrix operations rather than complex full-signal processing, reducing computational burden while maintaining accuracy.
2Reliability
If more reception antennas are used to improve signal separation, then signal-to-noise ratio improves, but device size and complexity increase
Solution Approach 1:
The patent changes the processing parameter from full complex signal processing to phase angle extraction only. By focusing on phase angle information and constructing the projector matrix based on these parameters, the system achieves improved signal-to-noise ratio and signal separation without requiring additional reception antennas, thus avoiding increased device size.
3Productivity
If blind signal separation using independent component analysis is used, then signal separation can be achieved without propagation coefficients, but computational complexity and processing time increase
Solution Approach 1:
The patent performs preliminary action by extracting phase angles and constructing the projector matrix before the actual signal separation process. This pre-processing step organizes the essential information in a structured matrix form, which enables faster and simpler subsequent separation operations compared to performing blind signal separation directly on the mixed signal.
Data Source
AI summary
A radio communication apparatus is described that includes a reception antenna, a converter, a calculator, and a separator. The reception antenna receives a mixed signal including two or more backscatter signals respectively transmitted from two or more tag devices and the converter converts the mixed signal into complex data on a complex plane. The calculator calculates phase angles of carrier waves of the two or more backscatter signals to approximate the phase angles into a complex data sequence of a predetermined length, and generates a projector matrix formed of a combination of the phase angles of carrier waves of the two or more backscatter signals. The separator separates the two or more backscatter signals from the mixed signal based on an inverse matrix of the projector matrix and the complex data sequence.