Radio Signal Sensing for Identifying Coexisting Active Systems
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Solution Overview
Problem
Conventional spectrum sensing techniques in cognitive radio networks are inadequate for identifying multiple coexisting systems, particularly in environments with inter-system interference, and fail to provide reliable networking-level functions for optimizing radio spectrum utilization.
Innovation Solution
A method and apparatus that process radio signals by squaring, filtering, and analyzing them to identify fundamental frequencies and power spectrum density, using techniques like Singular Value Decomposition and Multiple Signal Classification to determine active systems, even in the presence of colored Gaussian noise with unknown covariance matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spectrum sensing techniques (energy detection, pilot detection) are used, then the sensing process is simple and fast, but the ability to identify multiple coexisting systems is insufficient and unreliable
Solution Approach 1:
The patent segments the spectrum sensing process into multiple stages: initial energy detection, followed by fundamental frequency detection using squaring and filtering operations, and finally system identification through power spectrum density analysis. This segmentation allows the system to progress from simple to complex analysis only when needed, improving identification accuracy while managing computational complexity.
Solution Approach 2:
The patent transitions from conventional single-dimension energy detection to multi-dimensional analysis by incorporating fundamental frequency detection (through signal squaring and filtering) and power spectrum density estimation. This dimensional expansion enables discrimination between multiple coexisting systems that would otherwise appear identical in simple energy detection.
2Reliability
If traditional sensing techniques are applied in environments with inter-system interference, then the implementation is straightforward, but the reliability of system identification deteriorates
Solution Approach 1:
The patent introduces fundamental frequency detection as an intermediary step between energy detection and final system identification. By detecting fundamental frequencies through squaring and filtering operations, the system creates an intermediate representation that helps distinguish between interfering systems, thereby improving reliability in interference-prone environments.
Solution Approach 2:
The patent changes the detection parameters from simple energy levels to include fundamental frequencies and power spectrum density characteristics. This parameter transformation allows the system to differentiate between coexisting systems even when they operate in the same frequency band, improving reliability without requiring overly complex measurement procedures.
3Adaptability or versatility
If only link level sensing capability is provided, then the implementation is simple, but networking level functions for optimizing network efficiency cannot be achieved
Solution Approach 1:
The patent creates a multi-functional sensing apparatus that performs both link level detection (energy detection) and networking level identification (system identification through fundamental frequency and power spectrum analysis). This universal sensing capability enables the cognitive radio to adapt to different operational requirements, supporting both simple connectivity and optimized network-wide spectrum management.
Data Source
AI summary
The present invention discloses a method of multiple systems sensing for coexisting radio networks, including: performing energy detection and carrier locking; detecting the fundamental frequencies; and identifying the corresponding active systems from the detected fundamental frequencies and the evaluation of the estimated power spectrum density vector or the estimated trispectrum matrix. Based on the method, an apparatus capable of multiple systems sensing is presented. Furthermore, the present invention also provides an apparatus of multiple systems sensing for coexisting radio networks.