Cognitive Radio Spectrum Availability Determination
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Solution Overview
Problem
Existing methods for determining available white space spectrums in cognitive radio systems only consider interference from the cognitive system to the incumbent system, neglecting interference from the incumbent system to the cognitive system, which can render detected spectrums not truly available for the cognitive system.
Innovation Solution
A method and device that determine available spectrums by calculating co-channel and corresponding frequency coexistence criteria between the cognitive and incumbent systems, ensuring both systems can operate without interference by assessing distances and signal strengths, and reporting available frequencies to a database server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only the interference from cognitive system to incumbent system is considered, then the determination process is simple, but the detected spectrums are not truly available for cognitive system
Solution Approach 1:
The interference protection is divided into two independent segments: protection of incumbent systems from cognitive system interference, and protection of cognitive systems from incumbent system interference. Each segment is evaluated separately using distance calculation and coexistence criterion comparison, making the complex bidirectional protection manageable through systematic segmentation.
Solution Approach 2:
The patent applies inversion by not only considering the traditional direction of interference (cognitive to incumbent) but also explicitly evaluating the reverse direction (incumbent to cognitive). This dual-directional approach ensures that spectrums are only determined as available when both systems can coexist without interference in either direction.
2Reliability
If bidirectional interference protection is implemented, then spectrum availability is ensured, but the determination process becomes more complex
Solution Approach 1:
The distance calculation module and coexistence criterion evaluation module serve multiple functions: they evaluate both the cognitive-to-incumbent interference and the incumbent-to-cognitive interference. This multi-functionality reduces overall system complexity by reusing the same computational components for both protection directions.
Solution Approach 2:
The system implements feedback by continuously monitoring the actual interference levels and comparing them against the pre-calculated coexistence criteria. When the measured interference exceeds the threshold, the system dynamically adjusts spectrum determination results, creating a closed-loop control mechanism that ensures reliable spectrum sharing.
3Reliability
If distance calculation and coexistence criterion evaluation are performed, then mutual interference is protected, but computation time increases
Solution Approach 1:
The coexistence criteria and distance thresholds are pre-calculated and stored in the system before actual spectrum determination is needed. During spectrum determination, the system only needs to compare measured distances against these pre-established criteria, significantly reducing the computation time required for each individual spectrum availability check.
Data Source
AI summary
A method and device for determining available spectrums is disclosed in embodiments of the present invention. By applying the technical solution of the embodiments of the present invention, with consideration on the bi-directionality of the interference between wireless communication systems, when introduction of the cognitive system is required, the corresponding frequency will be determined as an available frequency only in the case the incumbent system and the cognitive system can be simultaneously guaranteed to meet the corresponding coexistence criterion among the corresponding frequency and adjacent frequencies thereof, thus ensuring that the determined available frequency band guarantees that the normal operation of the incumbent system is not interfered by the cognitive system while ensuring that the newly-introduced cognitive system can also operate normally without interference of the incumbent system, thereby improving the communication quality of the wireless communication systems.