Distributed Spectrum Sensing Management in Cognitive Radio Networks

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Solution Overview

Problem

Cognitive radio networks face challenges in reliably detecting unoccupied spectrum and avoiding interference with primary users due to limitations in single sensor systems, leading to delays, excessive control channel bandwidth usage, and inaccurate identification of malicious nodes in dynamic environments.

Innovation Solution

A distributed spectrum sensing management and control system using a centralized decision engine and decentralized sensing engines for cooperative sensing, which interprets sensor data, optimizes channel selection, and schedules quiet periods to ensure reliable detection and fast network recovery without interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooperative sensing techniques are used to improve detection reliability, then detection accuracy is improved, but decision delay increases

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddecision delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The sensing system is segmented into multiple distributed sensing nodes that independently perform local sensing operations. Each node processes its own sensor data locally and only communicates necessary information with the central decision engine, enabling parallel processing and reducing the time required for collective decision-making while maintaining detection reliability through multiple independent sensing points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Sensing nodes perform preliminary sensing operations continuously and maintain local state information about spectrum conditions. When a sensing opportunity arises, the system can quickly make decisions based on pre-collected data and recent measurements, reducing decision delay while ensuring reliable detection through the accumulated preliminary observations.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If distributed sensing is implemented to improve detection accuracy, then measurement precision is improved, but control channel bandwidth usage increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidcontrol channel bandwidth usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system extracts only the essential sensing results and key metadata from the distributed sensing nodes rather than transmitting all raw sensor data through the control channel. The sensing nodes perform local data processing and filtering, extracting only the necessary information (such as detected primary users, signal strength thresholds, and location data) for the central decision engine, thereby reducing control channel bandwidth usage while maintaining detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Each sensing node performs local processing and quality assessment of its measurements independently. The nodes filter and validate their own sensor data locally before transmitting to the central decision engine, ensuring that only high-quality, relevant information is transmitted over the control channel. This local quality control reduces unnecessary bandwidth consumption while maintaining the precision of detection results.

Inventive Principle:
Principle #3Local quality

3Device complexity

If single sensor systems are used to simplify the system, then device complexity is reduced, but reliability deteriorates

Engineering Contradiction:
Improvesensor system complexityVSAvoidsensor measurement confidence
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Multiple distributed sensing nodes are merged into a cooperative sensing network that shares information with a central decision engine. The system combines the observations from multiple independent sensors through data fusion algorithms, achieving higher reliability and confidence in sensor measurements while keeping individual node complexity low. The merging occurs at the decision-making level rather than at the sensor level, maintaining simplicity of individual components while improving overall system reliability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2327242B1Method and system for distributed sensing management and control within a cognitive radio network
Publication Date: 2018.04.18 MOTOROLA SOLUTIONS INC
  • EP2327242B1 patent drawingFigure 1
  • EP2327242B1 patent drawingFigure 2
  • EP2327242B1 patent drawingFigure 3~4

AI summary

A technique for spectrum sensing management and control for a secondary communication system seeking to utilize another communication system's spectrum is provided (600). Sensor control data is sent from a base station to subscriber units (604). Sensing measurements are taken and sent back to the base station for ranking (608) as sensed feedback information. Comparisons of the sensed feedback information are made to each other and to thresholds aligned with the types of measurements taken (610). An initial ranked channel list is generated (612). Weighting of the initial ranking list and secondary ranking list is followed by re-ranking the channels according to the weighting into a final ranking list (612). The final ranking list is transmitted to the mobile units to enable operation within the other communication system's spectrum within interfering with that system (614). The weighting is based on the type of sensing measurement taken as opposed to the channel.