Cognitive Radio Spectrum Sensing via Database and Correlation

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Solution Overview

Problem

Current spectrum management techniques for cognitive radio devices face challenges in accurately determining location, especially in indoor environments, and struggle to differentiate between licensed and unlicensed signals, leading to inefficient use of TV white space and other unlicensed bands.

Innovation Solution

A system with a variable resolution geo-location server and cognitive radio spectrum database that provides a location indicator and spectrum map, combined with a spectrum sensor capable of detecting specific signal types, to enhance spectrum sensing and ensure reliable protection for licensed services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spectrum sensing is used to detect available TV white space channels, then the device can operate without database inquiry, but the sensitivity levels are difficult to achieve in the presence of high power adjacent channel signals

Engineering Contradiction:

Improvespectrum sensing capabilityVSAvoidsensitivity level

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary signal processing approach that uses reference signals and correlation techniques to detect incumbent signals. Instead of relying solely on direct spectrum sensing at very low sensitivity levels, the system uses known reference signals from licensed services to correlate and detect their presence, thereby achieving reliable detection without requiring extreme sensitivity in noisy environments

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary actions by maintaining a database of known incumbent signal characteristics and reference signals before actual spectrum sensing. This pre-characterization of licensed signals allows the cognitive radio to efficiently detect their presence through correlation matching, reducing the burden on real-time sensing sensitivity

Inventive Principle:

Principle #10Preliminary action

2Productivity

If spectrum sensing is used to detect signals, then the device can identify signal presence, but it cannot determine if the signal originated from a licensed or unlicensed source

Engineering Contradiction:

Improvesignal detection efficiencyVSAvoidsignal source identification

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent implements feedback mechanisms where the cognitive radio continuously monitors detected signals and compares them against known incumbent signal patterns. When a signal is detected, the system provides feedback by matching it against reference databases to identify whether it originates from licensed or unlicensed sources, thereby recovering the lost information about signal origin

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system uses an intermediary classification mechanism that acts as a bridge between raw spectrum sensing data and signal source identification. By introducing signal characterization databases and pattern matching algorithms as intermediaries, the system can determine the origin of detected signals without requiring the sensing hardware itself to have this capability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If geo-location information is provided with low precision, then the database must return conservative inquiry results, but this compromises TV white space utility

Engineering Contradiction:

Improveincumbent protectionVSAvoidTV white space utility

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamic adaptation by adjusting the level of geo-location precision required based on the operational context and detected signal environment. When incumbent signals are detected through spectrum sensing, the system dynamically refines its location estimation and inquiry parameters, allowing it to operate effectively even when initial geo-location data has low precision, thereby maintaining both reliability and utility

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If the sense-only mode is used, then the device can rely exclusively on spectrum sensing, but it does not provide a mechanism to permit governing authority to exclude the device from particular channels

Engineering Contradiction:

Improvespectrum sensing autonomyVSAvoidregulatory control capability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a hybrid system that combines spectrum sensing capabilities with database inquiry functionality, creating a multi-functional platform. This universal system can operate in different modes depending on regulatory requirements - it can perform autonomous spectrum sensing when permitted, or consult regulatory databases for channel exclusions, or use both methods together, thereby achieving both operational simplicity and regulatory adaptability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8928759B2System and method of implementing a cognitive radio device with enhanced spectrum sensing

Publication Date: 2015.01.06 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A cognitive radio band device uses information gleaned from a database inquiry based on geo-location information in combination with spectrum sensing to determine if cognitive radio channels are available for unlicensed use.