November 3, 2011
The Art of Cognitive Radio in
Unmanned Vehicles Robert White – Director – RF Neulink
www.rfneulink.com
November 3, 2011
What You Will Learn
• Basic Cognitive Radio Architecture • Basic Concepts of Software Defined Radio (SDR) • Basic Concepts of the Cognitive Unit & its relationship to SDR. • Spectrum Sensing - Radio Environment • Software Architecture Theory • Cognitive Radio Techniques - Benefit Unmanned Vehicles
Service Bandwidth
Channel Bandwidth Wc
Power
Frequency
November 3, 2011
Basic Cognitive Radio Architecture
“Ability to learn from the environment and adapt its internal states by making corresponding changes in operating parameters in real-time”
• A flexible Software Defined Radio unit whose operating software provides a range of possible operating modes • A Cognitive Unit that makes decisions based on various inputs - Cognitive Engine - optimize performance based on Inputs - Cognitive Policies - compliance with external rules & policies • A separate Spectrum Sensing Subsystem to measure the signal environment
What Defines a Cognitive Radio
What is Required
“All of The Above May Be Part of a System or Network”
November 3, 2011
Software Defined Radio (SDR)
SDR is a radio that has the ability to be transformed through the use of software or re-definable logic. Quite often this is done with general-purpose Digital Signal Processors (DSPs) or Field Programmable Gate Arrays (FPGAs)
Possible dynamic characteristics of an SDR:
• Channel bandwidth
• Data rate
• Modulation type
• Error Correction – S/N vs
• Dynamic Configurations
November 3, 2011
• Digital Signal Processors (DSPs) provide flexible programmability
• All modulation, cryptography, protocols, and source coding (voice, data, imagery) are established using software
• Many types of modulation can be accomplished over a broad range of frequencies, thereby an SDR is capable of servicing more than one class of service
• Field serviceable, when requirements change, upgrades and modifications are relatively easy to execute
SDR Technology Fundamentals
November 3, 2011
Cognitive Unit
Cognitive Engine Function (Free Form) • Analyze Inputs Received – Spectrum Sensing • Optimize to a Performance Goal
• Define the Radio’s Current Internal State & Operating Environment Cognitive Policies • Check “Cognitive Engine” is in Compliance With:
* Regulatory Rules * Policies External to the Radio
Service Bandwidth
Channel Bandwidth Wc
Power
Frequency
November 3, 2011
1) Radio-scene analysis, which encompasses the following: • Estimation of interference temperature of the radio environment; • Detection of spectrum holes.
2) Channel identification, which encompasses the following: • Estimation of channel-state information (CSI) BER/SN • Prediction of channel capacity for use by the transmitter
3) Transmit-power control and dynamic spectrum management.
Spectrum Sensing - Radio Environment
• Bit Error Rate (BER) • Signal to noise ratio (SIR) • Signal to interference & noise ratio (SINR) • Received signal strength
November 3, 2011
Software Architecture Theory
Awareness
Sensing &
Modeling
Adapting Evolution & Optimization
Learning
Building & retaining
Knowledge Radio
Hardware
Ideal Characteristics: • Intelligence (Accurate decisions)
• Reliability (Consistent decisions)
• Awareness (Informed decisions)
• Adaptability (Situation dependent decisions)
• Efficiency (Low overhead decisions)
• Excellent Quality of Service (Good decisions)
Tradeoffs exist between these characteristics
November 3, 2011
Cognitive Radio Techniques - Benefit Unmanned Vehicles
• One Common Radio Platform for all Unmanned Vehicles • Frequency Agile - Multi-Channel – Multi-Band SDR • Optimize Radio Links Under Changing Channel Conditions And Evolving Mission Requirements • Employ Cooperative Communications Techniques to Enhance the Performance of Unmanned Vehicle Networks
www.RFNeulink.com
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