Cognitive Radio
Short Description
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Description
Advanced Internet
Cognitive Radio Principles
Hyewon Lee M.S. Candidate Company LOGO Multimedia & Wireless Networking Lab. Seoul National University
Topics in Future Internet – Cognitive Radio
Contents
1
Cognitive Radio
2
Reference survey paper
3
Cognitive Networks
4
Concluding Remark
Topics in Future Internet – Cognitive Radio
Cognitive Radio Motivation: Spectrum Scarcity
Spectrum utility
Topics in Future Internet – Cognitive Radio
Cognitive Radio Cognition (Noun):
Cognition is the mental process involved in knowing, learning, and understanding things. - Collins Cobuild Dictionary
Cognitive Radio
Cognitive Radio is an intelligent wireless communication system that is aware of its surrounding environment and uses the methodology of understanding-by-building to learn from the environment and adapt its internal states to statistical variations in the incoming RF stimuli by making corresponding changes in certain operating parameters in real-time. - S. Haykin, “Cognitive Radio,” JSAC 2005
Topics in Future Internet – Cognitive Radio
Cognitive Radio Cognitive Radio
Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum, user behavior and network state.
- Wikipedia, “Cognitive Radio”
Topics in Future Internet – Cognitive Radio
Spectrum access policy
Fixed Spectrum
Spectrum Trading
Open Spectrum
Topics in Future Internet – Cognitive Radio
Terminology Capability of cognitive radio
Full cognitive radio
Every possible parameter observable is taken into account
Spectrum sensing cognitive radio
Only radio frequency band is taken into account
Licenses of spectrum band
Licensed band cognitive radio
Primary network (user)
Secondary network (user)
Unlicensed band cognitive radio
Topics in Future Internet – Cognitive Radio
Cognitive Radio Basic cognitive cycle •Estimation of interference temperature of the radio environment •Detection of spectrum holes
•Estimation of channel-state information •Prediction of channel capacity for use by the transmitter
•Ref.: S. Haykin, “Cognitive Radio,” JSAC 2005
Topics in Future Internet – Cognitive Radio
Cognitive Radio Main functions
Spectrum sensing
Spectrum management
Detecting unused spectrum Capturing the best available spectrum
Spectrum mobility
Maintaining seamless communication during the spectrum transition
Spectrum sharing
Providing fair spectrum scheduling method
•Ref.: Ian F. Akyildiz, et al., “NeXt generation/dynamic spectrum access/cognitive radio wireless networks: A survey,” ComNet 2006
Topics in Future Internet – Cognitive Radio
Cognitive Radio – Main functions Spectrum sensing
Detecting unused spectrum
Non-cooperative detection
Energy detection
Matched filter detection
Cyclostationary feature detection
Cooperative detection
Cooperation with
Primary network
Secondary users
Topics in Future Internet – Cognitive Radio
Interference Temperature Transmission power control
Transmitter-centric
Receiver-centric
Interference temperature
Real-time interaction between transmitter and receiver in adaptive manner
Topics in Future Internet – Cognitive Radio
Interference Temperature Limitations of interference temperature model
Level of interference temperature limit
Transmission power of secondary users
Number of secondary users
Coordination with primary network
Interference level of primary users
Location information of primary users
FCC has not shown any progress since 2005
Topics in Future Internet – Cognitive Radio
Cognitive Radio – Main functions Spectrum management
Capturing the best available spectrum
Spectrum analysis
Interference/Path loss
Link errors/delay
Channel holding time
Spectrum decision
Decision model
Multi-band decision
Topics in Future Internet – Cognitive Radio
Cognitive Radio – Main functions Spectrum mobility
Maintaining seamless communication during the spectrum transition
Spectrum handoff
Topics in Future Internet – Cognitive Radio
Cognitive Radio – Main functions Spectrum sharing
Spectrum sensing Æ spectrum allocation Æ spectrum access Æ transmitter-receiver handshaking Æ spectrum mobility
Spectrum sharing architecture
Spectrum allocation behavior
Cooperative vs. Non-cooperative
Spectrum access technique
Centralized vs. Distributed
Overlay vs. Underlay
Rendezvous problem
Common control channel
Topics in Future Internet – Cognitive Radio
SDR Software Defined Radio (SDR)
A technology that enables “reconfigurable system” for wireless networks. SDR builds up ‘multimode, multiband’ wireless device.
SDR and Cognitive Radio
Cognitive radio is the ‘intelligence’ that sits above the SDR and lets a SDR determine which mode of operation and parameters to use. - Ryan W. Thomas, “Cognitive Networks,” DySPAN 2005
Topics in Future Internet – Cognitive Radio
Cognitive Networks Cognitive Networks (DySpan 2005, MobiCom 2007)
A network with a cognitive process that…
Perceive current network conditions
Plan, decide, and act on such conditions
Learn and adapt for future decisions
Takes into account end-to-end goals
Comparison between Cognitive Networks and Cognitive Radios
End-to-end vs. point-to-point
Topics in Future Internet – Cognitive Radio
Cognitive Networks Cognitive Network Framework End-to-endEnd-to-endEnd-to-end Goal Goal Goal
Requirements Layer
Cognitive Specification Language
Cognitive ElementCognitive ElementCognitive Element
Cognitive Process
Software Adaptable Network API Network Status Sensors
Configurable Configurable Elements Elements
Software Adaptable Network
Topics in Future Internet – Cognitive Radio
Cognitive Networks Cognitive Specification Language
Translates end-to-end goal into local goals of cognitive elements
Cognitive Elements
Run algorithms that reason, learn, and plan
Actuate configurable elements
Degree of Control
Full control vs. partial control
Complexity
Topics in Future Internet – Cognitive Radio
Concluding Remark Challenges
Spectrum policy
Spectrum sensing
Spectrum sharing
Questions
Cognitive radio vs. AI
Portion of spectrum sensing in cognitive radio
Topics in Future Internet – Cognitive Radio
References Ian F. Akyildiz, et al., “NeXt generation/dynamic spectrum access/cognitive radio wireless networks: A survey,” ComNet 2006 S. Haykin, “Cognitive Radio,” JSAC 2005 Online link: http://en.wikipedia.org/wiki/Cognitive_radio Ryan W. Thomas, “Cognitive Networks,” DySPAN 2005 Ryan W. Thomas, et al., “Tutorial: Cognitive Networks,” MobiCom 2007
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