Institute of Communications Engineering, EE, NCTU 1

Cognitive Radio Systems andExperiments

Instructor: Sau-Hsuan WuInstitute of Communications EngineeringDepartment of Electrical and Computer Engineering

Institute of Communications Engineering, ECE, NCTU 2

Unit 0: Cognitive Radio Sau-Hsuan Wu

What are cognitive radio? What does it make cognitive radio most different from

typical wireless communications systems Traditional wireless systems are typically designated to

operate over a certain frequency band under a well-designedtransmission format and infrastructure, including: Physical (PHY) layer modulation/demodulation (MODEM),

channel coder/decoder (CODEC) Medium access control (MAC) protocols Networking infrastructure

Simply speaking, legacy wireless systems are inflexible Is it possible to design a wireless system that are flexible and

can interact with the legacy systems? Why do we need a flexible wireless communication system?

Institute of Communications Engineering, ECE, NCTU 3

Unit 0: Cognitive Radio Sau-Hsuan Wu

Why do we need a flexible wireless communication system Wireless channels are scarce resources

Sweet spot for radio transmissions: 200MHz ~ 3GHz TV, microwave ovens, mobile phones, WiFi, Bluetooth, Zigbee, GPS…

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Unit 0: Cognitive Radio Sau-Hsuan Wu

4

Area: Over the world

1000million

5000million

2017 : 3000 (peta bytes/month)

The number of mobile devices increases exponentially The data traffic in mobile network increases exponentially, as

well, while the voice traffic increases linearly

Institute of Communications Engineering, ECE, NCTU 5

Unit 0: Cognitive Radio Sau-Hsuan Wu

While some legacy systems are spectrally or temporally inefficient

Temporal and geographical variations in spectrum utilization range from15% ~ 85%

Institute of Communications Engineering, ECE, NCTU 6

Unit 0: Cognitive Radio Sau-Hsuan Wu

Spectrum usage varies in different areas as well TV white spaces

http://whitespaces.spectrumbridge.com/WhiteSpaceSearch/interactive-map.aspx

Institute of Communications Engineering, ECE, NCTU 7

Unit 0: Cognitive Radio Sau-Hsuan Wu

What are the advantages of a flexible radio system? Reutilization of idle frequencies in white spaces Adaptive communications

Robust wireless systems (network switches) Dynamic spectrum access

Institute of Communications Engineering, ECE, NCTU 8

Unit 0: Cognitive Radio Sau-Hsuan Wu

ON-demand spectrum sharing, exchanges and merchandising

Institute of Communications Engineering, ECE, NCTU 9

Unit 0: Cognitive Radio Sau-Hsuan Wu

What does it take to make a flexible\cognitive radio system? Spectrum and wireless environment cognition (radio power map)

Spectrum sensing, user positioning, radio activity monitoring System performance analysis and learning (cognitive multiple access)

Spectrum allocation, power control, interference management Interaction, cooperation and decision making (dynamic spectrum access)

Spectrum management, sharing, exchanges, and pricing Systems and networks adaptation (reconfigurable radio and networks)

Software define radio: reconfigurable PHY and MAC systems Software define network: heterogeneous networks

What are new features and fundamental concept of cognitive radioadded to wireless communications engineering Radio environment cognition and reconfigurable radio Heterogeneous MAC and networking

Institute of Communications Engineering, ECE, NCTU 10

Unit 0: Cognitive Radio Sau-Hsuan Wu

Why do we offer this course? Meet the rapid research growth on cognitive radio

Publications have grown from 2~3/year to 2000+ /year

Institute of Communications Engineering, ECE, NCTU 11

Unit 0: Cognitive Radio Sau-Hsuan Wu

Introduce the engineering fundamentals of CR systems What are we going to learn in this course Spectrum sensing theories and practices

Traditional spectrum sensing: Lab1: RSSI measurement Cooperative spectrum sensing: Lab2: Cooperative sensing Wideband spectrum sensing: Lab3: Spectrum sensing Radio source mapping: Lab4: RSSI based positioning

Cognitive and heterogeneous MAC protocols Cognitive radio MAC: Lab5: CR MAC Heterogeneous MAC: Lab6: Network handoffs

Grading In-class and home Lab projects (60%) A final Lab projects (25%) and written report (15%)

Institute of Communications Engineering, ECE, NCTU 12

Unit 0: Cognitive Radio Sau-Hsuan Wu

References Cognitive radio technology, Bruce Fette (Ed.), 2006

Chap 4: Cognitive radio: The technologies required Chap 7: Cognitive techniques: Physical and Link layers Chap 8: Cognitive techniques: Position awareness Chap 9: Network support: The radio environment map

T. Yucek and H. Arslan, “A survey of spectrum sensing algorithms forcognitive radio applications,”IEEE Comm. surveys & tutorials, 2009

I. F. Akyildiz et al, “Cooperative spectrum sensing in cognitive radionetworks: A survey,”Physical Comm. 2011

B. Wang and K. J. Ray Liu, “Advances in cognitive radio networks: Asurvey,”IEEE Journal of selected topics in signal processing, 2011

C. Cormio and K. R. Chowdhury, “A survey on MAC protocols forcognitive radio networks”, Ad Hoc Netoworks, 2009

A. D. Domenico et al , “A Survey on MAC Strategies for CognitiveRadio Networks,”IEEE Comm. surveys & tutorials, 2012