Cognitive Radio Networks

1. Cognitive Radio Networks Lecture-5 Mazhar Hussain

2. Contents Introduction Literature ReviewCRN Architecture/RoutingChallenges Issues Applications Conclusion & Issues for future workReferences

3. Introduction (Increased user demand) • The ISM (industrial, scientific and medical) band is a host of many different wireless technologies. • WiFi • Bluetooth • Wimax • The number of devices that function at the ISM band is constantly growing. • Interference between these devices is growing as well. • This means degradation of performance.

4. “Regional Area Network” RAN IEEE 802.22 30-100 km 18 Mbps BW= 6,7,8 MHz 54 - 862 MHz IEEE Standards Fig. 1: IEEE Standards

5. Spectrum and Management • Set of Electromagnetic radiation and frequency bands • Ranges up to 300 GHz • Government entities own frequency channels, which are divided according to common frequency band characteristics • The International Telecommunications Union (ITU) divides the world into three different regions that influence wireless signal propagation: • Region 1 : Europe, Africa, parts of the Middle East and Northern Asia • Region 2 : The Americas, Caribbean and Hawaii • Region 3 : Asia, Southeast Asia, the Pacific Islands, Australia and New Zealand

6. Wireless Networking Terminologies Wireless Radio Spectrum • Fixed Spectrum Assignment • Shared Spectrum Concept Dynamic Spectrum Access (DSA) NeXt Generation (xG) Network • DAPRA* Dynamic Spectrum Access *Defence Advance Research Project Agency

7. Cognitive Radio Network Wireless communication in which the transmissionor reception parameters (Operating Spectrum, Modulation, Transmission power and communication Technology) are changed to communicateefficiently without interfering with licensed users. Parameter changes are based on the active monitoring of several factors in the radio environment (e.g. Radio frequency spectrum).

8. Literature Review CRN was first described by Mitolain his Ph.D Thesis, “Cognitiveradio: integrated agent architecture for software defined radio” in 2000. Federal Communications Commission (FCC )has given the report in 2003. DSA concept was firstly implemented by DARPA in 2003. Radio‐scene analysis, Channel‐state estimation, predictive modeling,Transmit‐power control, dynamic spectrum management are describedextensively by Simon Haykin in Feb. 2005.

9. Literature Review Dynamic Shared Spectrum access concept is described by I.F. Akyildiz in2006 and also introduced concept of Cognitive Radio Ad Hoc Network(CRAHN) which is infrastrureless cognitive radio network in July 2009. Wireless Regional Area Network (WRAN), also known as IEEE 802.22Working Group on Wireless Regional Area Networks. Brief detail of CRN platforms : Universal Software Radio Peripheral(USRP), Wireless open Access Research Platform (WARP) andSundance .

10. CognitiveRadio Network • Intelligent devices that can coexist with licensed users without affecting their quality of service. • Licensed users have higher priority and are called primary users. • Cognitive radios access the spectrum in an opportunistic way and are called secondary users. • Networks of cognitive radios could function at licensed portions of the spectrum. • Demand to access the ISM bands could be reduced.

11. CognitiveRadio Network Fig. 3: Primary and Secondary User Concept

12. Why Cogitative Network Underutilization of licensed spectrum • Licensed portions of the spectrum are underutilized. • According to FCC, only 5% of the spectrum from 30 MHz to 30 GHz is used in the US. Fig. 4: Licensed Spectrum utilization analysis

13. How Cogitative Network Works Restrictions to secondary users • Licensed portions of the spectrum consists of frequency bands that belong to one of the following categories: • White spaces: Primary users are absent. These bands can be utilized without any restriction. • Gray spaces: Primary users are present. Interference power at primary receivers should not exceed a certain threshold called interference temperature limit. • Black spaces: Primary user’s power is very high. Secondary users should use an interference cancellation technique in order to communicate.

14. How Cogitative Network Works • Secondary users can identify white, gray and black spaces and adapt according to the corresponding restrictions. Fig. 5: Secondary User and Spaces

15. Infer from Radio Model Infer from Context Orient Pre-process Normal Plan Parse Stimuli Learn New States Observe Decide States User Driven (Buttons) Autonomous Determine “Best” Plan Outside World Act Allocate Resources Initiate Processes Cognition Cycle Level 0 SDR 1 Goal Driven 2 Context Aware 3 Radio Aware 4 Planning 5 Negotiating 6 Learns Environment 7 Adapts Plans 8 Adapts Protocols Select Alternate Goals Generate Alternate Goals Establish Priority Immediate Normal Urgent Generate “Best” Waveform Determine “Best” Known Waveform Negotiate Negotiate Protocols Source: “Cognitive Radio for Flexible Mobile Multimedia Communications ”, IEEE Mobile Multimedia Conference, 1999, pp 3-10.

16. Hole or White Space Concept Fig. 6: CRN Concepts

17. CRN Architecture Fig. 7: CRN Architecture

18. CRN Core Functions Spectrum Spectrum Spectrum Spectrum sensing management mobility sharing Detecting Maintaining unused seamless Providing the Capturing thespectrum and communicati fair spectrum best availablesharing the on scheduling spectrum tospectrum requirements method meet userwithout during the among communicatiharmful transition to coexisting CR on interference requirements better usersspectrum. with other users.

19. Cognitive Cycle Cognitive capability Reconfigurability Fig 8: Cognitive Cycle

20. Cognitive Routing Schemes Fig. 9: Cognitive Routing Scheme

21. Cognitive Routing Challenges CRN Key Consideration Spectrum Awareness Setting Quality of Routes Maintaining / Reproducing Routes

22. Cognitive Routing Challenges Cognitive Networks challenges Spectrum Knowledge Overhead Link Failure Mobility handling Best Path Selection

23. Some Other Issues Routing challenges • Common control channel • Intermittent connectivity • Re‐routing • Queue management Transport layer challenges • Spectrum Handoff Latency

24. Cross‐layer challenges Challenges in spectrum management • Dynamic Nature and Re‐routing Challenges in spectrum handoff • Spectrum Handoff Latency, Route Failure and Recovery Challenges in spectrum sharing • Spectrum Sensing Capability and Sharing Delay Challenges in upper layers • Dynamic Frequency, Multiple Hops and Spectrum handoffs,

25. Cognitive Routing Challenges CR Support Tools The following can be support tools for CR PRISM OPNet Modular 14.5 or above Ns-2 Matlab

26. Challenges in spectrum sensing Interference temperature measurement Spectrum sensing in multi‐user networks Detection capability

27. Spectrum management challenges Decision model. Multiple spectrum band decision.Cooperation with reconfiguration. Spectrum decision over heterogeneousspectrum bands.

28. Challenges of spectrum mobility Spectrum handoff. Spectrum mobility in multiple users.

29. Spectrum sharing challenges Common control channel (CCC). Dynamic radio range . Spectrum unit.

30. Implementation issues Readiness of the CRN backbone Defining point of Interconnect and Interface.Definition of Uniform service based priorities.Default service and routing requirement.Service authentication and Authorization.

31. Regulatory issues Migration from service based licensing to service neutral licensing regime.Issues related with converged licensing. Re‐classification of the licenses. Pricing issues to end users. Migration from service based pricing to service neutral pricing. Revenue settlement of the operators in CRN environment.

32. QoS issues Need to define Quality of services parameters in CRN environment. Monitoring QoS in various networks and ensuring compliance to definedQoS parameters in CRN environment. Ensuring End to End QoS across the networks. Need to define unique service based priorities. Reliability across diverse applications.

33. Security issues Protection from various protocol attacks. Application attacks. Unauthorized user introduction. Unauthorized access to system data. Denial of services (DOS) and Distributed Denial of services attacks(DDOS).

34. CRN Applications CR Mesh Military Network Network Emergency Network Multimedia CRN Leased Cellular Applications Network Networks

35. Conclusion Spectrum Awareness Concept. Very Useful for B3G Networks. Spectrum sharing techniques can help us fill the regulatory“gaps” in a particular interference environment. A great deal of research still needs to be done on simulatingand explore these intelligent network ideas.

36. Conclusion Cognitive radio technology can solve the problem of spectrumunderutilization. Channel assignment in cognitive radio networks is especiallychallenging in CRN. Main aim of this research is Characterize and analyze, and enhancethe throughput and provide security solutions

37. References 1. I.F. Akyildiz, Y. Altunbasak, F. Fekri, R. Sivakumar, ” AdaptNet: adaptive protocol suite for next generation wireless internet”, IEEE Communications Magazine 42 (3) (2004) 128‐138. 2. FCC, ” ET Docket No 03‐222 Notice of proposed rule making and order ”, December 2003. DARPA XG WG, The XG Architectural Framework V1.0, 2003. 3. S.A. Zekavat, X. Li, User‐central wireless system: ultimate dynamic channel allocation, in: Proc. IEEE DySPAN 2005, November 2005, pp. 82‐87. DARPA XG WG, The XG Vision RFC V1.0, 2003. 4. S. Haykin, Cognitive radio: brain‐empowered wireless communications, IEEE Journal on Selected 5. Areas in Communications 23 (2) (2005) 201‐ 220. R.W. Thomas, L.A. DaSilva, A.B. MacKenzie, Cognitive networks, in: Proc. IEEE DySPAN 2005, 6. November 2005, pp. 352‐360. 7. F.K. Jondral, Software‐defined radio‐basic and evolution to cognitive radio, EURASIP Journal on Wireless Communication and Networking 2005 8. M.M. Buddhikot, P. Kolody, S. Miller, K. Ryan, J. Evans, DIMSUMNet: new directions in wireless networking using coordinated dynamic spectrum access, in: Proc. IEEE WoWMoM 2005, June2005, pp. 78‐85. 9. O. Ileri, D. Samardzija, N.B. Mandayam, Demand responsive pricing and competitive spectrum allocation via spectrum server, in: Proc. IEEE DySPAN 2005, November 2005, pp. 194‐202.

38. Questions