C OGNITIVE R ADIO N ETWORKS

1. COGNITIVE RADIO NETWORKS INSTRUCTOR PROF. Dr. DOğU ARIFLER PRESENTED BY NIVINE SAMARJI CMPE 542 TERM PROJECT PRESENTATION Eastern Mediteranean University Computer Engineering Department Tuesday, March 25th , 2014

2. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

3. Overview Broadcast links connect two or more nodes and support broadcast transmission, where one node can transmit so that all other nodes can receive the same transmission. Ethernet Radio Broadcasting is a one-way wireless transmission over radio waves for a large coverage. Broadcasting by radio takes several forms. These include AMand FM stations. AM refers to Amplitude Modulation, altering the amplitude of the carrier signal in response to the amplitude of the signal to be transmitted. FM refers to frequency modulation and the range is: 88 to 108 MHz everywhere except Japan and Russıa. 76 to 90 MHz band in Japan. Russia has two bands: 65.9 to 74 MHz (which was widely used in the former Soviet Union) and 87.5 to 108 MHz worldwide standard.

4. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

5. What is a Radio Network? In 1920’s Radio networks rose rapidly with the growth of regular broadcasting of radio to home listeners . • Two types of radio networks : • one-many broadcast network used for public information and mass media entertainment • Two way radio type used for public safety and public services such as police, fire, taxicabs and delivery services.

6. Radio Network • Two-way type of radio network shares many of the same technologies and components as the Broadcast type radio network but is generally set up with fixed transmitters with co-located receivers and mobile Tran-ceivers for widely communication. • The term transmitter is usually limited to equipment that generates radio waves for communication purposes. • Multiple fixed tranceiver sites can be wirelessly interconnected to achieve the range of coverage in numerous frequency bands, fibre-optic links, or micro-wave links. • The signals are typically backhauled to a central switch that sends the signals to all transmitter sites. • The term backhaulgenerally refers to the side of the network that communicates with the global Internet • What is Broadcasting network? • The Broadcast type of radio network is a network system which distributes programming to multiple stations simultaneously.

7. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

8. What is cognitive radio? • The concept of CR was first proposed by Joseph Mitola III in a seminar at the Royal Institute of Technology in Stockholm in 1998. • Has been considered as a key technology for future wireless communication technology. • Intelligent wireless communication system • Aware of its surrounding environment (i.e., outside world), • Learn from the environment and adapt its internal states to statistical variations in the incoming RF stimuli, • highly reliable communication • efficient utilization of the radio spectrum. • Macro scale diversity

9. Cognitive Radio network • Is formed by extending the radio link features of CR to network layer functions and above. • A key for dynamic access of radio spectrum. • However, cognitive radio doesnt only provides spectrum advantages but also networking “macro-scale diversity”, Therefore, this form of scenario of wireless networks called cognitive radio networks (CRN)

10. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

11. Cognitive Radio network Terminal Capabilities • Cognitive Capability • Spectrum Sensing • A cognitive radio can sense spectrum and detect “spectrum holes” which are those frequency bands not used by the licensed users or having limited interference with them. • Spectrum Sharing • A cognitive radio enables sharing of spectrum and spectrum use on an ad hoc or real-time basis, without the need for prior agreements between all parties. Spectrum holes are those who are not occupied by licensed users For example, when a cognitive radio mobile terminal sensed that there are WiFi and GSM systems nearby while spectrum holes exist in the frequency band of digital TV, it may decide to download files from a certain WiFi AP, make a phone call through GSM system and communicate with other cognitive radio users using those spectrum holes.

12. Cognitive Radio network Terminal Capabilities • Cognitive Capability • Location Identification • The ability to determine its location and the location of other transmitters, and then select the appropriate operating parameters such as the power and frequency allowed at its location. In bands such as those used for satellite downlinks , location technology is an appropriate method of avoiding interference because sensing technology would not be able to identify the locations of nearby receivers. • Network/System Discovery • For a cognitive radio terminal to determine the best way to communicate, it shall first discover available networks around it. These networks are reachable either via directed one hop communication or via multi-hop relay nodes. • CR select routing by applying good mobility and connection management which helps neighborhood discovery, detects available Internet access. Example, when a cognitive radio terminal has to make a phone call, it shall discover if there is GSM BTSs or WiFi APs nearby. If there is no directed communication link between the terminal and the BTSs/Aps, it still can make a call through other cognitive radio terminals .

13. Cognitive Radio network Terminal Capabilities • Reconfiguration Capability • Frequency Agility: • Sensingof signals from other transmitters in order to select an appropriate operating frequency • DynamicFrequency Selection: A mechanism used to decide when to change frequency, includesspectrum sensing, geographic location monitoring, or an instruction from a network or another device . « Cognitive Capabilities » • Spectrum management scheme is necessary to efficiently manage and organize spectrum holes information among cognitive radios

14. Cognitive Radio network Terminal Capabilities • Reconfiguration Capability • Transmit Power Control • Enables a device to dynamically switch between several transmission power levels in the data transmission process. • It manipulates the transmitter power to allow greater sharing ;ı.e, reduces the transmitter power to a lower level to allow greater sharing of spectrum when higher power operation is not necessary. • Dynamic System/Network Access • Cognitive radio reconfigures itself to be compatible with systems which run different protocols . • Trust is a prerequisite for securing operations in CRNs since CRNs are heterogeneous networks in nature (e.g. wireless access technologies, system/network operators)

15. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

16. Spectrum utilisation • Spectrum utilization can be improved by allowing a secondary user (SU) to utilize a licensed band when the primary user (PU) is absent. • Cognitive radio (CR) senses and adapts to the environment • CR is able to fill in spectrum holes and serve its users without causing harmful interference to thelicensed user. • To do so, the CR must continuously sense the spectrum it is using in order to detect the reappearance of the PU. Once the PU is detected, the CR should withdraw SU from the spectrum so as to minimize the interference it may cause

17. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

18. CRN’s Architecture • The CRNs are composed of various kinds of communication systems and networks. The main objective is improving the entire network utilization. • From the users’ perspective, the network utilization means that they can always fulfill their demands anytime and anywhere through accessing CRNs. • From the operators’ perspective, they can provide better services to mobile users, and allocate radio and network resources to deliver more packets per unit bandwidth in a more efficient way

19. CRN’s Architecture • Network architecture • The CRNs can be deployed in three kinds of network architectures : • Infrastructure, Ad-hoc and Mesh architectures • The basic components of CRNs are: • Mobile station (MS) • Base station/access point (BSs/APs) • Backbone/core networks

20. CRN’s Architecture • Network architecture • Infrastructure Architecture • MS can only access a BS/AP in the one-hop manner. • MSs communicate with each other through the BS/APunder the transmission range of the same BS/AP • Communications between different cells are routed through backbone/core networks. • The BS/AP may be able to execute one or multiple communication standards/protocols to fulfill different demands from MSs. • A terminal in CRN communicate with its BS or AP to access different communication systems.

21. CRN’s Architecture • Network architecture • Ad hocArchitecture • No infrastructure support in ad-hoc architecture. • If an MS recognizes that there are some other MS nearby and are connectable through certain communication standards/protocols, they can set up a link and thus form an ad hoc network. • Two cognitive radio terminals can either communicate with each other by using existing communication protocols (e.g. WiFi, Bluetooth) or dynamically using spectrum holes

22. CRN’s Architecture • Network architecture • Mesh Architecture • This architecture is a combination of Infrastructure and Ad Hoc architectures by enabling the wireless connections between BSs/Aps that use spectrum holes for communication • BSs/APs work as wireless routers and form wireless backbones • MSs can either access the BSs/Aps directly or use other MSs as multi-hop relay nodes.

23. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

24. CRN’s links There are two kinds of wireless communication systems in CRNs :Primary system referred to an existing system, operates in one or many fixed frequency bands and works either in licensed or unlicensed bands, and cognitive radio system that has two components CR-BS and CR-MS • Primary system in either licensed or unlicensed bands: • Primary system in licensed bands • A primary system operated in the licensed band has the highest priority to use that frequency band (e.g. 2G/3G cellular, digital TV broadcast). • Other unlicensed users/systems can neither interfere with the primary system nor occupy the license band. • Primary system in unlicensed bands • A primary system operating in the unlicensed band called unlicensed band primary system. • Entities of primary system communicate with each other by using spectrumholes. There are two components in CR systems: Cognitive Radio Base Station (CR-BS) and Cognitive Radio Mobile Station (CR-MS).

25. CRN’s links • Cognitive radio base station (CR-BS) • Fixed component in the cognitive radio system that represents the infrastructure side of the system and provides services to CR-MSs(e.g. spectrum holes management, mobility management, security management) • It provides a gateway for CR-MSs to access the backbone networks (e.g. Internet). • CR-BSs are wirelessly connected with each others forming a mesh wireless backbone network and some of them act as gateway routers if they are connected with wired backbone networks. • If a CR-BS can run PR system protocols, it can provide access network services to PR-MSs. • Cognitive radio mobile station (CR-MS) • Portable device with cognitive radio capabilities. • Reconfigures itself in order to connect to different communication systems. • Sense spectrum holes and dynamically use them to communicate with CR-MS or CR-BS.

26. CRN’s links • Since the Cognitive Radio System can provide interoperability among different communication systems, some inter-system connections should be enabled. Shown in Table 1

27. CRN’s links • CR-MS CR-MS • A CR-MS can communicate with other CR-MSs in direct links. • Sense spectrum holes in different frequency bands which may be licensed or unlicensed and utilize it as their operating frequency band. • CR-MS CR-BS • A CR-MS connects using one hp access to CR-BS under BS coverage area. • CR-MS can either access the backbone networks or communicate with other communication systems.

28. CRN’s links • CR-MS PR-BS • If there is a need for a CR-MS to connect to a PR-BS, it willreconfigure itself and become one part of the primary system (i.e.PR-MS). In this case, it will become a primary user on that band. • CR-BS CR-BS • CR-BSs can form mesh wireless backbone network. • PR-MS PR-BS • It is the typical one-hop connection between mobile stations andbase stations. • The PR-BS is responsible for coordinatingcommunications in its coverage and providing backbone networkaccess to the PR-MS

29. CRN’s links • PR-MS CR-MS • In order for CR-MS to be connected to PR-MS, the CR-MS shall reconfigure itself to be one part of theprimary system. • PR-MS CR-BS • In order for CR-BS to be connected to PR-MS, CR-BS has to run the protocol of primary system, to provide • access service to the PR-MS. • PR-MS PR-MS • This link enables the possibility of ad hoc connectionsbetween PR-MSs.

30. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

31. Crn’s cycle • Levels of cognitive radio functionality

32. 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 • CRN 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

33. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

34. Typical cognitive radio application • What does cognitive radio enable?

35. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

36. Crn challenges • Determine the spectrum block is empty or not? Consider primary transmitter A, primary receiver B, and secondary user C who would like to use the spectrum licensed for use by A and B. Before operating C determines if the band is in use. In the case when the secondary user C is out of range of the primary transmitter A, it may conclude that there is no primary user and co-opt the spectrum and begins to transmit its signals. Interference will block those transmissions preventing the licensed spectrum usage between A and B.

37. Crn challenges • As in this figure a spread spectrum user may only require a very low power signal spread across a wide bandwidth. If a PU is transmitting its signals at low power, cognitive radio might detect these signals as a background noise and will act accordingly which will lead to false identification of an empty spectrum.

39. Outline • Overview • Radio & Broadcast network • Cognitive Radio Network • CRN terminal capabilities • spectrum utilisation • CRN’s Architecture • CRN’s links • CRN CYCLE • Crn applications • Challenges • References Eastern Medıteranean Unıversıty Computer Engıneerıng Department Tuesday, March 25, 2014

40. [1]. http://en.wikipedia.org/wiki/Radio_netork#See_also [2]. M.Cesana, F.Cuomo, E.Ekici. Routing in Cognitive Radio Networks: Challenges and solutions, Volume 9, Issue 3, May 2011 [3] S. Haykin.Cognitive radio: brain-empowered wireless communications. IEEE Journal on Selected Areas in Communications, vol.23, no.2, pp. 201-220, Feb. 2005. [4] FCC, ET Docket No 03-222 Notice of proposed rule making and order, December 2003. [5] K. –C. Chen, Y. –J. Peng, N. Prasad, Y. –C. Liang, S. Sun. Cognitive Radio Network Architecture: Part I – General Structure [6] K. B. Letaief , W. Zhang. Cooperative Communications for Cognitive Radio Networks, Vol. 97, No. 5, May 2009. [7] D. Adams. Cognitive Radio: Advantages and Challenges, June 11, 2012 • references

41. Thank you 