Cognitive Radio, Introduction and Main Issues


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Cognitive Radio, Introduction and Main Issues

  1. 1. Kuncoro WastuwibowoIEEE Indonesia Section
  2. 2. The current policies of spectrum Mobile and multi-device lifestyle block result in inefficiency of currently requires multi-band and spectrum usage. In some block, the multi-platform wireless technology, spectra are saturated, whereas which should be simplified and/or other bands are underused. The future-enhanced with software-improvement will need a flexible yet defined wireless technology. regulated use of spectrum band. Context-aware service and applications could be improved with cross-layer optimization including the flexible use of spectrum.
  3. 3. Y U NO make wireless systemscomputationally intelligent ??
  4. 4. Most-Effective Cognitive Generic (or Any AvailableDevice Radio TX / RX Spectrum)
  5. 5. Aspects Covering Standard BodiesDefinition IEEE Dyspan, ETSI, ITU-RCoexistence IEEE 802.19, IEEE DyspanSoftware-Defined Radio IEEE Dyspan, SDR Forum, ITU-R, OMGRadio Interfaces IEEE 802.22, 3GPPHeterogeneous Access ETSI, IEEE DyspanSpectrum Sensing IEEE 802.22, IEEE DyspanTestingNetworkingSecurity
  6. 6. 2005• IEEE Communications Society & IEEE Electromagnetic Compatibility Society established IEEE P1900 Standard Committee to develop supporting standards for dynamic spectrum management.2007• IEEE Standard Board reorganised P1900 SC as Standards Coordinating Committee 41 (SCC41), Dynamic Spectrum Access Networks (DySPAN).2010• SCC41 voted to be organised under IEEE Communications Society Standards Board, and was renamed as IEEE DySPAN SC (Standard Committee).
  7. 7. New techniques and DSA radio systems and methods of DSA includingnetworks with the focus on the management of radioimproved use of spectrum transmission interference Coordination of wireless technologies including network management and information sharing amongst networks deploying different wireless technologies
  8. 8. 1900.1 •Terminology and Concepts for Next Generation Radio Systems and Spectrum Management1900.2 •Interference and Coexistence Analysis1900.3 •Conformance Evaluation of Software Defined Radio (SDR) Software Modules1900.4 •Architectural Building Blocks Enabling Network-Device Distributed Decision Making in Heterogeneous Wireless Access Networks1900.5 •Policy Language and Policy Architectures for Managing Cognitive Radio for Dynamic Spectrum Access Applications1900.6 •Spectrum Sensing Interfaces and Data Structures for Dynamic Spectrum Access and other Advanced Radio Communication SystemsP1900.7 •Radio Interface for White Space Dynamic Spectrum Access Radio Systems Supporting Fixed and Mobile Operation
  9. 9. IEEE 802.22• 802.22 is a wireless communication at 54–863 MHz. It has an arrangement related to the identification of the PUs and defining the power levels so as not to interfere with the adjacent bands. BS controls all the CPE’s decisions as to when to send data and the channels to use. CPE senses the spectrum in its vicinity, helping in distributed detection of PU activity.IEEE 802.16• 802.16 (WiMAX) has its own set of standards that support CR-like functionalities, including methods of efficient coexistence of multiple BWA systems. It also discussed interference analysis and coexistence issues for BWA networks in its bands.
  10. 10. IEEE 802.15• 802.15 (WPAN) works in the license-exempt bands and also have their own set of standards related to coexistence.IEEE 802.11• Coexistence mechanisms are also included in 802.11 WiFi standards, including dynamic frequency selection and transmit power control for coexistence with satellite and radar systems operating in the 5 GHz band.IEEE 802.19• This standard defines general coexistence metrics for all IEEE 802 networks working in the unlicensed bands. Although focusing on IEEE 802 networks, the guidelines of the standard can be applicable to other unlicensed wireless systems
  11. 11. Cognitive radio (CR)• is a type of wireless transmission in which communication systems are aware of their environment and internal state and can make decisions about their radio operating behavior based on that information and predefined objectives.Dynamic Spectrum Access (DSA)• is the real-time adjustment of spectrum utilisation in response to changing circumstances and objectives.
  12. 12. Radio Type Platform Reconfiguration & Intelligence AdaptabilityHardware Hardware Minimal NoneSoftware HW/SW Automatic MinimalAdaptive HW/SW Automatic / predefined Minimal / noneReconfigurable HW/SW Manual / predefined Minimal / nonePolicy-based HW/SW Manual (database) / Minimal / none automaticCognitive HW/SW Full Artificial / machine learningIntelligent HW/SW Full Machine learning / prediction
  13. 13. Policies, Rules, etc TX Reconfigurable Radio Decision Radio Platform Environment Database RX , User Behaviour, Device State, etc Learning & Reasoning Sensing
  14. 14. System A System B System CSystem A System B System C System A System B System CHeterogeneous-type Cognitive Radio Spectrum Sharing type Cognitive Radio
  15. 15. RAN Cross- Oper CTM CNM Network ator Signalling RATHeterogeneous type cognitive radio selects optimal radio access networks (RAN) oroperators and radio access technologies (RAT) based on collaboration betweencognitive terminal manager (CTM/TRM) and cognitive network managers (CNM/NRM)via cross-network signalling.
  16. 16. 2. Collect sensing info CNMfrom terminals (NRM)Decide networkpolicy for users Network Reconfiguration Operator 3Operator 1 CNM CNM Operator 2 (NRM) (NRM) CROSS NETWORK SIGNALLING Reconfiguration 3. Request network policy and send it from CNM to CTM 4. Decide radio access technology 1. Sense radio link quality CTM and/or operators using user (TRM) preference & network policy
  17. 17. Adaptive gain-controlled Tunable filter or band Broadband up- amplifier selection RF filter conversion mixer Cognitive Radio Baseband Signal Processor FILTE AMP D|A R Multi-core Interfaces Part Tunable IP Part Multiband Multiband Multiband Antenna MIXER Synthesizer Clock SWITCH Full Parameter Reconfigurable Control Part FILTE FILTE Part AMP A|D R R Tunable filter or band Adaptive gain-controlled Broadband down- Tunable & selectable selection RF filter amplifier conversion mixer baseband / IF filter
  18. 18. Single/multiple primary operators andmultiple secondary operators managed Operator Independentdynamic spectrum access network NRM Operator Operator Dependent Dependent NRM NRM Operator 1 Operator 2 Network based on Cognitive Base Station Cognitive Base StationSecondary operators use frequency bandand period that primary operators does not Sensinguse by sensing spectrum and link quality
  19. 19. Network Management Cellular Metropolitan Short-Range Network reconfiguratio n management 3G 4G WiMAX WiMAX II WiFi WiFi NG (806.16m) (802.11n) Terminal Terminal 1900.4 1900.4 DSA-enabled IEEE Radios 1900.4 Legacy Terminal Terminalterminal reconfiguratio reconfiguratio n n management management
  20. 20. RAN Terminal Context Information Context Information• RAN radio resource • User preferences optimisation objectives • Required QoS levels• RAN radio capabilities • Terminal capabilities• RAN measurements • Terminal measurements• RAN transport • Terminal geo-location capabilities information • Geo-location-based terminal measurements
  21. 21. NRM: Network TRM: Terminal Reconfiguration Reconfiguration Management Management• Responsible for • Responsible for managing composite managing the terminal, wireless network (CWN) within the framework• Accepting spectrum defined by the NRM, for assignment policies network-terminal from Policy block distributed optimisation• Transmit radio resource of spectrum usage selection guide to TRM • Accepting radio resource selection guide from NRM
  22. 22. TRC RAN(1) OSM RRC RMC TRM RAN(N) NRM TMC Terminal Packet Based Core NetworkTRM Terminal reconfiguration managerTRC Terminal reconfiguration controllerTMC Terminal measurement collectorOSM Operator spectrum managerNRM Network reconfiguration managerRRC RAN reconfiguration controllerRMC RAN measurement collector
  23. 23. TRC Packet Based Core Network OSM TRM RAN Terminal NRM Network reconfiguration, reconfiguration, RRC decision, and control decision, and control RAN RAN selection selection Spectrum assignment Information RMC evaluation extraction, collection, and Policy derivation storage Policy efficiency evaluation TMC Information extraction, collection, and storageFunctions related to decision making & reconfigurationFunctions related to context awareness
  24. 24. Assume: N = number of networks competing M = number of bandTwo networks cannot share a band, because it will suffer the QoSAny interfering network i in a specific band may choose to ‘stay’ or‘switch’Expected cost to find a clear channel:where si, s-i  strategy chosen by i and by other network c  cost of single switching f(N,M)  function that depicts the varying behavior of the cost with N and M. For example f(N,M) = NM/(M-N)
  25. 25. ChallengeAccepted
  26. 26. If i chooses to stay, possibly:(i) All others will switch, creating clear band for i(ii) All others might stay, wasting the stage, and repeating the game G(iii) Some networks will switch, while the rest will stay and creating a subgame G’The cost function is:The optimization problem in this game is to find a mechanism of switchingor staying such that the cost incurred can be minimized and an equilibriumcan be achieved. Assuming all the players (networks) are rational, theremight be a set of strategies with the property that no network can benefitby changing its strategy unilaterally while the other networks keep theirstrategies unchanged (Nash equilibrium).
  27. 27. If:p is the probability to switch and (1-p) is the probability of stayj is the number of other networks willing to switchQj denotes the probability of j networks switching out of other N − 1 networksThen: the expected costs of i if it chooses to switch or to stay are
  28. 28. To find the optimal value, both equations are equatedUsing binomial equations etc,For any values of N and M, p has a nonzero finite value, thus proving theexistence of a mixed strategy Nash equilibrium point.
  29. 29. • Average system convergence cost with 20 competing cognitive radio (CR) networks.• With increase in number of available bands, the convergence cost decreases.• The convex nature of the curves proves that a point of minima exists for each of the curve. This minima corresponds to the Nash equilibrium strategy (p).
  30. 30. • System convergence costs following mixed strategy space for a varying network:band ratio (50−90%)• With an increase in the network : band ratio the system convergence cost increases almost exponentially.
  31. 31. PHY MAC Network e Radio Cognitiv + Policy Enforcement Entity Incentive Entity Security Module Coexistence ModuleMIMO Topology Network Coding Cross-Layer Optimisation
  32. 32. Fabrizio Granelli & al. Standardization and Research in Cognitive andDynamic Spectrum Access Networks: IEEE SCC41 Efforts and OtherActivities. IEEE Communications Magazine, January 2010.Krzysztof Iniewski (ed). Convergence of Mobile and Stationary Next-Generation Networks. Wiley, 2010.Lee Pucker. Review of Contemporary Spectrum Sensing Technologies.Report for IEEE-SA P1900.6 Standards GroupMin Song & al. Dynamic Spectrum Access: From Cognitive Radio toNetwork Radio. IEEE Wireless Communications, February 2012.Paul Houze & al. IEEE 1900.4 WG: IEEE 1900.4 Standard Overview.Presentation.R. Venkatesha Prasad & al, Cognitive Functionality in Next GenerationWireless Networks: Standardization Efforts. IEEE CommunicationsMagazine, April 2008.Soodesh Buljore & al. Architecture and Enablers for Optimized RadioResource Usage in Heterogeneous Wireless Access Networks: The IEEE1900.4 Working Group. IEEE Communications Magazine, January 2009.
  33. 33. Telkom Indonesia Multimedia Division Senior Service Creation (now)IEEE Indonesia Section Vice Chair (2012) Comsoc, Indonesia Chapter Chairman (2009-2011) Vice Chair (2007-2008)Internetworking Indonesia Journal Editor Contact Mail / Gtalk Twitter @kuncoro Mobile +62-21-3375-8000