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NeXt Generation Wireless Networks: Smart Radios

NeXt Generation Wireless Networks: Smart Radios. Suzan Bayhan bayhan@boun.edu.tr http://satlab.cmpe.boun.edu.tr http://www.cmpe.boun.edu.tr//~bayhan. Outline. Problem Definition & Motivation Software Defined Radio + Cognitive Radio Standardization What about Satellites?

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NeXt Generation Wireless Networks: Smart Radios

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  1. NeXt Generation Wireless Networks: Smart Radios Suzan Bayhan bayhan@boun.edu.tr http://satlab.cmpe.boun.edu.tr http://www.cmpe.boun.edu.tr//~bayhan NETLAB Seminar 7 March 2007

  2. Outline • Problem Definition & Motivation • Software Defined Radio + Cognitive Radio • Standardization • What about Satellites? • Conclusion and References NETLAB Seminar 7 March 2007

  3. Motivation • Going wireless more and more... • Lack of interoperability bw. different technologies • Lack of spectrum (???) NETLAB Seminar 7 March 2007

  4. Spectrum Facts • More clever radio • Frequency Agility----SPECTRUM SHARING • Fixed Spectrum Assignment • Bandwidth is expensive and good frequencies are taken • Recent measurements by the FCC in the US show 70% of the allocated spectrum is not utilized • Time scale of the spectrum occupancy varies from msecs to hours SOLUTION NETLAB Seminar 7 March 2007

  5. Solution Joseph Mitola 1999 Cognitive Radio(CR) SDR + Intelligence Joseph Mitola 1992 Software Defined Radio(SDR) radio primarily defined in software, which supports a broad range of frequencies, and its initial configurations can be modified for user requirements. NETLAB Seminar 7 March 2007

  6. Outline • Problem Definition & Motivation • Software Defined Radio + Cognitive Radio • Standardization • What about Satellites? • Conclusion and References NETLAB Seminar 7 March 2007

  7. SDR properties Reconfigurable Easily Upgradeable Responds to the changes in the operating environment Lower maintenance cost NETLAB Seminar 7 March 2007

  8. If SDR technology is properly applied... • it will facilitate this single platform design, and willalso provide a path towards the realization of concepts such as • Reconfigurability (single platform concept) • run-timereconfiguration (run-time bug fixes) • and eventually self-governed learning (cognitive) radio. NETLAB Seminar 7 March 2007

  9. FINAL GOAL... UNIVERSAL WIRELESS DEVICE that can seamlessly handle a range of frequencies, modulation techniques, and encoding schemes. NETLAB Seminar 7 March 2007

  10. Secondary User (Unlicensed User)Cognitive-radio enabled users Lower priority than PUs Some definitions Primary User (Licensed User)the user which has an exclusive right to a certain spectrum band. In other words, the license holders... No need to be aware of cognitive users No additional functionalities or modifications needed NETLAB Seminar 7 March 2007

  11. SPECTRUM HOLE • A spectrum hole is a band of frequencies assigned to a primaryuser, but, at a particular time and specific geographic location,the band is not being utilized by that user. NETLAB Seminar 7 March 2007

  12. Definition (1) • In the 1999 paper that first coined the term “cognitive radio”, Joseph Mitola III defines acognitive radio as • “A radio that employs model based reasoning to achievea specified level of competence in radio-related domains.” NETLAB Seminar 7 March 2007

  13. Definition (2) • Simon Haykin defines a cognitive radio as “An intelligent wireless communication system that is aware of its surrounding environment (i.e., outside world),and uses the methodology of understanding-by-building to learn from the environmentand adapt its internal states to statistical variations in the incoming RF stimuli by makingcorresponding changes in certain operating parameters (e.g., transmit-power, carrierfrequency,and modulation strategy) in real-time, with two primary objectives in mind: • · highly reliable communications whenever and wherever needed; • · efficient utilization of the radio spectrum. NETLAB Seminar 7 March 2007

  14. Properties • Cognitive radio properties • RF technology that "listens" the spectrum • Knowledge of primary users’ spectrum usage as a function of location and time • Rules of sharing the available resources (time, frequency, space) • Embedded intelligence to determine optimal transmission (bandwidth, latency, QoS) based on primary users’ behavior • Cognitive radio requirements • co-exists with legacy wireless systems • uses their spectrum resources • does not interfere with them NETLAB Seminar 7 March 2007

  15. Main Cognitive Functions • Spectrum Sensing • Spectrum Management • Spectrum Mobility • Spectrum Sharing NETLAB Seminar 7 March 2007

  16. But... • Hard to design a radio front end in software... • A single antenna with good gain across a wide range of frequencies. NETLAB Seminar 7 March 2007

  17. 9 levels of CR functionality NETLAB Seminar 7 March 2007

  18. External Intelligence Sources Orient Establish Priority Infer on Context Hierarchy Normal Plan Generate Alternatives (Program Generation) Evaluate Alternatives Pre-process Immediate Urgent Parse Register to Current Time Learn Observe New States Receive a Message Decide Read Buttons Save Global States Prior States Alternate Resources Outside World Act Initiate Process(es) (Isochronism Is Key) Send a Message Set Display The Cognition Cycle How Does a Cognitive Radio Get So Smart? OODA loop OBSERVE-ORIENT-DECIDE-ACT NETLAB Seminar 7 March 2007

  19. NETLAB Seminar 7 March 2007

  20. SPECTRUM SENSING • Goal: Reliably detect presence of a Primary User • Different Primary Users have different sensitivity thresholds • Three possible approaches: • 1. Matched Filter • 2. Energy detector • 3. Cyclostationary Feature detector • Local Spectrum Sensing • – Each user makes decision on a Primary User presence based on its local sensing measurements • Cooperative Spectrum Sensing NETLAB Seminar 7 March 2007

  21. Outline • Introduction • Software-defined radio-Cognitive Radio • Standardization • Research Issues • References NETLAB Seminar 7 March 2007

  22. Standardization efforts • IEEE 802.22 WRAN • SDR Forum • GNU Radio Project • DARPA xG • JTRS North R., Browne N., Schiavone L., Joint Tactical Radio System- Connecting the GIG to the tactical Edge, MILCOM 2006, 23-25 Oct, 2006, Washington, DC. USA. NETLAB Seminar 7 March 2007

  23. FCC approves first software-defined radio...2004 • IEEE Spectrum, January 2007 • The Vanu Software Radio GSM Base Station from Vanu can support multiple cellular technologies and frequencies at the same time and can be modified in the future without any hardware changes. • GSM + CDMA waveforms • Written in C++, running under the Linux OS. NETLAB Seminar 7 March 2007

  24. Challenges and Research Issues • Hardware • Learning Mechanisms • Routing and Upper layer Issues (Networking, QoS) • Developing spectrum sharing behaviors • Sensitive detection • Frequency assignment negotiation • Resource allocation • Security (Unintentional config..) • Integration with “spectrum market” NETLAB Seminar 7 March 2007

  25. Application Layer Transport Layer Network Layer MAC Layer Physical Layer Cross-layer design Routing, System Management, QoS and other upper layer issues... • Optimize transmission parameters • Adapt rates through feedback • Negotiate or opportunistically use resources • OFDM transmission • Spectrum monitoring • Dynamic frequency selection, • modulation, power control • Analog impairments compensation NETLAB Seminar 7 March 2007

  26. Some SDR platforms NETLAB Seminar 7 March 2007

  27. Outline • Problem Definition & Motivation • Software Defined Radio + Cognitive Radio • Standardization • What about Satellites? • Conclusion and References NETLAB Seminar 7 March 2007

  28. What about satellites!!! How can satellites take role in the game? Or can they? • Satellite knowledge chunk in Mitola’s book (2000) • Software Radio in Space Segment by Catherine Morlet, European Space Agency (ESA), 2006. NETLAB Seminar 7 March 2007

  29. WAND (softWare rAdio techNology in space segment stuDy) Software Radio in Space Segment Final Report v1.1 20 April 2006 Alcatel Alenia Space France (FR) Alcatel Alenia Space Espana (SP) Atos Origin (SP) Carlo Gavazzi (IT) The introduction of Software Radio Technology at the satellite level has particular interest for: • Improving the functionalities of a payload/repeater. • Introducing standard updates. • Modifying the mission of a payload/repeater. • Introducing new concepts (e.g. adaptative coding and modulation). NETLAB Seminar 7 March 2007

  30. Satellite Lifetime ~ 10-15 years • Standards and associated algorithms are going to evolution during this period putting the satellite in risk of obsolescence during its lifetime period. NETLAB Seminar 7 March 2007

  31. Other issues • Intelligence in satellite • Spectrum Manager(!)  Can it be logical? • Policy Updates by satellites (Broadcasts) NETLAB Seminar 7 March 2007

  32. Simulation ScenarioA 1000 m X 1000 m areaSome WLAN users Some SUs (mobile)High Altitude Platform decides on frequency and other transmission parameters based on feed-back from the SUs and the policies from LEO or Command Center. NETLAB Seminar 7 March 2007

  33. Performance Evaluation • Effect of number of SUs • Overall Throughput • SU Throughput • Interference by SUs • Spectrum Utilization • RESULTS COMING SOON! NETLAB Seminar 7 March 2007

  34. To conclude... • More efficient use of spectrum (may decrease cost of the services like GSM calls) • Flexibility (Interoperability) • Dreaming of a universal device! NETLAB Seminar 7 March 2007

  35. References • S. Haykin, "Cognitive radio: brain-empowered wireless communications," IEEE Journal Selected Areas in Communications, vol. 23, no. 2, pp. 201 - 220, 2005. • J. Mitola III, “Software radios survey, critical evaluation and future directions,” IEEE AES Systems Magazine, Vol. 8, No. 4, pp. 25-36, Apr. 1993. • I.F. Akyıldız, W-Y.Lee, M.C. Vuran, S.Mohanty,”NeXt generation/dynamic spectrum access/cognitive radio wireless networks: A survey”, Computer Networks Journal (Elsevier), vol. 50, pp. 2127-2159, September 2006. • David Scaperoth, Cognitive Software Defined Radio: Applications of Cognitive SDR using the GNU Radio and the USRP, 09/09/05. • http://www.cognitiveradio.wireless.vt.edu/dokuwiki/doku.php?id=research:radio_hw_sw • http://web.syr.edu/~ejhumphr/ • http://bwrc.eecs.berkeley.edu/Research/Cognitive/publications.htm • Neli Hayes, JTRS Specification: The past, the present, and the future..., MILCOM 2005. • J. Powell, “Public safety perspectives on cognitive radio–Potential and pitfalls,” presented at the Conf. Cognitive Radios, Technology Training Corporation, Las Vegas, NV, Mar. 15–16, 2004. • J. D. Shilling, “FCC rulemaking proceeding on cognitive radio technologies,” presented at the Conf. Cogn. Radios, Technol. Training Corp., Las Vegas, NV, Mar. 15–16, 2004.IEEE Spectrum, January 2007. NETLAB Seminar 7 March 2007

  36. Thank You! Questions? bayhan@boun.edu.tr www.satlab.cmpe.boun.edu.tr NETLAB Seminar 7 March 2007

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