Cognitive Radio for Future Internet Survey on CR Testbed & Product

Transcription

1 Cognitive Radio for Future Internet Survey on CR Testbed & Product Munhwan Choi Multimedia & Wireless Networking Laboratory School of Electrical Engineering and INMC Seoul National University, Seoul, Korea

2 Contents Software Defined Radio (SDR) Examples of Cognitive Radio Project & Testbed Future of Cognitive Radio Standardization Conclusion

3 Software Defined Radio (SDR) Radio s physical layer behavior is primarily defined in software Accepts fully programmable traffic & control information Supports broad range of frequencies, air interfaces, and application software Changes its initial configuration to satisfy user requirements

4 How is a Software Radio Different from Other Radios? Application, Design, Upgrade Conventional Radio Supports a fixed number of systems Reconfigurability decided at the time of design May support multiple services, but chosen at the time of design Traditional RF Design Traditional Baseband Design Cannot be made future proof Typically radios are not upgradeable Software Radio Dynamically support multiple variable systems, protocols and interfaces Interface with diverse systems Provide a wide range of services with variable QoS Conventional Radio + Software Architecture Reconfigurability Provisions for easy upgrades Ideally software radios could be future proof Many different external upgrade mechanisms Over-the-Air (OTA) Cognitive Radio Can create new waveforms on its own Can negotiate new interfaces Adjusts operations to meet the QoS required by the application for the signal environment SDR + Intelligence Awareness Learning Observations SDR upgrade mechanisms Internal upgrades Collaborative upgrades

5 Cognitive Radio & SDR Some believe SDR is not necessary for cognitive radio Cognition is a function of higher-layer application Cognitive radio without SDR is limited Underlying radio should be highly adaptive Wide QoS range Better suited to deal with new standards Resistance to obsolescence Better suited for cross-layer optimization

6 Example SDR: GNU Radio What is GNU Radio? GNU Radio is a set of S/W signal processing building blocks that allow users to create their own S/W radio GNU Radio is an open-source software defined radio (SDR) platform Why GNU Radio? Attempts to solve the complexity issues of both H/W and S/W of SDR Modular (use with most any GPP) S/W used on Windows, Linux, Mac

7 Implementing a SDR with the GNU Radio USRP - Universal Software Radio Peripheral GNU Radio software - core s/w - user made s/w GNU Radio S/W available at Courtesy of

8 Summary of Trends SDR need is driven by two principal factors New applications Cognitive radio, collaborative radio & advanced roaming Increased number of protocols to support Potential cost reductions ADC is no longer the key bottleneck Flexible RF products starting to come to market Software architecture critical Additional technology supporting architectural approach available Reconfigurable hardware needed General-purpose hardware approach is likely to be unable to keep up with wireless bandwidth growth Component-based reconfigurable hardware architectures present powerful solution Multi-core processors show promise

9 Military SDR Market Today JTRS program created multi-billion dollar SDR market DARPA next Generation (XG) Communications project International derivatives of JTRS/SCA (EU, Canada, etc) Commercial Digital RF processors (TI Bluetooth and GSM) Multi-standard basestation implementations (Vanu) SDR handsets probably within 3 years as low power processors become available Regulatory Recent FCC directive to ensure code and RF compatibility Mark Scoville, Stephen Berger, Richard C. Reinhart, Dr. Jeffrey E. Smith, THE SOFTWARE-DEFINED RADIO & COGNITIVE RADIO INTER-CONSORTIA AFFILIATION, Software Defined Radio Technical Conference 2006, Nov. 2006

10 DARPA next Generation Program - Motivation XG is trying to Develop the Technology and System Concepts to Dynamically Access Available Spectrum Problems: Spectrum Scarcity Spectral resources are not fully exploited Opportunities exist in space, time, frequency Current static spectrum allocation prevents efficient spectrum utilization Deployment difficulty Different policy regimes in different countries Deployment of communication networks tedious Of particular interest in military applications Proposed solution: Complement static spectrum allocation with "Opportunistic spectrum access" Primary users Licensed Priority to use allocated spectrum Guaranteed QoS Secondary users Non-licensed Can allocate unused spectrum among themselves Have to vacate bands if required by primaries Unless otherwise stated, all the information in this description of the DARPA XG program is based on the XG Vision rfc, available online:

11 DARPA next Generation Program: Research Goals Development of technologies that enable spectrum agility Sensing and characterization of the (RF-) environment Identification of unused spectrum ("opportunities") Allocation and exploitation of opportunities Development of standards for a software based policy regime to enable policy agility Sense Decoupling of policies from implementation Real Real time, time, Low- Low- Define abstract behaviors, e.g., "Channel can be vacated within t sec." power, power, wideband wideband monitoring monitoring Policies implement (dictate) behaviors Protocols instantiate Autonomous behaviors Adapt Characterize Traceability Dynamic Transition Rapid Transition Rapid waveform All behaviors must be Spectrum traceable to policies: waveform network network to to new determination new Each Utilization emission operational emission plan mode a device is capable of is tied to a specific policy plan which allows it Software based React Spectrum use policies have to be machine understandable Formulate Formulate Best Best Course Course of of Action Action Policy constraints can be implemented "on-the-fly" via software downloads

12 XG Dynamic Spectrum Sharing Field Test Results M. McHenry, E. Livsics, T. Nguyan, and N. Majundar, XG Dynamic. Spectrum Sharing Field Test Results, DYSPAN 2007, Apr. 2007

13 CR Test-bed under development Virginia Tech. Cordless Phone Bluetooth MWOL TV station REM online updating Neighbor WLANs AP (Data Collection Node) AP (Data Collection Node) Actions Observations Interference Detection, Classification, Location AP (Data Collection Node) Arbitrary Waveform Generator Analysis and decision OSSIE Framework Ethernet Distributed Measurement Collaborative Processing Tektronix TDS694C: Digital Real-time Oscilloscope Tektronix RSA3408A: Real- Time Spectrum Analyzer

14 Cognitive Radio Testbed - Georgia Tech Maximum H/W flexibility Full S/W Control : MATLAB

15 The Future of Cognitive Radio Public Safety - Interoperability Focus on multi-agency interoperability since 9/11/2001 Cognitive radio technology can improve interoperability by enabling devices to bridge communications between jurisdictions using different frequencies and modulation formats. Such interoperability is crucial to enabling public safety agencies to do their jobs.

16 IEEE WRAN system based on will make use of unused TV broadcast channels Interoperable air interface for use in spectrum allocated to TV Broadcast Service Allows Point to Multi-point Wireless Regional Area Networks (WRANS) Supports a wide range of services Data, voice and video Residential, Small and Medium Enterprises Small Office/Home Office (SOHO) locations

17 IEEE Project 1900 (P1900) The IEEE P1900 Standards Group was established in 1Q 2005 jointly by the IEEE Communications Society (ComSoc)) and the IEEE Electromagnetic Compatibility (EMC) Society. The objective of this effort is to develop supporting standards related to new technologies and techniques being developed for next generation radio and advanced spectrum management.

18 IEEE P1900 Working Group: IEEE P Working Group: Objective document: Standard Terms, Definitions and Concepts for Spectrum Management, Policy Defined Radio, Adaptive Radio and Software Defined Radio. Purpose: This document will facilitate the development of these technologies by clarifying the terminology and how these technologies relate to each other. IEEE P Working Group: Objective document: Recommended Practice for the Analysis of In-Band and Adjacent Band Interference and Coexistence Between Radio Systems. Purpose: This standard will provide guidance for the analysis of coexistence and interference between various radio services.

19 IEEE P Working Group: Objective document: Recommended Practice for Conformance Evaluation of Software Defined Radio (SDR) Software Modules. Purpose: This recommended practice will provide guidance for validity analysis of proposed SDR terminal software prior to physical programming and activation of SDR terminal components.

20 IEEE h IEEE h & a h helps WLANs share spectrum h implements two methods to help spectrum sharing: Dynamic Frequency Selection (DFS) Transmission Power Control (TPC) DFS is used to select the appropriate spectrum for WLAN TPC is used to manage WLAN networks and stations for Reduction of interference, Range control (setting borders for WLAN), and Reduction of power consumption (beneficial in laptop use e.g.) IEEE a Multiband OFDM for Personal Area Network Wireless USB2.0 (480Mbps) at 5 meters distances Cognitive Radio - Plausible Application to UWB Regulation Very fast spectrum sculpting via OFDM technology with wide bandwidth 528MHz QoS Support QoS can be supported by controlling the number of sub-carriers

21 Hurdles in CR FCC Development Policies The process and rules governing how frequencies and waveforms are selected and approved for use by cognitive equipment must be addressed. Software Flexibility Interface with policy updates Real-life functionality CR devices are smart enough to understand user request and surrounding environments Network availability for CR Network needs to announce their availability to CR Flexible or Reconfigurable Hardware Requires a language and protocols for initial interfacing with software and validation for existing devices as policies change across time and space Software Architectures More dynamic than SCA

22 Predictions for Future Evolution SDR with high ASIC content Factory reprogrammable Reprogrammable for fixed number of systems Early cognition Increased use of reconfigurable hardware Limited reconfiguration by user Adaptive spectrum allocation Mid-level cognition Cognitive radios Time

23 Conclusion The testbed will serve, not only as a technical development platform, but also as an educational tool that provides insight and deep understanding of cognitive radio technology. Dell, HP, Google, and others want the FCC to sign off on letting consumer devices utilize the "white space."

24 Reference Dr. Jeffery H. Reed. Understanding the Issues in Software Defined Cognitive Radio Ettus Research,.Universal Software defined radio Peripheral (USRP)., M. McHenry, E. Livsics, T. Nguyan, and N. Majundar, XG Dynamic. Spectrum Sharing Field Test Results, DYSPAN 2007, Apr Y. Hur, J. Park, K. Kim, J. Lee, K. Lim, C.-H. Lee, H.S. Kim, and J. Laskar, A Cognitive Radio (CR) Testbed System Employing A Wideband multi-resolution Spectrum Sensing (MRSS) Technique, VTC 2006, Sep. 2006

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