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June 10, 2014
Cognitive Radio Network (CORNET) Testbed Vuk Marojevic, [email protected] REU Class, Summer 2014
You will learn 1. A little bit of Spectrum Sharing Concepts and Terminology 2. What CORNET is 3. How to access CORNET 4. What you can do with CORNET
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Contents 1. Mission 2. Context 3. Hardware 4. Software 5. Applications 6. How to Use 7. Use Case (Demo)
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Mission
Develop a large-scale university testbed for research and education in software-defined radio, cognitive radio and dynamic spectrum.
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CORNET uses…. • Commercial off-the-shelf (COTS) hardware • Open-source software
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CORNET provides…. • Free access to abundant resources • Common research tools • Testing facility for experimenting with custom hardware and software
Software-Defined Radio (SDR) Functionality of radio transmitter or receiver defined in software Caution: it’s not just about software!
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Cognitive Radio Ambient-aware system able to reason, adapt and learn (cognitive engine)
Spectrum Sharing Opposed to licensed, single-operator controlled spectrum
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Spectrum Sharing Concepts TV White Space (TVWS) Dynamic Spectrum Access (DSA)
TVWS DSA Channel 6 MHz channels in UHF band (470-
790 MHz) Potentially any
Secondary Access
Database Sensing
Deployment Trial and commercial pilots. TVBD* to provide Interent access in unserved/ underserved areas: US, Europe, Asia, Africa, Australia
Research testbeds and trials, DoD-funded programs, …the future of wireless communications
*TV band devices (TVBD)
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Levels of Spectrum Sharing
Level Description Examples 0 Exclusive Use Spectrum assigned on an exclusive basis Licenses for cellular
communications today 1 Static Spectrum
Sharing Spectrum shared by primary users on geographic basis, not temporal basis
Exclusion zones
2 Managed Shared Access
Subleasing for a certain period Licensed Shared Access (LSA)
3 Dynamic Spectrum Sharing
First-come, first-serve of SUs, which must not interfere with primary users
TVBD, 3.5 GHz
4 Pure Spectrum Sharing
Spectrum not assigned to a primary user, different levels of protection/rules
3650 to 3700 MHz Spe
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Exc
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Spectrum Sharing Trials and Testbeds • Sharing of government spectrum (PCAST), FCC workshop & NPRM • TVWS trials and commercial pilots around the world • DARPA Spectrum Challenge 2013/14 • EU Cognitive Radio Experimentation World (EW) Federated Test Platform • PCAST Report: mobile test beds, test cities, … • WInnForum’s Annual Report, Section 5: DSA, White Space and Spectrum
Sharing Test Beds, Field Trials World Wide • …
12 * PCAST: Presidential Council of Advisors for Science and Technology
Info on Spectrum Sharing • Wireless Innovation Forum (SDR Forum), http://www.wirelessinnovation.org/
• DSA Alliance, http://www.dynamicspectrumalliance.org/
• FCC, http://www.fcc.gov/
• PCAST Report 2012, http://www.whitehouse.gov/administration/eop/ostp/pcast
• Presidential Memorandum -- Expanding America's Leadership in Wireless Innovation • http://www.whitehouse.gov/the-press-office/2013/06/14/presidential-memorandum-expanding-americas-
leadership-wireless-innovatio
• Academic papers: IEEE Xplore Digital library, http://ieeexplore.ieee.org/Xplore/home.jsp
• …
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http://cornet.wireless.vt.edu
• 48 software radio nodes, 12 per floor • Free access for registered users • Each node individually accessible, remotely • FCC experimental license for several bands, 138 MHz – 3.6 GHz
Physical Layout
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SDR Node
Radio Front End Server Equipment Ettus Research/NI USRP2
WBX daughterboard
Intel Xeon Quad-core (2.13 GHz)
12 GB RAM
1000baseT Ethernet NIC (2x per node)
IPMI remote administration port
Devices FPGA, ADCs & DACs Processor, hard drive, memory, Gbit Ethernet
Purpose Filtering, up & down-conversion, ADC, DAC, …
Digital signal processing (DSP)
Radio Front End Server Gbit Ethernet
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Architecture User Plane • Users provided with personal NFS directory • Web-based utilities for debugging and scenario
deployment
Management Plane • Quick automated reimaging • Flexible authentication services
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Open Source
• Linux – Ubuntu 10, 13 • GNU Radio – 3.5, 3.7 • Open-Source SCA Implementation::Embedded (OSSIE) • LiquidDSP • ALOE Framework + open-source LTE waveform • LibLTE • …
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FCC Experimental License Lower Bound (MHz)
Upper Bound (MHz)
138 144 150.5 156 157.45 161.575 162.0375 174 450 512 764 862 776 787 788 793 824 849 869 894 1850 1910 1930 1990 3400 3600
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Community Resource
University Education/Research - Masters/PhD Thesis - Class Projects - Application development
Corporate Research - Sponsored Research - Rapid Prototyping
Knowledge Database - Architecture replication - User/Application Management
Main sources: • http://cornet.wireless.vt.edu/
• http://www.trac.cornet.wireless.vt.edu/trac/wiki/CORNET/HowToUseCORNET
• http://scholar.lib.vt.edu/theses/available/etd-06052012-142737/unrestricted/DePoy_DR_T_2012.pdf
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USRP/GNU Radio: • Check the availability of USRP: uhd_find_devices • Visualize the spectrum: uhd_fft or uhd_fft.py
• Simple signal generators: uhd_siggen or uhd_siggen_gui
• check options with … –h or … -- help • OFDM Receiver: • $ cd /home/cornetadmin/gnuradio_uhd/gr-digital/examples/narrowband • $ ./benchmark_rx.py -f 460M -r 500k • OFDM Transmitter: • $cd /home/cornetadmin/gnuradio_uhd/gr-digital/examples/narrowband • $ ./benchmark_tx.py -f 460M -r 500k
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Broadcast Channel
QPSK De-
modulation
Initial Processing
CRC detach
Descram- bling
Subframe 0, 10, 20, 30, 40, 50, 60 , 70, 80, 90, 100, 110, 120, ...
Decoding & Rate
matching
24 bits every 10 ms
QPSK Modulation
CRC attach
24 bits every 40 ms
Coding & Rate
matching
Scram- bling
Subframe 0, 40, 80, 120, ...
Subframe 0, 40, 80, ...
40 bits 1920 bits
480 bits
Scram- bling
Subframe 10, 50, 90, ... 480 bits
Scram- bling
Subframe 20, 60, 100, ... 480 bits
Scram- bling
Subframe 30, 70, 110, ... 480 bits
Further Processing
Further Processing
Further Processing
Further Processing
240 symbols
QPSK Modulation
QPSK Modulation
QPSK Modulation
288 samples
288 samples
288 samples
288 samples
240 symbols
240 symbols
240 symbols
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PBCH (Transport channel): PHY Layer Resources 72 central subcarriers, first 4 OFDM Symbols of slot 1 of subframe 0, each radio frame 72*4 = 288 time-domain samples
Physical Broadcast Channel (PBCH)
Radio Frame (10 ms)
PBCH carrying BCCH (MIB)
MIB: Master Information Block
35 http://www.pewscorner.host-ed.me/LTE/lte_resource_grid.html
5 ms 5 ms
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Demo
https://github.com/libLTE/libLTE
You can download and install on CORNET (any node) from
and try yourself
CORNET (VT)
EMULAB (Utah)
ORBIT (Rutgers)
WNRT (UC Riverside)
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Cognitive Radio Testbeds – US Universities (extract)
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LTE-CORNET New DURIP Grant
RF nest allows: - Using any frequency and bandwidth - Using any modulation scheme - Using different power levels for
signals and interferers - CoMP Tx/Rx - Carrier aggregation
Rack
24 Cornet Servers (48 processors), already deployed, connected to 48 USRPs
Software eNB+EPC Software eNB+EPC
Software LTE UE Software LTE UE
Interferers/jammers Interferers/jammers
Ethernet
LTE Spectrum Analyzer
Rfnest (8 ports)
Channel emulator
Server room Control room
LTE UE
LTE UE
Switch
SBX N210 SBX N210 SBX N210
SBX N210
SBX N210 SBX N210
RF Switch Matrix
… 8 Filter banks
Software eNB+EPC
Software eNB+EPC
Σ
Σ
SBX N210
SBX N210
Hallway
Mobile nodes
Software eNB+EPC
SBX N210
Desktop
Filter
Software eNB+EPC
Desktop
Filter SBX N210