June 10, 2014

Cognitive Radio Network (CORNET) Testbed Vuk Marojevic, maroje@vt.edu 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

2

Contents 1. Mission 2. Context 3. Hardware 4. Software 5. Applications 6. How to Use 7. Use Case (Demo)

3

Mission

Develop a large-scale university testbed for research and education in software-defined radio, cognitive radio and dynamic spectrum.

4

CORNET uses…. • Commercial off-the-shelf (COTS) hardware • Open-source software

5

CORNET provides…. • Free access to abundant resources • Common research tools • Testing facility for experimenting with custom hardware and software

Context

6

Software-Defined Radio (SDR) Functionality of radio transmitter or receiver defined in software Caution: it’s not just about software!

8

Cognitive Radio Ambient-aware system able to reason, adapt and learn (cognitive engine)

Spectrum Sharing Opposed to licensed, single-operator controlled spectrum

9

Protect Incumbent

Users

Spectrum Sharing Challenges

10

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)

11

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

ctru

m s

harin

g

Exc

lusi

ve u

se

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

13 Ongoing Trials Completed Trials Testbeds

34

16

17

12

Programs

251

6

8 9

11

13

14

15

7

10

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

• …

14

Hardware

15

16

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

3550-3650 MHz NTIA Exclusion Zones

17

Physical Layout

18

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

19

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

Software

20

21

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 • …

License

22

23

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

Applications

24

25

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

How to Use CORNET

26

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

27

Linux • Check who is using that node: who • Check who used that node: last

28

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

29

Use Case (Demo) --LTE broadcast channel--

30

OFDM

32

OFDM

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

34

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

36

Demo

https://github.com/libLTE/libLTE

You can download and install on CORNET (any node) from

and try yourself

Summary

37

CORNET (VT)

EMULAB (Utah)

ORBIT (Rutgers)

WNRT (UC Riverside)

38

Cognitive Radio Testbeds – US Universities (extract)

39

NITRD Testbed Inventory http://www.nitrd.gov/Subcommittee/wsrd/Testbeds/map.aspx

Outlook

40

41

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

REDHAWK

CORNET Outreach

libLTE

…