GNUradio_20061208

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GNU Radio

Chen ZhifengChen Ke-Yu

Electrical and Computer EngineeringUniversity of Florida

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OutlineWhy GNU Radio?Extensive knowledge involvedWhat is implemented currently?Library

Architecture

Development environmentDevelopment BoardsCurrent Issues

What is next?

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Why GNU Radio? Almost free!

All the software are free (Python and C++ source code/linux environment)In most condition, no need expensive RF test machine!No need to purchase development and emulation toolsOnly a development board needed (Universal Software Radio Peripheral)

FlexibleSoftware:

reconfigurable for many other modulation methods for both standardizeradio or self-defined radioit is possible to improve the quality of the received signal by utilizing, insoftware, certain mathematical algorithms

Hardware:Rx and Tx are selectableIntermediate frequency is controllable

Best choice for research use and radio amateur

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Extensive knowledge involved

Software and environment:

Python/Numeric python library/wxPython

C++/boost C++ libraties

Linux environment and lots of support packages:FFTW/cppunit/SWIG/SDCC/

GNU Radio architecture

Communications and RF:

DSPDigital communications

Wireless communications theory

FPGA and Assemble language may be used

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What is implemented currentlyBase System

Provides the runtime and various signal processing primitives

Hardware Support

Universal Software Radio Peripheral (USRP)

Audio Device Support ALSA (Advanced Linux Sound Architecture)

OSS (Open Sound System)

Graphics Support

wxPython based GUISDL video library

General Signal Processing

Specialty Application Areas

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Library

Communication related implementation AM demodulationDifferential BPSK / QPSKGMSK modulation / demodulationNarrow band FM transmitter / receiverWide band FM transmitter & broadcast FMreceiver

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Library (cont.)

GNU radio utilitiesCRC generatorSocket setup (TCP / UDP)Compute frequency response of a digital filterControl National IMX2306 & SDR-1000frequency synthesizerSome utilities

Convert unsigned mask into signed integerGcd, Lcm, Log2Return input x that is reverse order

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Library (cont.)

GUI examplesProvide window application for different usageFFT sink testwxPython EditBox, SliderDrawingWaterfall sink testOscilloscope Test Application

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Library (cont.)

pagerCreate USRP source object supplyingcomplex floatsFlex pager protocol demodulation block

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Architecture overall

Software

Hardware

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Architecture Hardware

User-definedCode

RFFront end

Sender

User-definedCode

Receiver

DAC

ADC RFFront end

FPGAUSB

USB FPGA

USRP (mother board)PC

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User-definedCode

RFFront end

DACUSB FPGA

Support USB2.0/At this stage, USB 1.x is not supported at all

1. Support 32MB/sec across the USB.

2. All samples sent over the USB interface are in 16-bit signed integers in IQformat,16-bit I and 16-bit Q data (complex), resulting in 8M complex samples/secacross the USB.

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User-definedCode

RFFront end

DACUSB FPGA

Includes digital down converters (DDC) implemented with cascadedintegrator-comb (CIC) filters.DDC

Down converts the signal from the IF band to the base band.Decimates the signal so that the data rate can be adapted by the USB2.0 and is reasonable for the computers' computing capability.

Digital up converters (DUCs) on the transmit side are actually contained inthe AD9862 CODEC chips, not in the FPGA.

The only transmit signal processing blocks in the FPGA are theinterpolators.

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User-definedCode

RFFront end

DACUSB FPGA

4 high-speed 14-bit DA converters, DAC clock frequency is 128 MS/s(stay below about 50MHz or so to make filtering easier.)

4 high-speed 12-bit AD converters, sampling rate is 64M samples persecond.

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User-definedCode

RFFront end

DACUSB FPGA

One mother board support up to four daughter boards.2. Several kinds of daughter boards available

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Architecture Software

GNU radio has provided some useful APIsWhat we are interested in at this time ishow to use the existing modules that hasbeen provided in GNU radio project tocommunicate between two end systems

User-definedCode

RFFront end

Sender

DACUSB FPGA

PC

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How these modules co-work?C++

Performance-critical modules

PythonGlue to connect modulesNon performance-critical modules

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At python level, what we need to do is always justto draw a diagram showing the signal flowfrom the source to the sink in our mind.

C++

C++

V1

V2

V3

C++

C++

C++

V1

V2

V3

C++

Source

Sink

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SPE (Stanis Python Editor) FreeLack of powerful debug tool (breakpoint)

Development environment

Explorer ofProject and

Class members

Code editor

Interpreter & debug window

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Development environment (cont.)

WingwareMore powerfulFor personal version, the license fee to twostations are $60

Code editor

Interpreter

Explorer ofProject and

Class members

Debuginformation

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Development BoardsDescription Price

USRP Motherboard $700.00

BasicTX -- 2 MHz to 200 MHz Transmitter $75.00

BasicRX -- 2 MHz to 300+ MHz Receiver $75.00

LFTX -- DC-30 MHz Transmitter $75.00LFRX -- DC-30 MHz Receiver $75.00

TVRX -- 50 MHz to 870 MHz Receiver $100.00

DBSRX -- 800 MHz to 2.4 GHz Receiver $150.00

RFX400 -- 400-500 MHz Transceiver $275.00

RFX900 -- 800-1000MHz Transceiver $275.00

RFX1200 -- 1150 MHz - 1450 MHz Transceiver $275.00

RFX1800 -- 1.5-2.1 GHz Transceiver $275.00

RFX2400 -- 2.3-2.9 GHz Transceiver, 20+mW output $275.00

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USRP Motherboard Four 64 MS/s 12-bit analog to digitalConvertersFour 128 MS/s 14-bit digital to analogConvertersFour digital downconverters withprogrammable decimation rates

Two digital upconverters withprogrammable interpolation ratesHigh-speed USB 2.0 interface (480 Mb/s)Capable of processing signals up to 16MHz wideModular architecture supports widevariety of RF daughterboards

Auxiliary analog and digital I/O supportcomplex radio controls such as RSSI and

AGCFully coherent multi-channel systems(MIMO capable)

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BasicTX2 MHz to 200 MHz Transmitter

designed for use withexternal RF frontendsas an intermediate

frequency (IF) interface.DAC outputs aredirectly transformer-coupled to SMAconnectors (50impedance)direct access to all ofthe signals on thedaughterboard interface

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BasicRX2 MHz to 300+ MHz Receiver

designed for use withexternal RF frontendsas an intermediate

frequency (IF) interface. ADC inputs are directlytransformer-coupled toSMA connectors (50impedance)direct access to all ofthe signals on thedaughterboard interface

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LFTXDC-30 MHz Transmitter

very similar to theBasicTX and BasicRX,respectively, with 2main differencesUse differentialamplifiers instead oftransformers, theirfrequency responseextends down to DC.have 30 MHz low passfilters for antialiasing.

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LFRXDC-30 MHz Receiver

very similar to theBasicTX and BasicRX,respectively, with 2main differencesUse differentialamplifiers instead oftransformers, theirfrequency responseextends down to DC.have 30 MHz low passfilters for antialiasing.

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TVRX50 MHz to 870 MHz Receiver

a complete VHF andUHF receiver systembased on a TV tunermodulecan receive a 6 MHzwide block of spectrumfrom anywhere in the 50-860 MHz range.

All tuning and AGCfunctions can becontrolled from software.

Note: The TVRX is the only daughterboard which is NOT MIMO capable. A MIMO

capable version is expected in Q1 2007.

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DBSRX800 MHz to 2.4 GHz Receiver

a complete receiversystem for 800 MHz to 2.4GHz with a 3-5 dB noise

figure.features a softwarecontrollable channel filteras narrow as 1 MHz, or aswide as 60 MHz.MIMO capable, and canpower an active antennavia the coax.

Note: The DBSRX is NOT guaranteed to cover the 2.4-2.48 GHz ISM band.

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RFX400400-500 MHz Transceiver

100+mW output (20dBm) ideal for UHF TV, public safety

and land-mobile

communications, low-powerunlicensed devices (like key-fobs), wireless sensor networks(motes), and amateur radio.

minor modifications to the boardcan move the frequency rangeto anywhere from 200 MHz to800 MHz

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RFX900800-1000MHz Transceiver

200+mW output (23dBm)with a 902-928 MHz ISM-band filter installed forfiltering strong out-of-band signals (like pagers).The filter can easily be bypassed to allow usageover the full frequency range, enabling use with

cellular, paging, motes, and two-way radio, inaddition to the ISM band.

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RFX12001150 MHz - 1450 MHz Transceiver

200+mW output (23dBm) Coverage of navigation,

satellite, and amateurbands.

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RFX18001.5-2.1 GHz Transceiver

100+mW output (20dBm)Coverage of DECT, US-DECT, and PCS(including unlicensed) frequencies.

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RFX24002.3-2.9 GHz Transceiver

50mW output(17dBm)with a bandpass filteraround the ISM band(2400-2483 MHz).The filter can beeasily bypassed,allowing for coverageof the full frequencyrange.

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Demo

SocketJPEG

EncoderModulationHard Disk

SocketHard Disk Demodulation

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Demo (cont.)Modulation

Demodulation

Bit to Byte Gray codeEncoderDifferential

EncoderReal toComplex

Byte to Bit Gray codeDecoderDifferentialDecoder

Real toComplex

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Current issues

Need a USRP + Microtune 4937Need a python IDE

A long way to be commercializedHigh performance CPU requirementThe software is still under development

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What is next?--possible applications and issues

The clock recovery block doesnt work in theDBPSK modulation

Add more functions, such as DQPSK, FSKinto our demoWe may test the transmission by actual wirelessconnection, since receiver doesnt ensurecorrect demodulation, for example, carriertracking, clock recovery, we may need to add:

cyclic redundancy check (CRC)Retransmission control (ARQ)Based on what we have done, we may deploy aresearch-oriented project next

GNUradio_20061208

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