P R O F . S H A R L E N E K A T Z P R O F . J A M E S F L Y N N

P R O F . D A V I D S C H W A R T Z

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Senior Design and Graduate Projects Using Software Defined

Radio (SDR)

Overview

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  What is a Communications System?   Traditional hardware radio versus Software Defined

Radio   What is SDR?   Advantages and applications of SDR   Projects   Schedule for Summer/Fall

What is a Communications System?

  A communications system transfers an information bearing signal from a source to one or more destinations.

  Examples:   Radio   TV   Telephone (landline or wireless)   Computer Network (terminal-computer or computer-

computer)   Radar   Wireless Microphone

July 16, 2008

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Flynn/Katz - SDR

Communications System Diagram

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Information Source and

Input Transducer

Transmitter Channel Receiver Output Transducer

Traditional Transceiver (Hardware)

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• Amplifiers • Modulators • Demodulators • Mixers • Filters • Oscillators

Disadvantages of the Traditional Hardware Receiver

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  Simple modulation / demodulation only   Limited implementation of filters   Alignment   Aging   Complexity   Fixed design: frequency/mode   Non linearity – unwanted signals   These are limitations of a hardware based system

What is Software Defined Radio (SDR)?

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•  A new technology for implementing radio

communications systems

•  Art and science of building radios using primarily

software

•  Eliminating hardware and moving software as close to the

antenna as possible

•  Future direction of communications systems

•  Encompasses many areas of EE: communications, signal

processing, antennas, RF, digital design, software

Software Defined Radio

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SoftwareAnalog to

DigitalConverter

Radio is modified by changing the

software. The hardware remains

the same

Advantages of SDR

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  Makes communications systems reconfigurable (adapting to new standards)

  Flexibility (universal platform – not special purpose) – Hardware stays the same

  Upgradable, modifiable   Filters/other hardware   Cognitive/Smart Radio

SDR Applications

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  Military

  Radio Astronomy

  Amateur Radio

  Future   Personal Communications

 Cell phones  Wi Fi  Entertainment distribution

  Public Safety   Broadcasting

 Digital Radio

 Digital Television

Components of a SDR System

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ADC

FPGA (Decimator, MUX, etc.)

USB Controller PC

Daughterboard (optional) Motherboard

Shifts the frequency of the desired

signal

Samples the

analog signal

Performs initial signal processing

Software for Transmitter/

Receiver

For development purposes

USRP - Motherboard/Daughterboard

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GNU Radio Software

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  Community-based project started in 1998   GNU Radio application consists of sources (inputs),

sinks (outputs) and transform blocks   Transform blocks: math, filtering, modulation/

demodulation, coding, etc.   Sources: USRP, audio, file input, signal generator, …   Sinks: USRP, audio, file output, FFT, oscilloscope, …   Blocks written in C++   Python scripts used to connect blocks and form

application

Previous SDR Projects

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  Unmanned Air Vehicle (UAV) Telemetry Link   Two way communications link between a ground station and a UAV   Transfers images, location, temperature, battery information   Includes Automatic Target Recognition feature

  General Purpose Transceiver   Multi-mode: AM/FM/ SSB/Digital, Voice/Data/CW   Wide frequency spectrum: HF, VHF, UHF, +   Signal processing

  Development of Hardware Platform for SDR   FPGAs   Amplifier and associated control and safety features

Future SDR Projects

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  Continued work on the UAV link and HF transceiver   Development of Hardware Platform for SDR   Optical Link from Aircraft Cockpit to

instrumentation on the wing   Applications of Spread Spectrum in SDR systems   Cognitive Radio   Hardware for human/SDR interface   Implementation of chirp radar system   Front End for Transceiver

Demonstration

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  Transceiver demonstration

Schedule

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  Summer   Introduction to Communications (for undergrads)   Learning to use GNU Radio   Preliminary project planning   Accessing the lab with card   Installing Ubuntu and GNU Radio

  Fall Semester   Regular working meetings

  Sources of Information   Project web page

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Questions?