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SeniorDesignProjectsUsingSoftwareDesignedRadio(SDR)

Prof.SharleneKatzProf.JamesFlynn

Dec.2,2008 1Flynn/Katz‐SDR

Overview

•  TraditionalhardwareradioversusSoftwareDefinedRadio

•  WhatisSDR?

•  AdvantagesandapplicationsofSDR•  Groupprojects•  ScheduleforWinter/Spring

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TraditionalTransceiver(Hardware)

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

DisadvantagesoftheTraditionalHardwareReceiver

•  Simplemodulation/demodulationonly

•  Limitedimplementationoffilters•  Alignment•  Aging•  Complexity•  Fixeddesign:frequency/mode•  Nonlinearity–unwantedsignals•  Thesearelimitationsofahardwarebasedsystem

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WhatisSoftwareDefinedRadio(SDR)?

•  Anewtechnologyforimplementingradiocommunications

systems

•  Artandscienceofbuildingradiosusingprimarilysoftware

•  Eliminatinghardwareandmovingsoftwareasclosetothe

antennaaspossible

•  Futuredirectionofcommunicationssystems

•  EncompassesmanyareasofEE:communications,signalprocessing,antennas,RF,digitaldesign,software

TraditionalHardwareReceiver

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RFAmplifier

IFAmplifierx

Demod‐ulator

LocalOscillator

ReceiverFrontEnd

Traditional/HardwareReceiver

Shiftsspectrumdowntolowerfrequency

Hardware:Envelopedetector,slopedetector,etc.

Dec.2,2008 Flynn/Katz‐SDR 7

SoftwareDefinedRadio

SoftwareAnalog to

DigitalConverter

Radioismodifiedbychangingthesoftware.Thehardwareremains

thesame

AdvantagesofSDR

•  Makescommunicationssystemsreconfigurable(adaptingtonewstandards)

•  Flexibility(universalplatform–notspecialpurpose)–Hardwarestaysthesame

•  Upgradable,modifiable

•  Filters/otherhardware•  Cognitive/SmartRadio

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SDRApplications•  Current

–  Military

–  RadioAstronomy

–  AmateurRadio

•  Future–  PersonalCommunications

•  Cellphones•  WiFi•  Entertainmentdistribution

–  PublicSafety–  Broadcasting

•  DigitalRadio•  DigitalTelevision

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ComponentsofaSDRSystem

ADC

FPGA(Decimator,MUX,etc.)

USBController PC

Daughterboard(optional) Motherboard

Shiftsthefrequencyofthedesired

signal

Samplesthe

analogsignal

Performsinitialsignalprocessing

Softwarefor

Transmitter/Receiver

Fordevelopmentpurposes

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USRP‐Motherboard/Daughterboard

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GNURadioSoftware

•  Community‐basedprojectstartedin1998

•  GNURadioapplicationconsistsofsources(inputs),sinks(outputs)andtransformblocks

•  Transformblocks:math,filtering,modulation/demodulation,coding,etc.

•  Sources:USRP,audio,fileinput,signalgenerator,…•  Sinks:USRP,audio,fileoutput,FFT,oscilloscope,…•  BlockswritteninC++•  Pythonscriptsusedtoconnectblocksandformapplication

SDRDemonstration

•  AMReceiver•  SystemcanbechangedtoFM,SSB,DigitalModulation,etc.byjustchangingthesoftware.

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GroupProjectsforSpring2009

•  UnmannedAirVehicle(UAV)TelemetryLink– TwowaycommunicationslinkbetweenagroundstationandaUAV

– Usedtosendlocationinformationandimages

•  GeneralPurposeTransceiver– Multi‐mode:AM/FM/SSB/Digital,Voice/Data/CW– Widefrequencyspectrum:HF,VHF,UHF,+– Signalprocessing

•  Groupswillworktogether

Dec.2,2008 Flynn/Katz‐SDR 14

Schedule•  WinterBreak

– LecturesonSDR(fornewgroupmembers)

–  Introductiontodigitalcommunications(everyone)– Developingaworkplanfortheyear

•  SpringSemester– Regularworkingmeetings

– Workplan

•  WinterMeetingtimes

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Questions?

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