SeniorDesignProjectsUsingSoftwareDesignedRadio(SDR)
Prof.SharleneKatzProf.JamesFlynn
Dec.2,2008 1Flynn/Katz‐SDR
Overview
• TraditionalhardwareradioversusSoftwareDefinedRadio
• WhatisSDR?
• AdvantagesandapplicationsofSDR• Groupprojects• ScheduleforWinter/Spring
Dec.2,2008 2Flynn/Katz‐SDR
TraditionalTransceiver(Hardware)
Dec.2,2008 Flynn/Katz‐SDR 3
• 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
Dec.2,2008 Flynn/Katz‐SDR 6
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
Dec.2,2008 Flynn/Katz‐SDR 10
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.
Dec.2,2008 Flynn/Katz‐SDR 13
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
Dec.2,2008 Flynn/Katz‐SDR 15
Questions?
Dec.2,2008 16Flynn/Katz‐SDR
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