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SOFTWARE DEFINED

RADIO

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PRESENTATION OVERVIEW

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DEFINITION

Whats SDR

Software-dened radio(SDR) is a radio communicatsystem were com!onents tat a"e #een ty!ica$$y

im!$emented in ardware (e%&% mi'ers$ters am!$iers modu$ators *demodu$ators detetc%) are instead im!$emented #y means o+ so+tware!ersona$ com!uter or em#edded system%

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,ISTOR- OF SDR

Te term .So+tware Dened Radio. was coined in/00/ #y 1ose! 2ito$a wo !u#$ised te rst!a!er on te to!ic in /003

One o+ te rst !u#$ic so+tware radio initiati"eswas a 4%S% mi$itary !ro5ect named S!ea6Easy%

Te !rimary &oa$ o+ te S!ea6Easy !ro5ect was tuse !ro&ramma#$e !rocessin& to emu$ate moretan /7 e'istin& mi$itary radios o!eratin& in+re8uency #ands #etween 3 and 3777 2,9%

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Complete Base band processing digital Reconfigurable

Software upgrading of commercial radios Future proof

Generic hardware can be used for a variety of applicatio Inventory

Software prototyping faster and cheaper than hardware

prototyping Time to maret!ibraries of software radio components are easily create

and shared Reuse

"igital processing of signals is ideal# unencumbered by tnon$linearities that plague analog hardware$Reliability

SDR ADVANTAGES

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MOTIVATION TOWARDS SDR

Commercial wireless communication industry is currenfacing problems due to constant evolution of link-layerprotocol standards (2G, 3G, and 4G)

eistence of incompatible wireless network tec!nologiedifferent countries in!ibiting deployment of global roafacilities

problems in rolling-out new services"features due to wspread presence of legacy subscriber !andsets#

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TE:,NI:A; OVERVIEW

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IDEA; SDR

The ideal SDR will cover all frequencies from 9kHz to 300GHz

!t will receive"transmit and modulate"demodulate all modulatimodes and #andwidths

!t will confi$ure itself automaticall%

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IDEA; TRANS2ITTER AND RE:EIVER

Te idea$ recei"er sceme wou$d #e to attac anana$o&

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PRA:TI:A; RE:EIVERS

:urrent di&ita$ e$ectronics are too s$ow to recei"ety!ica$ radio si&na$s tat ran&e +rom /7 6,9 to 3 =,9

Pro#$em so$"ed #y usin& a mi'er and a re+erenceosci$$ator to eterodyne te radio si&na$ to a $ower+re8uency%

Di&ita$ I> modu$ator used%

Rea$ ana$o&

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Typical Components of S"R

Ana$o& Radio Fre8uency (RF) recei"er*transmitter in te 3772,9 to mu$ti

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(rchitectures of S"R

")C* "ig

upconve

""C* "igdowncon

CFR* Cre

reductio

predisto

'(* 'ow

!+(* !ow

amplifie

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RF Front ,nd

The principle of operation depends on the use of heterodyning or fre&uencymi-ing.

The signal from the antenna is filtered sufficiently at least to re/ectthe image frequencyand possibly amplified.

( local oscillator in the receiver produces a sine wave which mi-es with thatsignal# shifting it to a specific intermediate fre&uency 0IF1# usually a lower

fre&uency. The IF signal is itself filtered and amplified and possibly processed in

additional ways

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"IGIT(! I2 modulator

Two carriers of same fre&uency but 34 deg out of phase are used# which are

combined at transmission.

5essage too is modified to consist of two separate signals 34 deg phaseshifted version

original 34 deg phase shifted version

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("C 6 "(C

("C$ Sampling 0 +y&uist theorem1

2uantisation

Flash ("C is the fastest of all.

"(C$ weighted resistor

R$7R ladder 80out19 80 ref1: 0";7

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DD:< Di&ita$ Down :on"ersion

Digital radio receivers often have fast ADC converters delivering vastamounts of data; but in many cases, the signal of interest represents a smal

proportion of that bandwidth. A DDC allows the rest of that data to be

discarded. When performed in a field programmable gate array (F!A",

simple digital down conversion is bro#en up into three distinct steps$

fre%uency shifting, filtering, and decimation

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D4:

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Crest factor REDCTION !

Crest factoris a measure o+ a wa"e+orm suc as a$ternatsound sowin& te ratio o+ !ea6 "a$ues to te a"era&e "a$words crest +actor indicates ow e'treme te !ea6s are in

modu$ation tecni8ues tat a"e sma$$er crest +actors usumore #its !er second tan modu$ation tecni8ues tat a"+actors%

:rest +actor reduction (:FR) reduces te out!ut !ea6

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DI=ITA; PREDISTORTION (D

DPD is an acti"e $inearisation tecni8ueused to com!ensation +or am!$ierBsnon

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FP=A

SDR system uses a &eneric ardware !$at+orm wit !ro&ramodu$es (DSPs FP=As micro!rocessors) and ana$o& RF m

FP=As ("ie$d $ro&ramma#$e Gate Arrays) are ama9in& de"a$$ow te a"era&e !erson to create teir "ery own di&ita$ c

It is an I: tat cou$d contain mi$$ion o+ $o&ic &ates tat can con&ured to !er+orm a certain tas6 usin& ,D; ( ,ardware;an&ua&es)

2ore Ce'i#$e tan microcontro$$er%

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Software =verview "igital Signal 'rocessing 0"S'1 software applicatio

employ the math of Fourier Transforms..

FT describes which fre&uencies are present in theoriginal function.

(n open architecture

(llows third party waveform;component development

Standardised procedure for !oading and Controlof

software modules

Should be one relying on proven technologies shorte

development time

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T%E END

&ESTIONS