FundamentalsofChannelCodingNewwordsandphrases1selectivelyadv.善于挑選地，仔細(xì)挑選2formulan.公式(pl.formulas,formulae)3sacrificev.犧牲4redundantadj.冗余的，多余的5demonstratevt.證明，論證6orthogonaladj.正交的，直角的7arbitrarilyadv.任意地8rawadj.未加工的(rawdata原始數(shù)據(jù))9denotevt.指示，表示10retransmissionn.轉(zhuǎn)發(fā)，轉(zhuǎn)播，中繼11sophisticatedadj.復(fù)雜的12impracticaladj.不切實(shí)際的,不能實(shí)行的[JP]13parityn.奇偶校驗(yàn)14encodern.編碼器15codewordn.碼字16moduloprep.以…為模(modulo2adder模2加法器)FundamentalsofChannelCoding17alphabetn.字符表，字母表18linearityn.線性19systematicadj.系統(tǒng)的，體系的(systematiccode系統(tǒng)碼)20cyclicn.循環(huán)的,周期的(cycliccode循環(huán)碼cyclicshift循環(huán)移位)21subsetn.子集22convolutionaladj.卷積的(convolutionalcode卷積碼)23algebraicadj.代數(shù)的;代數(shù)學(xué)的(algebraicfunction代數(shù)函數(shù))24stagen.級(jí)25outlinen.提綱；要點(diǎn)；概要26fundamentallyadv.基礎(chǔ)地，根本地27polynomialn.多項(xiàng)式(generatorpolynomial生成多項(xiàng)式)28addern.加法器29vectorn.矢量，向量(vectorarray向量數(shù)組(矩陣))30identicaladj.一致的，相同的31revealvt.揭示，顯示，展現(xiàn)32trellisn.格子，格子結(jié)構(gòu)trellisdiagram網(wǎng)格圖)33emanatevi.散發(fā)，發(fā)出，發(fā)源(emanatefrom發(fā)出,發(fā)源)FundamentalsofChannelCoding1errordetectioncode檢錯(cuò)碼2errorcorrectioncode糾錯(cuò)碼,差錯(cuò)檢驗(yàn)碼3AWGN(AdditiveWhiteGaussianNoise)加性高斯白噪聲4channelcapacity信道容量5transmissionbandwidth傳輸帶寬6signalpower信號(hào)功率7singlesidednoisepowerdensity單邊噪聲功率密度8bandwidthefficiency帶寬效率9SNR(S/N,signaltonoiseratio)信噪比,信號(hào)噪聲比10BER(BitErrorRatio)誤碼率,誤比特率11inthelimit在極限情況下12blockcode分組碼,塊碼FundamentalsofChannelCoding13FEC(ForwardErrorCorrection)前向糾錯(cuò)14coderate編碼率15codedistance(distanceofacode)碼距16codeweight(weightofacode)碼權(quán),碼重17Hammingdistance漢明距離，漢明間距18codinggain編碼增益19shiftregister移位寄存器20constraintlength制約長(zhǎng)度21generator生成矩陣22logictable邏輯表23statediagram狀態(tài)圖24treediagram樹形圖FundamentalsofChannelCoding

Channelcodingprotectsdigitaldatafromerrorsbyselectivelyintroducingredundanciesinthetransmitteddata.Channelcodesthatareusedtodetecterrorsarecallederrordetectioncodes,whilecodesthatcandetectandcorrecterrorsarecallederrorcorrectioncodes.In1948,Shannondemonstratedthatbyproperencodingoftheinformation,errorsinducedbyanoisychannelcanbereducedtoanydesiredlevelwithoutsacrificingtherateofinformationtransfer.Shannon’schannelcapacityformulaisapplicabletotheAWGNchannelandisgivenbyC=Blog2(1+P/N0B)=Blog2(1+S/N)(4.1)whereCisthechannelcapacity(bitspersecond),Bisthetransmissionbandwidth(Hz),Pisthereceivedsignalpower(W),andN0isthesinglesidednoisepowerdensity(W/Hz).ThereceivedpoweratareceiverisgivenasP=Eb/Rb(4.2)whereEbistheaveragebitenergy,andRbisthetransmissionbitrate.Equation(4.1)canbenormalizedbythetransmissionbandwidthandisgivenbyC/B=log2(1+Eb/N0*Rb/B)(4.3）whereC/Bdenotesbandwidthefficiency.FundamentalsofChannelCoding

Thebasicpurposeoferrordetectionanderrorcorrectiontechniquesistointroduceredundanciesinthedatatoimprovewirelesslinkperformance.Theintroductionofredundantbitsincreasestherawdatarateusedinthelink,henceincreasesthebandwidthrequirementforafixedsourcedatarate.ThisreducesthebandwidthefficiencyofthelinkinhighSNRconditions,butprovidesexcellentBERperformanceatlowSNRvalues.Itiswellknownthattheuseoforthogonalsignalingallowstheprobabilityoferrortobecomearbitrarilysmallbyexpandingthesignalset,i.e.,bymakingthenumberofwaveformsM→∞,providedthattheSNRperbitexceedstheShannonlimitofSNRb≥-16dB.Inthelimit,Shannon’sresultindicatesthatextremelywidebandsignalscouldbeusedtoachieveerrorfreecommunications,aslongassufficientSNRexists.Errorcontrolcodingwaveforms,ontheotherhand,havebandwidthexpansionfactorsthatgrowonlylinearlywiththecodeblocklength.

FundamentalsofChannelCodingErrorcorrectioncodingthusoffersadvantagesinbandwidthlimitedapplications,andalsoprovideslinkprotectioninpowerlimitedapplications.Achannelcoderoperatesondigitalmessage(orsource)databyencodingthesourceinformationintoacodesequencefortransmissionthroughthechannel.Therearetwobasictypesoferrorcorrectionanddetectioncodes:blockcodesandconvolutionalcodes.ExercisesⅠ.PleasetranslatethefollowingwordsandphrasesintoChinese.1.channelcoding2.transmissionbandwidth3.Singlesidednoisepowerdensity4.orthogonalsignaling5.FEC6.logictable7.systematiccode8.AWGN信道編碼傳輸帶寬單邊帶噪聲功率密度正交信號(hào)前向糾（forwarderrorcorrection)邏輯表系統(tǒng)碼加性高斯白噪聲(additivewhiteGaussiannoise)Exercises9.BER10.trellisdiagram11.constraintlength12.vectorarray13.algebraicfunction14.statediagram15.cyclicshift16.generatormatrix誤碼率,誤比特率(BitErrorRatio)網(wǎng)格圖制約長(zhǎng)度向量數(shù)組(矩陣)代數(shù)函數(shù)狀態(tài)圖循環(huán)移位生成矩陣ExercisesⅡ.PleasetranslatethefollowingwordsandphrasesintoEnglish.1.檢錯(cuò)碼2.信道容量3.分組碼4.卷積碼5.移位寄存器6.漢明距離7.碼重8.樹形圖9.編碼增益errordetectioncodeschannelcapacityblockcodesconvolutionalcodesshiftregisterHammingdistancecodeweight(weightofacode)treediagramcodinggainExercises10.平均比特能量11.碼距12.糾錯(cuò)碼13.帶寬效率14.模2加法器15.原始數(shù)據(jù)16.編碼率17.生成多項(xiàng)式18.循環(huán)碼averagebitenergycodedistance(distanceofacode)errorcorrectioncodesbandwidthefficiencymodulo2adderrawdatacoderategeneratorpolynomialcycliccodesExercisesⅢ.Fillintheblankswiththemissingword(s).1.Channelcodingprotectsdigitaldata

errorsbyselectivelyintroducingredundanciesinthetransmitteddata.2.Byproperencodingoftheinformation,errorsinduced

anoisychannelcanbereduced

anydesiredlevelwithoutsacrificingtherateofinformationtransfer.3.Errorcontrolcodingwaveforms,

theotherhand,havebandwidthexpansionfactorsthatgrowonlylinearly

thecodeblocklength.4.Inablockencoder,kinformationbitsareencoded

ncodebits.frombytoonwithintoExercises5.Theblockcodeisreferredto

an(n,k)code,andtherateofthecodeisdefined

Rc=k/nandisequal

therateofinformationdividedbytherawchannelrate.6.Convolutionalcodesarefundamentallydifferent

blockcodesinthatinformationsequencesarenotgrouped

distinctblocksandencoded.7.Thetreediagramshowsthestructureoftheencoder

theformofatreewiththebranches

（represent，represented，representing）thevariousstatesandtheoutputsofthecoder.8.Thisreducesthebandwidthefficiencyofthelink

highSNRconditions,butprovidesexcellentBERperformance

lowSNRvalues.9.Asystematiccodeisone

whichtheparitybitsareappended

theendoftheinformationbits.10.Achannelcoderoperates

digitalmessage(orsource)databyencodingthesourceinformation

acodesequencefortransmission

thechannel.astoasfromintoinrepresentinginatintoonintothroughExercisesⅣ.Answerthefollowingquestionsaccordingtothetext.1.PleasewritedowntheShannon’schannelcapacityformula.2.Whatisthebasicpurposeoferrordetectionanderrorcorrectiontechniques?3.Howtodefinethedistanceofacodeword?4.PleasedescribethecyclicshiftpropertyinEnglish.C=Blog2(1+P/N0B)=Blog2(1+S/N)Thebasicpurposeoferrordetectionanderrorcorrectiontechniquesistointroduceredundanciesinthedatatoimprovewirelesslinkperformance.ThedistanceofacodewordisthenumberofelementsinwhichtwocodewordsCiandCjdifferd(Ci,Cj)=∑(Nl=1)(Ci,Cj,)(moduloq)wheredisthedistanceofthecodewordandqisthenumberofpossiblevaluesofCjandCj.If