#5 Demodulation and Detection Error due to Noise

Transcription

1 06 Q Wirele Communicaion Engineering #5 Demodulaion and Deecion Error due o Noie Kei Sakaguci akaguci@mobile.ee. Jul 8, 06

2 Coure Scedule Dae Tex Conen # June 7, 7 Inroducion o wirele communicaion em # June 7, 5, ec Link budge deign of wirele acce #3 June 4 Up/down converion and equivalen baeband em #4 June 4 3.3, 3.4 Digial modulaion and pule aping Jul No cla #5 Jul Demodulaion and deecion error due o noie #6 Jul Cannel fading and diveri combining Jul 8, 06 Wirele Communicaion Engineering

3 From reviou Lecure n Digial modulaion + j D DI DQ f m Ampliude ae Frequenc Daa rae, power efficienc, complexi, error rae n ule aping band limiaion g τ D τ dτ Recangular Nqui Gauian andwid, error rae n IQ analog modulaion I coπf c Q inπf c Carrier frequenc Jul 8, 06 Wirele Communicaion Engineering 3

4 Conen Srucure of receiver Analog demodulaion Maced filer Coeren deecion Error rae of SK ignal Error rae of QAM ignal Demonraion Jul 8, 06 Wirele Communicaion Engineering 4

5 m f Digial modulaion D Tranmier g ule aping D/A D/A Analog modulaion co πf 0 Carrier freq. f 0 Coverage Smbol leng T andwid T Modulaion order M log Daa rae M T c d 0 4πf αn γ Modulaion f Energ efficienc, Complexi of circui, i error rae ule g ower leackage Jul 8, 06 Wirele Communicaion Engineering 5 S g f SD f p e

6 Receiver n Analog demod. coπ f 0 g r Maced filer D kt Cannel e. Co. de. ĥkt ŝ D kt Digial demod. mˆ kt Addiive wie noie Termal noie generaed in receiver andpa fileer Iner em inerference cancellaion Analog demodulaion Conver ignal from RF o Maced filer Maximizaion of SNR Coeren deecion Compenaion of cannel repone Digial demodulaion Conver complex ignal o meage Jul 8, 06 Wirele Communicaion Engineering 6

7 f 0 Tranmier Up converer [ ] RF & τ n Down converer Re τ τ dτ R Receiver f 0 jπf0 R e + R j ilb jπf0 R e Jul 8, 06 Wirele Communicaion Engineering 7

8 Analog Demodulaion receive ignal I + jq R e jπ f 0 Re R [ ] Ico πf 0 Q in πf 0 Analog demod. coπ f 0 Analog demodulaion Low pa filer I I co πf 0 d π Q in πf 0 d Q Jul 8, 06 Wirele Communicaion Engineering 8

9 Narrow and Sem Equivalen em Narrow band aumpion τ! τ dτ jπf0τ τ τ e τ 0! τ 0 e jθ 0 H f τ 0 f 0 τ 0 τ Jul 8, 06 Wirele Communicaion Engineering 9

10 Noie noie n ni + jnq n R n e jπ f 0 n Re n R [ ] n nico πf 0 nq in πf 0 Analog demod. coπ f 0 n Analog demodulaion n n I Q n co πf 0 d n in πf 0 d Jul 8, 06 Wirele Communicaion Engineering 0

11 roper of Noie Noie power n ni + nq N 0 σ DF of noie p n x n p n e I Q E[ n I ] E!" n Q # $ 0 E σ πσ [ ] [ ] ni E nq σ S n f Jul 8, 06 Wirele Communicaion Engineering S n R f S n f f c f c 0 f f f N 0 N 0 N 0

12 n received ignal + n ranmi ignal Maced Filer Analog demod. coπ f 0 g r Maced filer D kt g a g nt D n n Oupu of receiver filer D gr gr g D + gr n Jul 8, 06 Wirele Communicaion Engineering

13 Receive filer oupu SNR Maced Filer γ g0 g g E[ n ] r g nd gr n D 0 n Combined pule of ranmier & receiver Frequenc domain anali Signal power r Analog demod. coπ f 0 g r Maced filer Noie power g G f G f df E[ n D ] N 0 G r f d f D kt Jul 8, 06 Wirele Communicaion Engineering 3

14 Scwarz inequali g n Maced Filer 3 0 Gr f G f df Gr f df G f df Maced filer SNR maximizaion G * G g g r f f Maximum SNR γ g0 r E[ n ] N 0 G f Analog demod. Energ of ranmi pule coπ f 0 g r d f E N 0 T N 0 N 0 σ Maced filer D kt Jul 8, 06 Wirele Communicaion Engineering 4

15 Received ignal Deecion Sceme D k D k + nd k Deecion Modulaion Demodulaion Envelope ASK ˆ k D D k Correlaion FSK exp jπδfd exp jπδf d Differenial Differenial mod. ~ θ k θ k + θ k ˆ D k D k D k Coeren SK, QAM, MSK ˆ D D Jul 8, 06 Wirele Communicaion Engineering 5

16 n Coeren Deecion Analog demod. coπ f 0 g r Maced filer D kt Oupu of maced filer D g D + gr n Cannel e. Co. de. ˆ ŝ D kt kt Digial demod. D k D k + nd k Nqui maced filer k k + n k g gr g Coeren deecion g 0 d ˆ k k ˆ G f f Compenaion of Gr f df cannel repone Digial demodulaion mˆ k f ˆ k for eac modulaion meod of ASK, SK, FSK mˆ kt Jul 8, 06 Wirele Communicaion Engineering 6

17 Oupu of maced filer k k + TR ~ k Cannel Eimaion TR k n k Training ignal Cannel eimaion g r Maced filer D kt Cannel e. Co. de. Frame rucure of ranmi ignal # of raining mbol: K ˆ ŝ D kt kt ˆ ~ K k K k Training ignal Daa ignal Jul 8, 06 Wirele Communicaion Engineering 7

18 Error Rae of SK Signal Oupu of coeren deecion ˆ k E [ k ] k Tranmi power k + n k Error rae of SK ignal x eb exp dx 0 / / + πσ σ Jul 8, 06 Complex Gauian wi variance σ / erfc σ erfc γ γ erfc x σ Wirele Communicaion Engineering 0 π x Receive SNR exp Re[ ˆ k] Complemenar error funcion z dz 8

19 Error Rae of QSK Signal Oupu of coeren deecion ˆ k k I k + j Q k + n k Tranmi power E [ k ] E[ k ] I Q QSK Q I i error rae eb Jul 8, 06 erfc Smbol error rae σ erfc γ eb eb eb eb eb e I Q Wirele Communicaion Engineering roporional o SNR per bi 9

20 Error Rae of QAM Signal Smbol error rae ei eq ei eq e 6QAM M SK ei eb + M M Cener erfc M SK eb Two edge E 0 σ Tranmi power M E0 M E i M i 3 0 i error rae eb log M e Smbol error correpond o one bi error owing o Gra coding E 0 Jul 8, 06 Wirele Communicaion Engineering 0

21 Error Rae erformance i error rae performance SK QSK 6QAM 64QAM i Error Rae Average SNR per anenna [d] Jul 8, 06 Wirele Communicaion Engineering

22 Summar Jul 8, 06 Wirele Communicaion Engineering n Analog demodulaion & maced fileer n Cannel eimaion & coeren deecion n Error rae of SK ignal γ σ erfc erfc eb ˆ k n k k k + K k k k K TR ˆ ] exp Re[ 0 f j π n + r D D n g g + r g g g g g d 0 f f G g d r f f G Nqui maced fileer 0 eb erfc log σ E M M n Error rae of QAM ignal

23 Tranmier Training ignal Demo Coeren deec. Digial demod. Jul 8, 06 Cannel eimaion Wirele Communicaion Engineering 3

24 Error Rae of MSK Oupu of coeren deecion ˆ k k + MSK modulaion n k k exp jθ k πa θ k k + θ k Conellaion a k a k θ k T 0,π θ k T π, π ER of MSK ignal eb erfc σ erfc γ Jul 8, 06 Wirele Communicaion Engineering 4