OFDMA for Access Networks: Optical Setup

Transcription

1 OFDMA or Access Neworks: Opical Seup Johannes von Hoyningen-Huene Lehrsuhl ür Nachrichen- und Überragungsechnik CAU Kiel Workshop der ITG-Fachgruppe Kiel,

2 Moivaion or OFDMA in Opical Access Goals or Fuure Opical Access Neworks Increase daa rae Inroduce WDM, increase daa rae per λ Increase user coun WDM + muliple access (MA) echniques on each wavelengh: TDMA, CDMA, FDMA, OFDMA Sae o he ar Discussed here Advanages o OFDMA: Flexibiliy in ime and requency domain MUX/DeMUX Coninuous operaion (insead o burs operaion) λ M 1:N 1:N ONU N ONU N... however, here are challenges! Chair or Communicaions -2-

3 Ouline Opics in Downsream Direcion Direc Deecion vs. Coheren Deecion Opics in Upsream Direcion Aspecs o upsream wih dieren wavelenghs Aspecs o upsream wih common wavelengh Duplex o Up- and Downsream Summary Chair or Communicaions -3-

4 Concep o OFDMA in PON: Downsream Example wih 4 ONUs Groups o OFDM subcarriers assigned o ONU 4 ONU 4 IFFT-window Chair or Communicaions -4-

5 90 hybrid Characerisics o Opical Modulaion/Deecion IM-DD DSB IM-DD SSB S 2 Opical specrum C C S 1 Elecrical specrum C 2 S + S B B B B B B C S + C S C 2 S1 C S 2 1 S 1 E S 2 S 1 LO 2 IM-CO DSB LO LO S 2 LO S 1 2 S 1 as in OFC 14 Shor Course, OFC 12 Tuorial by Sander Jansen Chair or Communicaions -5-

6 OFDMA-Downsream: Experimen (CAU, OFC 12) Seup PSD Oline processing Poin-o-poin ransmission over 100 km SMF SSB-ilering o avoid powerading Single Tx: Single Rx Emulae muliple Rx: Full daa rae Dieren reducion acors (r) Full / hal / quarer daa rae Dieren LO-requencies -40 Oline OFDM DSP 10 GS/s AWG7102 IQ DFB IM -50 v. Hoyningen-Huene e al., OFC 2012, OW4B SSBF 100 km SMF [nm] noise loading PD IQ LPF LPF DPO GS/s oline processing LPF LPF r r OFDM DSP Variable bandwidh Chair or Communicaions -6-

7 Concep o OFDMA in PON: Upsream ONU 4 Chair or Communicaions -7-

8 Concep o OFDMA in PON: Upsream ONU 4 Challenges: Carrier requency ose Dieren pah lenghs Dieren saes o polarizaion Dieren opical phase Chair or Communicaions -8-

9 Opical Modulaion in Upsream Dieren Wavelengh, Direc Deecion Opical specrum 1:N λ 4 λ 3 λ 2 IM ONU N C 1 C2 S1 C3 S2 C4 S3 S Elecrical specrum LPF E Desired pars Inermodulaion producs Chair or Communicaions -9-

10 Opical Modulaion on Same Wavelengh Direc Deecion 1:N IM ONU N Opical specrum Elecrical specrum E (Larger bandgap required) Equal carrier requencies required Chair or Communicaions -10-

11 Opical Modulaion on Same Wavelengh Direc Deecion 1:N IM ONU N Opical specrum Elecrical specrum E 2 Equal carrier requencies required Insensiive o polarizaion Desrucive beaing o carriers possible Loss o sub-signals No direc deecion possible Chair or Communicaions -11-

12 Opical Modulaion on Same Wavelengh Coheren Deecion 90 hybrid CO-Rx 1:N IM ONU N Opical specrum E 2 Elecrical specrum X-pol. LO, X-pol. LO, Y-pol. Y-pol. Equal carrier requencies required Add carrier a receiver, no a ransmier Coheren deecion o boh polarizaions Chair or Communicaions -12-

13 OFDMA-Upsream: Experimens (CAU, OFC 13+14) ONUs: Generaion o 4 real-valued OFDM signals Synchronized AWG Adjusable iming ose PON: Individual disribuion ibers Bidirecional eeder iber : Tx DSP DAC 25 km Coheren recepion (dual pol.) Tx DSP Tx DSP Tx DSP ONU 4 DAC DAC DAC VOA 25 km VOA 4:1 4:1 RN 25 km VOA PolMux CO Rx 2:1 ADC ADC ADC ADC ECL OFDMA Rx DSP von Hoyningen-Huene e al., OFC 2014, Tu2F.4. Chair or Communicaions -13-

14 OFDMA-Upsream: Experimens (CAU, OFC 13+14) Opical Specra 2 GHz 20 db 0 (GHz) 7 Tx DSP ONU 4 Opical Specrum (dbm/0.01 nm) Wavelengh [nm] DAC 25 km 4:1 4:1 RN von Hoyningen-Huene e al., OFC 2014, Tu2F km (GHz) VOA X-polarizaion Y-polarizaion CO Rx 2:1 ADC ECL 10 db OFDMA Rx DSP Chair or Communicaions -14-

15 Duplex o Downsream and Upsream Dieren ibers Simple concep, relaively expensive Dieren wavelenghs Separaion wih WDM componens Disribuion o common US-λ required Small inererence o US and DS NEC, CAU Kiel, ec. Downsream Upsream λ DS λ US λ Duplex on same wavelengh Remodulaion o downlink signal Technion, HHI Berlin, NEC, ec. DS US λ DS/US λ Chair or Communicaions -15-

16 Summary OFDMA or lexible capaciy allocaion among ONUs Downsream direcion: sraigh orward Single opical source, single opical modulaion Cos eicien opics Upsream direcion: challenging bu possible Individual wavelenghs or each ONU Cos eicien deecion, bu (grealy) reduced WDM scalabiliy Common wavelengh or all ONUs Disribuion o opical carrier required (or precise conrol o opical sources) Coheren deecion required Chair or Communicaions -16-