1. Hybrid Fibre-VDSL Transmission over a CWDM Passive Ring Access Network Jason J. Lepley, Ioannis Tsalamanis, Manoj P. Thakur and Stuart D. Walker University of Essex, Colchester, United Kingdom. Kai Habel and Klaus-Dieter Langer Heinrich-Hertz Institute, Berlin, Germany.

2. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 2 Introduction – IST MUSE  MUSE (Multi Service Access Everywhere)  A large integrated European R&D project (28 organisations)  Strategic objective of providing “Broadband for All”  Phase I Jan 2004 to Dec 2005  Phase II Jan 2006 to Dec 2007  This work presents results from the end of Phase I lab trials, conducted in Berlin  MUSE subproject ‘D’  studying last-mile access technologies based on FTTH, hybrid fibre/copper wireline links and FWA

3. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 3 Background to the work – Broadband Access  Currently relies heavily on DSL  Optimises re-use of copper infrastructure with minimum additional hardware  represents 2/3 of all broadband access connections  operates on 1/5 of the world’s telephone lines  Within MUSE we are looking at how broadband will evolve towards the 100Mbps target.  Fibre is starting to be deployed, some countries more forthright than others  How might DSL fit into the picture?  DSL seriously distance limited as we move to higher data rates  High rate DSL will require some fibre penetration, i.e. FTTCab or FTTKerb

4. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 4 VDSL over Optics – the concept  DSL transmitted over telephony link  High speed DSL is strongly distance limited  ADSL(2) ~3-5 km  VDSL(2) <1 km  Network change required to place the DSLAM (physically or virtually) closer to the CPE OLT 16-24 way ONU DP Fibre link WA N CPE modem DSLAM CO  VDSL over Fibre to the X – enables re-use of some copper whilst increasing the data rate to near FTTH levels  Advantages over digital means:  No DSLAM required at the ONU point  Lower power requirements (typically ~20% that of RDSLAM), possibly power fed from the CO or CP  Easier upgrade path (zero touch) – rate agnostic  Optical hardware consists of single transmitter for the (potentially) 25 CPEs – signals multiplexed using SCM Typ. 3-5 km

5. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 5 CWDM ring  Heinrich-Hertz Institute  CWDM rings for access networks  Advantages:  Can cover large distribution areas with few fibres  Rings offer greater resilience against breaks  Multiple wavelengths offers scalability and the ability to carry multiple signal types across a network – e.g. as part of a staged network upgrade  CWDM currently more expensive than single channel solutions but less expensive than DWDM

6. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 6 Ring setup  16 channel CWDM ring using ZWPF  Rang also carrying Fast Ethernet in FTTH  7.3 km OLT to ONU separation  US and DS carried on separate fibres

7. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 7 Simplified VDSL over optics hardware setup 100BASE-T CP modem CPE Upstream Downstream CO DSLAM 100BASE-T CO modem 100BASE-T CO modem Garabit 100BASE-T CO modem Garabit 100BASE-T CO modem Garabit OLT ONU 7.4 km, 6.8 dB loss @1550nm

8. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 8 OLT configuration HPF DFB-LD LO Photodiode DC OLT Upstream Downstream CO DSLAM HPF LO DC HPF LO DC 100BASE-T HPF LO DC CO modem Optical Interface 100BASE-T CO modem 100BASE-T CO modem 100BASE-T CO modem

9. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 9 Downstream characteristics  60 MHz channel separation  4 channels using 998-138-1200 VDSL band plan

10. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 10 ONU to CP 100BASE-T HPF DFB-LD LO Photodiode DC CPE modem ONU Downstream Upstream Optical Interface Splitter/combiners for further channels  ONU hardware identical to OLT  This shows a single DSL channel setup with duplex fibre input

11. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 11 ONU hardware Directional coupler Frequency down-converter Frequency up-converter To/from CPE Received Up-converted signal Transmitted Up-converted signal Local oscillator  Op-Amp based hybrids to separate downstream and upstream channels  Lossless  Forward isolation ~21dB  Reverse isolation >80dB  Bandwidth ~1GHz  Connections to the DFB laser and PIN photodiode  Setup uses common oscillator and passive mixers  High drive power requirements + imperfect conversion efficiency

12. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 12 VDSLoO: Bit Loading characteristic  aggregate downstream (blue) rate = 19 Mbps  upstream (red) rate = 10.6 Mbps  data transmission efficiency  25 … 30%  70% efficiency has been shown in stand-alone setup (with higher powered mixers)  Interchannel crosstalk measured at <23 dB at 30 MHz channel spacing

13. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 13 Higher Layer demonstrations/tests  In the trial we also demonstrated higher layer transmission  Successful video transmission (DVD stream ~10Mbps) from Video server (at CO) to VDSL client and also between clients  Video conferencing link established between two remotely situated customers attached to CWDM Ring network, one using the VDSL connection discussed the other using FTTH (bandwidth ~1Mbps)

14. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 14 Conclusions  We have demonstrated the transmission of analogue VDSL signals over ~7.2km CWDM ring access network and ~100m twisted pair  The CWDM technology allows for various feeder architectures (ring, star, …) and is capable of carrying different distribution technologies simultaneously  DSL signals carried simultaneously with FTTH Ethernet and FWA signals with no discernable crosstalk effects  Transmitted data rates over the VDSL link of up to 19Mbps DS  Power consumption of the ONU ~450mW per channel

15. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 15 The End Thank you for your attention

16. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 16 Trial setup: Overview/Motivation  Optical feeder carrying three technologies  Demonstration of interoperability on physical layer  Combination of analogue and digital signals  distortions?  The work presented focuses on VDSLoO solution OLT feeder fibre (or ring) VDSLoO VDSL CWDM GbE VDSL modem FWA headend RAP e.g. WiMAX AON with protection ONU FWA shared GbE

17. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 17 ONU/OLT hardware circuit design  Directional coupler characteristics  Lossless  Forward isolation ~21dB  Reverse isolation >80dB  Bandwidth ~1GHz  Setup uses common oscillator and passive mixers  High drive power requirements + imperfect conversion efficiency

18. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 18 100BASE-T HPF DFB-LD LO Photodiode 106m UTP Directional Coupler HPF DFB-LD LO Photodiode Directional Coupler Internet DSLAM CPE modem ONU OLT/CO Optical fibre Upstream Downstream Hardware setup CP

19. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 19 VDSL over Optics  University of Essex  Studying techniques for carrying analogue VDSL signals over fibre  Advantages over digital means:  No DSLAM required at the ONU point  Lower power requirements (typically ~20% that of RDSLAM)  Easier upgrade path (zero touch) – rate agnostic  Lower Capex  Disadvantages  More susceptible to nonlinear elements in the link (L-I curve etc.)

20. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 20 Hardware setup 100BASE-T CO modem CPE Upstream Downstream CO DSLAM 100BASE-T CO modem 100BASE-T CO modem Garabit 100BASE-T CO modem Garabit 100BASE-T CO modem Garabit OLT ONU

21. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 21 CWDM Rings system: lab setup (HHI) CWDM feeder ring < 20km circumference with up to 9 remote nodes and 18 channels single wavelength distribution ring (can be grey by using a media converter) System provides protected path to ONUs ONU Ethernet switch protection normal HUB @ CO to metro domain 1-10Gbps SFP-TRx 1 DMUX SFP-TRx MUX DMUXMUX OADM Controller (PC) NIC/SFP NIC(s) Controller (PC) NIC/SFP NIC(s) client PC client RN#1 (1570nm) 5.1 km 5.0 km 2.0 km 1.9 km 1570nm

22. ICT - Funchal, Madeira 12 th May 2006 J.J. Lepley 22 Sub carrier multiplexing f1f1 f2f2 f3f3 f4f4 f5f5 f6f6 fNfN Baseband VDSL signal 12MHz 1GHz Optical carrier direct modulation spectrum 300MHz