G.fast Shifting the limits of copper

Transcription

1 G.fast Shifting the limits of copper Bell Labs, Alcatel-Lucent - Jochen Maes 19 January, UKNOF

2 FTTH - the next big thing for decades

3 Reality gradual deployment of fiber deeper in network CO deployment Fiber to the Node / Cabinet Fiber to the Curb / Distribution Point <5km, 24 Mb/s <1km, 100 Mb/s <200m, 1 Gb/s CO cross-connect cabinet CO mini DSLAM CO micro node 3

4 Shifting the limits of copper PON 1 Gbps 500 Mbps The Gap + G.fast 100 Mbps 50 Mbps 10 Mbps 5 Mbps ADSL2 ADSL2+ VDSL2 17a VDSL(2) 8b + Phantom + vectoring + bonding 1 Mbps ADSL Copper innovations allow operators to gradually build up their fiber network 4

5 Vectoring Phantom mode +a +c+a DSLAM -a +c -c +b -b voltage +c -c +c-a c+b c-b virtual plus virtual pair virtual minus Customer modem Data rate (Mb/s) Bandwidth (Mbps) % Reduced field performance due to crosstalk Optimal VDSL2 performance Near-optimal field performance with vectoring Loop length (m) Loop length / distance (m) Data rate (Mb/s) Single line Bonding Vectored Phantom Phantom on Phantom 5

6 ITU project G.fast Standardizing copper physical layer aspects of FTTdp Initiated February 2011 Earliest opportunity for consent: e.o Means, earliest, standard could be approved in 2013; products could be available in 2014 Contributions by DSL and G.hn vendors Main requirements High peak data rate, e.g. 500 Mb/s at 100 m Suited for reverse powering Allowing for customer self-install Optimized for short loops - not a substitute for FTTCab 6

7 G.fast is becoming technologically feasible Digital computation complexity relative to ADSL in 2001 Along x-axis, cost of complexity is scaled with Moore s law Timmers et al., proceedings of Access2011 Technologically feasible analog will be limiting design factor 7

8 FTTdp architecture Fits within TR-156 and TR-167 deployment model CO Passive splitter 8-24 users per remote network equipment RE CPE Up to 1 Gb/s net rate G.fast transceiver CPE powered network equipment RE Power extraction 60 Vdc Power insertion CPE G.fast transceiver RE power supply unit Power source 8

9 Reverse power feed power transfer capability ETSI TR : Reverse Power Feed for Remote Nodes Source voltage 60 V, within SELV limit, current < 300 m Load power (W) mm Cu at 20 C mm Cu at 20 C 0.4 mm Cu at 20 C mm Cu at 65 C 0.4 mm Al at 65 C Loop length (m) System design for worst case when single long line is connected 9

10 Time division duplexing Advantages of TDD: Reduction in analog complexity Increases transmission efficiency Halves the modulation complexity Starting frequency above VDSL2, for legacy compatibility Time (µs) Arrival delay Excess delay Total delay CE in TDD Loop length (m) Required CE in FDD TDD allows relaxing analog requirements 10

11 P2P and P2MP system architecture Control function Point-to-multipoint with TDMA MAC Analogy with cable Switch function LD amp 1 Gb/s aggregation G.fast DSP DAC ADC Tx filter Rx filter LD amp LD amp Point-to-point DAC Tx filter LD ADC Rx filter amp Several Gb/s aggregation G.fast DSP DAC ADC Tx filter Rx filter LD amp DAC Tx filter LD ADC Rx filter amp Options under consideration in ITU G.fast 11

12 UK Reference loops P2MP vs. P2P comparison Hlog (db) D1H1 D2H2-40 D2H1 D3H5-45 D4H5 D4H Frequency (MHz) Net sustainable BHOL (Mb/s) Average TDMA rate of N-1 users if 1 user is at 500 Mb/s peak rate MHz 12 MHz 17.7 MHz 30 MHz Node size P2P rate (vectored) Start frequency D1-H1 D2-H2 D2-H1 D3-H5 D4-H5 D4-H3 Loop length m m m 45.6 m 83.3 m 93.3 m 2.2 MHz MHz MHz MHz UK reference loops Key question: up to or guaranteed bandwidth 12

13 Transmitter Controlled Adaptive Modulation Operator benefit: Robustness Self-install Spectral efficiency Throughput Green Reverse powering With minimal implementation impact Noise driven grid control Traffic driven power control Automatic adaptation to traffic load and channel conditions 13

14 CuGAR Copper Gigabit Access Research evaluation platform D6 LAB off-line connection real-time connection SERVER place and route FPGA Front end remote connection FPGA cable Bit loading Front end Test bed for candidate technologies 14

15 FTTdp - G.fast Continued copper access innovations facilitate operators to spread fiber investments G.fast is targeted for short loops up to 200 m from the last distribution point Being standardized in ITU-T, promising up to 1 Gb/s Transmitter controlled adaptive modulation is proposed, enabling high throughput, self-install and reverse powering P2P and P2MP system architectures under study in ITU TDMA offers high peak rate, but lower sustainable rate applied to UK reference loops behaves like cable or PON 15

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