Gigabit Copper 2015 David Baum Keynote Speech

ULTRA BROADBAND FOR THE MASSES

27-Mar-15Sckipio | How Do We Make G.fast Real 2

HOW DO WE MAKE G.FAST REALThe Best Practices for Deploying G.fast

David BaumCo-founder and CEO, Sckipio Technologies


7 SECRETS TO SUCCEEDING

IN G.FAST DEPLOYMENTS


SECRET #1: MODEL THE

BUSINESS


WHAT’S THE BIG

G.FAST IDEA?Leverage your existing

copper wiring to deliver ultra

broadband to the masses


PROBLEM OF SUBSCRIBER DROP

•Trenching on premises

• Installation scheduling & cost

•Right of way issues

•Roll-out delays due to capacity of installers

•Very expensive overall

Average 1.8km

Average 500m

Average 100m

$$$


Central Office

VDSL2

800-1,000 meters

Less than 140Mbps

G.fast Distribution Point

30-400 meters

Up to 1Gbps

Fiber to the Home

Over 1 Kilometer

Over 1Gbps

Fiber

Twisted Pair


G.FAST IS VERY FAST!

700

Mbps

100 meters

500Mbps

200 meters

350Mbps

300 meters

270Mbps

400 meters

150Mbps

500 meters

Numbers are aggregate

upstream/downstream

16 lines with crosstalk


NEW ≠ MORE EXPENSIVE

Cost per

port

FTTH

Cost per

port

VDSL VECTORING

Cost per

port

G.FAST

G.FAST

Lowest cost

per port


SECRET #2: FOCUS ON

POWER


IMPORTANCE OF POWER

• G.fast leverages reverse

power

• Everything driven from

power budget– Distance it can go

– Size of unit

– Overall cost


Cost vs. Power ConsumptionImpact of power consumption on the equipment housing cost

• Reference: Adtran ITU-T contribution 2012-02-4A-058R1, a case study done in 2012

0

1

2

3

4

5

6

7

8

0 10 20 30 40 50 60 70

No

rmal

ize

d C

om

ple

xity

Max Power Dissipation (Watts)

16

with DO

no DO

16

24

24


WHAT DRIVES POWER CHOICES

• Discontinuous operation

• Vectoring

• Training times and low power states

• G.int and network management


POWER COMPARED TO VDSL

• Time Division Duplexing • Frequency Division Duplexing

• Fast retraining • Slow retraining

• Low power default • Default: Always broadcasting

• Power down each port • All ports active

• Fast vector pairing • Slow vector pairing

VDSL


SECRET #3: UNDERSTANDING

VECTORING


CROSSTALK IS BANDWIDTH KILLER

0 20 40 60 80 100 120 140 160 180 200-160

-150

-140

-130

-120

-110

-100

-90

-80

-70Channel and FEXT for BT 100m line

Frequency [MHz]

Sig

nal and F

EX

T [

dB

m/H

z]

10dB

Received signal FEXT sum


G.FAST = VECTORING


DYNAMIC VECTORING IS KEY

• Real time

• Must respond in time

• Built-in vectoring critical


SECRET #4: UNDERSTAND

THE TRANSITION FROM VDSL


HOW G.FAST DIFFERS FROM VDSL

Parameter VDSL G.FAST

Frequency Range Up to 30MHz (30a) 2-106MHz, 2-212MHz (future)

Max Rate Up to 250Mbps (30a) and

150Mbps (17a) for short loops,

real-world is 30-80Mbps

1Gbps over short loops,

exceeding 500 Mbps over real

100m lines

Modulation OFDM OFDM

Number of carriers 4K (8K for future V+) 2K (for 106MHz profile)

Multiplexing scheme FDD TDD, synchronized among the

different copper pairs

Symbol time ~250 μsec (17MHz profile) ~20 μsec

Vectoring Via G.993.5 Supported, with adaptations

needed for higher frequency

Tx power Varies by profile, 14.5dBm 4dBm

FEC RS + Trellis code RS + Trellis code


HOW G.FAST DIFFERS FROM VDSL

Parameter VDSL G.FAST

Downstream/Upstream ratio Fixed Configurable: 90:10 to 30:70

Customer self-install Questionable. i.e. rates become

marginally low

Yes

xDSL Spectral compatibility Issues with 17M/30M mix

Issues with CAB/DP Mix

Yes, fresh start with new

frequency band

Retrain time Very long (30-90 second range) Very short – few seconds

Rate adaptation Very slow, 128 carriers at a time,

SOS not robust

Very fast, quick and robust

adaptation – within few msec

Low power mechanisms Under definition, expected

savings up to 50%, very slow

wake up time

Specified from day one,

discontinuous operation, scales

with traffic rate


CO-EXISTENCE WITH VDSL

• VDSL and G.fast can

co-exist

• Separate by frequency

VDSL

G.FAST

Up to 17Mhz

20-106Mhz


VDSL & G.FAST ARE USUALLY NOT

CO-LOCATED

•Most operators install VDSL far from the DP

•When deploying G.FAST, legacy VDSL service will continue

without interferences

•The service can be gradually upgraded to G.FAST

Average 500m

Average 100m

VDSLG.FAST

20-106MHz

17MHz

Co-Existence


APPROACH MOST ARE TAKING

• Bring fiber to the DPU

• Keep infrastructure as is (ADSL/VDSL)

• Using diplexer in the DPU to merge the lines

• Migrate gradually to G.fast over time without truck roll


VDSL FALLBACK• Not required by ITU or Broadband Forum

• Most service providers won’t deploy

• Don’t want to double pay for existing VDSL customers – They already have VDSL running, no need to pay again

• Cross-technology vectoring is challenging– If integrated into a single chip – extremely complex and inefficient

• If needed, can be implemented with two-chip solution


SECRET #5: FIND THE SWEET

SPOT


DEPLOYMENT OPTIONS


MDU IS KEY USE-CASE


DPU IN THE BASEMENT

• Smaller buildings

• Fiber to the DPU

• DPU in basement

• 1:16 today to CPE

• 24 feasible now, 48 future


DPU ON EACH FLOOR

• FTTF (Fiber to the Floor)

• Larger buildings

• Fiber to riser (WDM-PON, GPON)

• DPU on each floor

• 1:16 for each floor

• 24 feasible now, 48 future

x16

x16

x16

x16

x16

Fiber

.

.

.

Floor 1

.

.

.

.

.

.

Floor 2


OUTDOOR PLANT

• Row housing

• Fiber down street

(WDM-PON, GPON)

• DPU to each building or

section of building

• Reverse power feed

from CPE to power

DPU


SECRET #6: STAY DYNAMIC


PROBLEMS TO SOLVE

• The high G.fast frequencies increase the risk of changes

in the channel– Lower noise floor on the high band with vectoring implies exposure to various noise

sources

– Higher cross-talk cancellation levels (as FEXT is very high) implies higher sensitivity

– Neighboring lines

• Lessons learned from VDSL– You cannot avoid changes on the line, you can only:

• Adapt quickly and reliably to avoid retrains

• If retrain still occurs, shorten the retrain time to keep good user experience

• Higher performance– Increasing the noise margin to improve stability is not a good strategy!

– Noise margin is never high enough, need to use it only when we have to (for a short

time)


FAST OLR -

Online Reconfiguration

Use of noise margin

Slow adaptations

Fast and robust

adaptation

Old paradigm New paradigm


FAST RETRAINING

• Critical to success

• Responsive to dynamic line conditions

• Target - limited to just few seconds


SECRET #7: CHALLENGE

YOUR ASSUMPTIONS


G.FAST GOING FURTHER

700

Mbps

100 meters

500Mbps

200 meters

350Mbps

300 meters

270Mbps

400 meters

150Mbps

500 meters

Numbers are aggregate

upstream/downstream

16 lines with crosstalk


CHALLENGES TO OVERCOME

• Bad environments– Untwisted pairs

– Quad pairs

– Power lines running in parallel

– Ham radio interferences

• Dynamic response works


FUTURE OPPORTUNITIES

• Bonding

• Mobile backhaul

• Wider bandwidth

• New applications


7 SECRETS TO SUCCEEDING

IN G.FAST DEPLOYMENTS

1. Model the business

2. Focus on power

3. Understand vectoring

4. Understand the transition from VDSL

5. Find the sweet spot

6. Stay dynamic

7. Challenge your assumptions

ULTRA BROADBAND FOR THE MASSES

Gigabit Copper 2015 David Baum Keynote Speech

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Transcript of Gigabit Copper 2015 David Baum Keynote Speech