1 Maui 2011 08/01/11 Dynamic Spectrum Management A path to ubiquitous 100+ Mbps DSL Service ICCCN 2011 August 1, 2011 Maui, Hawaii John M. Cioffi Chairman.

1Maui 201108/01/11

Dynamic Spectrum ManagementA path to ubiquitous 100+ Mbps DSL Service

ICCCN 2011August 1, 2011

Maui, Hawaii

John M. CioffiChairman and CEO, ASSIA Inc.

Prof Emeritus, Stanford U

ASSIA: G. Ginis, W. Rhee, B. Lee, C. Chen, M. Mohseni, W. Lee,

Stanford: A. Chowdhery, H. Zou, H. Mehmood, and M. Chen

2Maui 201108/01/11

• 50% growth per year – high-end users• Suggests 100 – 200 Mbps access desirable in 2015

Internet Access Bandwidth Growth

Source: J. Nielsonuseit.com

3Maui 201108/01/11

Global Broadband Access

• DSL is largest fraction (over 70% of broadband)– And growing faster, still gaining– It costs a lot less

600M in 2015

4Maui 201108/01/11

Mobile Data ( Cell + Wi-Fi ) Growth

74.4 PB

2.46 EB

Offloaded Data over

Wi-Fi x26 Growth

factor !!

5Maui 201108/01/11

Wireless Multiplier:Evolution to Smaller Cells

• Increase capacity 2-10x • More subscribers• More “smart phones”

• Solution: • Smaller cells

• DSL connection to small cell

• Wifi or femto

6Maui 201108/01/11

Service Providers are Aggressively Deploying IPTV

2005 2006 2007 2008 20090

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

WW IPTV Subscriber Growth

Western Europe

South and East Asia

North America

ME&A

Latin America

Eastern Europe

Asia Pacific

IPTV SubscribersCAG

R = 9

2%

7Maui 201108/01/11

Video Quality (IPTV, tablet, smartphone)

CPEDSLAM/RT

8 U

Transmission Source

Multiplexer/Streamer

Consumer

>90% of problems originate here

Core Network

Tablet

IPTV

8Maui 201108/01/11

How Fast is Copper?

• 10 Gbase-T is 2.5 Gbps/pair – at 100m on category 6 twisted pair

• 150Mbps – 500Mbps DSLs demonstrated– 100m on category 3 twisted pair

• 100Mbps to 1 Gbps DSLs?– Dynamic Spectrum Management (DSM)

9Maui 201108/01/11

DSM: Managing Copper is Key

Crosstalk

Core Network

DSLAM

Radio Interference

Copper Impairments

In-home InterferenceDSM Level 1: external noises vary with timeDSM Level 2: crosstalk among unvectored pairsDSM Level 3: crosstalk among vectored pairs

Results: - higher speeds - improved stability - longer loops - reduced costs

fiber

ASSIA

10Maui 201108/01/11

• Range-Planning Tool– Can use fiber to shorten copper (VDSL)

• 2:1 Asymmetry ratio (Down/Up) on speeds above 20 Mbps

DSL (with DSM) Rate Reach Steps

0 500 1000 1500 2000 2500 30000

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

DSL Deployment boundary (fiber > x)

Des

ired

Com

mer

cial

Dat

a R

ate

Length beyond which fiber is deployed

current DSL2011 Level 1&2 DSM2012/2013 Vector + Level 3 DSM2014/2015 2 pair bond + phantom

Mbps

11Maui 201108/01/11

DSM Level

First Availability

Speeds (Mbps)

Description

1 2007 < 25-50 Function: Single-line Data and Single-Line ControlGoal: Line Stability: reduce retrains and packet errorsStandard: ITU – G.997.1, G.992.1,5 (ADSL1, ADSL2+, VDSL2)

2 2010 <100 Function: Multiline Data Collect, Single-Line Control Goal: Power control and savingsStandard: ITU – G.997.1, G.992.1,5 (ADSL1, ADSL2+, VDSL2)

3 2013 100+ Function: Multiline Data and Control (VECTORED)Goal: Cancel Noises and Crosstalk (100+ Mbps)Standard: ITU, G.vector (G.993.5)

3 Standardized DSM Levels

12Maui 201108/01/11

Level 1 = Stabilization• Most networks see 30-60% reduction in unstable lines• Example from US DSL operators (30M on DSM)

– Call, dispatch rates closely correlated to DSL stability

– Level 1 DSM reduces unstable lines by 60%

13Maui 201108/01/11

Speed Increase - Europe

3%

47%

29%

19%

Dnstrm Rates Before TRA

14%

24%

21%

19%

11%

13%

Dnstrm Rates After TRA

Above 14.5Mbps

12~14Mbps

10~12Mbps

7~10Mbps

5.7~7Mbps

Below 5.7Mbps

40%

23%

16%

13%

8%

Stability Before TRA

61%

29%

3%1%5%

Stability After TRA

CV<=50 and Retrain<=0

CV<=250 and Retrain<=1

CV<=1000 and Retrain<=2CV<=5000 and Retrain<=3

Others

14Maui 201108/01/11

Rate and Loop Length Extension European Example

500 1000 1500 2000 2500 3000 3500 4000 4500 50000

10

20

30

40

50

60

70

80

90

100Before and After - Synch rate

Loop length (m)

Per

cent

age

of s

tabl

e lin

es

Before >=2Mbps

Before >=6Mbps

Before >=10MbpsAfter >=2Mbps

After >=6Mbps

After >=10Mbps

At 1500m, fraction of lines that can support 10 Mbps increases from 18% to 42% or a 133% increase

Distance at which 50% of the lines can support 2 Mbps increases from 2200m to 3200m or 45%


Distance at which 50% of the lines can support 6 Mbps increased to 2500m. Previously, no distance existed for 50% coverage at 6 Mbps


15Maui 201108/01/11

South America

# Calls Before # Calls After0

1000

2000

3000

4000

5000

6000

7000

8000

Unstable Lines - calls

# Dispatches Before # Dispatches After0

200400600800

100012001400160018002000

Unstable Lines - Dispatches

55% Reduction

16Maui 201108/01/11

South America


500

1000

1500

2000

2500

3000

3500

Network - Calls

21% Reduction


1000

2000

3000

4000

5000

6000

7000

8000

Unstable Lines - calls

36% Reduction


100

200

300

400

500

600

Network - Dispatches

25% Reduction


200400600800

100012001400160018002000

Unstable Lines - Dispatches

55% Reduction

17Maui 201108/01/11

Chinese Results (customers)• Success rate calculated on 24 hour period

1.5

2

2.5

3

3.5

2.982.992.892.872.92.93

3.013.052.993.01

2.892.882.892.942.892.92.992.972.952.922.97

2.912.992.95

2.792.752.822.792.74

2.81

2.34

2.092.12.032.06

2.122.01

1.921.891.940000000000011.911.91.921.960000000000012.012.062.12.031.990000000000012.012.052.12.1

1.970000000000011.85

1.911.960000000000011.950000000000011.990000000000012.012.02

2.923.01

2.92.822.842.81

2.972.952.922.942.892.842.872.882.882.81

2.913.023.03

2.892.952.94

3.113

2.892.92.942.953.022.982.98

2.923.043.013.053.01

3.072.96

3.043.042.982.972.992.982.952.972.95

3.013.013.043.023.032.94

3.082.993 3 3.043.053.012.98

Daily % of Unsuccessful Lines

PO Group: Unsuccess Rate Control Group: Unsuccess Rate

Initial optimization period

Maintenance optimizations

reprofiling normally done daily to avoid variability

18Maui 201108/01/11

DSM Level

First Availability

Speeds (Mbps)

Description

1 2007 < 25-50 Function: Single-line Data and Single-Line ControlGoal: Line Stability: reduce retrains and packet errorsStandard: ITU – G.997.1, G.992.1,5 (ADSL1, ADSL2+, VDSL2)


3 2013 100+ Function: Multiline Data and Control (VECTORED)Goal: Cancel Noises and Crosstalk (100+ Mbps)Standard: ITU, G.vector (VDSL3)

DSM Levels

19Maui 201108/01/11

DSM Achievable Rate Regions

• DSM can use the region – any point– But spectra for different points may differ– Static SM leads to smaller region (really a point)

Rlong

Rshort

Spectral pair 1

Spectral pair 2

“static spectrum management”

20Maui 201108/01/11

Upstream VDSL2 Configuration

• Upstream VDSL has large crosstalk issue– More coupling at higher frequencies used

21Maui 201108/01/11

Rate Regions for Level 1 and 2

0 10 20 30 40 50 60 70 801.5

2

2.5

3

3.5

4

4.5

5

5.5

6

Avg rate of users in vectored group (Mbps)

Data

rate

of n

on-v

ecto

red

long

line

(Mbp

s)

Robustness DSM for the mixed binder scenarioPSDMASK imposition with 6dB tolerance

PSDMASK imposition with 12dB tolerance

PSDMASK imposition with 18dB tolerance

PSDMASK imposition with 24dB toleranceIterative Water-filling

• Level 2 often doubles data rates of both long and short lines

22Maui 201108/01/11

USA and UK DSM Standards/Reports on L2

• Both Recommend Tiered Rate Adaption (TRA)

• Both reviewed and recommend AGAINST use of Virtual Noise

• This curve is Figure 7 from UK NICC (Ofcom) standards group’s UK DSM Report– US conclusions similar

By analogy – Wireless systems equivalent would be “pretend other users always on,” which would lead to significant loss in number of users served.

23Maui 201108/01/11

DSM Level

First Availability

Speeds (Mbps)

Description

1 2007 <25-50 Function: Single-line Data and Single-Line ControlGoal: Line Stability: reduce retrains and packet errorsStandard: ITU – G.997.1, G.992.1,5 (ADSL1, ADSL2+, VDSL2)


3 2013 100+ Function: Multiline Data and Control (VECTORED)Goal: Cancel Noises and Crosstalk (100+ Mbps)Standard: ITU, G.vector (VDSL3)

DSM Levels

24Maui 201108/01/11

Vectored DSLs

• Like “MIMO” in wireless• Proposed, patented, Stanford 2001• ITU G.993.5 standard (2009)

– A component of DSM Level 3

CPE 1

CPE 2

0

Old DSLAMPort 1

Old DSLAMPort 2

crosstalk

“wireless”

Customer 1

Customer 2

VectoredDSLAM

25Maui 201108/01/11

17a 998 Downstream - worst case data rate - 50 users

0

25

50

75

100

125

150

175

200

225

250

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

Loop Length (Meters)

Do

wn

str

ea

m D

ata

Ra

te (

Mb

ps)

non-bonded 47 cancel min Bonded 47 cancel min Non-bonded 0 cancel min

Vectored VDSL FTTN (Downstream)

Vectoring - 1 pair

Bonding+Vectoring

Single-pair,No vectoring

• 100-pair Telco cable, 4x25-pair binders (NIPP-NAI model)• Does not include Telco cross-box, so gains may be larger!

EuropeResidential

North AmericaResidential

26Maui 201108/01/11

But is that all? (NO)

• Crosstalk removal “exposes” other noises– Back to stability (DSM Level 1)– Instability in USA field teststo 75-85% of vectored

lines become unstable• Up from 15-20% today

Noise A

NoiseB

Noise CNoisefloor

Vectoring does not cancel A,B,Cbecause they are not at transmitAntenna location (only at receiver)

Crosstalk noise

27Maui 201108/01/11

Downstream VDSL Mixture

• Vectoring cancels only FEXT among the N2 lines

28Maui 201108/01/11

Mixed Binder Rate Region

0 10 20 30 40 50 60 70 807

8

9

10

11

12

13

14

15A

vera

ge

ra

te o

f No

n-V

ect

ore

d li

ne

s (i

n M

bp

s)

Average rate of Vectored lines(in Mbps)

Static-band MLWFIWFDynamic-band MLWFZero-CrosstalkUPBO

29Maui 201108/01/11

Bonded and vectored DSLs• Use 2 lines at receiver

– Roughly doubles the data rate for bonding– But allows one of noise A, B, or C to be removed so even more than 2x,

• But which to remove? (DSM)

Multi-line

CPE 1

0

crosstalk

“wireless”

Customer 1

Customer1

VectoredDSLAM

rcvr

-

rcvr

-

Noises A, B, and C

30Maui 201108/01/11

G(iga)DSL?(use of phantoms, 4GBB)

• Recognizes that vectoring enables the use of “phantoms” or split pairs– Can eliminate crosstalk (vectoring) and up to 6 other noise sources simultaneously

• Invented by ASSIA Inc (2003)– Patents already issued– World Telecommunications Conference (WTC/ISSLS), Edinburgh 2004

76

54

32

10

31Maui 201108/01/11

4-Pairs? (Gigabit @ 500m)

0 100 200 300 400 500 600 700 800 900 10000.5

1

1.5

2

Cable Length in meters

Dat

a R

ate

in Gbps

Symmetric Data Rate vs Cable Length for 4 twisted pairs as a MIMO Channel 35 MHz band plan, 21 dBm aggregate power (US and DS combined), -150 to -140 dBm/Hz linear noise increase, Coding gain 6 dB

Bit cap = 20

32Maui 201108/01/11

Copper PON? (Cu-PON or PCN)

• Homes have “party” lines (same as passive split in PONs)– Requires dispatch to “pedestal” or “drop” point– Up to 4 pairs in “higher-revenue neighborhoods” – sometimes called “G.fast”

• 1 Gbps shared over 2-4 customers– Can use same “dynamic bandwidth assignment” as GPON or

EPON– Higher data rate per user by 10x

200 pair, 200 customers (so no extra copper at LT)

LT

VDSL3

LTVDSL3

33Maui 201108/01/11

• Range-Planning Tool– Error (+/- 15%)

• 2:1 Asymmetry ratio (Down/Up) on speeds above 20 Mbps

DSL (with DSM) Rate Reach Steps

0 500 1000 1500 2000 2500 30000

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

DSL Deployment boundary (fiber > x)

Des

ired

Com

mer

cial

Dat

a R

ate

Length beyond which fiber is deployed

current DSL2011 Level 1&2 DSM2012/2013 Vector + Level 3 DSM2014/2015 2 pair bond + phantom

Mbps

34Maui 201108/01/11

The Broadband Path Forward• Leverages reasonable cost-effective steps with

existing copper– Each step increasing available bandwidth in timely fashion– Requires very high-speed and accurate management

• Most of which is not in the equipment

• Allows broadband investment to match customer demand as it increases

• Increases for IPTV or video to more customers• Increases for wireless smaller-cell or network offload• Timely manner – no step requires large infrastructure rebuilding

Level 1X € value Level 2

3X valueLevel 210X value

1 Maui 2011 08/01/11 Dynamic Spectrum Management A path to ubiquitous 100+ Mbps DSL Service ICCCN 2011 August 1, 2011 Maui, Hawaii John M. Cioffi Chairman.

Documents

chen slide

femto slide

mbps dsls

mbps access desirable

time dsm level

core network tablet

mbps dsl service icccn

unvectored pairs dsm