1 maui 2011 08/01/11 dynamic spectrum management a path to ubiquitous 100+ mbps dsl service icccn...
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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%
At 3000m, fraction of lines that can support 2 Mbps increases from 33% to 52% or a 58% increase
Distance at which 50% of the lines can support 6 Mbps increased to 2500m. Previously, no distance existed for 50% coverage at 6 Mbps
At 2500m, fraction of lines that can support 6 Mbps increases from 25% to 52% or a 108% increase
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
# Calls Before # Calls After0
500
1000
1500
2000
2500
3000
3500
Network - Calls
21% Reduction
# Calls Before # Calls After0
1000
2000
3000
4000
5000
6000
7000
8000
Unstable Lines - calls
36% Reduction
# Dispatches Before # Dispatches After0
100
200
300
400
500
600
Network - Dispatches
25% Reduction
# Dispatches Before # Dispatches After0
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)
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 (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)
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 (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