Transcript 30209072 (023t23) ETSI Presentation 8-29-02A.ppt

Network Access Transmission Model
for Evaluating xDSL Modem Performance
Jack Douglass, Paradyne International
Chair TIA TR30.3
Sept 9 - 13, 2002, ETSI TM6 TD23
TR30.3 302090067
023t23
[email protected]
Presentation Overview
•
•
•
•
•
Purpose of Presentation to
Value of xDSL Network Model
Network Model Template
Access Network Simulator
Proposal for Creating European Network
Model
Purpose of Presentation
• Skeleton Network Model to form the basis
of Permanent Document TM6(02)07
(m02p07)
– European Network Access Model(s) for xDSL
Performance testing.
Value of xDSL Network Model
Value to Operating Companies and
Service Providers
• Predict candidate product performance on their networks
as Percentage of the network where satisfactory operation
will be obtained
• Determine the potential market coverage as a function of
different parameters/factors such as: Quality of Service,
line rate, data throughput, connect time, stability,
technology, modulation technique and modem
enhancements
• Select optimum technology for a proposed service based
its Network Model Coverage Performance
• Develop Business Cases and establish Tariff objectives
• Minimize costs associated with loop qualification, loop
modifications and truck rolls
Value to Manufactures and Design Engineers
• Helps find design weaknesses
• Facilitates isolating and resolving field
problems
• Assists in evaluating different technologies
• Predicts real access network performance
Comparison Testing
• Model can be used by test houses, magazines
and product reviewers to compare the
performance of different brands of xDSL
modems or systems
– Test results are intended to reflect the customer
experience
Network Model Template
Example General European
Access Network Model
• Cable lengths and types are intended as a basis for discussion.
• Intermediate noise injection (Remote DSLAM) point may not be
necessary.
Exchange
0.5 mm
150 m
Telephone
Exchange
Street
Cabinet
MDF
Drop Wire
0.5 mm PE
50 m
Local
Distribution
Point
DSLAM
Branch Cable
25-pair binder
0.5 mm PE
0.25, 0.5, 0.63, 1.0 km
Distribution Cable
25(?)-pair binder
0.4, 0.5, 0.63 mm
2 to 7 km
Exchange
Noise
Injection
Intermediate
Noise
Injection
CPE
Noise
Injection
Cumulative Distribution for Crosstalk Models
• Cumulative Distribution Values
– Basis for the crosstalk mix used in Crosstalk Impairment
Combination Tables
• Residential/Multiunit Model
– asymmetrical weighting
• Business Model
– symmetrical weighting
• Projected for the year 200x
– Current xDSL deployment statistics
– Projected xDSL deployment
• Assumes 25 (?) -pair binders with yy% vacant pairs
– Churn/disconnect — cross-connected at street cabinet to reserve
loop assignment for the next tenant
– Defective pairs
– Reserved for future growth
Residential/Multiunit Cumulative Distribution
(CD) Number of Disturbers of Each Type
CD
Associat
ed
Severity
50%
D
70%
C
85%
B
95%
A
ISDN
BA
2B1Q
ISDN
BA
4B3T
2 Mbit/s HDSL
HDSL
HDSL
HDSL
HDB3
2B1Q
2B1Q
2B1Q
CAP
(2-pair) 392 ks/s 584 ks/s 1160
2320
(3-pair) (2-pair) ks/s (1 kbit/s
pair)
( 1 pair)
ADSL
over
POTS
FDD
ADSL
over
POTS
EC
ADSL
over
ISDN
FDD
ADSL
over
ISDN
EC
ADSL
lite
SDSL
784
kbit/s
SDSL
1505
kbit/s
SDSL
2056
kbit/s
Business Cumulative Distribution (CD)
Number of Disturbers of Each Type
CD
Associat
ed
Severity
50%
D
70%
C
85%
B
95%
A
ISDN
BA
2B1Q
ISDN
BA
4B3T
2 Mbit/s HDSL
HDSL
HDSL
HDSL
HDB3
2B1Q
2B1Q
2B1Q
CAP
(2-pair) 392 ks/s 584 ks/s 1160
2320
(3-pair) (2-pair) ks/s (1 kbit/s
pair)
( 1 pair)
ADSL
over
POTS
FDD
ADSL
over
POTS
EC
ADSL
over
ISDN
FDD
ADSL
over
ISDN
EC
ADSL
lite
SDSL
784
kbit/s
SDSL
1505
kbit/s
SDSL
2056
kbit/s
Crosstalk Impairment Combinations
•
Crosstalk Impairment Combinations (IC) are specified for each Loop
– Residential/Multiunit model
– Business model
– A, B, C and D Crosstalk severity levels
• A — Most severe
• D — Least severe
– LOOs — A = 5%, B =15%, C = 30% and D = 50% (Total = 100%)
•
FEXT may be handled differently in mathematical analysis and hardware
simulation
– Hardware simulator
• NEXT is inserted at both ends so that tests can be run in both directions simultaneously
• Insertion of NEXT at one end of the loop produces an approximation of FEXT at the other
end
– Mathematical analysis
• FEXT should be included at both ends
•
•
•
Assumes Worst-case crosstalk coupling
Disturber Model may vary between Exchange and CPE end
CPE Crosstalk is xx% co-located and yy% distributed
– Distributed crosstalk may be do to operating range of some system is less than the
loop can accommodate
– Crosstalk may be distributed as a result of distributing services to other customer
along the way.
Crosstalk Impairment Combinations (IC)
Loop XX (LOO/Length) – Residential/Multiunit
Impairment Severity
Impairment LOO
NEXT
Exchange Injection Point
Exchange Wiring (150 m)
Self-NEXT
MDF
ISDN BA 2B1Q
ISDN BA 4B3T
2 Mbit/s HDB3 (2-pair)
HDSL 2B1Q 392 ks/s (3-pair)
HDSL 2B1Q 584 ks/s (2-pair)
HDSL 2B1Q 1160 ks/s (1-pair)
HDSL CAP 2320 kbit/s (1-pair)
ADSL over POTS FDD
ADSL over POTS EC
ADSL over ISDN FDD
ADSL over ISDN EC
ADSL lite
SDSL 784 kbit/s
SDSL 1505 kbit/s
SDSL 2056 kbit/s
CPE Injection Point
ISDN BA 2B1Q
ISDN BA 4B3T
2 Mbit/s HDB3 (2-pair)
HDSL 2B1Q 392 ks/s (3-pair)
HDSL 2B1Q 584 ks/s (2-pair)
HDSL 2B1Q 1160 ks/s (1-pair)
HDSL CAP 2320 kbit/s (1-pair)
ADSL over POTS FDD
ADSL over POTS EC
ADSL over ISDN FDD
ADSL over ISDN EC
ADSL lite
SDSL 784 kbit/s
SDSL 1505 kbit/s
SDSL 2056 kbit/s
A
5%
B
C
15%
30%
Number of Interferers
D
50%
Crosstalk Impairment Combinations (IC)
Loop XX (LOO/Length) – Business
Impairment Severity
Impairment LOO
NEXT
Exchange Injection Point
Exchange Wiring (150 m)
Self-NEXT
MDF
ISDN BA 2B1Q
ISDN BA 4B3T
2 Mbit/s HDB3 (2-pair)
HDSL 2B1Q 392 ks/s (3-pair)
HDSL 2B1Q 584 ks/s (2-pair)
HDSL 2B1Q 1160 ks/s (1-pair)
HDSL CAP 2320 kbit/s (1-pair)
ADSL over POTS FDD
ADSL over POTS EC
ADSL over ISDN FDD
ADSL over ISDN EC
ADSL lite
SDSL 784 kbit/s
SDSL 1505 kbit/s
SDSL 2056 kbit/s
CPE Injection Point
ISDN BA 2B1Q
ISDN BA 4B3T
2 Mbit/s HDB3 (2-pair)
HDSL 2B1Q 392 ks/s (3-pair)
HDSL 2B1Q 584 ks/s (2-pair)
HDSL 2B1Q 1160 ks/s (1-pair)
HDSL CAP 2320 kbit/s (1-pair)
ADSL over POTS FDD
ADSL over POTS EC
ADSL over ISDN FDD
ADSL over ISDN EC
ADSL lite
SDSL 784 kbit/s
SDSL 1505 kbit/s
SDSL 2056 kbit/s
A
5%
B
C
15%
30%
Number of Interferers
D
50%
Specified Steady-State Impairments
• Specified Steady-State Impairment Combinations Severity
levels 0 - 3
–
–
–
–
Primarily ingress noise
Severity 0 is a baseline null case
Severities 1 through 3 have increasing levels of ingress noise
Do not have an associated LOO
Impairment
Severity
0
Exchange Injection
Point
Splitter amplitude distortion
Splitter delay distortion
Background noise
Balance
AC power interference
CPE Injection Point
Splitter amplitude distortion
Splitter delay distortion
Background noise
Balance
AM radio interference
AC power interference
1
Notes
2
3
AM Radio Interference
• Severity level 1, 2, and 3
Signal Type
Centre
Frequency
(kHz)
Common
mode level
Differential
mode level
Specified Transient Impairments
• Not part of the NMC calculation
– Important part of the Access Network
Transmission Model
– Must be accounted for in testing
Impairment
Severity
0
POTS ringing signal
POTS call progress tones
POTS hook transients
POTS ring trip
Impulse noise
Microinterruptions
Voiceband coupling to DSL
band
I
Notes
II
III
Example General Loop Diagram
MDF Wiring
0.5 mm
100 m
DSLAM
Distribution Cable
xx-pair binder
0.4, 0.5, 0.6 mm
2 to 7 km
Branch Cable
25-pair binder
0.5 mm PE
0.25, 0.5, 1.0 km
Drop Wire
0.5 mm PE
50 m
CPE
Test Loop Make-up and LOOs
Loop
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Exchange
Wiring
(0.5 mm)
Length (m)
Distribution Cable
Length
(0.4 mm)
Length
(0.5
mm)
Length
(0.63
mm)
Loop
Branch Cable
Length
(0.5
mm)
Length
(0.63
mm)
Total
Loop
Length
(km)
DC
Resista
nce
(ohms)
Loop
Loss @
100 kHz
(dB)
Loop
Loss @
300 kHz
(dB)
Drop Wire
Gauge
(mm)
PE
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
6.75
7.00
*Loop Loss values @ 100 kHz and @ 300 kHz are approximate and assume same cable type is used for entire length
Length
(m) PE
LOO
%
Example Test Loop Make-up and LOOs
Loop
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Exchange
Wiring
(0.5 mm)
Length (m)
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
150
Loop
Branch Cable
Distribution Cable
Length
(0.4 mm)
1.75
1.75
2.25
2.65
2.50
2.25
3.25
3.25
3.00
4.00
3.75
3.75
3.00
3.25
3.50
2.25
1.75
2.00
1.00
1.50
2.00
Length
(0.5
mm)
0.25
0.00
1.75
1.50
1.00
3.25
3.75
3.25
4.25
3.75
3.00
Length
(0.63
mm)
Length
(0.5
mm)
1.00
1.00
1.00
0.25
0.50
0.25
0.10
0.50
1.00
0.25
0.50
1.00
0.25
0.50
1.00
0.25
0.50
1.00
0.25
0.50
1.00
0.25
0.50
1.00
Length
(0.63
mm)
Total
Loop
Length
(km)
DC
Resista
nce
(ohms)
Loop
Loss @
100 kHz
(dB)
Loop
Loss @
300 kHz
(dB)
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
6.75
7.00
560
630
700
770
840
910
980
1050
1120
1190
1095
1050
1153
1179
1159
1212
1161
1142
1154
1204
1210
21.06
22.90
26.56
29.85
31.14
32.07
37.54
39.38
40.31
45.78
46.71
48.55
47.65
50.40
53.14
50.43
50.44
53.19
49.16
52.82
56.48
27.60
30.27
34.72
38.81
40.95
42.74
48.96
51.63
53.42
59.64
61.43
64.10
64.11
67.67
71.23
69.46
70.35
73.91
70.83
75.28
79.73
Drop Wire
Gauge
(mm)
PE
Length
(m) PE
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
*Loop Loss values @ 100 kHz and @ 300 kHz are approximate and assume same cable type is used for entire length
LOO
%
Premises Wiring Models
• Based on G.996.1, section 6.2.2
• Single Family and Small Office Premises Models
– Daisy Chain Wiring
– Star Wiring
– Star Wiring with Central ADSL Splitter and Direct Line
• Multi-Unit/Business Wiring
–
–
–
–
Multi-Tenant Residence / Business -- Daisy Chain Wiring
Multi-Tenant Residence / Business -- Star Wiring
Small Office Wiring
Large Office Wiring
Example Customer Premises Models
Based on G.996.1, section 6.2.2
Daisy Chain Wiring Model
Network Model Coverage Tables
• Tables for Network Model Coverages (NMC) of
100%, 95%, 90% and 65% are typically provided
– Used for both Residential/Multiunit and Business
Models
• Test Channel Score
– intersection of the IC and test loop
– Score is Product of Loop LOO and IC LOO
• < 100% NMC Tables
– Remove Loop/IC combinations with lower percentage
Scores
– Run on Test Channels that have Scores
– Reduces the test time with slightly reduced resolution
Network Model Coverage Tables
Network Model Coverage = 100%
IC
Severity
D
C
B
A
Loop No.
LOO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
50%
30%
15%
5%
Network Model Coverage = 95%
IC
Severity
D
C
B
A
Loop No.
LOO
1
2
3
4
5
6
50%
30%
15%
5%
Network Model Coverage = 90%
IC
Severity
D
C
B
A
Loop No.
LOO
1
2
3
4
5
6
50%
30%
15%
5%
Network Model Coverage = 65%
IC
Severity
D
C
B
A
Loop No.
LOO
50%
30%
15%
5%
1
2
3
4
5
6
Example Network Model Coverage Tables
• Examples NMC=100% and NMC=90% Tables are
provided to illustrate how to construct and use NMC
Tables
• Arbitrary values have been assigned to the loop LOO, so
that the example test channel scores can be calculated
• A Test Channel Score is calculated by taking the product of
the loop LOO and the IC LOO
• All Test Channels are included in an 100% NMC Table
• Lower percentage scores have been removed from 90%
NMC Table (actual total score is 90.05)
• Actual NMC Table can be constructed once the Loop
LOOs have been assigned based on loop network statistics
Example Network Model Coverage = 100%
IC
Severity
D
C
B
A
Loop No.
LOO
1
5%
2
8%
3
9%
4
10%
5
8%
6
7%
7
6%
8
6%
9
6%
10
5%
11
5%
12
4%
13
4%
14
3%
15
3%
16
3%
17
2%
18
2%
19
2%
20
1%
21
1%
50%
30%
15%
5%
2.50%
1.50%
0.75%
0.25%
4.00%
2.40%
1.20%
0.40%
4.50%
2.70%
1.35%
0.45%
5.00%
3.00%
1.50%
0.50%
4.00%
2.40%
1.20%
0.40%
3.50%
2.10%
1.05%
0.35%
3.00%
1.80%
0.90%
0.30%
3.00%
1.80%
0.90%
0.30%
3.00%
1.80%
0.90%
0.30%
2.50%
1.50%
0.75%
0.25%
2.50%
1.50%
0.75%
0.25%
2.00%
1.20%
0.60%
0.20%
2.00%
1.20%
0.60%
0.20%
1.50%
0.90%
0.45%
0.15%
1.50%
0.90%
0.45%
0.15%
1.50%
0.90%
0.45%
0.15%
1.00%
0.60%
0.30%
0.10%
1.00%
0.60%
0.30%
0.10%
1.00%
0.60%
0.30%
0.10%
0.50%
0.30%
0.15%
0.05%
0.50%
0.30%
0.15%
0.05%
Example Network Model Coverage = 90%
IC
Severity
D
C
B
A
Loop No.
LOO
1
5%
2
8%
3
9%
4
10%
5
8%
6
7%
7
6%
8
6%
9
6%
10
5%
11
5%
12
4%
13
4%
14
3%
15
3%
16
3%
17
2%
18
2%
19
2%
20
1%
21
1%
50%
30%
15%
5%
2.50%
1.50%
0.75%
4.00%
2.40%
1.20%
4.50%
2.70%
1.35%
5.00%
3.00%
1.50%
4.00%
2.40%
1.20%
3.50%
2.10%
1.05%
3.00%
1.80%
0.90%
3.00%
1.80%
0.90%
3.00%
1.80%
0.90%
2.50%
1.50%
0.75%
2.50%
1.50%
0.75%
2.00%
1.20%
2.00%
1.20%
1.50%
0.90%
1.50%
0.90%
1.50%
0.90%
1.00%
0.60%
1.00%
0.60%
1.00%
0.50%
0.50%
Test Procedure and Network Model Coverage
(NMC) Curves
•
•
•
•
•
•
Run each test channel (that has an associated score), in the NMC
Table along with Specified Steady-State Impairment Severity 0 (null
case) and one of the Premises Wiring Models. Note: The number of
tests can be reduced by using a lower percentage NMC Table.
Measure desired parameter(s) (e.g., connect rate, throughput,
connect time, etc.).
Repeat each test channel with Specified Steady-State Impairment
Severities 1 through 3. Tests may also be repeated with different
Premises Wiring Models and/or Specified Transient Impairments.
Sort measured parameter(s) along with associated NMC Scores in a
descending order using a spreadsheet or similar mechanism.
Plot the measured parameter(s) on the Y axis and the associated
NMC Score on the X axis.
The resulting curve shows the performance (in terms of the
measured parameter) as a percentage of the Network Model.
Family of 65% NMC Curves for Steady-State
Impairments Severity 0 to 3
Throughput vs Network Model Coverage Percentage for 62% Residential Model with Premises
Wiring Model – P1
8000
7000
Connect Rate (k/b/s)
6000
5000
Severity 3
Severity 2
Severity 1
Severity 0
4000
3000
2000
1000
0
0.00%
10.00%
20.00%
30.00%
40.00%
% of Network
50.00%
60.00%
70.00%
Access Network Simulator
Network Model Simulator Implementation
• Network Model Simulators
– Mathematical Simulator
– Hardware Simulator
• Ideal Network Model Simulator
– Separate Loop sections
– Separate Noise sources
• Practical and Cost-Effective Simulator
– Single loop simulator
•
•
•
•
Exchange wiring
Distributed Cable
Branch Cable
Drop wire
– Composite Exchange Interferers and the Composite CPE Interferers
•
•
•
•
FSAN mixed crosstalk combination method
Account for associated loop sections
Account for noise injection points.
Typically use Arbitrary Waveform Generator (AWG).
– Premises wiring simulator
– Device(s) Under Test (DUT).
Ideal Network Model Simulator
Exchange
xx mm
yy m
DSLAM
DUT
*Exchange
injection Point
Drop Wire
Zz mm
PE
ww m
MDF
Street
Cabinet
*MDF
Injection Point
*Intermediate
Injection Point
Local
Distribution Point
*Inject noise at designated point as specified in Tables 5, 6, 7 and 10
Network
Interface
*CPE
Injection Point
CPE
DUT
Practical and Cost-Effective
Network Model Simulator
PSDX Exchange (f)
Exchange Composite Interferer*
AWG
DSLAM
DUT
PSDX CPE (f)
CPE Composite Interferer*
Loop Simulator
AWG
Premises
Wiring
*Crosstalk simulation is a composite of different interferers from different injection points and includes the
effects of loops
CPE
DUT
Typical Test Setup
xDSL Simulator and Modems
Telephone Network Simulator
(Line Current/Dial Tone) – ADSL only
xDSL
CPE Modems (ATU-R)
xDSL
DSLAM s
(ATU-C)
Loop Simulator
Premises
Wiring
Simulator
AWG
AWG
Screen of Arbitrary Waveform Generator (AWG)
showing Crosstalk Impairment on CO Side
Uses Loop and Crosstalk transfer functions to
accurately simulate impairment combinations
Screen of Arbitrary Waveform Generator(AWG)
showing Crosstalk and RFI Impairment on CPE Side
Uses Loop and Crosstalk transfer functions to
accurately simulate impairment combinations
Proposal
for Creating European xDSL Network Model
Obstacles
• Country to country variations of
loop/crosstalk/noise statistics and
characteristics
• Lack of publicly available information
regarding loop/crosstalk statistics
• Unbundling Competition
• Regulations
Proposed Procedure
•
•
Create straw-man Network Model(s) using sample template and
experience
Gather anonymous statistical information on European Access
Network where ever possible
– Loop (configuration, binder size, type of cable, gauge, etc.)
– Crosstalk data (numbers and types of interferers currently installed and
marketing deployment information)
– Steady-State Impairments (e.g., Ingress impairments, AM Radio, etc.)
– Transient Impairments
•
•
•
Revise straw-man Network Model(s) based on statistical information
Validate model using real xDSL equipment of different technologies
Compare validation results with known real world performance