ETSI TR 102 530 V1.2.1 (2011-07)

Technical Report
Environmental Engineering (EE);
The reduction of energy consumption
in telecommunications equipment and
related infrastructure
2 ETSI TR 102 530 V1.2.1 (2011-07)

Reference
RTR/EE-00019
Keywords
control, environment, power, power supply
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ETSI
3 ETSI TR 102 530 V1.2.1 (2011-07)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Symbols . 7
3.3 Abbreviations . 8
4 Company Environmental Procedures . 8
4.1 Guidance on Company Environmental Procedures . 8
5 Telecom System Power and Energy Efficiency . 9
5.1 Introduction . 9
5.2 Power consumption of telecom systems - ICT view . 9
5.3 Reference models . 10
5.3.1 Reference model content . 10
5.3.2 Reference Model Network . 11
5.3.3 Node Site Reference Model . 11
5.4 Operating conditions . 13
5.4.1 Traffic pattern . 13
5.4.2 Operational modes and power management . 13
5.4.3 Traffic models and operational modes . 13
5.4.4 Reach/coverage/rate impact . 14
5.4.5 Climate impact and models . 15
5.5 Power efficiency . 16
5.5.1 Useful output . 16
5.5.2 Power consumption dependencies . 16
5.5.3 Proposed Energy Efficiency definition for fixed BB equipment . 16
5.5.4 Examples . 16
5.5.4.1 Power consumption values used . 16
5.5.4.2 NPC for DSLAM, ADSL2+ Tier 1 and VDSL2 Tier 2 DC consumption . 16
5.5.4.3 AC Site energy consumption and cost for DSLAM and Modem ADSL 2+ Tier 1 and VDSL2
Tier 2 . 17
5.5.5 Way forward, using power/energy efficiency view . 19
6 Energy saving methods for telecom infrastructure equipment . 19
6.1 Infrastructure equipment introduction . 20
6.2 Cooling systems . 20
6.2.1 Use of fresh air cooling . 20
6.2.2 Use of water cooling . 21
6.2.3 Fans . 21
6.2.4 Room temperature set-points . 21
6.2.5 Thermal management . 21
6.3 Power system . 22
6.3.1 Power architecture . 22
6.3.2 -48 V DC power distribution . 22
6.3.3 AC/DC power systems. 22
6.3.4 DC/AC power supply systems (inverters) . 23
6.3.5 Diesel generator (Diesel GenSet) . 24
6.3.6 AC distributions . 24
6.3.7 UPS . 25
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4 ETSI TR 102 530 V1.2.1 (2011-07)
6.3.8 Architecture comparison . 26
6.3.9 Battery . 27
6.3.10 Batteries in outdoor enclosure . 28
6.3.11 Battery and Genset in alternating operation . 28
6.4 DC generators . 29
6.4.1 PV systems as energy saving system . 29
6.5 Energy aware design . 29
6.6 Energy efficiency benchmark . 29
6.7 Software or firmware techniques to reduce energy . 29
6.8 Energy management unit . 30
6.9 Increase efficiency of components . 30
6.10 Metering and Sub-metering . 30
6.10.1 Type of meter . 30
6.10.2 Deployment. 31
6.10.3 Energy Data Management . 32
6.10.4 Other metering aspects related to energy management . 32
6.11 Subrack fans . 33
Annex A: Use of reference models . 34
A.1 Central office node site, AC and DC consumption . 34
Annex B: DSL simulation results . 35
Annex C: DSLAM power consumption and performance . 36
Annex D: Efficiency calculation of different power architecture . 37
Annex E: Bibliography . 39
History . 40

ETSI
5 ETSI TR 102 530 V1.2.1 (2011-07)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Environmental Engineering (EE).
Introduction
Recent Life Cycle Assessment (LCA) studies have revealed that the energy consumption of network telecom equipment
during operation is one of themost significant environmental impact factor of the telecom business.
Raw material production, manufacturing, distribution and disposal have also an energy impact which can be pointed out
in a complete the LCA Telecom operators should pay attention on several factors linked to energy consumption:
• the cost of the energy is significant and rising due to the cost of raw materials and government policies, which
will impact on the operating cost of telecom services. It is therefore in the interest of operators to reduce their
energy usage, distribution and unit cost;
• CO emission at each step of the life cycle;
• compliancy with current and anticipation with future regulation on energy saving and CO emission reduction.
The present document covers various methods of increasing the energy efficiency of telecom systems by
controlling/reducing the energy consumption in the telecommunication network equipment and related infrastructure.
The present document is in particular dedicated to the Broadband Access technology.
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6 ETSI TR 102 530 V1.2.1 (2011-07)
1 Scope
The present document is an accumulation of ideas on the methods to increase the energy efficiency of
telecommunication systems in order to reduce its operational energy use; the present document considers
telecommunication equipment and infrastructure equipment (power station, air cooling, control of equipment, etc.) in
telecommunication centres.
The energy efficiency of end-user equipment is not considered.
Focus is on the operational phase.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI EN 300 019 (all series): "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment".
[i.2] ETSI EN 300 132-2: "Environmental Engineering (EE); Power supply interface at the input to
telecommunications equipment; Part 2: Operated by direct current (dc)".
[i.3] ETSI EN 300 132-3: "Environmental Engineering (EE); Power supply interface at the input to
telecommunications equipment; Part 3: Operated by rectified current source, alternating current
source or direct current source up to 400 V".
[i.4] IEC 60896-21:2004: "Stationary lead-acid batteries; Part 21: Valve regulated types. Methods of
test".
[i.5] IEC 60950-22: "Information technology equipment Safety; Part 22: Equipment to be installed
outdoors".
[i.6] BS EN 50272-2: "Safety requirements for secondary batteries and battery installations -
Part 2: Stationary batteries".
[i.7] ETSI TS 102 533: "Environmental Engineering (EE) Measurement Methods and limits for Energy
Consumption in Broadband Telecommunication Networks Equipment".
[i.8] IEC 60950-1: "Radiation monitoring equipment for accident and post-accident conditions in
nuclear power plants. Part 1: General requirements".
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7 ETSI TR 102 530 V1.2.1 (2011-07)
[i.9] ETSI TR 102 532: "Environmental Engineering (EE) The use of alternative energy sources in
telecommunication installations".
[i.10] ETSI EN 300 132 (all parts): "Environmental Engineering (EE); Power supply interface at the
input to telecommunications equipment".
[i.11] ETSI TR 102 121: "Environmental Engineering (EE); Guidance for power distribution to
telecommunication and datacom equipment".
[i.12] ETSI ES 202 336 (all series): "Environmental Engineering (EE); Monitoring and Control Interface
for Infrastructure Equipment (Power, Cooling and Building Environment Systems used in
Telecommunication Networks)".
[i.13] ISO 14001:2004: "Environmental management systems - Specification with guidance for use".
[i.14] ISO/TR 14062:2002: "Environmental management -- Integrating environmental aspects into
product design and development".
[i.15] IEC Guide 114 (Ed 1.0, 2005-05): "Environmentally conscious design - Integrating environmental
aspects into design and development of electro technical products".
[i.16] ECMA-341 (2nd Edition, December 2004): "Environmental design considerations for electronic
products".
[i.17] Ericsson (internal report): "Data on Power consumption of telecom systems".
[i.18] "Estimating total power consumption by servers in the U.S. and the world", Jonathan G. Koomey,
Ph.D, Staff Scientist, Lawrence Berkeley National Laboratory and Consulting Professor, Stanford
University. Final Report, February 15 2007.
[i.19] EPA Report on Server and Data Center Energy Efficiency. On August 2, 2007 and in response to
Public Law 109-431.
NOTE 1: Available at: http://www.energystar.gov/ia/products/downloads/Public_Law109-431.pdf) the U.S. EPA
ENERGY STAR Program released to Congress a report assessing opportunities for energy efficiency
improvements for government and commercial computer servers and data centers in the United States.
NOTE 2: The present document is considered final and therefore, EPA is not taking any additional comments on
the report at this time.Energy consumption by consumer Electronics in U.S. Residences. Kur W. Roth &
Kurtis McKenney. TIAX LLC. TIAX Reference: D 5525.
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
infrastructure equipment: power, cooling and building environment systems used in telecommunications centres and
Access Networks locations
telecommunication centre: location where telecommunications equipment is installed and which is the sole
responsibility of the operator
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Ln Line
Po Power output
V Volts
W Watt
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8 ETSI TR 102 530 V1.2.1 (2011-07)
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3rdpp 3rd party products
AC Alternating Current
Aux Eq. Auxiliary Equipment
BB BroadBand
BBCoC BroadBand Code of Conduct
CDF Cumulative Distribution Function
COP Coefficient Of Performance
CPA Central Power Architecture
DC Direct Current
DPA Distribution Power Architecture
DS Mbps Down Stream Mbps
DSL Digital Subscriber Line
DSLAM Digital Subscriber Line Access Module
DSM Dynamic Spectrum Management
EC Electrically Commutated
EN European Norm
HW HardWare
IBA Inter media Bus Architecture
ICT Information and Communication Technology
ISDN Integrated Services Digital Network
ISO International Standards Organisation
LCA Life Cycle Assessment
MOD Mask On Demand
MODEM MOdulator and DEModulator
NPC Normalized Power Consumption
OEM Original Equipment Manufacturer
OSS Operational Support Systems (in text ‘Operational System Support’, you can change)
PA Power Amplifier
POTS Plain Old Telephony Service
SLA Service Level Agreement
SW SoftWare
TLC Telecommunication
Transm Transmission equipment
TRX Tansmitter-Receiver
UPS Uninterruptible Power Supply
US Mbps UpStream Mbps
VDSL Very high speed Digital Subscriber Line
VDSL2 Very high speed Digital Subscriber Line 2
VRLA Valve regulated lead acid
4 Company Environmental Procedures
4.1 Guidance on Company Environmental Procedures
A number of international standards and guides related to companies' environmental work have been prepared or are
under preparation. Some of these are given in clause 2.2 from [i.13] to [i.16].
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9 ETSI TR 102 530 V1.2.1 (2011-07)
5 Telecom System Power and Energy Efficiency
5.1 Introduction
Power consumption figures are comparable, if done on similar equipment, with similar conditions and measured at the
same interfaces. However, if we want to compare products with different technologies, with new features and higher bit
rates or improved distance coverage, we need to evolve our view from power consumption towards energy efficiency. If
we want to set requirements on new technology, we need to consider the demands for increased performance and
corresponding impact on power consumption. A measure of power or energy efficiency is needed.
In the following, a number of terms are proposed in order to properly define power consumption and energy efficiency.
The energy efficiency is understood as the relation between the Useful Output and the Energy or Power Consumption.
This efficiency measure could either be defined on power scale, or on energy scale as an integration of power
consumption over time.
In the following examples, for Broadband access equipment, Useful Output is defined as the peak performance of bit
rate and reach distance. Useful Output is compared with the long term Average Power Consumption of the equipment
or the site.
The power consumption is related to a number of conditions as:
• Configuration and involved equipment.
• Operational conditions.
• Measurement interfaces.
A set of definitions is needed. The following terms are proposed:
• Reference models.
• Operating conditions.
• Power efficiency.
• Useful unit.
NOTE: This covers operation phase only.
5.2 Power consumption of telecom systems - ICT view
Average power consumption of ICT and telecom systems is indicated in figure 1, for further information see [i.17] to
[i.19]. The Broadband Access part is used for further analysis.
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10 ETSI TR 102 530 V1.2.1 (2011-07)
Global ICT ”Watts” (mid 2005)
850 million PCs
IT "overhead" [/PC]
1 050 million “users” (30 million servers)
5 20
"The Net" [/PC]
Telecom "overhead". 1,2 ∼ 4 000 million users (all together)
1 ∼ 4 000 million users (all together)
...& Transport [/user]
0,8
70 million subscribers
WCDMA RAN [/sub.]
0,6 Manufacturing
1 700 million subscribers
GSM RAN [/sub.] 2
Operation
0,2
180 million lines
Broadband access [/line] 2,6
0,5
1 275 million lines
4,5
"Ordinary fixed" [/line]
0,4
1,1 ∼ 400 million
PBX [/line]
23 27 595 million desktop PCs
Desktop PC
255 million laptop PCs
13 10
Laptop PC
∼ 180 million
Home network 1 8
2 0,6 1 975 million
Mobile phone
1 3 ∼ 700 million
Cordless phone
0,2 ?
"Old analogue phone"
0 1020 3040 50 60
W
Figure 1: Average power consumption of ICT equipment, use phase and production
The CO equivalent of the complete manufacturing (production) chain, from mine through end of life treatment, is
estimated. The CO value is recalculated into electrical energy, using the global energy production mix index of 0,6 kg
CO /kWh. The energy is distributed over the life-time of the device, resulting in average power consumption of
manufacturing.
Life time assumptions used in the examples reported in the present document:
• Server: 4,25 years.
• DSLAM: 10 years.
• Radio Base Station: 10 years, mechanically, 5 years for the circuit boards.
• Radio Base Station Site: 20 years for Tower, Antenna and Shelter, 3,5 years for the batteries.
For more details, see [i.17], [i.18] and [i.19].
5.3 Reference models
A Reference model is needed to indicate what equipment is involved and what measurement interfaces are used.
Example: The reference model will make it clear whether power consumption is measured at DC or AC, what
functional units/configurations are included in the power measurement.
A number of reference models may be needed to cover different types of telecom equipment.
Reference model example proposals for DSLAM and Radio Base nodes are provided below.
5.3.1 Reference model content
The reference model is a block diagram that may include:
• Interfaces, internal and external.
• Climate shell(s).
ETSI
Terminals
Access Transport & Servers
11 ETSI TR 102 530 V1.2.1 (2011-07)
• Level functional parts like nodes - for a model network, or functional units like climate equipment, rectifiers,
modems, etc., for a node site model.
5.3.2 Reference Model Network
Network model
Use-
AC
Node A
ful
In-
. .
Out-
put
put
~
Node B # N
�
Node B # 1
Figure 2: Reference Model Network
Basic reference model network is needed to calculate the overall efficiency of telecom networks and the impact of
different nodes in the Network.
It is important to include the nodes typically needed and to capture the typical proportions of the different node types in
order to estimate how the different nodes contribute to power consumption of a typical network.
5.3.3 Node Site Reference Model
It is important to compare equipment power consumption at similar conditions. Usually the power consumption at site
is relevant. A site model should be applied that includes climate equipment, rectifiers and other infrastructure
equipment, if typically needed on a site level.
Preferable the site power should be measured at the AC level. See annex A for explanation.
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12 ETSI TR 102 530 V1.2.1 (2011-07)
DSLAM Site Model
Internet
Enclosure
DC1 DC2
AC1 AC2
.
-48V .
Recti- DSLAM
.
.
.
fier
.
”A”
Split
.
-ter
.
AC
Climate
.
.
Input
Unit
.
Battery
.
{
Line
Input /
3pp/Aux Eq
Output
Signal
POTS/ISDN
Figure 3: DSLAM Node Site reference model
RBS Site Model
An-
Enclosure
tenna
Feeder
DC1 DC2 DC3
AC1 AC2 Cable
-48V
Recti-
fier
Radio
.
Base
.
Station
AC
.
Climate
Input
Battery
Unit
Out-
put
RF1
RF2
Signal
Transm/3PP/Aux Eq
Transport NW
Figure 4: RBS Node site reference model
Different reference points are available to support different aspects of energy optimisation. E.g. consideration of "RF2"
reference point may lead to support "Remote Radio Head" technology instead of using coaxial feeder cables.
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13 ETSI TR 102 530 V1.2.1 (2011-07)
5.4 Operating conditions
Power consumption depends on a number of operating conditions like:
• traffic pattern;
• operational mode;
• reach;
• climate (including temperature operating condition).
5.4.1 Traffic pattern
Traffic pattern and traffic intensity has an impact on energy consumption. The impact varies with the type of telecom
system. For POTS and cellular systems, traffic intensity has a substantial impact on power consumption. For fixed line
BB systems like DSL and VDSL, the traffic impact on consumption is negligible if low power modes are not activated,
but considerable if low power modes are activated. See examples in clause 5.4.4.
5.4.2 Operational modes and power management
Telecom equipment energy consumption varies with the power management . Power saving modes should be
implemented in telecom systems, like L2 and L3 modes in DSLAM equipment and corresponding or standby modes in
modem equipment. Corresponding examples on power saving techniques for GSM/UMTS radio equipment are Standby
power saving modes like TRX shutdown, HW/SW-triggered PA bias switching.
As the subscriber equipment is in active use only a fraction of the time, it is imperative for every standard to make
energy saving modes fully operable at low or no traffic periods. It is imperative to have a power management that
effectively will activate the different power saving modes minimizing the power consumption.
Traffic models indicating the typical traffic intensity and statistic behaviour over day and week are important tools to
calculate the power consumption as a result of the combination of traffic pattern and power management behaviour.
When defining the traffic models, the impact of subscription rate as well as impact from different services and use cases
should be considered. A common use case is a computer that is always on - even when not in active use. The computer
may send "keep alive" signals periodically. VoIP will be a future common use case, with a requirement for access "to
the line" in < 1 second. As the power saving effect of low power mode is also wanted, a solution would be to define a
low power mode that can transmit a low rate signal for control, "keep alive", equalizing and VoIP start up. 100 kbps is
proposed as relevant rate for such signalling.
The examples in clause 5.5 assume that complete traffic interruptions occur when not in active use and that energy
saving modes are controlled by inactivity period triggers. The different trigger criteria and the assumed active time per
mode and per day are shown in figures 5 and 6.
5.4.3 Traffic models and operational modes
When traffic models are defined and used in combination with assumed power management, the fraction of time that
different power modes are active can be calculated. Thus the power consumption and saving per day can be estimated.
In the following examples, a simple traffic pattern and mode management according to clause 5.4.2 is assumed. Traffic
models indicating the typical traffic intensity and statistical behaviour over a day and week are important tools for
calculation of power consumption. When defining those models, the subscription rate structure impact on traffic
patterns should be considered.
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14 ETSI TR 102 530 V1.2.1 (2011-07)
DSLAM
Operational Modes & user traffic models
L0 Today
< 5 min
L2
interrupt
L3
5 - 30 min
interrupt > 30 min interrupt
User type L0 L2 L3 time/Day
time/Day time/Day
Private DSL 1hr 1hr 22hr
Private 3-play & 6hr 2hr 16hr
SOHO
Average user 3,5hr 1,5hr 19hr
Figure 5: Example DSLAM operational modes L0-L3 and 24 hour traffic model
DSL - Modem
Operational Modes & user traffic models
ON Today
< 30 min
Std By
Transition interrupt
OFF
> 30 min interrupt
Manual
User type ON, Std By, OFF
time/Day time/Day
Private DSL 2hr 22hr 0hr
Private 3-play 8hr 16hr 0hr
& SOHO
Average user 5hr 19hr 0hr
Figure 6: Example DSL Modem operational modes and 24 hour traffic model
averaged on 1 year period
5.4.4 Reach/coverage/rate impact
Modern Broadband Radio and wire line Broadband systems share the same behaviour - the bandwidth and power usage
is depending on the reach or coverage.
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15 ETSI TR 102 530 V1.2.1 (2011-07)
Tier1 ADSL2+ DSLAM line performance
DS Mbps US Mbps Power Consumption
20,00 1,55
18,00
1,50
16,00
1,45
14,00
1,40
12,00
1,35
10,00
8,00
1,30
6,00
1,25
4,00
1,20
2,00
0,00 1,15
0,501,00 1,502,00 2,503,00 3,504,00 4,505,00
Distance km
Figure 7: Example, performance simulation ADSL2+ line bit rate performances
and line power consumption, based on TS 102 533 [i.7]
5.4.5 Climate impact and models
The power consumption of climate equipment and fans is dependent on the temperature. Use of standard climate
models is essential for estimating peak and average power consumption of the climate equipment.
Temperature CDF
Climate Model Frankfurt
0 2000 4000 6000 8000 10000
(1Year)
-10
-20
Annual hours
Figure 8: Climate model for Frankfurt as temperature CDF over an average year
NOTE: When dimensioning cooling systems it should be noted that temperatures > 30 °C occur for only a limited
period each year.
ETSI
Temperature C
Mbps
Power Consumpion W
16 ETSI TR 102 530 V1.2.1 (2011-07)
5.5 Power efficiency
There is a need to measure and bench-mark power consumption consistently, i.e. relate the power consumption to the
useful output, i.e. a need to define power efficiency.
Useful output or "useful unit" should be defined. Usually capacity and coverage are the most important parameters. It
may not be possible to find a single efficiency definition that covers all telecom systems and the definitions may be
multiple, depending on the type of telecom system.
When Power efficiency is defined and measured, it is an important tool for comparing different products and
technologies. The power efficiency is simply the useful output divided by the power consumption. The inverse measure,
the power consumption divided with the useful output, could be used as an alternative. This measure is chosen in the
examples in this clause.
5.5.1 Useful output
Bit rate and power consumption is dependant on the distance from the BB Network node to the subscriber.
As distance reach is important for the operator - enabling improved subscriber coverage or lower density of nodes - the
reach aspect should be considered as a desirable aspect, in parallel with bit-rate. A relevant "Useful unit" should be the
product of reach [km] and Bandwidth [Mbps].
5.5.2 Power consumption dependencies
As described previously in the present document, the power consumption is depending on the configuration, the
measurement interfaces and the operating conditions. By combination of those factors, average power consumption can
be properly estimated as a base for energy consumption calculations.
5.5.3 Proposed Energy Efficiency definition for fixed BB equipment
Normalized Power Consumption (NPC), i.e. the power consumption related to useful output.
NPC = Average Power Consumption/Useful output, i.e. Power/(Bit rate x distance) [mW] / [Mbps x km]
NPC could be used at different equipment levels like magazine level - DSLAM, based on DC consumption, or on site or
node level, based on AC consumption. The Average Power Consumption is mesures in [mW] and the 'Useful output' is
measured in i.e. Bit rate x distance [Mbps x km].
5.5.4 Examples
5.5.4.1 Power consumption values used
DSLAM DC power consumption limit values from TS 102 533 [i.7] are used in the following examples. DSL Modem
AC power consumption limit values from EC Code od Conduct on Broadband Equipment, version 1.1.1 in 2008 are
used in the following examples.
5.5.4.2 NPC for DSLAM, ADSL2+ Tier 1 and VDSL2 Tier 2 DC consumption
The calculation is based on:
• Simulations of DSL performance with 24 disturbers. See annex B for any details.
• Power consumption based on TS 102 533 [i.7], for DSLAM DC power consumption. AC values can be
achieved by multiplying the NPC values with a site correction factor. Typical value is 1,7 for an
air-conditioned site. For details, see clause A.1.
• L2 and L3 modes are not considered operable, i.e. traffic model has negligible impact on power consumption.
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17 ETSI TR 102 530 V1.2.1 (2011-07)
Tier1 ADSL2+ DSLAM line performance
Total Mbps NPC mW/Mbps*km
25,00 180
20,00
15,00
10,00
5,00
0,00 0
0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00 4,50 5,00
Distance km
NOTE: Total bit rate upstream/downstream and NPC figures,
based on example in annex C. Best NPC value is 52 at 2 km distance.

Figure 9: ADSL Tier 1
DSLAM ADSL2+ VDSL2 NPC comparison
(Based on performance silulations)
VDSL2 Tier 3* ADSL2+ Tier 1 VDSL2 Tier 1
0,51,0 1,52,0 2,53,0 3,54,0 4,5 5,0
Distance km
NOTE: Conclusion is that ADSL2+ is the most efficient access for distances above 1,3 km, while VDSL2 Tier 3 is
the most efficient for shorter distances.

Figure 10: NPC comparison ADSL2+ Tier 1 and VDSL2 Tier 1 and 3.Best NPC values:
Tier1 ADSL2+: 52 at 2 km. Tier3 VDSL 2: 48 at 0,6 km
5.5.4.3 AC Site energy consumption and cost for DSLAM and Modem ADSL 2+
Tier 1 and VDSL2 Tier 2
The calculation assumptions for the graphs in this clause are:
• Power consumption values according to tables in clause 5.5.4.1.
• DSLAM L2 and L3 modes are considered operable.
ETSI
NPC mW/Mbps*km
Mbps
NPC mW/Mbps*km
18 ETSI TR 102 530 V1.2.1 (2011-07)
• Modem Standby mode is considered operable.
• User traffic profile and management of low power modes as described in clause 5.4.2.
• Site energy consumption correction factor from DC to AC is 1.7 according to clause A.1.
• Comparison based on site power consumption per line, not on energy efficiency.
• Energy cost is e.g. 0,15 €/KWh.
DSLAM Site AC Energy costs
Average traffic model.
L0 only and L0-L3 modes.
Euro/
Sub, Y
VDSL 2
ADSL 2+
0,15
L0 only
Euro/
L0-L3
kWh
Tier Tier Tier Tier Tier Tier
1 2 3 1 2 3
NOTE: Light blue - full power mode only. Dark blue - L0 and low power modes L2-L3 are active according to
clause 5.4.2. Tier 1 is products available on market 2007, Tier 2, products available 2008 and Tier 3
products available 2009.
Figure 11: DSLAM Site AC Annual Energy costs - per line
ETSI
19 ETSI TR 102 530 V1.2.1 (2011-07)
DSL-Modem AC Energy costs
Average traffic model
On only and ON/StandBy modes
Euro/
Sub, Y
0,15
ON only
Euro/
kWh
4 StdBy/ON
ADSL ADSL VDSL VDSL
Tier1 Tier2 Tier1 Tier2
NOTE: Light blue - full power mode only. Dark blue - L0 and low power modes L2-L3 are active according to
clause 5.4.2. Tier 1 is products available on market 2007, Tier 2, products available 2008.

Figure 12: DSL Modem AC Annual Energy costs - per modem
5.5.5 Way forward, using power/energy efficiency view
Power consumption can be reduced using different improvement methods. The efforts should focus on investigation of
the power saving potential of different improvement proposals. Each combination of improvements - features as well as
Hardware solutions - could be evaluated on a system energy efficiency level, either on an average power dimension, or,
by integrating over time - evaluated in the energy dimension.
However, requirements should be set on an efficiency dimension, not in implementation terms. Each vendor or operator
needs to make their own decision on selection of methods for power efficiency improvements. The resulting power or
energy efficiency could then be estimated, using the described tools.
For equipment with similar "useful output", the comparison could be done in the power consumption dimension,
considering the parameters impacting the annual average site power consumption.
For equipment with different "useful output" - the comparison should be done in the efficiency dimension.
6 Energy saving methods for telecom infrastructure
equipment
The different methods listed here should be used at the vendors or operators discretion in a way that optimizes the
energy efficiency of the nodes and the network.
Power consumption of the support systems is more or less proportional to the power consumption of the telecom
equipment. As power consumption of the access or transport equipment is reduced, the infrastructure equipment like
cooling and rectifiers can be downsized with substantial energy and cost savings at the site.
ETSI
20 ETSI TR 102 530 V1.2.1 (2011-07)
6.1 Infrastructure equipment introduction
The telecom equipment power and cooling infrastructure equipment are vital in maintaining the operation of the
telecomm equipment in providing service to the customer. If the power or cooling system is not available for the
telecom equipment it will not be operational and therefore no service can be provided and revenue will not be
generated. Customers will seek compensation for the loss of service and ultimately change to a different provider.
The area of equipment that could be optimized is depicted in figure 13.
Rectifier/battery/DC distribution
EN 300 132-3(AC) EN 300 132-2 (DC)
EN 300132-3 (DC up to 400V DC)
AC switchgear
and distribution
AC
Telecom Equipment
Mains
TR 102 121
DC
A
interface
UPS
AC
AC
Telecom Equipment
DC
TR 102 121
EN 300 132-3(AC)
EN 300132-3 (400V)
AC generator
Diesel,
Turbo, …
- Essential services
Air conditioning
System
- Common building
EN 300 019
Grid connexion option
series
IEM&C  interface
Alternative energy source
Fuel cell, PV,
Control-Monitoring
wind generator, …
DC connexion option
ES 202 336 series
To reduce power
consumption on mains
TR 102 532
NOTE: In figure 13 the power interface EN 300 132-3 [i.3] is either a DC up to 400 V DC or an AC.

Figure 13: Area of equipment contributing to power consumption reduction
or optimization (grey rectangle)
6.2 Cooling systems
Cooling systems are an integral part of the telecomm system. Without cooling (regardless of which form it takes) the
telecomm system is likely to overheat and fail or greatly shorten its life. In some cases temperatures that are too low can
have the same effect of equipment failure and shortening of its life. The effect of lifetime reduction should be balanced
with the operator's expectation on lifetime. Product life cycle, market conditions and costs should be taken into account.
6.2.1 Use of fresh air cooling
The environmental classes of EN 300 019 [i.1] allows the environment in which the equipment is installed to vary. For
examples Class 3.1 allows the room temperature to vary from 5 °C to 40 °C and cl
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