ETSI TR 103 540 V1.1.1 (2018-04)

Environmental Engineering (EE); Mobile Network (MN) Energy Consumption (EC) estimation method; Energy estimation method based on statistical approach

DTR/EE-EEPS29

General Information

• Status: Published
• Publication Date: 26-Apr-2018
• Technical Committee: EE EEPS - EE Eco Environmental Product Standards
• Current Stage: 12 - Completion
• Due Date: 07-May-2018
• Completion Date: 27-Apr-2018

Standards Content (Sample)

ETSI TR 103 540 V1.1.1 (2018-04)






TECHNICAL REPORT

Environmental Engineering (EE);
Mobile Network (MN) Energy Consumption (EC)
estimation method;
Energy estimation method based on statistical approach

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2 ETSI TR 103 540 V1.1.1 (2018-04)



Reference
DTR/EE-EEPS29
Keywords
access, base station, energy management, GSM,
LTE, network, power measurement, radio, UMTS,
WCDMA
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3 ETSI TR 103 540 V1.1.1 (2018-04)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 RAN Energy Consumption Estimation Method . 7
4.1 General description. 7
4.2 Basic Estimation Method . 8
4.2.1 Select a Confidence Level . 8
4.2.2 Specify the Sample Size "n" . 8
4.2.3 Select the Random Sample of Base Station Sites . 9
4.2.4 Choose a Measurement Period. 9
4.2.5 Measure the Energy Consumption of the Base Station Site Sample . 10
4.2.6 Estimate the Radio Access Network Energy Consumption . 10
4.2.7 Calculate the Margin of Error of the Mobile Network Estimate . 11
4.2.8 State the Radio Access Network Energy Consumption Estimate . 11
4.3 Stratified Estimation Method . 12
4.3.1 General description . 12
4.3.2 Define the Mobile Network Strata . 13
4.3.3 Divide the Mobile Network into the Site Strata . 13
4.3.4 Select a Confidence Level . 13
4.3.5 Specify the Sample Size "n" . 13
4.3.6 Determine each Stratum's Contribution to the Overall Sample . 14
4.3.7 Select the Random Sample of Base Station Sites from Each Stratum . 14
4.3.8 Measure the Energy Consumption of each Stratum Sample . 14
4.3.9 Estimate the Mobile Network Energy Consumption . 14
4.3.10 Calculate the Margin of Error of the Mobile Network Energy Consumption Estimate . 15
4.3.11 State the Mobile Network Energy Consumption Estimate . 15
5 Future Estimations and Network Upgrades . 16
5.1 General description. 16
5.2 Estimation Method as Path to Full-Network Measurements . 16
Annex A: Implementation examples Implementation of Estimation Method Using Statistical
Sampling . 17
A.1 General description. 17
A.2 Basic Estimation Method . 18
A.2.1 Select a Confidence Level . 18
A.2.2 Specify the Sample Size "n" . 18
A.2.3 Select the Random Sample of Base Station Sites . 18
A.2.4 Choose the Measurement Period . 20
A.2.5 Measure the Energy Consumption of the Base Station Site Sample . 20
A.2.6 Estimate the Mobile Network Energy Consumption . 20
A.2.7 Calculate the Margin of Error of the Mobile Network Estimate . 21
A.2.8 State the Mobile Network Energy Consumption Estimate . 22
A.3 Stratified Estimation Method . 22
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4 ETSI TR 103 540 V1.1.1 (2018-04)
A.3.1 General description. 22
A.3.2 Define the Mobile Network Strata . 23
A.3.3 Divide the Mobile Network into the Site Strata . 23
A.3.4 Select a Confidence Level . 24
A.3.5 Specify the Sample Size "n" . 25
A.3.6 Determine each Stratum's Contribution to the Overall Sample . 25
A.3.7 Select the Random Sample of Base Station Sites from Each Stratum . 25
A.3.8 Measure the Energy Consumption of each Stratum Sample . 26
A.3.9 Estimate the Mobile Network Energy Consumption . 27
A.3.10 Calculate the Margin of Error of the Mobile Network Energy Consumption Estimate . 28
A.3.11 State the Mobile Network Energy Consumption Estimate . 30
Annex B: Bibliography . 31
History . 32


ETSI

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5 ETSI TR 103 540 V1.1.1 (2018-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Environmental Engineering (EE).
The present document has been developed in collaboration with 3GPP SA5 and RAN3; GSMA has given also valuable
suggestions and contributions. Moreover, the present document is developed jointly with ITU-T SG5 Q17/5.
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
In the absence of direct measurements, a radio access network's energy consumption can be estimated using a simple
random sample of base station sites from the mobile network. There are two estimation methods described in the
present document which can be used for this purpose: the basic estimation method, and the stratified estimation method.
In the basic estimation method, the sample is created with no consideration for the constitution of the mobile network.
This method is well-suited for mobile networks generally characterized as homogenous, with normal statistical
distributions of energy-influencing site characteristics across the network (e.g.base stations per site, radios per site).
In the stratified estimation method, the sample is created while taking the constitution of the mobile network into
account. This method is well-suited to mobile networks generally characterized as heterogeneous, or mobile networks
with non-normal statistical distributions of energy-influencing site characteristics.
An example of application of these two methods is given for better readability and ease of use in annex A.
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6 ETSI TR 103 540 V1.1.1 (2018-04)
1 Scope
The present document is aimed to define an estimation method for anticipating the total energy consumption of a radio
access network based on measuring energy consumption of a few randomly chosen sites. The present document is used
when measuring energy consumption of the whole network is either impossible or costly to an operator. Two different
methods have been presented in the present document , one based on Basic Estimation Method and another based on
stratified Estimation Method.
The present document deals with any type of radio access network such as homogeneous and heterogeneous network
and technologies such as GSM, UMTS and LTE.
The estimation of energy consumption User Equipment (UE) is not within the scope of the present document.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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.
Not applicable.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Base Station (BS): network component which serves one or more cells and interfaces the user terminal (through air
interface) and a radio access network infrastructure
Energy Efficiency (EE): relation between the useful output and energy consumption
Mobile Network (MN): set of equipment from the radio access network or sub-network that are relevant for the
assessment of energy efficiency
power consumption: power consumed by a device to achieve an intended application performance
Radio Access Network (RAN): telecommunications network in which the access to the network (connection between
user terminal and network) is implemented without the use of wires and that is part of GERAN, UTRAN or E-UTRA
networks defined by 3GPP
Radio Access Network Energy Consumption (RANEC): overall energy consumption of equipment included in the
RAN under investigation
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Telecommunication Network (TN): network operated under a license granted by a national telecommunications
authority, which provides telecommunications between Network Termination Points (NTPs)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3GPP 3G (mobile) Partnership Project
BS Base Station
CL Confidence of Level
EC Energy Consumption
E-UTRA Evolved UMTS Terrestrial Radio Access Network
GERAN GSM/EDGE Radio Access Network
GSM Global System for Mobile communication
GSMA GSM Association
ICT Information Communications Technology
ITU International Telecommunications Union
ITU-T International Telecommunications Union - Telecommunication
LTE Long Term Evolution
MN Mobile Network
PDF Probability Distribution Function
RAN Radio Access Network
RF Radio Frequency
T Period of Time over the estimate is made
TLAF Transmission Loss Adjustment Factor
UMTS Universal Mobile Telecommunication Service
UTRAN UMTS Terrestrial Radio Access Network
4 RAN Energy Consumption Estimation Method
4.1 General description
A simple random sample of radio access network energy consumption is supported by the following definitions:
• A RAN is a population consisting of "N" base station sites.
• A sample from the RAN population consists of "n" base station sites.
• All possible samples of "n" base station sites from the RAN population are equally likely to occur.
• Each sample of the RAN population has a mean site energy consumption of .
• The value of serves as an estimate of the true mean site energy consumption for the entire RAN (denoted as
).
• The size (n) of each RAN sample needs to be sufficiently large such that all possible values of mean site
energy consumption () form a normal (or near normal) sample distribution.
• The mean of the sample distribution () is also the true mean of the site energy consumption () for the ̅
entire RAN, as shown in figure 1.
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8 ETSI TR 103 540 V1.1.1 (2018-04)
True mean of the mobile network's site energy consumption
Sample estimate ̅
2  2 3 3 ̅̅̅̅̅̅̅

Figure 1: Normal Distribution of a Randomly Sampled Population
Using the above definitions, the radio access network's energy consumption is estimated by multiplying the sample
estimate of the mean site energy consumption ( by the number of sites in the mobile network population .
∙
,̅
The above estimate of RAN energy consumption also includes some indication of its accuracy relative to the true RAN
energy consumption value. Therefore, energy consumption estimates are expressed as a confidence interval consisting
of:
• The sample estimate of the RAN energy consumption , extrapolated from the sample mean (̅.
,̅
• The amount of time covered by the energy consumption estimate.
• A margin of error expressing the maximum expected difference between the true energy consumption of the
RAN and the sample estimate.
• The confidence level ( ) in the sampling method. Specifically, it reflects the percentage of sample estimates
whose mean energy consumption and margin of error are expected to include the true mean site energy
consumption.
Based on the above, a RAN energy consumption estimate is expressed in the following form:
The CL % confidence interval for the mobile network energy consumption
over a period of T is EC ME % Watt ∙ Hours
,
As an example, an estimate of a mobile network's energy consumption would be expressed as follows:
The 95 % confidence interval for the energy consumed by the mobile network
over a one-month period is 1,05x102,4 % Watt ∙ Hours
4.2 Basic Estimation Method
4.2.1 Select a Confidence Level
The confidence level reflects the confidence that one wants to have in the energy consumption estimate. It is an
individual choice not specified by the present document, and it influences the size of the margin of error associated with
the energy consumption estimate. It can be any percentage value up to 100 %, with 95 % being a common value. Note
that choosing a confidence level of 100 % implies that every site in the network would have to be measured, thus
defeating the purpose of the estimation method.
4.2.2 Specify the Sample Size "n"
In order to satisfy the requirements of the central limit theorem, the sample size (n) needs to be large enough to produce
a normal sampling distribution. The less "normal" the shape of the network's underlying site energy consumption
distribution, the larger the sample size needs to be in order for any estimate and associated margin of error to be valid.
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9 ETSI TR 103 540 V1.1.1 (2018-04)
Since the shape of the network is likely an unknown before any measurements take place, it is difficult to predict the
sample size required to achieve a certain margin of error. Thus the sample size has to be chosen and measurements
made first, with the associated margin of error calculated afterwards.
While the sample size is an individual choice, it is recommended that the sample measurement consist of:
• at least 50 of the network sites, representing at least 5 % of the network
A representative estimate and associated margin of error is more likely if both of these sample size requirements are
satisfied.
4.2.3 Select the Random Sample of Base Station Sites
In order to be a truly random sample of base station sites, the site selection needs be totally blind to such energy
consumption influences as data traffic load, climate, site solution, site configuration, RF output power, and site
capability. This can be achieved using the following site selection procedure:
• Itemize the population of mobile network base station sites in a vertical list consisting of "N" rows (i.e. one
row for each base station site in the overall mobile network population). All information regarding the site
configuration and environment should be excluded from the list in order to avoid the unconscious introduction
of statistical bias.
• Using a random number generator, assign each entry in the site list a random number in the range of 0:1 to at
least 6 decimal places. A spreadsheet's rand-function can be useful for this purpose.
• Sort the population site list based on the random number assignments, from the lowest random number to
highest, as shown in figure 2.
• The first "n" base station sites in the sorted list (where "n" was determined in the previous step) should serve
as the mobile network population sample. These "n" sites will have their energy consumptions directly
measured.
Use first "n"
base station
sites in
re-ordered
mobile network
site list
population
sample

Original Base Station List Re-Ordered List Using Random Numbering

Figure 2: Creating the Random Site Sample
4.2.4 Choose a Measurement Period
The value of the measurement period is an individual choice and is not specified by the present document.
However, some consideration needs to be given to the fact that this value also determines the time period over
which the estimate applies. For example, if the energy consumption measurements are performed during a two-week
period, the resulting estimate for the mobile network's energy consumption can only pertain to the same two-week
period. The two-week measurement cannot be extrapolated to a year-long measurement, because other factors
influencing energy consumption (such as yearly temperature fluctuations) would not be accounted for in the margin of
error.
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4.2.5 Measure the Energy Consumption of the Base Station Site Sample
The energy consumption measured at each base station site in the mobile network population sample, for measurement
period (), is denoted as:

,
These sample energy consumption site values can be obtained from either:
• direct on-site measurements; or
• energy consumption metering information supplied by the electrical utility.
Electrical utility metering is only used for the sample provided the following conditions are met:
• The utility supplies a site energy consumption value in units of Watt-Hours or similar.
• The site energy consumption value is representative of the site only, and only includes equipment which fulfils
the site function.
• Any transmission loss adjustment factors (TLAF) applied by the utility are fully quantified and understood.
• TLAFs are removed from the site energy consumption values provided by the electrical utility, since direct
energy consumption measurements at the site would not capture the transmission loss effect.
• The energy billing information (i.e. the financial cost of the electricity) is not used to derive a site's energy
consumption value.
Having met the above criteria, site energy consumption values based on metering information is calculated as:

,
=
,


Where:
The site energy consumption value supplied by the electrical utility which includes a

,
transmission loss adjustment factor (TLAF)

The transmission loss adjustment factor applied by the electrical utility

4.2.6 Estimate the Radio Access Network Energy Consumption
The RAN energy consumption sample estimate ( ) is based on the mean energy consumption (̅) of the sites in
,̅
the base station sample calculated as:

1
̅=



Where:
̅ Sample estimate of the RAN's mean site energy consumption
Number of sites in the mobile network sample
Energy consumption of a site within the sample


The mean site energy consumption (̅) for the sample is then multiplied by the number of sites in the mobile network
population () to determine the sample estimate for the mobile network energy consumption ( ):
,̅
= ∙̅ ̅ ,
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11 ETSI TR 103 540 V1.1.1 (2018-04)
Where:
Energy consumption of a site within the sample

Sample estimate of the RAN’s total energy consumption ,̅
Number of sites in the mobile network sample
̅ Sample estimate of the RAN’s mean site energy consumption
Total number of base station sites in the mobile network

4.2.7 Calculate the Margin of Error of the Mobile Network Estimate
The margin of error is the maximum difference between the sample estimate and the true value of the radio access
network's energy consumption. The confidence in this maximum is described by the confidence level chosen in
clause 4.2.1.
As a numerical value, the margin of error is calculated as follows:
−
= ∙∙ ∙

−1√
As a percentage, the margin of error is calculated as follows:

 = ∙100
%
∙̅
Where:
T-score for a sample of size n, determined from an online t-score calculator applying (−1)

degrees of freedom, and a cumulative probability (CP) calculated as:

100 − %
=1−
200

Where (CL) is the confidence level (in %) chosen in clause 4.2.1.
Standard deviation of the site energy consumptions of the mobile network sample

In the above equations, a t-score (rather than a z-score) is used since the standard deviation of the mobile network

population is unknown. In addition, the � term is the finite population correction formula, and is included since


the mobile network site population is finite and is being sampled without replacement. Finally, the term represents
√
the standard error of the sample mean, with the standard deviation () of the sample calculated as:

∑ −̅

=
−1
4.2.8 State the Radio Access Network Energy Consumption Estimate
The resulting radio access network energy consumption estimate includes the chosen confidence level, the measurement
period, the estimated mobile network energy consumption,
...