ETSI TR 103 820 V1.1.1 (2015-11)

TECHNICAL REPORT
Fixed Radio Systems;
Energy efficiency metrics and test procedures
for Point-to-point fixed radio systems

2 ETSI TR 103 820 V1.1.1 (2015-11)

Reference
DTR/ATTM-04021
Keywords
energy efficiency, point-to-point, radio
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3 ETSI TR 103 820 V1.1.1 (2015-11)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Symbols and abbreviations . 8
3.1 Symbols . 8
3.2 Abbreviations . 8
4 Definition of the EE metrics of Point-to-point fixed radio systems . 9
4.1 General . 9
4.2 Parameters affecting the EE of Point-to-point fixed radio systems . 9
4.3 Equipment Energy Efficiency Ratio . 10
4.3.1 Definition of EEER . 10
4.3.2 EEER applicability . 11
5 EEER evaluation . 12
5.1 EEER at different frequency ranges . 12
5.2 EEER for frequencies up to 13 GHz . 12
5.2.1 Introduction. 12
5.2.2 Reference factors . 13
5.2.2.1 Reference system . 13
5.2.2.2 Reference parameters . 13
5.2.3 Reference case . 13
5.2.3.1 Reference system . 13
5.2.3.2 Reference parameters . 14
5.2.4 SG, Signature and HL . 15
M
5.2.4.1 Methodology . 15
5.2.4.2 Reference tables for (SG + Signature) HL conversion . 16
M
5.2.4.3 Example of EEER calculation for 6 GHz . 19
5.3 EEER for 15 GHz frequency range and above . 20
5.3.1 Introduction. 20
5.3.2 Reference factors . 20
5.3.2.1 Reference system . 20
5.3.2.2 Reference parameters . 20
5.3.2.3 Reference case . 21
5.3.2.3.1 Reference system . 21
5.3.2.3.2 Reference parameters . 21
5.3.3 Reference table for SG HL conversion . 22
M
6 Test conditions . 23
6.1 Introduction . 23
6.2 Capacity . 23
6.3 Power Consumption . 23
6.4 Measurements . 24
6.4.1 Measurements conditions . 24
6.4.2 Not considered equipment . 24
7 Conclusions . 24
Annex A: Relationship between HL and SG for frequencies above 15 GHz . 26
M
Annex B: EEER examples . 28
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4 ETSI TR 103 820 V1.1.1 (2015-11)
B.1 Practical equipment . 28
B.1.1 Calculations and frequency bands . 28
B.1.2 Input parameters . 28
B.2 Numerical results . 28
B.3 Analysis and comments . 29
B.3.1 P [W] versus [dBW] . 29
in
B.3.2 EEER variation with RX threshold . 30
B.3.3 EEER absolute values versus rain-rate . 31
B.4 Conclusions . 31
Annex C: Comparison between Vigants-Barnett and Recommendation ITU-R P.530-15
methods . 33
C.1 4 GHz case . 33
C.2 11 GHz case . 34
Annex D: Bibliography . 35
History . 36

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5 ETSI TR 103 820 V1.1.1 (2015-11)
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 Access, Terminals, Transmission and
Multiplexing (ATTM).
Modal verbs terminology
In the present document "shall", "shall not", "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
The present document deals with the definition of the metrics, methodology and test conditions for the evaluation of the
Energy Efficiency of Point-to-point fixed radio systems.
The tremendous growing of telecom applications is leading to a strong escalation in bandwidth needed to expand
telecom solutions. Improved telecommunication networks are under deployment, and consequently the power needed to
operate and cool the connected equipment is also likely to increase. As a consequence, the concept of "Energy
Efficiency" is getting more and more important in the telecommunication world. Numerous definitions are in use
according to the different technologies and network segments they are applied to.
Most of the standardization organizations have identified "Energy Efficiency" as a key area, looking at it from different
perspectives as the standards can help providing a common base of understandings, concepts and targets.
The initial stimulus for the present document comes from the European Mandate M/462 [i.1] on the "efficient energy
use in fixed and mobile information and communication networks", which among other things states that "it is vital to
consider ways to maintain sustainable growth in the transmission capacity of telecommunication networks while
limiting and optimizing the energy consumption". However, in line with the European Code of Conduct on Energy
Consumption [i.2], it is as much important that the intention of reducing the energy consumption is pursued without
hampering the technological developments and the services provided.
Although in the European Mandate M/462 [i.1] and most of the relevant technical documents, Fixed Radio access and
transport infrastructures are still mostly disregarded or just mentioned without any specific treatment, the present
document aims at giving a correct technical interpretation of the concept of Energy Efficiency when applied to
Point-to-point fixed radio systems.
It is important to consider that unlike wired networks, the performance characteristics of a microwave radio system is
prone to variations, either due to external factors (e.g. weather) or by the action of the network operator. In a given
frequency band, there may be requirements for maximum radiated power levels, particular efficient modulation types,
and even standards for the radiation patterns of directional antennas. These criteria are established to reduce or
minimize interference among systems that share the same spectrum, and to ensure that the spectral efficiency is
sufficiently high to justify the occupancy of the spectrum.
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6 ETSI TR 103 820 V1.1.1 (2015-11)
Moreover, propagation characteristics of the microwave signal can differ significantly according to the operating
conditions, like frequency band and geographical location.
All the different operating conditions summarily mentioned here above have led to the development of many types of
equipment that can address different applications and can work in a large variety of set-up.
It follows that any definition of the Energy Efficiency for Point-to-point fixed radio systems should not be considered
without taking into account the specific characteristics of those systems collected in the present document. The present
document is thus intended also to provide the necessary technical background in the event that in the future any of the
Technical Committees in charge wanted to define any Energy Efficiency KPI's related to P-t-p wireless fixed radio
systems.
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7 ETSI TR 103 820 V1.1.1 (2015-11)
1 Scope
The present document defines the Energy Efficiency specifically for Point-to-point fixed radio systems, taking into
account the specific characteristics of that technology. The technical background and the methodology used to obtain
the formula are described together with the test conditions within which carrying out the related measures.
Due to the peculiarity of fixed wireless systems, having various architectures, applications and set-ups, the target to
define the Energy Efficiency with a single formula valid for all the categories of systems is very challenging and could
be even technically misleading.
As consequence, the main part of the present document is intended to explain the methodology used to derive the
EEER, defined as the Equipment Energy Efficiency Ratio. The provided technical description is the necessary
complement of the given definition, as it helps to understand the complexity of the matter and how the formula should
be used.
That is particularly important in the event that Technical Committees intend to further proceed with the present analysis
and derive from the given definition any practical standardization activities.
2 References
2.1 Normative 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.
The following referenced documents are necessary for the application of the present document.
Not applicable.
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
reference 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.
[i.1] European Commission - M/462 EN: "Standardisation mandate addressed to CEN, CENELEC and
ETSI in the field of ICT to enable efficient energy use in fixed and mobile information and
communication networks".
[i.2] European Commission, Veer 4, Feb 2011: "Code of Conduct on Energy Consumption of
Broadband Equipment".
[i.3] Recommendation ITU-R F.1703 (2005): "Availability objectives for real digital fixed wireless
links used in 27 500 km hypothetical reference paths and connections".
[i.4] ETSI EN 302 217-1 (V1.3.1): "Fixed Radio Systems; Characteristics and requirements for point-
to-point equipment and antennas; Part 1: Overview and system-independent common
characteristics".
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8 ETSI TR 103 820 V1.1.1 (2015-11)
[i.5] ETSI EN 302 217-2-2 (V2.2.1): "Fixed Radio Systems; Characteristics and requirements for point-
to-point equipment and antennas; Part 2-2: Digital systems operating in frequency bands where
frequency co-ordination is applied; Harmonized EN covering the essential requirements of
article 3.2 of the R&TTE Directive".
[i.6] Recommendation ITU-R P.530-15 (2013): "Propagation data and prediction methods required for
the design of terrestrial line-of-sight systems".
[i.7] Recommendation ITU-R P.837-6 (2012): "Characteristics of precipitation for propagation
modelling".
[i.8] Recommendation ITU-R P.838-3 (May 2005): "Specific attenuation model for rain for use in
prediction methods".
[i.9] Recommendation ITU-T G.826 (2002): "End-to-end error performance parameters and objectives
for international, constant bit-rate digital paths and connections".
[i.10] ITU-R WP5C, Contribution 345, Huawei Technologies Co. Ltd., Oct 2014: "Error performance
and availability issues in ITU: Background and current status".
[i.11] Bell System Technical Journal, Barnett, W. T.: "Multipath propagation at 4, 6 and 11 GHz",
Vol. 51, No. 2, 311-361, Feb 1972.
[i.12] Bell System Technical Journal, Vigants A.: "Space-diversity engineering", Vol. 54, No. 1,
103-142, Jan 1975.
[i.13] Recommendation ITU-R F.1668-1 (2007): "Error performance objectives for real digital fixed
wireless links used in 27.500 km hypothetical reference paths and connections".
[i.14] IETF RFC 2544 (1999): "Benchmarking Methodology for Network Interconnect Devices".
[i.15] IEC 60038: "IEC standard voltages".
[i.16] ETSI EN 300 132-2: "Environmental Engineering (EE); Power supply interface at the input to
telecommunications and datacom (ICT) equipment; Part 2: Operated by -48 V direct current (dc)".
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
Kn normalized system signature parameter
p multipath occurrence factor
P input power (power consumption)
in
PTx output transmitted (radio) power
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
AM Adaptive Modulation
C Capacity
CS Channel Spacing
DC Direct Current
dN1 point refractivity gradient
EE Energy Efficiency
EEER Equipment Energy Efficiency Ratio
f Frequency Band
BAND
FS Fixed Service
HL Hop Length
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9 ETSI TR 103 820 V1.1.1 (2015-11)
HL Maximum Hop Length
M
IDU InDoor Unit
L2 Layer 2
MW MicroWave
ODU Outdoor Unit
QAM Quadrature Amplitude Modulation
RF Radio Frequency
RIC Radio Interface Capacity
RTh Receiver Threshold
SES Severely Errored Second
SG System Gain
4 Definition of the EE metrics of Point-to-point fixed
radio systems
4.1 General
In general, the energy efficiency of a system should reflect its ability in exploiting the external resources (energy)
needed for its operation in order to reach a certain defined level of quality in terms of performance.
The list here below summarizes the different factors that heavily influence the performance of a wireless Fixed Service
system:
• Type of application: FS systems can be used in different network segments like access, short haul or long haul.
Systems located in different portions of the network are required to provide different features and to work for
different link lengths, capacity and quality of service, with consequent impact on their settings and power
consumption.
• Frequency bands: FS applications expand from "low" frequencies at around 2 GHz up to 95 GHz or more,
though the typical use can be restricted from 6 GHz to 42 GHz. It is well known that in such a wide spectrum
range the propagation characteristics are rather different and heavily influence the systems behaviours.
• Environment: those generic terms can refer to different geographical areas of application, including different
climatic conditions, but also different morphology like flat ground areas instead of mountainous regions, rural
environment up to dense urban.
• Architectures: different systems architectures are available on the market, like all indoor, split-mount indoor-
outdoor or full outdoor.
• Features: some equipment types have integrated data processing, including switch devices, monitoring
capabilities or ancillary equipment, that can drive the overall power consumption of the system.
All the listed elements can have a direct and relevant impact on the power level needed by the FS systems to handle the
traffic and correctly transmit the microwave signal through the hop, and that can clearly influence the evaluation of the
their efficiency from the energy point of view.
4.2 Parameters affecting the EE of Point-to-point fixed radio
systems
According to the considerations reported in clause 4.1, the following parameters have been identified as possible
candidates in the definition of the metrics:
• Frequency band (f )
BAND
• Bandwidth (Channel Spacing, CS)
CS represents the amount of spectrum (Bandwidth) used for the transmission of the MW signal.
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10 ETSI TR 103 820 V1.1.1 (2015-11)
• Capacity (C)
The transmission of a certain amount of traffic over the radio link, here called Capacity, is the main purpose of
the system and thus considered one of the main important performance indicator, also because the needed
capacity is the driver for the operative set-up (CS, modulation format, etc.) The relationship between capacity
and bandwidth represents actually another characteristic parameter of the FS systems, the Spectral Efficiency.
)
• Power consumption (P
in
Input DC Power (P ) has been identified as power consumption parameter, thus excluding any AC-DC
in
converter.
• Maximum Hop length (HL )
M
The capability to reach longer distances is related both to the system technical quality and to the operative set-
up (f , modulation format, etc.). As a consequence, the definition of maximum hop length is meaningful
BAND
only when the operative conditions are clearly stated.
• Output power (PTx, dB )
m
• Receiver Thresholds (RTh, dB )
m
• System Gain (SG)
Another noteworthy parameter for p-t-p fixed wireless links is the System Gain (SG), defined as the difference
in dB between the transmitter RF output power and the practical thresholds of the receiver.
SG = PTx - RTh 4.2a)
dB
SG and maximum hop length are strictly related, as in principle a higher SG implies a better capability of the system to
reach longer distances maintaining the needed signal level.
However, the relationship between SG and maximum hop length can be rather complicated to be defined, and is subject
to variation according to the propagation conditions, mainly frequency.
It can be shown that while for frequencies above about 15 GHz the SG and HL are almost linearly related, for lower
M
frequencies HL depends also on other significant parameters like the signature, making the SG to HL relation more
M M
complex.
Another difference related with the frequency range is the reference application of systems: while lower frequencies are
generally used for long distance transport links (typically between 30 km and 100 km) which can anyway include
mobile backhaul application, higher frequencies are more typically employed for short range links (from a few hundred
meters up to a few tens of kilometres) and very often as mobile infrastructure like backhaul. The different application
justifies also the fact that while for the lower frequencies the link performance in terms of quality is used as main
requirement for the link design, for the higher frequencies one of the most important requirement is the link availability,
as explained in the next clauses.
The different behaviour in frequency explains the reason why in the following clauses a separate analysis has been
carried out for frequencies up to about 13 GHz and for 15 GHz and above.
4.3 Equipment Energy Efficiency Ratio
4.3.1 Definition of EEER
A straightforward way to define the concept of Energy Efficiency for systems within the scope of the present document,
is the Equipment Energy Efficiency Ratio (EEER), defined as the simple ratio among the relevant quantities listed in
clause 4.2:
HL × C
M
EEER =
Log (Pin) × CS
4.3a)
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11 ETSI TR 103 820 V1.1.1 (2015-11)
where:
• C is the link Capacity, expressed in Mbit/s.
• HL is the maximum hop length that can be covered under a set of conditions, expressed in km.
M
• CS is the channel spacing, in MHz.
• P is the power consumption in Watt, even if in the formula its weight is in logarithmic units.
in
bit
⎡ ⎤
[]km ×
⎢ ⎥
s []km ×[bit]
⎣ ⎦
Looking at the dimensional analysis []EEER = =
[]W ×[Hz] []W
However, it is important to note that the link capacity (C) is very variable according to the width of the channel used for
the signal transmission. As consequence any numerical outcome of the formula 4.3a) has to be correlated with a specific
value of CS. In other words, the EEER definition can be normalized with respect to the specific reference CS and that
term can be removed from the formula, which thus becomes:
HL × C
M
EEER =
Log (Pin)
4.3.b)
bit
⎡ ⎤
[]EEER = []km ×
and its dimensional analysis
⎢ ⎥
s
⎣ ⎦
In the formula 4.3b) the two elements C and P are easily found for the systems under analysis, while the term HL has
in M
to be calculated or derived from SG. This last step can be easily performed for frequencies above about 15 GHz, where
the dependency between SG and HL is almost linear, while can be rather complicated for lower frequencies, where
M
other factors like signature enter into the calculation.
4.3.2 EEER applicability
There are many factors that influence the operating settings of a microwave system, and the parameters included in the
EEER definition given in formula 4.3b) are strongly impacted by those operating settings or design objectives.
As consequence, the given formulation of Energy Efficiency is consistent only if associated with the specific operating
conditions listed here below:
• Frequency band f : the propagation conditions are different in the different frequency bands. The
BAND
relevance of that parameter is of immediate comprehension considering that the term HL is very sensitive to
M
the frequency band it is referred to. It means the EEER given in formula 4.3b) for the fixed wireless system is
not an absolute value, but is defined per each frequency band of interest.
• Channel spacing CS: it is the assumption for the definition given in formula 4.3b).
• Spectral Efficiency Class: the same way of the above point, it is possible to show that the same equipment
operating with the same CS, but with different Modulation formats (alias different Spectral Efficiency Classes)
would obtain different values for its EEER. That requires the EEER to be defined per each Spectrum
Efficiency Class.
• Features list: the presence of different features embedded into the system, like switching or routing parts or
data compression techniques, can have a not negligible impact on the P and/or on C.
in
• Architecture: different system architectures like full-indoor, split-mount or full-outdoor, can address different
purposes/scopes, with a consequent impact on performances and power consumption.
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12 ETSI TR 103 820 V1.1.1 (2015-11)
• Work objective (similar SG): EEER can be very different for systems designed for different application
purposes, like the case of equipment designed with low PTx level to target short hops compared with a
solution with higher PTx level to target longer hops. This condition implies also that the SG of the systems
under analysis has to be specified with no more than 10 dB of margin.
5 EEER evaluation
5.1 EEER at different frequency ranges
The EEER definition described in formula 4.3b) requires the calculation of the maximum hop length HL , which value
M
can be derived from the SG.
Unfortunately, from practical exercises (see Annex A) it comes out that the question is definitely not trivial.
To solve the problem it has been considered to define some "reference deployment scenarios", and to have an overall
evaluation of the system performances on them. In the intentions, these scenarios should represent the most typical
conditions in the European area and the most typical application/objectives for PtP links.
Once defined such scenarios, a conversion table is provided for transforming SG into HL , avoiding any
M
misinterpretation in the conversion.
The relation between the two parameters is simpler for frequencies above about 15 GHz, where the dependency is
almost linear and the rain fading has a major impact on the propagation performances.
Multipath effects are predominant at lower frequencies up to about 13 GHz. However, the multipath and the rain effects
are not mutually exclusive to each other and for bands around about 13 GHz to 15 GHz, depending on system
parameters (system gain and signature) and propagation conditions (i.e. the chosen reference rain rate and multipath
occurrence factor), one might be predominant.
Separate analysis have been carried out for frequencies up to 13 GHz (see clause 5.2) and frequencies from 15 GHz and
above (see clause 5.3).
5.2 EEER for frequencies up to 13 GHz
5.2.1 Introduction
This clause focuses on the lower frequency range, while the analysis of higher frequencies is presented in clause 5.3.
One of the fundamental keys of the described methodology consists in the possibility to define in a user-friendly way
the value of HL , considering that at lower frequencies its value is affected by both SG and System Signature (Kn).
M
For that purpose, it is necessary to:
1) define suitable multipath parameters among the variability of Recommendation ITU-R P.530 [i.6]; they should
be of "medium" severity, so that no diversity is implied;
2) foresee the use of the "declared signature area" (according the principles in ETSI EN 302 217-1 [i.4]);
3) define a system configuration for "full indoor" systems, as that is the most common architecture used for the
considered frequency bands suitable for long distance radio links designed to carry high-capacity voice and
data.
The overall Recommendation ITU-R P.530 [i.6] reference parameters are actually valid for any frequency and HL is
M
determined through the multipath/rain (and, when would become necessary, oxygen absorption) comprehensive
approach. Before proceeding with the analysis, it is necessary to define all the reference factors that are expected go
together with the use of the EEER according to the definition given in clause 4.3.1. The factors are basically of two
categories:
• factors defining the reference system: this category includes the factors that identify the type of equipment
under analysis;
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13 ETSI TR 103 820 V1.1.1 (2015-11)
• factors defining the reference parameters: this category includes some additional parameters and reference
standards needed to specify the conditions under which the EEER is calculated and to which that specific
calculation is referred to.
5.2.2 Reference factors
5.2.2.1 Reference system
The reference system is used to describe the category of system under analysis, considering the main variants of the
equipment available on the market. For doing so, the following system characteristics are considered:
• Category: full indoor, capable of multichannel transmissions over a single antenna.
NOTE: For simplicity, systems with space diversity arrangement, providing longer hop lengths in critical
propagation conditions, are not considered. It should be noted that systems with space diversity
arrangements, reaching higher hop lengths with the same capacity at the expense of a few watts of power
consumption due to a double receiver, provide in general a better value of EEER.
• Traffic: suitable for packet traffic transport.
• Architecture for packet traffic handling: including relatively simple L2 switch between at least two Ethernet
ports.
• Frequency bands: any frequency band from 4 GHz to 13 GHz.
• Supporting Adaptive Modulation: from 4 QAM up to 512 QAM (or more).
• Typical application: long distance transport/backhaul.
5.2.2.2 Reference parameters
The evaluation of EEER needs a number of input parameters to be defined properly, in order to define the exact
conditions used for the EEER evaluation.
• Reference ITU Recommendations.
• Signature (Kn).
NOTE 1: In the typical applications on the frequency range under analysis, it is known that the impact of selective
fading is by far more influent than the effect of rain which has not been considered. Opposite approach
has been considered in clause 5.3 for higher frequency ranges.
• Reference channel spacing.
• Reference link design objective: link performance/quality (e.g. SES as defined in Recommendation
ITU-R F.1668 [i.13]).
NOTE 2: In the typical applications on the frequency range under analysis, the link performance in terms of quality
has been selected as reference parameter as normally that requirement is more stringent than the link
availability that has been used in clause 5.3 for higher frequency ranges.
• Reference antenna gain.
In clause 5.2.3 the reference factors, both reference system and reference parameters, are made explicit in order to
clearly define the conditions for which the EEER calculation is applicable.
5.2.3 Reference case
5.2.3.1 Reference system
• Full indoor systems suitable for packet data transmission
For indoor system in multi-branching arrangement, where the system baseband part can have a huge impact on
power consumption, it has been considered to average the power consumption based per equivalent channel.
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14 ETSI TR 103 820 V1.1.1 (2015-11)
• Configuration: 4+0 system using 4 RF channels.
The whole power consumption is in this case divided by 4.
For indoor systems the antenna interconnection losses are expected to be considered when whole system gain is
evaluated. It is considered here, a typical guideline length of 30 m + 30 m, including both sides of the link.
According to a typical commercial waveguide the following values are used:
• 6 GHz, 7 GHz, 8 GHz  4,9 dB / 100 m × 60 m = 2,94 dB
• 10 GHz and 11 GHz   8,9 dB /100 m × 60 m = 5,34 dB
• Average case        4 dB
NOTE: It has been assumed, in average, 4 dB for all cases, reflecting in higher interconnection length for lower
frequency bands or higher losses solution for the feeder and vice versa, lower interconnection length for
higher frequency bands or less losses solution for the feeder.
5.2.3.2 Reference parameters
Reference ITU-R recommendations:
• Rain attenuation model: Recommendation ITU-R P.530-15 [i.6].
• Performance objectives: Recommendation ITU-R F.1668-1 [i.13].
• Error performance parameters: Recommendation ITU-T G.826 [i.9].
Reference channel spacing
In practice, AM systems can be preset for a number of different CS (e.g. from 7 GHz to 56 MHz). The power
consumption does not depend on the selected CS.
However it is necessary to define a specific CS as reference, because that value is used when declaring the
supported capacity and the SG.
The recommendation is to use CS about 30 MHz (28 MHz to 30 MHz), as that is the most popular CS in the
considered frequency bands.
Reference link design objective: SES < 10
In frequency bands up to 13 GHz, it has been considered that the link design is done using as target the
concept of Severely Errored Second (SES) (According to Recommendation ITU-T G.826 [i.9],
Recommendation ITU-R F.1668-1 [i.13]) instead of the link availability.
Summarizing the assumptions: ITU quality target is usually between 0,1 SES/month/km and
0,2 SES/month/km with a minimum hop length of 50 km (i.e. 50 km 5 SES/month to 10 SES/month). As
consequence, SES < 10 is used as reference value as it is considered a "normal target".
A good summary of that matter can be found in ITU-R 5C/345 [i.10].
Reference Modulation
All the discussed parameters (SG, HL and Capacity) depend on the modulation format with which they are
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evaluated; therefore, one reference modulation for their calculation has to be defined.
Considering that the power consumption (P ) has little or no variation with the actual modulation format, it
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has been concluded that EEER should focus on "relatively high capacity" applications.
128 QAM has been chosen in the present case.
ETSI
15 ETSI TR 103 820 V1.1.1 (2015-11)
Reference antenna gain
Antennas are usually offered with different size options and that clearly influences the HL reachable by the
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system. For comparing EEER of different sources a reference antenna gain is recommended for each
frequency band.
Considering that the typical value of high gain antennas at various frequencies bands is ranging from 42 dBi to
46 dBi, the reference value of 44 dBi has been used.
Capacity
The most immediate choice for defining the system capacity would have been the RIC as defined in
ETSI EN 302 217-1 [i.4], but that is not the most appropriate definition for the purpose of the present analysis.
EEER is an index related to the "real work" made by the equipment; therefore, it seems more appropriate to
link it to the real Ethernet data capacity parameter.
This would mostly skip the capacity dedicated to error correction, which, on the other hand would already
directly impact HL through the improvement of SG. Therefore, it seems appropriate not to consider error
correction twice in the calculation.
Layer 2 header compression, if any, should also be excluded.
In conclusion the capacity is expected to be stated by the supplier with reference modulation and reference
channel spacing.
In conclusion, the capacity is defined as:
- Ethernet layer 2 throughput at 64 bytes frames (Mbit/s).
- No interframe gaps.
- No compressions.
TX output power
When calculating Hop length the output power used is the maximum output power used for planning the link
according to the conditions described above (modulation, availability, etc.).
RX threshold
When calculating Hop length the RX threshold used is the RX threshold used for planning the link according
to the conditions described above (modulation, quality, etc.).
Power consumption
The power consumption is the typical power consumption at nominal environmental conditions for the
equipment. For this specific case it is based on 4 channels system.
5.2.4 SG, Signature and HL
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5.2.4.1 Methodology
The method used for deriving the reference table for system gain (SG) plus Signature (Kn) to Max Hop Length HL
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conversion is according to the Recommendation ITU-R P.530-15 [i.6].
The main factor relevant for this calculation is the p parameter, defined as the "multipath occurrence factor". The
description of p and its impact on the fading occurrence is described in Figure 3 of Recommendation
ITU-R P.530-15 [i.6].
p , according Recommendation ITU-R P.530-15 [i.6], is derived considering the characteristics of a given region and
others parameters related to the link, such as "altitude of the lower antenna" hl (hl equal to 100 meters has been used in
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