ETSI TR 145 926 V13.0.0 (2016-02)

ETSI TR 1145 926 V13.0.0 (201616-02)






TECHNICAL REPORT
Digital cellular telecommmmunications system (Phase e 2+) (GSM);
Solutions for for or GSM/EDGE BTS Energy Savaving
(3GPP TR 45.9.926 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS

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3GPP TR 45.926 version 13.0.0 Release 13 1 ETSI TR 145 926 V13.0.0 (2016-02)



Reference
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3GPP TR 45.926 version 13.0.0 Release 13 2 ETSI TR 145 926 V13.0.0 (2016-02)
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 (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.
Foreword
This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
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.
ETSI

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3GPP TR 45.926 version 13.0.0 Release 13 3 ETSI TR 145 926 V13.0.0 (2016-02)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Symbols . 7
3.3 Abbreviations . 7
4 Study Considerations . 9
4.0 General . 9
4.1 Network Scenario Considerations . 9
4.2 Energy Consumption of BTS . 9
5 Objectives . 10
5.1 Performance Objectives: energy efficiency target . 10
5.2 Compatibility Objectives . 10
5.2.1 Avoid impact to voice user call quality . 10
5.2.2 Avoid impact to data user session quality . 10
5.2.3 Avoid impact to cell (re)selection and handover . 10
5.2.4 Support of legacy MSs . 10
5.2.5 Implementation impacts to new MSs . 10
5.2.6 Implementation impacts to BSS . 10
5.2.7 Impacts to network planning . 11
6 Common Assumptions . 11
6.1 Reference Configuration . 11
6.2 Evaluation Metrics . 12
6.3 Traffic Load profiles . 12
6.4 Reference deployment scenarios . 13
6.5 MS characteristics . 16
6.5.1 BCCH carrier power measurement sampling . 16
6.5.1.1 Idle mode . 16
6.5.1.2 Connected mode . 18
6.5.2 BCCH carrier power measurement accuracy . 18
6.5.3 BCCH carrier power measurement averaging . 18
6.5.4 BSIC Decoding . 18
6.5.5 Power reduction on TS preceding BCCH timeslot . 19
6.5.6 Handover, Cell Selection and Cell Reselection . 19
6.5.7 Mobile velocity . 19
6.5.8 Mobile station types . 19
6.6 BTS characteristics . 19
6.6.1 Network synchronization . 19
6.6.2 Modelling of TRX power consumption . 20
7 Candidate Solution: BCCH Carrier Power Reduction Methodology . 20
7.1 Introduction . 20
7.2 Methodology . 20
7.2.1 Variant 1 . 20
7.2.2 Variant 2 . 21
7.3 Evaluation. 21
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7.3.1 Simulation Assumptions . 22
7.3.2 Evaluations . 23
7.3.2.1 Impacts to Radiated Power and Power Consumption . 23
7.3.2.2 Impacts to Call Quality . 24
7.3.2.3 Impacts to Handover . 25
7.4 Conclusion . 26
8 Candidate Solution: Output Power Reduction on BCCH Carrier for GMSK . 27
8.1 Introduction . 27
8.2 Concept Description . 27
8.2.1 Overview . 27
8.2.2 Exemplary Scenario . 27
8.3 Concept Evaluation . 28
8.3.0 Overview . 28
8.3.1 Simulation Model . 28
8.3.1.1 Simulation Assumptions . 28
8.3.1.2 Channel Allocation Strategies . 31
8.3.1.3 Deployment Scenarios and Network Layout . 31
8.3.1.4 Output Power Reduction Settings on BCCH carrier . 32
8.3.1.5 Employed Link-to-System Mapping . 33
8.3.2 Simulation Results . 33
8.3.2.1 Scenario S1 . 33
8.3.2.2 Scenario S2 . 34
8.3.2.3 Scenario S3 . 35
8.3.2.4 Scenario S4 . 36
8.3.2.5 Scenario M1 . 36
8.3.2.6 Scenario M2 . 37
8.3.2.7 Impact on performance of neighbour cell identification in connected mode . 38
8.3.2.8 Impact on performance of neighbour cell identification in idle mode . 39
8.3.2.9 Results for the alternative MS velocity . 41
8.3.2.9.1 Scenario S5 . 41
8.3.2.9.2 Scenario S6 . 42
8.3.2.9.3 Impact on performance of neighbour cell identification in connected mode . 43
8.3.2.9.4 Impact on performance of neighbour cell identification in idle mode . 43
8.3.3 Impact to Specifications . 44
8.3.3.2.1 Example implementation of option 2 in the specifications . 47
8.3.3.3.1 Example implementation of option 3 in the specifications . 50
10.5.2.11 Control Channel Description . 50
8.4 Conclusion . 52
9 Summary and Conclusions . 53
Annex A: Bibliography . 55
Annex B: Change history . 56
History . 57

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3GPP TR 45.926 version 13.0.0 Release 13 5 ETSI TR 145 926 V13.0.0 (2016-02)
Foreword
rd
This Technical Report has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
Introduction
Energy saving is important for operators' operational efficiency. Energy consumption is a significant operational cost
factor, for example in developing markets, up to 30% of OPEX is spent on energy. For one operator group, almost 80%
of base stations in Africa and India use diesel as the primary or as a backup power source. Furthermore, base stations
account up to 80% of the total CO emissions in a mobile operator network. Many operators have a target to cut CO
2 2
emissions as part of their environmental objectives. With increasing voice usage, data usage (e.g. introduction of smart
phones, MTC devices, etc.) and more dense networks, the thirst for energy consumption is expected to increase further,
hence, motivating the need for low energy base station technology. Increasing the energy efficiency of base stations or
reducing the energy consumption of base stations will also facilitate the possibility for operators to power all types of
base stations with alternative fuels and rely less on fossil fuels either from diesel generators or from the electricity grid.
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1 Scope
The present document provides a study into BTS energy saving solutions. The present document analyses and evaluates
different solutions to determine the benefits provided compared to the legacy BTS energy consumption.
In the scope of this study there are following solutions:
- Reduction of Power on the BCCH carrier (potentially enabling dynamic adjustment of BCCH power)
- Reduction of power on DL common control channels
- Reduction of power on DL channels in dedicated mode, DTM and packet transfer mode
- Deactivation of cells (e.g. Cell Power Down and Cell DTX like concepts as discussed in RAN [4])
- Deactivation of other RATs in areas with multi-RAT deployments, for example, where the mobile station could
assist the network to suspend/minimize specific in-use RATs at specific times of day
- And any other radio interface impacted power reduction solutions
The solutions will also consider the following aspects:
- Impacts on the time for legacy and new mobile stations to gain access to service from the BTS
- Impacts on legacy and new mobile stations to keep the ongoing service (without increasing drop rate)
- Impacts on legacy and new mobile stations implementation and power consumption, e.g. due to reduction in DL
power, cell (re-)selection performance, handover performance, etc.
- Impacts on UL/DL coverage balance, especially to CS voice
Solutions will be considered for both BTS energy saving non-supporting and supporting mobile stations (i.e. solutions
that are non-backwards compatible towards legacy mobile stations will be out of the scope of this study).
The contents of the present document when stable will determine the modifications to existing GERAN specifications.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TR 41.001: "GSM Release specifications".
[3] ETSI TS 102 706: "Energy Efficiency of Wireless Access Network Equipment".
[4] 3GPP TR 25.927: "Solutions for Energy Savings within UTRA NodeB", V.10.0.0
[5] 3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
[6] 3GPP TS 45.008: "Radio subsystem link control".
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[7] 3GPP TR 45.913: "Optimized transmit pulse shape for downlink Enhanced General Packet Radio
Service (EGPRS2-B)".
[8] 3GPP TR 45.050: "Background for Radio Frequency (RF) requirements".
[9] 3GPP TR 45.914: "Circuit switched voice capacity evolution for GSM/EDGE Radio Access
Network (GERAN)".
[10] 3GPP TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".
[11] 3GPP TR 45.912: "Feasibility study for evolved GSM/EDGE Radio Access Network (GERAN)".
[12] 3GPP TS 44.018: "Mobile radio interface layer 3 specification; Radio Resource Control (RRC)
protocol".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A
term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].
busy hour: one hour period during which occurs the maximum total load in a given 24-hour period
busy hour load: average BTS load during busy hour
energy efficiency: relation between the useful output and energy/power consumption
low load: average BTS load during time when there is only very low traffic in network
medium term load: defined BTS load level between busy hour and low load levels
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
TR 21.905 [1].
AFS Adaptive multirate Fullrate Speech
AHS Adaptive multirate Halfrate Speech
APD Average Power Decrease
BBU Base Band Unit
BHT Busy Hour Traffic
BTS Base Transceiver Station
DARP Downlink Advanced Receiver Performance
EGPRS Enhanced General Packet Radio Service
EGPRS2 Enhanced General Packet Radio Service phase 2
FTP File Transfer Protocol
GoS Grade of Service
IRC Interference Rejection Combining
LA Link Adaptation
MCBTS Multi-Carrier BTS
MCPA Multi-Carrier Power Amplifier
NC1 Network Control mode 1
RE Radio Equipment
SAIC Single Antenna Interference Cancellation
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SCPA Single Carrier Power Amplifier
TRX Transceiver
VAMOS Voice services over Adaptive Multi-user channels on One Slot
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4 Study Considerations
4.0 General
This clause depicts considerations on appropriate network scenarios and on qualitative analysis of the BTS energy
consumption.
4.1 Network Scenario Considerations
All the scenarios to be studied in BTS energy saving are listed in this subclause. The scenarios should consider
deployment, GERAN configuration (e.g. CS+PS resource dimensioning, EGPRS, EGPRS2), cell utilization, etc.
Below is a list of aspects that could be used to characterize the energy saving scenarios:
- Deployment and coverage:
- GERAN only, multi cell, single band, 900 coverage layer
- GERAN only, multi cell, single band, 1800 capacity layer
- GERAN only, multi cell, dual band with 900 coverage layer, 1800 capacity layer
- BTS type and configuration:
- Number of sectors and carriers
- SCPA (Normal BTS) and MCPA (MCBTS)
- The following traffic and load models are assumed:
- SDCCH configuration model
- Traffic load profiles for low load, medium term load and busy hour load subscriber traffic (derived from
ETSI TS 102 706 [3], Annex D)
- Backward compatibility to previous MS releases
4.2 Energy Consumption of BTS
This clause contains a qualitative analysis of energy consumption breakdown of current BTSs for different
antenna/carrier configurations, topologies and DL and UL loading scenarios.
The components listed below are the main parts in a BTS energy consumption breakdown, containing BBU, REs,
power supply, coaxial feed, and other related consumptions. The relation in Table 4.2-1 is summarized based on a
variety of configurations of BTSs under a low load assumption specified as 10% in ETSI TS 102 706 [3].
Table 4.2-1: Power Consumption breakdown of a BTS
Qualitative contribution to
BTS component
Total Power Consumption of BTS
Base Band Unit (BBU) Medium
Radio Equipments (RE) High
Primary DC Power Supply (i.e.
Medium
rectifiers, battery)
Coaxial feed Medium
pressurization/dehydration (vary with feeder length and diameter)
Other related consumption(like
Low
fan, lighting, alarm, etc.） (under typical environmental conditions)

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From Table 4.2-1, the BTS component RE appears to contribute the most to the total BTS power consumption.
However, the qualitative analysis above does not take into consideration the different permutations of BTS type and
configuration, which can influence alternative energy saving solutions and is an important aspect in the definitions of
the scenarios.
5 Objectives
This clause describes how to evaluate the solutions and the rules for adopting energy saving solution into the present
document. To this purpose performance and compatibility objectives are defined. For each objective an evaluation
metric will be defined for benchmarking the proposed candidate solutions. A candidate solution will not be necessarily
discarded, if it does not fulfil a particular objective, but this will be taken into account in the overall evaluation of the
candidate solution and in the comparison against other candidate solutions.
5.1 Performance Objectives: energy efficiency target
The energy efficiency
...