ETSI TR 102 681 V1.1.1 (2009-06)

Reconfigurable Radio Systems (RRS); Radio Base Station (RBS) Software Defined Radio (SDR) status, implementations and costs aspects, including future possibilities

DTR/RRS-02003

General Information

• Status: Published
• Publication Date: 17-Jun-2009
• Technical Committee: RRS 2 - REA - Reconfigurable Radio Equipment Architecture
• Current Stage: 12 - Completion
• Due Date: 30-Jun-2009
• Completion Date: 18-Jun-2009

Standards Content (Sample)

ETSI TR 102 681 V1.1.1 (2009-06)
Technical Report


Reconfigurable Radio Systems (RRS);
Radio Base Station (RBS) Software Defined Radio (SDR)
status, implementations and costs aspects,
including future possibilities

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2 ETSI TR 102 681 V1.1.1 (2009-06)



Reference
DTR/RRS-02003
Keywords
air interface, base station, configuration
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3 ETSI TR 102 681 V1.1.1 (2009-06)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 6
4 RRS RBS requirements . 7
4.1 Re-configurability requirements from use cases . 7
4.1.1 Generic requirements for reconfigurable RBS . 7
4.1.2 Potential additional requirements for Femto/home-RBS . 8
4.2 Stakeholder requirements . 8
4.2.1 Operator requirements . 8
4.2.2 OEM requirements . 10
4.3 Power efficiency and energy consumption . 10
5 Architectures for current RBS . 10
5.1 Basic RBS architecture . 10
5.2 Re-configurable radio architecture examples . 11
5.2.1 Example architecture from E2R and E3 projects . 11
5.2.2 Re-configurable architecture from RRS for UE. 14
5.2.3 SDR Forum architectures . 15
5.3 Existing RBS interfaces . 15
5.3.1 CPRI . 15
5.3.2 OBSAI . 15
5.3.3 Other interfaces . 16
6 Re-configurable architectures . 16
6.1 Configuration control . 17
6.2 S/W management . 17
6.3 Operations and maintenance. 18
6.4 Backhaul management . 18
6.5 Spectrum management . 18
6.6 Multi-radio control . 18
6.7 Antenna management . 18
6.8 Power management . 18
6.9 Mobility management . 19
6.10 Radio resource management. 19
7 Technology development . 19
8 Energy consumption aspect of re-configurability . 20
9 Recommendations . 22
History . 24

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4 ETSI TR 102 681 V1.1.1 (2009-06)
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://webapp.etsi.org/IPR/home.asp).
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 Reconfigurable Radio Systems (RRS).
Introduction
The present document provides the results of a feasibility study carried out under the ETSI TC on reconfigurable radio
systems (RRS). The target of the study was to investigate the need for standardization within the cellular radio base
station to address the requirements resulting from on-situ reconfiguration of future RBS.
The study addresses current radio base station architectures, the possibilities provided by software radio architectures
and the requirements of future RBS. The study considers also the impact of re-configurability on the total life cycle
energy consumption and the environmental impact of radio base stations.
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5 ETSI TR 102 681 V1.1.1 (2009-06)
1 Scope
The scope of the present document is to investigate and assess possible architectures, related qualities and
corresponding costs of reconfigurable radio base stations (RBS). It covers public radio systems working on licensed
bands (including GSM, WCDMA, LTE, WiMax and similar).
The present document will include expected future technology and cost developments of these architectures. Definition
of key possible requirements for SDR applications in RBS, the impact on RBS architecture, network management and
equipment certification. It covers reconfigurable RBS on a generic level independent of power classes defined in 3GPP.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
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 indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
Not applicable.
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] White Paper of the European Project IST-E2R II (June 2007): "End-to-End Reconfiguration
Management and Control System Architecture", Zachos Boufidis, Eleni Patouni, Nancy
Alonistioti.
[i.2] IST-E2R II Contribution to ETSI Workshop (February 2007): "End-to-End Reconfigurability
(E2R II) Management and Control of Adaptive Communications Systems", Didier Bourse, Markus
Muck.
NOTE: Available at http://www.etsi.org/website/document/Workshop/SoftwareDefinedRadio/SDRworkshop1-
1DidierBourse.pdf.
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6 ETSI TR 102 681 V1.1.1 (2009-06)
[i.3] ICT Summit (2006): "E²R SDR Equipments : towards Proof-of-Concept and Standardization", E.
Nicollet, Ulf Lücking, Siegfried Walter, Björn Mennenga, Laurent Alimi.
NOTE: Available at http://www.vodafone-
chair.com/staff/mennenga/publications/2006/E2RII_35_ICT06_Paper.pdf.
[i.4] ETSI TR 102 680: "Reconfigurable Radio Systems (RRS); SDR Reference Architecture for
Mobile Device".
[i.5] SDRF-01-P-0006-V2.0.0: "Base Station System Structure".
NOTE: Available at http://www.sdrforum.org/pages/documentLibrary/documents/SDRF-01-P-0006-
V2_0_0_BaseStation_Systems.pdf.
[i.6] ETSI TR 102 530: "Environmental Engineering (EE); The reduction of energy consumption in
telecommunications equipment and related infrastructure".
[i.7] Life cycle analysis of communication system, Jens Malmodin, Green Telco 2009.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
radio application: software application executing in software defined radio equipment
NOTE Radio application is typically designed to use certain radio frequency band(s) and it includes agreed
schemes for multiple access, modulation, channel and data coding as well as control protocols for all
radio layers needed to maintain user data links between adjacent radio equipments, which run the same
radio application.
radio equipment: equipment using radio technology
radio technology: technology for wireless transmission and/or reception of electromagnetic radiation for information
transfer
radio system: system, which consists of a number of radio equipments using at least one common radio technology
reconfigurable radio equipment: radio equipment supporting reconfigurable radio technology
reconfigurable radio system: radio system using reconfigurable radio technology
reconfigurable radio technology: radio technology allowing the modification of modulation, frequency or power by
S/W, possibly with extensions for cognitive radio
NOTE: Re-configurability includes the typical understanding of SDR like the ability to change RAT
(Re-configurable within 3GPP standards like EDGE/ WCDMA/ LTE), re-configurability between all
standards, capacity upgrades to match future needs and mixed or flexible spectrum (single or multi-band)
usage.
software defined radio equipment: radio equipment supporting SDR technology
software defined radio system: radio system using SDR technology
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
BB BaseBand
CAPEX CAPital EXpenditure
CCM Configuration Control Module
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7 ETSI TR 102 681 V1.1.1 (2009-06)
CEM Configurable Execution Modules
CMM Configuration Management Module
CPRI Common Public Radio Interface
CR Cognitive Radio
EOL End Of Life
GSM Global System for Mobile communications
HSPA High Speed Packet Access
IP Intellectual Property
IP Internet Protocol (as in TCP/IP)
JEDEC Joint Electron Device Engineering Council
NOTE: JEDEC Solid State Technology Association.
LTE Long Term Evolution
MEMS Micro Electro-Mechanical Systems
MIMO Multiple Input Multiple Output
MURI MUlti-Radio access interface
OBSAI Open Base Station Architecture Initiative
OPEX OPerational EXpenditure
PCle Peripheral Component interconnect express
RAT Radio Access Technology
RBS Radio Base Station
REC Radio Equipment Control
RF Radio Frequency
RPI Radio Programming Interface
RRFI Reconfigurable RF Interface
RRS Reconfigurable Radio System
RX Receiver
SCA Service Component Architecture
SDR Software Defined Radio
SON Self Organizing Network
S-RMP Self-ware Reconfiguration Management and control Plane
TCP Transport Control Protocol
TM Trade Mark
TX Transmitter
URAI Unified Radio Application Interface
WCDMA Wideband Code Division Multiple Access
4 RRS RBS requirements
Re-configurability requirements are partly different for user equipment and RBS. In clause 4.1 we list general
requirements based on different use cases. In clause 4.2 different requirements based on telecom operator needs and
telecom infrastructure equipment manufacturers are listed.
4.1 Re-configurability requirements from use cases
4.1.1 Generic requirements for reconfigurable RBS
• Transition from one standard to a new (example GSM=> WCDMA, WCDMA=>LTE, etc.).
• Multi-standard use, frequency re-farming.
• Spectrum trading.
• Secondary spectrum usage.
• Dynamic capacity optimization depending on load (energy saving).
• Network planning and adaptation, antenna tuning.
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8 ETSI TR 102 681 V1.1.1 (2009-06)
• Backhaul reconfiguration for flat architecture.
These use cases above require the re-configurability of:
a) Modulation and BW.
b) Frequency allocation (existing bands and future bands, cognitive radio).
c) Dynamic spectrum allocation.
d) Multi-standard operation.
e) Power levels, capacity, efficiency.
f) FDD/TDD operation change.
g) Network architecture modifications.
4.1.2 Potential additional requirements for Femto/home-RBS
It is expected that there will be a future market for reconfigurable Mobile Devices that offer the possibility to either
operate as a standard Mobile Device entity providing voice/data service access to end-users and/or as a
Femto-Base-Station (Femto-BS). In order to enable an efficient implementation, such "Dual Mode" devices require the
following:
• The Femto-BS mode of the corresponding "Dual Mode" device should build on a standard architecture
typically applied for Reconfigurable Mobile Devices, for example such as it is defined in TR 102 680 [i.4].
Suitable extensions to such available architectures need to be defined.
• The corresponding device is expected to build on reconfigurable hardware, typically exploiting SDR
principles.
4.2 Stakeholder requirements
The following requirements are collected from the needs of current stakeholders. The requirements are separated
according to the different stakeholders. A requirement is mentioned in multiple sections if it applies for several stake
holders.
4.2.1 Operator requirements
The development of different systems which coexist temporally and geographically requires to manage at the same time
and in the same area, two or more systems in order to adapt the network to the characteristics of the traffic and optimize
the resource usage. Typically, said problem rises for an operator who has already an installed network and wants to add
a new network related to a new generation system (e.g. to add an LTE network to a 2G-3G network already deployed).
Moreover, the operator wants to be able to manage dynamically the hardware resources dedicated to the existing system
and to the new generation system, according to the traffic variation that insists on the cells of a certain area.
Considering a cell set in a certain area, it is possible that the traffic of different services on a specified system (or
different systems), changes from one area to the other according to the day period. Moreover it could happen that some
cells may be congested (high call blocking percentages) in some particular area while surrounding cells are less loaded
or characterized by low blocking percentages. In addition, in case of deployment of two or more RATs in the area, the
traffic from different services on each deployed RAT could also be differently distributed in time with respect to the
other deployed RATs.
In this context, the availability of reconfigurable nodes in the networks (i.e. nodes whose hardware and processing
resources can be reconfigured in order to be used with different RATs, frequencies, channels, etc.) will give the network
operators the means for managing in an overall efficient way the radio and processing resource pool, with the aim to
adapt the network itself to the dynamic variations of the traffic offered to the deployed RATs and to the different
portions of the area. Besides of that, possible OPEX and CAPEX reduction could be obtained in network deployment.
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9 ETSI TR 102 681 V1.1.1 (2009-06)
In a Basic scenario we consider a mature network evolution example. We assume a residual GSM and UMTS
infrastructure and starting LTE deployment: all standards within the operator's licensed spectrum. Currently the access
nodes are configured manually by Operator. In the future we expect that the access nodes are configured by the network
automatically. All RATs implemented (e.g. by software) in the RBS are fully compliant with the current existing
standards (e.g. GSM, UMTS, LTE, WIMAX, etc.) and related regulatory restrictions (bands, frequencies, power levels,
spectrum masks).
Basics requirements for network planning:
• Availability of a tool to make a coverage forecast considering different self configuring radio access network
scenarios.
Basic requirements for Radio network deployment:
• Reduced surface/volume radio nodes.
• Standardization of mechanical aspects of equipment installation like cabinet, number type and position of RF,
power, data and alarm connectors.
• Standardization of RF connection between access node and antennas (passive RF elements, duplexer,
combiners).
• Standardization of link between access node and core network (only one physical link to manage different
standards links).
• RBSs are completely compatible with the current deployed network elements; this means that RBSs should
use common standardized interfaces (new or existing modified ones) that guarantee a transparent introduction
in the current networks.
• RBSs are deployed and configured by the Operator according to its needs, e.g. exploiting current and future
standardized SON capabilities.
Basic requirements for Network operation:
• RBS is able to be reconfigured in both hardware (e.g. both BB and RF) and radio resources for each supported
RAT.
• RBSs should be multi-standard reconfigurable nodes.
• The percentage of hardware/processing resources devoted to each supported RAT can be dynamically
modified.
• The number of frequencies/channels assigned to each supported RAT can be dynamically modified.
• RBSs are able to be reconfigured taking into account the experimented network and users conditions
(e.g. traffic and/or interference conditions).
• RBS should be able to receive and execute reconfiguration commands coming from entities that manage the
reconfiguration of the network via common standardized interfaces; such entities should be located e.g. in
access or in core network or in O&M nodes, considering also flat architectures (e.g. HSPA+ and/or LTE
based).
• The reconfiguration phase of a RBSs are performed in real-time and/or in the fastest way without the necessity
to shut down and restart the device (e.g. in case of Multi-RAT operations/reconfigurations).
• RBS could be able to manage both operator's and other possible available spectrum to provide subscriber
demands, considering behaviour of standard/services (coverage, capacity, mobility) in different frequency
bands.
• RBSs should be efficient from the "green aspects" point of view (e.g. power consumption and related issues).
• Reduced power consumption according to TR 102 530 [i.6].
• Improved temperature operating range.
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10 ETSI TR 102 681 V1.1.1 (2009-06)
Maintenance requirements:
• Reduced number of different spare parts required for maintenance purposes: increasing compatibility degree
(mechanical, electrical, protocol level) between the building blocks of every node for every supplier, reduce
the number of building blocks of every node and making sure that building blocks will not need a hardware
upgrade for new standards.
4.2.2 OEM requirements
The growing number of radio standards, frequency allocations and RBS classes dramatically increase the number of
product variants. Re-configurability is considered to ease product logistics:
• Customer requirement/competition.
• S/W upgrade of existing products (GSM=> EDGE, WCDMA=>HSPA), capacity upgrade.
• Maintenance (O&M and other support system).
• Limited number of test cases.
• Certification.
• Reliability (H/W & S/W reliability).
• Product roadmap management.
4.3 Power efficiency and energy consumption
Energy consumption should be considered for the complete life cycle of the RRS (materials, production, delivery,
operation, end of life).
Lifetime energy consumption (energy consumed during operations).
Power efficiency is defined as RF power divided by DC input power for a given use pattern.
Embedded energy (materials, components, production, EoL).
5 Architectures for current RBS
The present document covers the part of the network which is typically called "radio base station" (RBS, NodeB,
eNodeB, etc.). It includes all elements of a RBS including:
• RBS control and reconfiguration control.
• Radio front-end (frequency selective part).
• Signal processing part.
• Network processor, RNC functionality, etc.
• RRS core network solutions are included in many SDR discussions. This is considered beyond the mandate of
the work item.
5.1 Basic RBS architecture
The RBS as considered above can be divided into high level functional blocks. The transport and baseband functions
are purely digital signal processing and provide the largest potential for S/W re-configurability. The TRX block
contains radio frequency components, which poses a basic H/W limits, also today's broadband technologies allow a
wide range of configuration. The final RF part is frequency selective and power limited by its H/W implementation. It
poses the biggest challenge regarding configurability.
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Antenna
Antenna(s)
Duplexer
Duplexer
Transport
Transport
Backhaul Backhaul
 11 ETSI TR 102 681 V1.1.1 (2009-06)
LinPA
Baseband TRX
TRX
LNA
Signal Broadband
Processing Frequency
processing radio
selective
f
REF
Frequency Broadband Freq. selective
Backhaul
independent RF RF power
Pow er supply O&M Co n t r o l
11-2008 © HOS
DC power

Figure 1: Basic RBS functional blocks
Above RBS block diagram is often split into a system unit and one or multiple radio units. The system unit includes the
transport (backhaul) unit, timing, coding, control, multi-radio and multi- antenna processing, control, O&M, etc. The
radio unit includes channelization, modulation, all analogue RF processing, power amplifier and filtering. This
architecture supports remote radio applications but also multi-antenna solutions like MIMO and beam forming.
System Unit
Radio Unit(s)
LinPA
Baseband
LNA
Signal
Frequency
processing
f
selective
REF
O&M
OBSAI/CPRI
11-2008 © HOS
TRX
TRX
Broadband
Processing
radio
Power supply Co n t r o l
DC power
DC power

Figure 2: RBS architecture with separate radio units
5.2 Re-configurable radio architecture examples
Several groups made an attempt to define re-configurable radio architectures with different key applications in mind.
5.2.1 Example architecture from E2R and E3 projects
2
The IST-E R II project addressed two distinct types of architecture: A System Architecture is defined as presented in
[i.1], relying on the definition of system-wide functionalities on an abstract plane (the so-called Self-Ware
Reconfiguration Management Plane (SRMP)). The break-down of these functionalities on the various physical entities
is performed in a second step.
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12 ETSI TR 102 681 V1.1.1 (2009-06)

2
Figure 3: E R II high-level system architecture for cognitive reconfigurable
wireless networks (see [i.1])
As detailed in [i.1], the S-RMP provides elements (terminal equipment, base stations, and routers) with the necessary
control and management capabilities so as to be autonomously reconfigured. The SRMP offers the following
reconfiguration services:
• over-the-air software-download resulting in upgrade of equipment capabilities;
• dynamic spectrum access and exchange;
• dynamic network attachment and intersystem handover; and
• reconfiguration
...