ETSI TR 102 802 V1.1.1 (2010-02)

Technical Report
Reconfigurable Radio Systems (RRS);
Cognitive Radio System Concept

2 ETSI TR 102 802 V1.1.1 (2010-02)

Reference
DTR/RRS-01002
Keywords
architecture, network, radio
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3 ETSI TR 102 802 V1.1.1 (2010-02)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 8
4 Objectives and Requirements for CR Systems . 9
4.1 Objectives of the CR Systems . 9
4.1.1 More efficient and flexible use of spectrum . 9
4.1.2 Enhancing User Experience . 9
4.1.3 Optimization of the mobile operator network . 10
4.1.4 Other Objectives of CR Systems . 11
4.2 Spectrum Use Scenarios for CRS . 11
4.2.1 Dedicated spectrum (licensed bands) . 11
4.2.2 Shared Spectrum in bands without primary users . 12
4.2.3 Secondary usage in bands with primary users . 12
4.2.4 Spectrum dedicated for CRS . 12
4.3 Technical Requirements on CR Systems . 12
5 Technical Framework for Cognitive Radio System . 14
5.1 Spectrum Management Layers for Cognitive Radio Systems . 14
5.2 Architectural Approaches for Cognitive Radio Systems . 15
5.3 Communication Planes in CRS Network Elements . 17
5.4 Enabling Technologies for CR Systems . 18
5.4.1 Pre-cognitive radio technologies . 18
5.4.2 Software Defined Radio and Multiradio . 18
5.4.3 Reconfigurable Base Stations Management . 19
5.4.4 Spectrum Sensing . 20
5.4.5 Cognitive Pilot Channel . 20
5.4.6 Cognitive Control Radio and Networking . 21
5.4.7 Geolocation . 22
5.4.8 Primary Protection Database. 22
5.4.9 Distributed Decision Making . 22
5.4.10 Other technical enablers . 22
6 CRS Standardization in other bodies . 22
6.1 IEEE Standard P1900.4 . 22
6.2 IEEE 802 activities on TV White Spaces . 23
6.3 ITU-R studies on Cognitive radio systems . 23
7 Conclusions and Recommendations . 23
Annex A: CRS Standardization in other bodies . 24
A.1 CRS concept in IEEE 1900.4 system . 24
A.1.1 Introduction . 24
A.1.2 IEEE 1900.4 context. 24
A.1.3 IEEE 1900.4 use cases . 25
A.1.4 CRS concept in IEEE 1900.4 . 26
A.2 CRS Standardization in IEEE 802 LAN/MAN Standards Committee . 27
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4 ETSI TR 102 802 V1.1.1 (2010-02)
A.2.1 Activities to define Cognitive Radio Systems . 27
A.2.1.1 IEEE draft standard P802.22. 27
A.2.1.2 IEEE draft standard P802.11af . 28
A.2.2 Activities to define components of Cognitive Radio System . 28
A.2.2.1 IEEE standard 802.21 . 28
A.2.2.2 IEEE draft standard P802.22.1. 28
A.2.2.3 IEEE draft standard P802.19.1. 29
A.3 ITU-R activities related to CRS . 29
Annex B: Bibliography . 30
History . 31

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5 ETSI TR 102 802 V1.1.1 (2010-02)
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 (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 a feasibility study on reconfigurable radio systems which are capable to use
technological elements known as Cognitive Radio. An overall and harmonized technical concept for future Cognitive
Radio Systems is outlined.
There are several factors driving the future evolution of radio technologies and network architectures towards more
flexible and reconfigurable Cognitive Radio Systems:
Increasing growth of mobile traffic in terms of subscribers, data volumes and data rates
There are more than 3 billion mobile phone users today. There are estimations (e.g. by WWRF) that by 2017 there will
be 7 trillion wireless devices serving 7 billion users. To meet these expectations with the limited amount of radio
spectrum, more flexible ways to exploit the radio frequencies among multiple services and radio networks are needed.
Multitude of standards, Composite wireless networks and multiradio terminals
Many communication applications, which originated as tightly-coupled with specific radio technologies, would benefit
from decoupling the application from the radio platform. At the same time network operators are building composite
wireless networks to provide access to multiple services. When a multiradio terminal is having multiple applications
simultaneously active, there is a need to coordinate the operations of the different radios in order to reach the cost and
energy efficient use of overall radio communications capacity.
Regulators are starting to consider the extension of the possibility to allow secondary access to some frequency
bands, increasing spectrum utilization
In order to meet the increasing data traffic volumes regulators have started to consider the extension of the possibility to
allow wireless data devices to operate as secondary users on spectrum bands which traditionally have been dedicated to
their primary users alone. In the case, this sets new requirements to future radio technologies to deal with this possible
scenario. In November 2008 the US FCC issued a report and order which adopts rules to allow unlicensed "white space"
devices to operate in the broadcast television spectrum at locations where that spectrum is not being used by licensed
primary users.
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6 ETSI TR 102 802 V1.1.1 (2010-02)
1 Scope
The present document provides the objectives and properties for and formulates an overall and harmonized technical
concept for Cognitive Radio Systems. Both infrastructure as well as infrastructure-less radio networks will be covered.
The main scope of the present document is to illustrate how the reconfigurability and cognition functionalities can be
introduced in the future radio networks both on the terminal and network sides. Based on such system concept and
requirements the identification of candidate topics for standardization at ETSI concludes this study. The feasibility
study includes also a survey of related activities in other standardization bodies.
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] ETSI TR 102 838: "Reconfigurable Radio Systems (RRS); summary of feasibility studies and
potential standardization topics".
[i.2] ETSI TR 102 680: "Reconfigurable Radio Systems (RRS); SDR Reference Architecture for
Mobile Device".
[i.3] ETSI TR 102 682: "Reconfigurable Radio Systems (RRS); Functional Architecture (FA) for the
Management and Control of Reconfigurable Radio Systems".
[i.4] ETSI TR 102 683: "Reconfigurable Radio Systems (RRS); Cognitive Pilot Channel (CPC)".
[i.5] IEEE Std 1900.4-2009: "IEEE Standard for Architectural Building Blocks Enabling Network-
Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous
Wireless Access Networks", February 27, 2009.
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7 ETSI TR 102 802 V1.1.1 (2010-02)
[i.6] Final Draft Report RSPG09-299: "Radio Spectrum Policy Group Report on Cognitive
Technologies", EU Commission DG INFSO/B4/RSPG Secretariat, Brussels, October 14, 2009.
[i.7] E3 Deliverable D4.5: "Final system specification for autonomous CR functions", December 2009.
[i.8] E3 Deliverable D3.3: "Simulation based recommendations for DSA and self-management",
July 2009.
[i.9] IEEE P802.22 D2.0: "Draft Standard for Wireless Regional Area Networks Part 22: Cognitive
Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies
and procedures for operation in the TV Bands", May 2009.
[i.10] IEEE 802.22-09/0159r10: "PAR modification for portable CPEs", November 2009.
[i.11] IEEE 802.11-09/0934r8: "TVWS PAR and 5C", November 2009.
[i.12] IEEE Std 802.21-2008: "IEEE Standard for Local and metropolitan area networks - Part 21: Media
Independent Handover Services", January 2009.
[i.13] IEEE P802.22.1: "PAR, Standard to enhance harmful interference protection for low power
licensed devices operating in TV Broadcast Bands", March 2006.
[i.14] IEEE P802.19-09/0078r5: "TVWS Coexistence PAR", November 2009.
[i.15] Working Document towards Draft CPM Text on WRC-12 Agenda Item 1.19, September 2009.
[i.16] Cognitive radio systems in the land mobile service, Working Document towards a Preliminary
Draft New Report ITU-R [LMS.CRS], Annex 15 to Document 5A/305-E, June 2009.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
cognitive radio system: radio system employing technology that allows the system to obtain knowledge of its
operational and geographical environment, established policies and its internal state; to dynamically and autonomously
adjust its operational parameters and protocols according to its obtained knowledge in order to achieve predefined
objectives; and to learn from the results obtained
NOTE: This is the current definition of ITU-R Recommendation WP 1B.
cognitive control network: network of nodes in different cognitive radio networks communicating with each other for
controlling the frequency agile behaviour among the set of cognitive radio networks
cognitive control channel: logical channel between nodes belonging to a same cognitive control network
cognitive control radio: radio (technology) designed to carry cognitivity control information between cognitive control
network nodes
cognitive pilot channel: channel which conveys the elements of necessary information facilitating the operations of
Cognitive Radio Systems
radio technology: technology for wireless transmission and/or reception of electromagnetic radiation for information
transfer
NOTE: Radio technology 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 logical links for user data, which run the same radio application.
radio equipment: equipment using radio technology
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8 ETSI TR 102 802 V1.1.1 (2010-02)
radio network: network of radio equipments communicating with each other by using a common radio technology
NOTE: Typically a radio network has both control plane and user plane with their own protocols. A radio
network may also be subject to radio network management by an external network management system;
in this case a third plane of protocols, management plane is used for communicating network
management information.
software defined radio: radio transmitter and/or receiver employing a technology that allows the RF operating
parameters including, but not limited to, frequency range, modulation type, or output power to be set or altered by
software, excluding changes to operating parameters which occur during the normal pre-installed and predetermined
operation of a radio according to a system specification or standard
NOTE: This is the current definition of ITU-R Recommendation WP 1B.
software defined multiradio: device or technology where multiple radio technologies can coexist and share their
wireless transmission and/or reception capabilities, including but not limited to regulated parameters, by operating them
under a common software system
NOTE 1: Examples of the regulated parameters are frequency range, modulation type and output power.
NOTE 2: Common software system represents radio operating system functions.
NOTE 3: This definition does not restrict the way software is used to set and/or change the parameters. In one
example, this can be done by the algorithm of the already running software. In another example, software
downloading may be required.
spectrum sensing: act of measuring information indicative of spectrum occupancy
NOTE 1: Information may include frequency ranges, signal power levels, bandwidth, etc.
NOTE 2: Spectrum sensing may include obtaining additional information on how the sensed spectrum is used.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AFA Adaptive Frequency Agility
AP Access Point
BB baseband
BS Base Station
BTS Base Transceiver Station
C-NMS Cognitive Network Management System
CCN Cognitive Control Network
CCR Cognitive Control Radio
CMN Cognitive Mesh Network
CR Cognitive Radio
CRS Cognitive Radio System
CWN Composite Wireless Network
DAA Detect And Avoid
DFS Dynamic Frequency Selection
GSM Global System for Mobile communications (originally Groupe Spécial Mobile)
HPR Hardware Processing Resources
JRRM Joint Radio Resource Management
LBT Listen Before Talk
LTE Long Term Evolution
MAC Medium Access Control
MUE Multiradio User Equipment
NBAP NodeB Application Part (protocol)
O&M Operation and Maintenance
OSM Operator Spectrum Manager
PHY Physical layer
QoS Quality of Service
RAT Radio Access Technology
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9 ETSI TR 102 802 V1.1.1 (2010-02)
RF Radio Frequency
R-RBS Reconfigurable Radio Base Station
RRM Radio Resource Management
RRS Reconfigurable Radio Systems
UE User Equipment
UHF Ultra High Frequency
UMTS Universal Mobile Telecommunications System
UWB Ultra Wide Band
WLAN Wireless Local Area Network
WRC World Radio Conference
4 Objectives and Requirements for CR Systems
4.1 Objectives of the CR Systems
Cognitive Radio Systems are expected to increase the efficiency of the overall spectrum usage by offering new sharing
opportunities and also to provide more flexibility to applications as a result of their ability to adapt their operations to
external and internal factors.
The new sharing possibilities can facilitate access to new spectrum bands and the increased flexibility to applications
can improve the cost efficiency and capabilities to deliver various services as well as better take into account the users'
needs.
Cognitive Radio Systems are also expected to increase the efficiency and flexibility of the radio resource management
within mobile operator networks as a result of their ability to adapt their operations to external and internal factors.
4.1.1 More efficient and flexible use of spectrum
In practice, not all frequencies are in use full time. CRSs are able to identify the unused portions of spectrum and share
that spectrum without interfering with the existing users harmfully. Furthermore, the usage of the spectrum may vary
over the time and over different locations and in such case CRS can improve the efficiency and flexibility of spectrum
usage utilising the envisaged CR capabilities.
For this purpose, the CR Systems need to perform three key activities:
1) obtain knowledge of the radio operational environment and location;
2) decide on the gathered information; and
3) act based on this decision.
This kind of new way of spectrum utilization is expected to increase the capacity of the networks, allow access to new
spectrum bands and also increase the economic value of spectrum.
4.1.2 Enhancing User Experience
Enhancing user experience is one of the main objectives of the CRS. A user of a radio system is interested in receiving
high quality seamless service. From this perspective the CRS can enhance user experience.
This can be applied to the following situations:
1) Cross-Operator Access: A user may have several subscriptions to different services provided by different
operators. Also, the user can have different preferences, for example, short download time, stable connection,
low cost. By analyzing user preferences and user environment, the CRS can allow user to connect its terminal
to the wireless access network that best fits his/her current preferences.
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10 ETSI TR 102 802 V1.1.1 (2010-02)
2) User Network: A user may have different devices in his/her flat that need to be connected to each other and/or
to Internet. For convenient connection different types of devices may have different requirements, e.g. high
bandwidth, low power consumption, etc. By selecting appropriate operations parameters and protocols, the
CRS can provide the connection that best fits types of devices that user owns.
3) Flexible Access to the Future Internet: As it is currently the case also future systems will continue to
provide network access as their main service. Future Internet access requires new and innovative ways to
access the network, route data flows to their destination, and access information. Further the amount of
required information is steadily increasing resulting in needs for higher data rates and improved spectrum
utilization.
4) Connecting the smart spaces: Next to accessing a central network, in the future more and more devices will
be interconnected wirelessly, resulting in the need for fast device discovery, agile use of the spectrum to
facilitate ad-hoc interactions between devices and long life-times of networks under uncertain connectivity
circumstances.
4.1.3 Optimization of the mobile operator network
The challenge from operator perspective is to answer user needs in a timely and adapted manner satisfying the
requirements in terms of Capacity (throughputs) and QoS. Cognitive Radio system having the potential to obtain
information from the radio eco-system and analyse the radio operational environment can make the operator's network
react accordingly by optimizing the choice of radio access technologies and associated radio resources (always
optimized connected approach).
This can be applied to assist the optimization of the mobile operator network the following situations:
1) Load balancing
When load balancing mechanism is part of the optimization process in case of traffic variations in space/time
or nature of required service/application. Uplink traffic demand information from UE and/or dedicated sensors
can trigger the needed reconfiguration of the Multiradio elements both in the network and user multimode
terminals.
2) Spectrum refarming
A particular situation is that of spectrum refarming in the context of technology evolution and periodical
emergence of new families of standards. This implies their progressive introduction/coexistence in the legacy
"bands" rather than a simple and quick switchover which is not appropriate due to the large amount of legacy
equipment and the corresponding investments. CR system can allow a smooth refarming transition period in
this case taking into account the traffic constraints and user requirements.
3) RRM optimization
Considering a cell set in a certain area, the traffic of different services on a specified RAT may change from
one sub-area to the other according to the day period. Moreover it could happen that some cells may be
congested (high blocking percentages) in some particular area (typically these portions are called hot-spots) in
which the traffic is more consistent, while surrounding cells are less loaded or characterized by low blocking
percentages. Moreover, in case of deployment of two or more RATs in the same area, the offered traffic of
different services on each deployed RAT may also be differently distributed in time and space with respect to
the ones of the other deployed RATs. In such contexts, in the longer term, CRS will give the network operators
the means for managing in an efficient way the radio resources within its own licensed frequency bands.
4) Cognition Enabler
Considering an heterogeneous or multi-RAT context in which Dynamic Spectrum Allocation schemes could
be performed, the mobile terminal will need to initiate a communication in a spectrum context which is mostly
unknown due to such dynamic allocation mechanisms, without requiring an excessive complexity. Efficient
mechanisms to provide the sufficient information to the terminals for initiating a communication session
appropriately are then needed.
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11 ETSI TR 102 802 V1.1.1 (2010-02)
5) Decentralized RRM
Contexts in which the system complexity can be relaxed by moving part of the radio resource management
functionality into more decentralized solutions, requires solutions for enabling such network-assisted
decentralized radio resource management. Context information (e.g. network radio capabilities,
network/mobile measurements, geo-location information, etc.), network policies and other kind of information
(e.g. operative software to reconfigure the terminal or advertising or road/car traffic information) have to be
efficiently provided to the interested devices.
4.1.4 Other Objectives of CR Systems
In the longer term cognitive radio technologies may play a fundamental role in the shift from static spectrum
management to dynamic spectrum management and access. This longer term goal has been recognized also by the EU
Commission Radio Spectrum Policy Group [i.6].
4.2 Spectrum Use Scenarios for CRS
In this clause different spectrum use scenarios for cognitive radio systems are considered. Each of the scenarios is also
categorized as a short-term, mid-term or long-term scenario based on the technological and regulatory evolution
expected to realize the scenario.
There are four different classes of radio spectrum use scenarios for the Cognitive Radio Systems described in the
present document:
• Dedicated spectrum (licensed bands).
• Shared spectrum (license-exempt bands).
• Secondary usage in dedicated spectrum.
• Spectrum dedicated for CRS.
The rest of this clause describes these spectrum use scenarios for cognitive radio systems in more detail.
4.2.1 Dedicated spectrum (licensed bands)
In this scenario the reconfigurability is introduced in the currently licensed bands.
Scenario L.1: Software defined multiradio in (end-user) mobile devices (short-term)
This first scenario assumes that software defined multiradio technology is used to realize reconfigurability of radio
equipments in mobile devices (end-user terminals). A reconfigurable radio is capable to scan the radio frequencies and
make an autonomous selection of radio (access) technology based on user preferences.
This scenario is covered by TR 102 680 [i.2].
Scenario L.2: Radio (access) technology selection in composite wireless networks (short-term)
In this scenario an operator is utilizing multiple radio (access) networks on different frequency bands as assigned to
them under the current regulation and wants to combine these radio networks into a single composite wireless network.
Similarly the subscriber devices are equipped with software defined multiradio capability in order to operate on
multiple radio networks. By monitoring the traffic load on different radio networks the cognitive network management
system can decide on the assignment of users to different radio (access) technologies in a dynamic manner, which leads
to optimal use of the composite capacity of the frequency bands. This scenario is also applicable to a situation where the
radio networks are not owned by a single operator but where several operators cooperate to manage their composite
radio networks jointly.
This scenario is covered by TR 102 682 [i.3].
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12 ETSI TR 102 802 V1.1.1 (2010-02)
Scenario L.3: Radio resource usage optimization in composite wireless networks (short-term)
In this scenario one or several operators operate multiple radio access networks on different frequency bands assigned
to them. Network side radio nodes of these radio access networks have reconfiguration capability implemented, for
example, using software defined radio technology. Similarly terminal side radio nodes also have reconfiguration
capability. Reconfigurable radio nodes on network side dynamically adjust their operational parameters and/or radio
resources in order to meet some predefined objectives (e.g. increase capacity and improve QoS) and according to the
current radio regulations. Such adjustment can include changing operating frequency band and radio access technology.
Following network reconfiguration, terminals may need to reconfigure.
This scenario is also covered by TR 102 682 [i.3].
4.2.2 Shared Spectrum in bands without primary users
Scenario U.1: Cognitive radio networks on unlicensed bands (short-term)
In this scenario cognitive radio networks are deployed in bands that do not require licensing (license exempt bands).
There is only one class of users sharing such a band. This potentially provides for easy deployment of cognitive radio
systems. There is an opportunity of sharing spectrum resources in these bands. This is already applied today, for
example collaboration between Bluetooth and WLAN in the 2,4 GHz band and more generally speaking most of the
ISM bands.
There are restrictions to the use of unlicensed bands in terms of transmit power and/or power density for instance that
do not allow such an approach to be used for wider areas. Further the amount of unlicensed spectrum is limited and
especially at the 2,4 GHz WLAN already heavily used.
4.2.3 Secondary usage in bands with primary users
Scenario S.1: Exploit spectrum opportunities in bands already assigned to primary users (mid-term)
In this scenario cognitive radio networks share, on a secondary basis, one band or several different bands assigned to
one (or several) primary user(s). Before accessing the spectrum the nodes should obtain information about the spectrum,
which is available for secondary usage on their particular location. Nodes have to have means how the cognitive
networks can avoid causing harmful interference to primary networks and co-exists with each others. This approach
results in a more efficient usage of the spectrum in selected band provided that there is no harmful interference to the
already deployed systems.
For example Dynamic Frequency Selection (DFS) for WLAN in 5 GHz band, to avoid interference to military and
meteorological radars, is a first step towards such secondary usage.
4.2.4 Spectrum dedicated for CRS
Scenario C.1: Specific band allocated for cognitive use (long-term)
In this scenario a specific dedicated band is assigned for a service utilizing cognitive radios. All radio technologies
accessing this band are designed to meet specific interference targets, and are aware of the interference that may be
caused by competing system. This means that the sharing of the spectrum resources in the band can be implemented in a
very efficient manner.
4.3 Technical Requirements on CR Systems
This clause introduces some key requirements for the Cognitive Radio Systems. Technical solutions to meet these
requirements are needed to provide cognitive radio services for mobile users. The enabling technology elements, on
which such technical solutions are dependent, are also mentioned for each requirement presented below.
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13 ETSI TR 102 802 V1.1.1 (2010-02)
R-I Scalability and Insensitivity to Network Topology Changes
The cognitive radio networks scale well with the number of users/nodes in the networks. The network can be
established with only two network nodes and scales gracefully with the number of nodes and area of the network. The
cognitive radio network reacts gracefully and is robust to changes in network topology. Links may disappear because of
agile spectrum conditions, and nodes may leave the network, for instance because of user mobility or powering off
devices. Connectivity between the network nodes should be maintained in a robust manner, and advanced protocols are
required that reconnect nodes via different frequency bands.
Enablers: Efficient routing algorithms, Dynamic distributed radio resource allocation, Distributed algorithms, Self
healing techniques, Self-organisation
R-II Power Efficiency
The power consumption of the CRS design allows long standby, monitoring and active times. As a whole this
requirement is expected to be met by each network node when taking also into account the new functions like relaying,
collaboration and cooperative spectrum sensing.
Enablers: Long sleep times, Multiple operational states, Cognitive control channels with efficient protocols.
R-III Network and Service Discovery
The CRS provides the first connection to the desired service in a short time, acceptable to a customer. A user can join a
network within a reasonable time. The CRS protocols are designed in such a way that the user can be informed in
reasonable intervals of delays and progress of a connection/service request, if a certain deadline defined by network
policies is not met.
Enablers: Network and service discovery protocols, Network policies, Fast initial access to cognitive radio network.
R-IV Robust Control Plane
The control planes both within all cognitive radio networks as well as between them should be robust and able to
continue to provide connectivity in frequency agile environments.
Enablers: Robust coding, Cognitive control channels with dedicated frequency bands
R-V Reconfigurability of the Radio Equipments
The radio equipments in the cognitive radio network nodes are capable of adjusting to different radio frequency
environments. This kind of frequency agility means that the transmission parameters and resource allocation can be
easily adjusted to the needs of the operator and/or the user, or the interference environment in a particular band.
More in detail:
• Reconfiguration in both hardware (e.g. both BB and RF) and radio resources for each supported RAT.
• All RATs implemented (e.g. by software) in the equipment will be fully compliant with the current existing
standards (e.g. GSM, UMTS, LTE, WIMAX, etc.) and related regulatory restrictions (bands, frequencies,
power levels, spectrum masks).
• Support of multi-standard operations.
• 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.
• Equipment reconfiguration taking into account the experimented network and users conditions (e.g. traffic
and/or interference conditions).
• Reconfigurable equipment 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 may
be located either in user devices or e.g. in access or in core network or in O&M nodes, considering also flat
architectures (e.g. HSPA+ and/or LTE based).
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14 ETSI TR 102 802 V1.1.1 (2010-02)
• Reconfiguration phase will be 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).
Enablers: Software defined multiradio, Frequency agility, Reconfigurable and tunable RF equipment
R-VI Context, policies and information provisioning support
For the purpose of supporting cognitive radio network nodes in their selection of radio technology and frequency band
as well as radio link configuration, context provision needs to provide the radio context information such as
e.g. available frequencies and radio technology selection constraints (policies).
Enablers: Spectrum database, Geo-location, Cognitive control channels, Spectrum policies
5 Technical Framework for Cognitive Radio System
This clause outlines the cognitive radio system concept. First a generic layered model for spectrum management is
presented. Based on that both centralized and decentralized approaches to architecting of CR systems is described.
Within those conceptual architectures we distinguish three communication planes, which may host the cognition
functions. Finally some of the key enabling technology elements, which were already identified in c 4.3, are described.
5.1 Spectrum Management Layers for Cognitive Radio Systems
While increasing the flexibility and dynamic use of spectrum it is useful to refer to a commonly agreed spectrum
management framework. By deriving from the overall objectives and technical elements presented in this study report
the following layered structure for spectrum management for CRS can be considered.
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Figure 1: Spectrum Management Layers for CRS
The time span of spectrum management actions carried out by the different layers in figure 1 is decreasing when
moving from the Regulation layer down towards Reconfigurable Radio Equipments. Depending on the different
objectives of CR systems, not all the reported layers need to be involved.
ETSI
RuRuRullleeesss
15 ETSI TR 102 802 V1.1.1 (2010-02)
Spectrum Regulation Layer
Due to the scarcity of radio spectrum it is foreseen that regulation will continue to play a role in assigning spectrum to
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