ETSI TR 102 684 V1.1.1 (2012-04)

Technical Report
Reconfigurable Radio Systems (RRS);
Feasibility Study on Control Channels for
Cognitive Radio Systems
2 ETSI TR 102 684 V1.1.1 (2012-04)

Reference
DTR/RRS-03008
Keywords
control, radio
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3 ETSI TR 102 684 V1.1.1 (2012-04)
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 . 8
3.1 Definitions . 8
3.2 Abbreviations . 9
4 Motivation . 11
5 Coexistence and coordination of different cognitive radio networks and nodes . 12
5.1 Discovery and identification of neighbouring devices and services . 12
5.1.1 Cognitive Pilot Channel . 12
5.1.2 Access Network Discovery and Selection Function (ANDSF) . 13
5.1.3 Assisted Cell search with a helper device . 14
5.2 Advanced Multi-RAT Assistance in Heterogeneous Networks . 14
5.2.1 Inter-Network Sensing Assistance . 15
5.2.2 Network Service Discovery Assistance . 16
5.2.3 Location Tracking by Proxy . 16
5.2.4 Network Optimization . 17
5.2.5 Assistance for Network Healing . 17
5.3 Retrieval of information on available White Spaces from a geo-location database . 18
6 Management of operator-governed opportunistic networks . 19
6.1 Scenarios . 19
6.2 Technical challenges . 20
6.2.1 Suitability determination . 21
6.2.1.1 Definition . 21
6.2.1.2 Triggers . 21
6.2.1.3 Sub-challenges . 22
6.2.1.3.1 Detection of opportunities for ON with respect to nodes . 22
6.2.1.3.2 Detection of opportunities with respect to potential radio paths . 22
6.2.1.3.3 Assessment of potential gains . 22
6.2.1.4 Output . 22
6.2.2 Creation . 22
6.2.2.1 Definition . 22
6.2.2.2 Trigger . 23
6.2.2.3 Sub-challenges/Output . 23
6.2.2.3.1 Infrastructure coverage extension . 23
6.2.2.3.2 Resolve capacity issues of the infrastructure . 23
6.2.2.3.3 Opportunistic ad-hoc networking (for localized service provision) . 23
6.2.2.3.4 Opportunistic traffic aggregation in the access network . 23
6.2.2.3.5 Opportunistic resource aggregation in the backhaul . 23
6.2.3 Maintenance . 23
6.2.3.1 Definition . 24
6.2.3.2 Trigger . 24
6.2.3.3 Sub-challenges/Output . 24
6.2.3.3.1 Monitoring . 24
6.2.3.3.2 Reconfiguration decisions . 24
6.2.4 Termination. 25
6.2.4.1 Definition . 25
6.2.4.2 Triggers . 25
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4 ETSI TR 102 684 V1.1.1 (2012-04)
6.2.4.3 Sub-challenges/Output . 25
6.2.4.3.1 Handover to infrastructure . 25
6.2.4.3.2 Resource release . 25
7 Implementation options for Control Channels for Cognitive Radio Systems . 26
7.1 Radio access technology independent implementation . 26
7.1.1 IEEE 1900.4 based Information model . 26
7.1.2 3GPP ANDSF-based/OMA DM-based implementation . 26
7.1.3 Distributed Agents based approach. 27
7.1.4 IETF DIAMETER based approach . 27
7.1.5 IETF PAWS based implementation . 28
7.1.6 IEEE 802.21 based approach . 29
7.1.7 Network management based implementations. 29
7.2 Radio access dependent implementation . 30
7.2.1 3GPP based L1 and L2 implementations . 30
7.2.2 IEEE 802.11 based . 31
7.2.2.1 Vendor Specific Information in MAC frames . 31
7.2.2.2 IEEE 802.11u . 32
7.2.2.3 Direct Wi-Fi Approach . 32 ®
7.2.3 Bluetooth based. 32
7.2.4 WiMedia UWB based . 34
7.3 New Common Multi-RAT Control Layer Approaches . 35
7.3.1 IEEE 802.19.1 TV White Space Coexistence Methods . 35
7.4 Overall assessment of implementation options . 37
8 Conclusion . 40
History . 41

ETSI
5 ETSI TR 102 684 V1.1.1 (2012-04)
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 Reconfigurable Radio Systems (RRS).
Introduction
For the efficient operation of Cognitive Radio Systems, mechanisms with that will allow for the exchange and
distribution of information as well the coordination between various management entities are essential. In this respect,
Control Channels have been identified as a key feature required for Cognitive Radio Systems, as means for transmitting
elements of information necessary to manage and realize various operations within a Cognitive Radio Systems. In this
scope, the present document aims to identify and study communication mechanisms:
1) for the coexistence and coordination of different cognitive radio networks and nodes, operating in unlicensed
bands like the ISM band or as secondary users in TV White Spaces;
2) for the management of Operator-governed Opportunistic Networks, operating in the same bands as mentioned
above. In particular, it is expected that these networks will include mechanisms for operator-governed ad-hoc
coverage extensions or capacity extensions of infrastructure networks. The communication is expected to
include procedures from terminal to terminal as well as between a terminal and infrastructure networks.
These mechanisms could be radio access technology (RAT) specific or/and be RAT-independent.
Further on, the present document presents and analyses implementation options for Control Channels for Cognitive
Radio Systems, taking into account previous work on in-band-Cognitive Pilot Channel (CPC) and Cognitive Control
Channel (CCC). The investigation of implementation options is a crucial step towards the realisation of the Control
Channels and the deployment of Cognitive Radio Systems.
ETSI
6 ETSI TR 102 684 V1.1.1 (2012-04)
1 Scope
The present document aims to identify and study potential communication mechanisms on Control Channels for
Cognitive Radio Systems:
1) for the coexistence and coordination among different cognitive radio networks and nodes, operating in
unlicensed bands like the ISM band or as secondary users in TV White Spaces;
2) for the management of operator-governed Opportunistic Networks, operating in the same bands as mentioned
above.
2 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.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
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] ITU-R Report M.225: "Introduction to cognitive radio systems in the land mobile service", 2011.
[i.2] ITU-R Report SM.2152: "Definitions of Software Defined Radio (SDR) and Cognitive Radio
System (CRS)", September, 2009.
[i.3] ETSI TR 102 683: "Reconfigurable Radio Systems (RRS); Cognitive Pilot Channel (CPC)".
[i.4] ETSI TS 122 234 (V7.5.0): "Digital cellular telecommunications system (Phase 2+); Universal
Mobile Telecommunications System (UMTS); Requirements on 3GPP system to Wireless Local
Area Network (WLAN) interworking (3GPP TS 22.234 version 7.5.0 Release 7)".
[i.5] ETSI TS 136 300: "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved
Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (3GPP TS
36.300)".
[i.6] ETSI TS 124 302: "Universal Mobile Telecommunications System (UMTS); LTE; Access to the
3GPP Evolved Packet Core (EPC) via non-3GPP access networks; Stage 3 (3GPP TS 24.302)".
[i.7] ETSI TR 102 907: "Reconfigurable Radio Systems (RRS); Use Cases for Operation in White
Space Frequency Bands".
[i.8] IETF Working Group on Protocol to Access WS database (paws).
NOTE: Available at http://datatracker.ietf.org/wg/paws/charter/.
ETSI
7 ETSI TR 102 684 V1.1.1 (2012-04)
[i.9] IEEE 802.19-10/0055r3 Baykas, Kasslin, Shellhammer: "IEEE P802.19 System Design
Document", March 2010.
[i.10] IEEE Standard 1900.4 for Architectural Building Blocks Enabling Network-Device Distributed
Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access
Networks, February 27, 2009.
[i.11] S.Buljore, H.Harada, P.Houze, K.Tsagkaris, O.Holland, S.Filin, T.Farnham, K.Nolte, V.Ivanov:
"Architecture and enablers for optimized radio resource usage in heterogeneous wireless access
networks: The IEEE 1900.4 Working Group" Communications Magazine, IEEE, Vol 47, no. 1, pp.
122-129, January 2009.
[i.12] P. Houze, S. Bonjour, L. Suciu, V. Gupta: "IEEE P1900.4 vs. IEEE 802.21", presentation, January
2009.
[i.13] ETSI TS 124 312: "Universal Mobile Telecommunications System (UMTS); LTE; Access
Network Discovery and Selection Function (ANDSF) Management Object (MO) (3GPP TS
24.312 Release 8)".
[i.14] OMA-ERELD-DM-V1-2: "Enabler Release Definition for OMA Device Management".
[i.15] ETSI TS 122 278 "Universal Mobile Telecommunications System (UMTS); LTE; Service
requirements for the Evolved Packet System (EPS) (3GPP TS 22.278 Release 8)".
[i.16] ETSI TS 123 402: "Universal Mobile Telecommunications System (UMTS); LTE; Architecture
enhancements for non-3GPP accesses (3GPP TS 23.402 Release 8)".
[i.17] Foundation for Intelligent Physical Agents (FIPA).
NOTE: Web site, http://www.fipa.org, accessed March 2011. ®
[i.18] Java Agent DEvelopment Platform (JADE).
NOTE: Web site, http://jade.tilab.com, accessed March 2011.
[i.19] JADEX Projects.
NOTE: http://vsis-www.informatik.uni-hamburg.de/projects/jadex/, accessed March 2011.
[i.20] ORBacus, IONA Technologies.
NOTE: http://www.orbacus.com/, accessed March 2011.
[i.21] A. Galani, K. Tsagkaris, N. Koutsouris, P. Demestichas: "Design and assessment of functional
architecture for optimized spectrum and radio resource management in heterogeneous wireless
networks", International Journal of Network Management, John Wiley & Sons, Vol. 20, Issue 4,
pp. 219-241, July/August 2010.
[i.22] V. Stavroulaki, N. Koutsouris, K. Tsagkaris, P. Demestichas: "A Platform for the Integration and
Management of Cognitive Systems in Future Networks", accepted in IEEE International
Workshop on Management of Emerging Networks and Services (IEEE MENS 2010), in
conjunction with IEEE Globecom 2010.
[i.23] ETSI TS 129 229: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Cx and Dx interfaces based on the Diameter
protocol; Protocol details (3GPP TS 29.229)".
[i.24] IETF RFC 3588: "Diameter Base Protocol", September 2003.
[i.25] IEEE 802.11-2007: "IEEE Standard for Information technology - Telecommunications and
information exchange between systems - Local and metropolitan area networks-Specific
requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
Specifications".
[i.26] IEEE 802.11u: Part 11 Amendment 9: "Interworking with external networks", February 2011.
ETSI
8 ETSI TR 102 684 V1.1.1 (2012-04)
® ®
[i.27] Bluetooth SIG: "Bluetooth 4.0 Specification".
[i.28] WiMedia Alliance: "Distributed Medium Access Control (MAC) for wireless networks", MAC
Specification: Release 1.5, December 1, 2009.
[i.29] IEEE 802.21TM-2008: "IEEE Standard for Local and Metropolitan Area Networks: Media
Independent Handover Services", IEEE Computer Society, Sponsored by the LAN/MAN
Standards Committee, January 2009.
[i.30] W3C Recommendation 10 February 2004: "Resource Description Framework (RDF): Concepts
and Abstract Syntax".
NOTE: Available online at http://www.w3.org/TR/rdf-concepts.
[i.31] IETF RFC 3416: "Version 2 of the Protocol Operations for the Simple Network Management
Protocol (SNMP)", December 2002.
[i.32] TR-069 Amendment 2: "CPE WAN Management Protocol v1.1", Broadband Forum, December
2007.
[i.33] ETSI TS 132 101: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Telecommunication management; Principles and
high level requirements (3GPP TS 32.101)".
[i.34] ETSI TS 125 331: "Universal Mobile Telecommunications System (UMTS); Radio Resource
Control (RRC); Protocol specification (3GPP TS 25.331)".
[i.35] ETSI TS 136 331: "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource
Control (RRC); Protocol specification (3GPP TS 36.331)".
[i.36] IETF RFC 4282: "The Network Access Identifier".
[i.37] ECMA-368: "High Rate Ultra Wideband PHY and MAC Standard". ®
[i.38] Bluetooth 2.1.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Cognitive Control Network (CCN): 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 (CCC): distributed approach for real time communication between different CRS nodes in
a specific geographical area
NOTE 1: CCC may enable different CRS nodes to exchange information related to coexistence, generic spectrum
usage rules or policies and/or specific capabilities and needs of different nodes.
NOTE 2: The information communicated on CCC may include, among other things, spectrum etiquette, rules for
accessing specific bands, local availability of different bands, sensing information, available applications,
or spectrum needs of different systems [i.1].
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9 ETSI TR 102 684 V1.1.1 (2012-04)
Cognitive Pilot Channel (CPC): channel (logical or physical) that is used to regularly push information out to the CRS
node
NOTE 1: It can include the use of specifically transmitted messages, and having known transmission
characteristics.
NOTE 2: The CPC can be used, among other things, to help a mobile terminal in identifying operators, policies and
access technologies and their associated assigned frequencies in a given region. In some cases, when an
uncoordinated deployed CRS base station (or Reconfigurable Base Stations) is booting up, CPC
information may also be utilized to identify available spectrum in its current location [i.1].
Cognitive Radio System (CRS): 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 [i.2]
Control Channels for Cognitive Radio Systems (CC-CRS): Control Channels for Cognitive Radio Systems are used
for sharing cognitive control information between or within Cognitive Radio Systems
NOTE: They may be logical channels transporting information on top of a physical channel. Such channels are
responsible for conveying information between entities involved in Cognitive Radio Systems, such as
devices, network elements, network/device management entities.
Opportunistic Network (ON): network which exploits opportunities with respect to the spectrum and the devices in
the area
operator-governed Opportunistic Network (ON): operator-governed (through the provision of spectrum, policies,
information and knowledge, exploited for its creation), temporary, localised network segment
NOTE: It involves devices organized in an ad-hoc manner, and is terminated at access points (macro base
stations, femto base stations) of the infrastructure. An opportunistic network is set up as a temporary,
coordinated extension of the infrastructure with the aim to improve the coverage and capacity of the
infrastructure network.
White Space (WS): part of the spectrum, which is available for a radio communication application (service, system) at
a given time in a given geographical area on a non-interfering / non-protected basis with regard to primary services and
other services with a higher priority on a national basis
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3GPP 3rd Generation Partnership Project
AAA Authentication, Authorization and Accounting
ACL Agent Communication Language
ANDSF Access Network Discovery and Selection Function
AP Access Point
ASCF Application Specific Command Frames
ASIE Application Specific Information Element
ASN.1 Abstract Syntax Notation One
ASN.1 Abstract Syntax Notation One
ATT Attribute Protocol
BCH Broadcast CHannel
BS Base Station
BS Broadcasting Service
CCC Cognitive Control Channel
CC-CRS Control Channel(s) for Cognitive Radio Systems
CCN Cognitive Control Network
CCP Central Control Point
CDIS Coexistence Discovery and Information Server
CE Coexistence Enabler
CM Coexistence Manager
CN Cognitive Network
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10 ETSI TR 102 684 V1.1.1 (2012-04)
CORBA Common Object Request Broker Architecture
CPC Cognitive Pilot Channel
CR Cognitive Radio
CRS Cognitive Radio System
DDF Device Description Framework
DM Device Management
DME Device Management Entity
DNS Domain Name System
EGAN Enhanced Generic Access Network
EIR Extended Inquiry Response
EPC Evolved Packet Core
FIPA Foundation for Intelligent Physical Agents
GAS Generic Advertisement Service
GSM General System for Mobile Communications
HSS Home Subscriber Server
HTTP Hyper Text Transfer Protocol
IE Information Element
IEEE Institute of Electrical and Electronics Engineers or IEEE
IEs Information Elements
IETF Internet Engineering Task Force
IIOP Internet Inter-object request broker Protocol
IMTP Internal Message Transport Protocol
IP Internet Protocol
ISM Industrial, Scientific and Medical
IWLAN Interworking Wireless LAN
JDK Java Development Kit
JRRM Joint Radio Resource Management
Leap Lightweight Extensible Agent Platform
LTE Long Term Evolution
MAC Medium Access Control
MAS Medium Access Slot
ME Micro Edition
MICS Media Independent Command Service
MIES Media Independent Event Service
MIH Media-Independent Handover
MIHF MIH Function
MIIS Media Independent Information Service
ML Markup Language
MLME MAC Sublayer Management Entity
MMPDU MAC Management Protocol Data Unit
MN Mobile Node
MO Management Object
MTP Message Transport Protocol
N2N Network To Network
NAI Network Access Identifier
NMS Network Management System
OMA Open Mobile Alliance
OMG Object Management Group
ON Opportunistic Network
ORB Object Request Broker
PAWS Protocol to Access White Space Databases
PM Performance Monitoring
PS Packet Switched
PVSA Public Vendor Specific Action
QoS Quality of Service
RAN Radio Access Network
RANOp Radio Access Network Operator
RAT Radio Access Technology
RDF Resource Description Framework
RF Radio Frequency
RFC Request For Comments
RMI Remote Method Invocation
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11 ETSI TR 102 684 V1.1.1 (2012-04)
RRC Radio Resource Control
RRM Radio Resource Management
RRS Reconfigurable Radio System
SAP Service Access Point
SDAP Service Discovery Application Profile
SDP Service Discovery Protocol
SDR Software Defined Radio
SI System Information
SME Station Management Entity
SMS Short Message Service
SNMP Simple Network Management Protocol
SP Service Provider
T2N Terminal to Network
T2T Terminal To Terminal
TCP Transmission Control Protocol
TLS Transport Layer Security
TR Technical Report
TS Technical Specification
TV Television
TVWS TV White Space
TVWSD TV White Space Device
UDP User Datagram Protocol
UE User Equipment
UHF Ultra High Frequency
UL Up-Link
UL/DL Up-Link/Down-Link
UMTS Universal Mobile Telecommunications System
USB Universal Serial Bus
USIM Universal Subscriber Identity Module
UTRAN Universal Terrestrial Radio Access Network
UWB Ultra Wide Band
VSA Vendor Specific Action
VSIE Vendor Specific information element
WAP Wireless Application Protocol
WFA Wi-Fi Alliance
WI-FI Wireless Fidelity
WiMAX Worldwide Interoperability for Microwave Access
WLAN Wireless Local Area Network
WS White Space
4 Motivation
The present document aims to identify and study communication mechanisms:
1) for the coexistence and coordination of different cognitive radio networks and nodes, operating in unlicensed
bands like the ISM band or as secondary users in TV White Spaces;
2) for the management of Operator-governed Opportunistic Networks, operating in the same bands as mentioned
above. In particular, it is expected that these networks will include mechanisms for operator-governed ad-hoc
coverage extensions or capacity extensions of infrastructure networks. The communication is expected to
include procedures from terminal to terminal as well as between a terminal and infrastructure networks.
These mechanisms could be radio access technology (RAT) specific or/and be RAT-independent. In particular, the
present document addresses the following issues:
• Discovery and identification of neighbouring devices and networks.
• Advanced Multi-RAT Assistance in Heterogeneous Networks.
• Retrieval of information on available White Spaces from a geo-location database.
ETSI
12 ETSI TR 102 684 V1.1.1 (2012-04)
• Management of operator-governed opportunistic networks in terms of creation, maintenance and termination.
• Implementation options for Control Channels for Cognitive Radio Systems, taking into account previous work
on in-band-Cognitive Pilot Channel (CPC) and Cognitive Control Channel (CCC).
5 Coexistence and coordination of different cognitive
radio networks and nodes
5.1 Discovery and identification of neighbouring devices and
services
Control Channels for Cognitive Radio Systems (CC-CRS) can be used to provide information on available networks
and/or devices and/or services in the geographical neighbourhood.
When a UE is powered on in today's cellular networks, the UE usually queries its USIM for information on stored
frequencies in an attempt to perform a Stored Information Cell Selection. This allows the UE to search for these
particular cells without having to scan the entire band or bands that the UE is configured to operate on. During this
process, the UE will traverse the list of stored cell frequencies in the USIM until it finds a suitable one.
If the UE is powered on in a completely new environment e.g. because the user has travelled into a foreign country,
then none of these cells stored in the USIM will be found. Then, the UE should perform an Initial Cell Selection which
requires no a priori knowledge of cell information and requires scanning of all frequencies to find a cell where the
energy level is sufficiently high to attempt synchronization. This process of an Initial Cell Selection takes a couple of
minutes before the UE successfully camps on a cell. Additionally, a UE should register on the network before knowing
the available services, and may waste time gaining access to a network that cannot satisfy the user's requirements.
In ad hoc networks the discovery and connection set-up are based on transmitting and scanning discovery signals: a
node in discoverable more transmits a discovery signal regularly (e.g. a beacon), and a node which wishes to detect and
connect to an ad-hoc network starts scanning for the discovery signals. Alternatively, in some ad-hoc network
technologies, a node in discoverable mode scans discovery signals regularly, and a node which wishes to detect and
connect to an ad-hoc network starts transmitting discovery signals. The discovery time depends on the amount of the
used discovery channels, and also on the beacon or scan interval of the discoverable node.
Different options exist on how control channels for cognitive radio systems can be used to improve the time to discover
a first network or to improve the discovery of other networks which may e.g. provide other services.
5.1.1 Cognitive Pilot Channel
The Cognitive Pilot Channel (CPC) [i.3] is defined as a channel which conveys the elements of necessary information
facilitating the operations of Cognitive Radio Systems. The CPC provides information from the network to the user
devices e.g. on available radio access networks, their frequency bands, radio access technologies and spectrum usage
possibilities. Two deployment options, the in-band CPC and the out-band CPC can be considered.
The in-band CPC is a logical channel within one or some of the technologies available in a heterogeneous radio
environment. The purpose of the CPC is to distribute information about the radio environment at a certain location.
Figure 1 shows the principle of the in-band CPC, with reference to the deployed RATs: The in-band CPC can be
implemented in one or more of the available RATs. The in-band CPC may support downlink as well as uplink
information transfer or alternatively only downlink information transfer. The CPC Manager may obtain the information
to be distributed over the CPC from the Joint Radio Resource Management (JRRM) or other functions on network side,
e.g. from the network management. The CPC Manager configures which information is to be distributed over the CPC.
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13 ETSI TR 102 684 V1.1.1 (2012-04)
CPC Configuration CPC
Out-band CPC
Manager
RAT Infos
RAT 1, e.g. UMTS
RAT Infos
RAT 2, e.g. GSM
CPC Configuration
In-band CPC Management
and Information
Entity
RAT Infos
RAT 3, e.g. WiMAX (e.g. JRRM,
O&M)
RAT Infos
RAT 4, e.g. WLAN
RAT Infos
RAT 5, e.g. LTE
Note: In-band CPC can also be deployed in more than one RAT

Figure 1: Principle of in-band and out-band Cognitive Pilot Channel (CPC) [i.3]
The out-band CPC is a CPC conceived as a radio channel outside the component Radio Access Technologies. The out-
band CPC as also shown in Figure 1 either uses a new radio interface, or alternatively uses an adaptation of a legacy
technology with appropriate characteristics. The out-band CPC ideally should operate on a well-know frequency,
however, it is likely difficult to agree and regulate a worldwide unique frequency for such an out-band CPC.
5.1.2 Access Network Discovery and Selection Function (ANDSF)
The 3GPP Access Network Discovery and Selection Function (ANDSF) [i.13] can be seen as higher-layer CPC using
RAT-independent, e.g. IP-based transport. The scope of the ANDSF is to support multi-access network scenarios with
intersystem-mobility between 3GPP-networks (GSM, UMTS, LTE) and non-3GPP networks (e.g. WiMAX, WLAN).
The ANDSF as defined in 3GPP provides inter-system mobility policies and access network specific information from
the network to the user equipment (UE) in order to assist the mobile node for discovery procedures and for performing
the inter-system handovers. This set of information can either be provisioned in the UE by the home operator, or
provided to the mobile node (MN) by the ANDSF [i.16].
ANDSF:
Access
Network
Discovery
LTE UMTS WLAN
and Selection
Function
Configuration of Database after startup of cell
Initial Access Selection:
Terminal to scan/discover
first RAT using existing methods
Setup of initial connection
Access Network Information Request (Current location and/or list of used/detected cell, QoS requirements, …)
Access Network Information Response (List of possible radio accesses at current location, policies)
Potential scanning of
additional RATs,
network selection and
handover execution
Figure 2: Example of radio access technology independent communication with ANDSF
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14 ETSI TR 102 684 V1.1.1 (2012-04)
5.1.3 Assisted Cell search with a helper device
Assisted Cell Search can be performed by helper device to provide cell information needed for a UE to synchronize
with a suitable local cell. This helper device can be a nearby network operator-provided device or another UE that is
capable of providing local cell information through a cognitive or ad-hoc network. When a UE is powered on in a new
location, it is likely to be in close proximity of a helper device. The Assisted Cell Selection procedure requires the UE
to discover the nearby helper device and establish communication with it. The UE will then query for the carrier
frequencies and cell parameters, which the queried device will provide and the UE can search for this cell. Once the UE
has found a suitable cell, the UE will select it. Since the information being provided is either from the network or by a
UE that is already camped on a cell, the likelihood of that cell being suitable for the UE is high.
In order for this procedure to be effective the information exchange should be performed over a known control channel. ®
This control channel could exist on any suitable RAT available to the UE i.e. Wi-Fi, or Bluetooth . It can be
implemented by means of one of the methods discussed in Clause 7.
The Assisted Cell Search concept is illustrated in Figure 3.

Figure 3: Assisted Cell Search concept
The helper devices can be also be used to speed up other processes. A UE which has synchronized to a suitable cell will
want to decode the BCH in order to obtain system information. The BCH broadcasts MIBs/SIBs according to a
schedule and it can take several seconds to acquire a full set of system information. In order to improve the performance
of the system by reducing this time, the UE may be able to acquire the broadcast information by prompting a helper
device.
The helper devices can also be used to share network functions and services e.g. instant messaging, push-to-talk
services etc. If a new UE is aware of the services being provided by a network before camping on it, it can save time by
choosing a cell that fulfils its needs on the first try.
5.2 Advanced Multi-RAT Assistance in Heterogeneous
Networks
Networks in a home/office environment may operate exclusively over a single RAT, but many of the devices within
these networks may be capable of operating on multiple different RATs simultaneously.
When networks operate independently on their respective RAT, each of these networks is typically ‘closed' that is, there
is no coordination between the network technologies, and they rely on their own procedures for network formation,
network discovery, service discovery, and interference management. Many coexistence issues exist because there is no
coordination between these cognitive radio networks, therefore networks operating in unlicensed bands will require new
coexistence schemes in order to optimize radio resource usage. These coexistence schemes can be enabled by a new
Control Channel for Cognitive Radio Systems. This channel can provide assistance for network coexistence, via the
transmission of context information and measurement results, and also enable Multi-RAT control.
ETSI
15 ETSI TR 102 684 V1.1.1 (2012-04)
Inter-working between different RATs has been considered or implemented in areas such as 3GPP and IEEE 802 (e.g.
I-WLAN, EGAN, IEEE 802.21 [i.29]). For instance, the IWLAN [i.4] suite of specifications allows UEs capable of
WLAN access to use 3GPP services at the application layer (e.g. access control and charging, PS services, service
continuity) through the WLAN RAT. I-WLAN and other multi-RAT services have focused mostly on data services and
session continuity-based services. 3GPP has also specified multi-RAT RRM between 3GPP access networks (GSM,
UMTS, LTE) [i.5] to dynamically select the best RAT for a particular service to reach a UE. However, these
specifications have not considered certain scenarios of the use of devices with Multi-RAT capability to provide
assistance services at the RAT and network layers for helping in network specific operations. Some of these scenarios,
discussed in further detail in the following, constitute a form of assistance service that will be referred to as Advanced
Multi-RAT Assistance.
Advanced Multi-RAT Assistance uses the ability of a particular device to communicate on different RATs in order to
provide advanced services to networks on which that device is not active. A device's multi-RAT capability can be used
to provide assistance to networks in an effort to coordinate transmissions across networks, and to improve the
performance within a network. As can be seen in Figure 4, devices exist that are active on one network but are still
capable of communicating with other network(s). A device that is active on RAT A could activate RAT B in order to
(for example) track a Network B device without tracking capability.
Advanced Multi-RAT Assistance requires a control channel for information collection from the networks as well as
signalling to carry control or assistance information to the networks, that is necessary for Advanced Multi-RAT
Assistance procedures. In order to provide some of the assistant services, a central control point (
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