ETSI TR 102 907 V1.2.1 (2012-11)

Reconfigurable Radio Systems (RRS); Use Cases for Operation in White Space Frequency Bands

RTR/RRS-01015

General Information

• Status: Published
• Publication Date: 15-Nov-2012
• Technical Committee: RRS 1 - RRS System Aspects & Cognitive functionalities
• Current Stage: 12 - Completion
• Due Date: 16-Nov-2012
• Completion Date: 16-Nov-2012
• Mandate: M/512

Standards Content (Sample)

Technical Report
Reconfigurable Radio Systems (RRS);
Use Cases for Operation in White Space Frequency Bands

2 ETSI TR 102 907 V1.2.1 (2012-11)

Reference
RTR/RRS-01015
Keywords
M2M, radio, use case, white space
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ETSI
3 ETSI TR 102 907 V1.2.1 (2012-11)
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 Motivation, goals . 9
5 Use Cases . 9
5.1 Overview . 9
5.2 Mid-/long range wireless access over white space frequency bands . 10
5.2.1 General Use Case Description . 10
5.2.2 Stakeholders . 12
5.2.3 Scenarios . 13
5.2.3.1 Mid-/long range, no mobility . 13
5.2.3.2 Mid-/long range, low mobility . 13
5.2.3.3 Mid-/long range, high mobility . 14
5.2.4 Information Flow . 14
5.2.4.1 Spectrum allocation when base station powers on . 16
5.2.4.2 Incumbent protection (Switch from TVWS frequency band to licensed TD-LTE frequency band
or candidate TVWS frequency band) . 17
5.2.4.3 Radio Resource Optimization (Switch from licensed TD-LTE frequency band to TVWS
frequency band) . 18
5.2.5 Derived potential System Requirements . 19
5.3 Short range wireless access over white space frequency bands . 20
5.3.1 General Use Case Description . 20
5.3.2 Stakeholders . 21
5.3.3 Scenarios . 21
5.3.3.1 Networks without coexistence management . 21
5.3.3.2 Networks with distributed coexistence management . 21
5.3.3.3 Networks with centralized coexistence management . 22
5.3.3.4 Hybrid of networks with distributed and centralized coexistence management . 23
5.3.4 Information Flow . 24
5.3.5 Derived potential System Requirements . 28
5.4 Ad-hoc networking over white space frequency bands . 29
5.4.1 General Use Case Description . 29
5.4.2 Stakeholders . 29
5.4.3 Scenarios . 30
5.4.3.1 Device-to-device connectivity. 30
5.4.3.2 Ad-hoc networking. 30
5.4.3.3 Infrastructure supported ad-hoc networking . 31
5.4.4 Information Flow . 31
5.4.5 Derived potential System Requirements . 32
5.5 Combined Ad-hoc networking and wireless access over white space frequency bands . 32
5.5.1 General Use Case Description . 32
5.5.2 Stakeholders . 33
5.5.3 Scenarios . 33
5.5.3.1 Expanding the coverage of the infrastructure . 34
5.5.3.2 Resolving cases of congested access to the infrastructure . 34
5.5.3.3 Direct device-to-device links in TVWS managed by access points or femto cells . 34
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4 ETSI TR 102 907 V1.2.1 (2012-11)
5.5.4 Information Flow . 35
5.5.5 Derived potential System Requirements . 36
5.6 Sporadic use of TV white space frequency bands . 37
5.6.1 General Use Case Description . 37
5.6.2 Stakeholders . 37
5.6.3 Scenario Case Description . 38
5.6.3.1 Lighter infrastructure deployment through larger cell sizes . 38
5.6.3.2 Increased spectral efficiency through reduced propagation loss . 38
5.6.3.3 Increased spectral efficiency through extended macro diversity . 39
5.6.3.4 TVWS Band-Switch in case that incumbent user re-enters . 40
5.6.3.5 Carrier Aggregation between IMT bands and TV WS band . 40
5.6.4 Information Flow . 43
5.6.4.1 Adding a New RAT Component Carrier into UHF TVWS Band . 43
5.6.4.2 UHF TVWS Band Component Carrier Reconfiguration . 44
5.6.4.3 Incumbent protection . 45
5.6.5 Derived potential system requirements . 46
5.7 Backhaul link using TV white space frequency bands . 46
5.7.1 General Use Case Description . 46
5.7.2 Stakeholders . 47
5.7.3 Scenarios . 47
5.7.3.1 Relay node backhaul link . 47
5.7.4 Information Flow . 48
5.7.4.1 Information Flow for Backhaul Link Initial Work Procedure . 48
5.7.4.2 Information Flow for Incumbent Protection on Backhaul Link . 49
5.7.5 Derived potential System Requirements . 50
5.8 MBMS operating in TV white space frequency bands . 50
5.8.1 General Use Case Description . 50
5.8.2 Stakeholders . 50
5.8.3 Scenarios . 51
5.8.3.1 LTE MBMS in TV white space frequency bands . 51
5.8.4 Information Flow . 52
5.9 Machine communications (M2M) systems operating in white space TV bands . 53
5.9.1 General use case description . 53
5.9.2 Stakeholders . 53
5.9.3 Scenarios . 53
5.9.4 Information flow . 54
5.9.5 Derived potential System Requirements . 55
6 Potential System Requirements . 55
7 Technical challenges . 57
7.1 Coexistence . 58
7.2 The role of sensing . 59
7.3 Challenges derived from TVWS propagation characteristics . 59
7.4 Challenges in regard to co-existence with RF Cable Systems . 59
Annex A: Summary of current regulatory status. 61
A.1 FCC regulation on White Space in the UHF TV bands . 61
A.2 Current activities in CEPT on White Space Usage in the UHF TV bands . 61
Annex B: Using white space frequency bands through temporary exclusive access rights . 63
B.1 Concept of temporary exclusive access rights . 63
B.2 Information Flow . 64
History . 66

ETSI
5 ETSI TR 102 907 V1.2.1 (2012-11)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Reconfigurable Radio Systems (RRS).
Introduction
The present document describes how radio networks can operate, on a secondary basis, in frequency bands
assigned/licensed to one (or several) incumbent user(s).
ETSI
6 ETSI TR 102 907 V1.2.1 (2012-11)
1 Scope
The present document describes Use Cases for the Operation of Reconfigurable Radio Systems within White Spaces in
the UHF 470 MHz to 790 MHz frequency band and gives an overview on methods for protecting the
primary/incumbent users like TV broadcasts and wireless microphones.
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] CEPT Report 24: "A preliminary assessment of the feasibility of fitting new/future
applications/services into non-harmonised spectrum of the digital dividend (namely the so-called
'white spaces' between allotments)", July 2008.
[i.2] CEPT ECC Report 159: "Technical and operational requirements for the possible operation of
cognitive radio systems in the 'White spaces' of the frequency band 470-790 MHz", January 2011.
[i.3] FCC Report 10-174: "Second memorandum opinion and order - in the matter of unlicensed
operation in the TV Broadcast bands - additional spectrum for unlicensed devices below 900 MHz
and in the 3 GHz band", 23. Sept. 2010.
[i.4] FCC Erratum: "Corrections to FCC Report 10-174", DOC-302279A1, 19. Oct. 2010.
NOTE: See http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-302279A1.pdf.
[i.5] "Implementing Geolocation", Ofcom UK, 9. Nov. 2010.
NOTE: See http://stakeholders.ofcom.org.uk/consultations/geolocation/.
[i.6] "Combination of Centralized & Decentralized Database and Terminal-based Spectrum Sensing for
Secondary Spectrum Access, Markus Mueck, Marco Di Renzo, Mérouane Debbah and Tobias
Renk", IEEE International Conference on Wireless Information Technology and Systems
(ICWITS), Hawaii, USA, 2010.
[i.7] "Opportunistic relaying for Cognitive Radio enhanced cellular networks: Infrastructure and initial
results", Mueck, Markus Dominik; Di Renzo, Marco; Debbah, Merouane; Wireless Pervasive
Computing (ISWPC), 2010 5th IEEE International Symposium on, 2010, Page(s): 556 - 561.
[i.8] IEEE 802: "Standard for Local and Metropolitan Area Networks: overview and architecture".
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7 ETSI TR 102 907 V1.2.1 (2012-11)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
cognitive radio: radio, which has the following capabilities:
• to obtain the knowledge of radio operational environment and established policies and to monitor usage
patterns and users' needs;
• to dynamically and autonomously adjust its operational parameters and protocols according to this knowledge
in order to achieve predefined objectives, e.g. more efficient utilization of spectrum; and
• to learn from the results of its actions in order to further improve its performance.
incumbent radio service: radio service authorized for operation on a given frequency band with a regulatory priority
NOTE: In the frequency band 470 MHz to 790 MHz, the following radio services are considered as incumbent
radio services:
� Terrestrial Broadcasting Service (BS) including DVB-T in particular.
� Program Making and Special Event (PMSE) services including radio microphones in particular.
� Radio Astronomy Service (RAS) in the 608 MHz to 614 MHz band.
� Aeronautical Radio Navigation Service (ARNS) in the 645 MHz to 790 MHz band.
Program Making and Special Events: general term to describe equipment used in program making
NOTE: Within the 470 MHz to 790 MHz band the use is mainly Radio microphones, In Ear Monitors (IEM) and
Audio links. Radio microphones may be single channel or in excess of 100 channels, IEM are fixed
transmitters (at the audio desk) and a receiver carried by the artist or presenter and will move around the
site, they are stereo transmissions, there can be up to 30 IEM in some productions ranging up to many
hundreds for events such as the Olympics. Audio links can be considered higher power radio
microphones but often using a stereo mode.
radio system: system capable to communicate some user information by using electromagnetic waves
NOTE: Radio system 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 devices.
reconfigurable radio systems: generic term for radio systems encompassing Software Defined and/or Cognitive Radio
Systems
use case: description of a system's behaviour as it responds to a request that originates from outside of that system
NOTE: In other words, a use case describes "who" can do "what" with the system in question. The use case
technique is used to capture a system's behavioural requirements by detailing scenario-driven threads
through the functional requirements.
White Space (WS): part of the spectrum, which is available for a radiocommunication application (service, system) at a
given time in a given geographical area on a non-interfering/nonprotected basis with regard to primary services and
other services with a higher priority on a national basis
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8 ETSI TR 102 907 V1.2.1 (2012-11)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
rd
3GPP 3 Generation Partnership Project
AP Access Point
ARNS Aeronautical Radio Navigation Service
BCCH Broadcast Control Channel
BS Base Station
BS Broadcasting Service
CA Carrier Aggregation
CAPEX Capital expenditures
CC Component Carrier
CCC Cognitive Control Channel
CCP Central Control Point
CCR Cognitive Control Radio
CEPT Conférence Européenne des Administrations des Postes et des Télécommunications
CPC Cognitive Pilot Channel
CR Cognitive Radio
CSMA Carrier Sense Multiple Access
DL Downlink
DTV Digital TeleVision
DVB-T Digital Video Broadcasting - Terrestrial
EIRP Equivalent Isotropically Radiated Power
eNB evolved Node B
FCC Federal Communications Commission
FDD Frequency Division Duplex
GNSS Global Navigation Satellite System
GPS Global Positioning System
GSM Global System for Mobile Communication
HO Handover
HSPA High Speed Packet Access
IEM In Ear Monitor
IMT International Mobile Telecommunications
ISM Industrial, Scientific and Medical
LTE Long Term Evolution
MBMS Multimedia Broadcast Multicast Service
MBR Maximum Bit Rate
MBSFN Multimedia Broadcast multicast service Single Frequency Network
MCCH MBMS point-to-multipoint Control Channel
MCE Multi-cell/multicast Coordination Entity
MME Mobility Management Entitiy
MNO Mobile Network Operator
MTCH MBMS point-to-multipoint Traffic Channel
NW Network
OAM Operations, Administration and Maintenance
OPEX Operational expenditure
PMSE Program Making and Special Events
QoS Quality of Service
RAS Radio Astronomy Service
RAT Radio Access Technology
REQ Requirement
RF Radio Frequency
RRM Radio Resource Management
RRS Reconfigurable Radio System
SDR Software Defined Radio
TDD Time Division Duplex
TD-LTE Time Division Duplex - Long Term Evolution
TR Technical Report
TV Television
TVBD Television Band Device
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9 ETSI TR 102 907 V1.2.1 (2012-11)
TVWS TV White Space
UE User Equipment
UHF Ultra High Frequency
NOTE: Within the context of the present document: 470 MHz to 862 MHz.
UL Uplink
UMTS Universal Mobile Telecommunication System
WLAN Wireless Local Area Network
WRC World Radio Conference
WS White Space
4 Motivation, goals
As a result of the transition from analogue to digital TV transmission in the 470 MHz to 862 MHz UHF frequency
band, certain parts of the spectrum are no longer used for TV transmission in some regions. Moreover, bands used for
TV transmissions are geographically interleaved to avoid causing interference to co-channel or adjacent channel DTV
transmitters - forming the so called TV white spaces. These characteristics of spectrum usage in the UHF band provide
an opportunity for deploying new wireless services.
These opportunities comprise:
• Reallocated bands which are made available for other services. In Europe for example, the 800 MHz band,
i.e. the 790 MHz to 862 MHz sub-band, has been reserved for mobile services to be allocated for IMT services
from the year 2015.
• Geographically interleaved bands (TV White Spaces - TVWS) available in the 470 MHz to 790 MHz
sub-band. Based on CEPT definition: these are frequencies available for a radiocommunication application
(service, system) at a given time in a given geographical area on a non-interfering/nonprotected basis with
regard to incumbent services and other services with a higher priority on a national basis.
The present document focuses on the second case, namely on use cases for operation in white space frequency bands.
The use cases assume a regulatory environment where the TV White Spaces can be used for free (spectrum commons).
A different potential future regulatory environment allowing e.g. secondary spectrum trading (paid with some sort of
exclusivity) is described in annex B.
5 Use Cases
5.1 Overview
Use Cases according to definition in clause 3.1 will describe a system from the user point of view, describing what the
actor achieves interacting with the system. Use Cases are used for deriving requirements on the system. For this purpose
each Use Case described in the following clause is documented in the same way by using the same structure:
1) General Use Case Description
2) Stakeholders
3) Scenario
4) Information Flow
5) Derived potential System Requirements
Below is the list of use cases, which are described in detail in the next clauses:
• Mid-/long range wireless access over white space frequency bands:
- Mid-/long range, no mobility
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10 ETSI TR 102 907 V1.2.1 (2012-11)
- Mid-/long range, low mobility
- Mid-/long range, high mobility
• Short range wireless access over white space frequency bands:
- Networks without coexistence management
- Networks with distributed coexistence management
- Networks with centralized coexistence management
- Hybrid of networks with distributed and centralized coexistence management
• Ad-hoc networking over white space frequency bands:
- Device-to-device connectivity
- Ad-hoc networking
- Infrastructure supported ad-hoc networking
• Combined Ad-hoc networking and wireless access over white space frequency bands:
- Expanding the coverage of the infrastructure
- Resolving cases of congested access to the infrastructure
- Direct device-to-device links in TVWS managed by access points or femto cells
• Sporadic use of TV white space frequency bands:
- Lighter infrastructure deployment through larger cell sizes
- Increased spectral efficiency through reduced propagation loss
- Increased spectral efficiency extended macro diversity
- TVWS Band-Switch in case that incumbent user re-enters
- Carrier Aggregation between IMT and TVWS bands
• Backhaul link using TV white space frequency bands:
- Relay node backhaul link
• Multimedia Broadcast Multicast Service (MBMS) operating in TV white space frequency bands:
- LTE MBMS in TV white space frequency bands
• Machine communications systems operating in white space TV bands
5.2 Mid-/long range wireless access over white space
frequency bands
5.2.1 General Use Case Description
Internet access is provided from a base station to the end users by utilizing white space frequency bands over ranges
similar to today's cellular systems, e.g. in the range of 0 km to 10 km.
This use case can be divided into three scenarios dependent on the mobility of the end-user devices:
• no mobility, e.g. the end-user device is fixed mounted at a wall;
• low mobility, e.g. the end-user can walk around with his device;
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11 ETSI TR 102 907 V1.2.1 (2012-11)
• high mobility, e.g. the end-user is travelling by car or a train.
This differentiation is made because the constraints for detecting incumbent users or other secondary users as well as on
retrieving the geographical position may differ dependent on the mobility of the users.
CommuniCommunicaticationon iinn Wh White Spacite Space e FrFreequencquency y
BaBannddss
Figure 1: Mid-/long range wireless access over white space frequency bands
In this use case, multimode user terminals (i.e. terminals that support multi-RAT in licensed spectrums for instance
HSPA and LTE) are also provided with the capability of accessing TV White Space spectrum bands in order to provide
wireless broadband access (e.g. TD-LTE) for instance in rural areas where high data rate connections are commonly not
available. This use case takes the benefit of the excellent propagation performance of a radio network operating in TV
White Space frequency bands i.e. 470 MHz to 790 MHz in Europe/Region 1.
TDD can be considered more suitable for a secondary/overlay spectrum access compared with FDD for the following
reasons:
1) TDD only needs one frequency band, so it is simpler to find one single suitable white space frequency band.
For FDD a pair of separated frequency bands (UL/DL) is required with strict separation bandwidth
requirements that makes candidates frequency bands more difficult to find.
2) With two frequency bands used by FDD, there are more chances to interfere with incumbent users on any of
the 2 bands than TDD in its single band - furthermore interference on any of the 2 frequency bands will result
in a handover or a break of the link both DL and UL.
3) It appears to be simpler to detect incumbent users on one single frequency band (TDD) than on a pair of
frequency bands (FDD).
4) TDD - allowing asymmetric DL/UL data connection on a single frequency band may fit well a dynamic
spectrum assignment with optimized/dynamic channel bandwidth.
ETSI
12 ETSI TR 102 907 V1.2.1 (2012-11)
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Figure 2: Architecture Illustration of the Incumbent Signal Detector
NOTE 1: The traditional drawback for a TDD system, i.e. network synchronization, is now shared with the FDD
system which also needs to be network synchronized because of the need to schedule quiet periods for
incumbent signal sensing e.g. synchronized with all neighbour cells.
NOTE 2: The increased interference level at the DL/UL switchover, especially in over-reach conditions may be
another concern of the TDD system. In order to solve this issue, the frequency band of the impacted
neighbour cells can be pre-configured in such a manner that it is different from the cell which may lead to
over-reach problem - this behaviour is inherent to TDD system and solutions used in current TDD wide
area such as TD-SCDMA and WIMAX deployment can be re-used.
NOTE 3: The present use case i.e. TD-LTE operating in TV White Space focuses primarily on low/no mobility
scenarios with larger cells (radius up to tens of kilometres) but high mobility scenarios are not excluded
and remain for further study.
5.2.2 Stakeholders
• End users: the users of the devices accessing internet and other similar mobile data services.
• (White Space) Operator: operates and maintains the required infrastructure; may operate other networks in
other frequency bands.
• White Space database service provider: in case frequency utilization of frequency bands is available in
geo-location databases as e.g. described in [i.5], this entity provides up-to-date information on incumbent
frequency usage.
• External entities: e.g. Internet service provider, in case (White Space) Operator only provides the radio access
on white space.
ETSI
13 ETSI TR 102 907 V1.2.1 (2012-11)
5.2.3 Scenarios
5.2.3.1 Mid-/long range, no mobility
In this scenario, wireless access is provided from a base station towards fixed devices, e.g. a fixed mounted home base
station/access point. The geo-location from both the base station as well as from the fixed device are well-known.
Range (order of magnitude): 0 km to 10 km
Mobility: None (0 km/h)
Geo-Location methods: e.g. GNSS (GPS) or professional installation
e.e.g. Wg. Wiiffii
CoCommmmunicatunicatiion ion inn W Whhiteite
SSppaacce Fre Freqequueennccyy Ba Bannddss

Figure 3: Mid-/long range wireless access, no mobility
5.2.3.2 Mid-/long range, low mobility
In this scenario, wireless access is provided from a base station towards mobile devices where the users have low
mobility, e.g. they are staying at their location or walking. In that respect, sensing results for incumbent users retrieved
for the current location are not getting invalid due to the mobility of the user.
The geo-location from the base station is well-known. The geo-location from the mobile device has to be determined
during operation, e.g. via GPS or cellular positioning systems.
Range (order of magnitude): 0 km to 10 km
Mobility: 0 km/h to 20 km/h
Geo-Location methods: e.g. GPS or cellular positioning systems
ComCommmunicatiunicatioonn i inn Wh Whiteite
SpacSpace Frequee Frequencyncy Ban Banddss

Figure 4: Mid-/long range wireless access, low mobility
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14 ETSI TR 102 907 V1.2.1 (2012-11)
5.2.3.3 Mid-/long range, high mobility
In this scenario, wireless access is provided from a base station towards mobile devices and the mobile devices may
move fast, e.g. because a user is in a car or a train. In that respect, sensing results for incumbent users retrieved for the
current location may get invalid quickly due to the mobility of the user. Thus, this use case sets high constraints for the
detection of incumbent users.
The geo-location from the base station is well-known. The geo-location from the mobile device has to be determined
during operation, e.g. via GPS or cellular positioning systems.
Range (order of magnitude): 0 km to 10 km
Mobility: 0 km/h to 250 km/h
Geo-Location methods: e.g. GPS
CoCommmmununicicatatioionn in in Whit Whitee
SpaSpaccee Fr Freqequeuencncy By Baandndss

Figure 5: Mid-/long range wireless access, high mobility
5.2.4 Information Flow
The available TVWS frequency band is considered based on location rather than in time, it is assumed that TVWS
would be largely available in rural area and in time. However dynamic change in the availability of the bands can not be
excluded and thus has to be taken into account by the system.
In the case of a Network Centric solution, the terminal can get the required information from its current connectivity
and its current RAT i.e. TD-LTE operating in TVWS, or from another RAT e.g. HSPA in 3G bands.
Once the terminal accesses the network it can be left under the control of the network, higher layer signalling can be
used for this purpose e.g. handover command to hand-off to a new frequency or system broadcast messages can be used
to notify terminals about change of the frequency.
A terminal centric solution i.e. where the terminal is able of detecting then accessing suitable TVWS frequencies with
or without the help of the network or a third party e.g. CPC and/or geolocation Database, is possible but not elaborated
in this scenario.
The dynamic spectrum access to the TVWS spectrum frequency band could be achieved by a centralized mode.
ETSI
15 ETSI TR 102 907 V1.2.1 (2012-11)

Figure 6: Access to TVWS, centralized mode
As shown in Figure 6, a central control point is deployed to manage the access of the TD-LTE system to the TV White
Space. It can be either an enhanced base station or a standalone node. The central control point may connect to a
geo-location database to get the information of TVWS spectrum usage status. The geo-location database contains the
information on the secondary user as well as the incumbent user. Alternatively, it may be able to collect the sensing
results from base stations and then produce a radio environment map. It manages the spectrum allocation of the TVWS
resource to the base stations. No negotiation is needed between the base stations in this case. When the base station
switches on, it inquires from the central control point whether there are available TVWS frequencies. If allocated, the
base station can reconfigure itself with the new allocated frequency bands, otherwise, the base station should operate in
the TD-LTE frequency band instead. The base station may be enhanced with the capability of sensing TVWS spectrums
and reports the sensing result to the central control point.
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16 ETSI TR 102 907 V1.2.1 (2012-11)
5.2.4.1 Spectrum allocation when base station powers on

Figure 7: Spectrum allocation when base station is switched on
Step 1: Base Station is initially installed to the network in the rural area.
Step 2: When Base Station powers on, it sends "TVWS Allocation Request" (including the location of base station and
possible early sensing measurements in the TV WS bands) to the central control point to ask for allocation of the
TVWS resources.
Step 3: The central control point inquires the geo-location database whether there are available TVWS frequency bands
at the location of the base station.
Step 4: The central control point makes decision on the TVWS frequency allocation to the Base Station based on the
information retrieved from the database and its knowledge of the neighbouring radio usage e.g. the central control point
will manage interference between neighbour cells within the same networks.
Step 5: If an available TVWS frequency exists at the location of the base station, the central control point sends "TVWS
Allocation Response" which includes the information of allocated TVWS to the base station. Other configuration
parameters (e.g. candidate frequency bands information, transmission power restricted by regulation) may be sent to the
base station as well. Otherwise, the central control point will notify the base station that no TVWS is available at its
location.
Step 6: Base station configures itself according to the parameters indicated by the central control point. If no available
TVWS is found at its location i.e. sensing the given bands, base station will operate on the licensed TD-LTE frequency
band.
Step 7: Base station sends "BS Configuration Update" message including the updated configuration parameters to the
central control point. The central control point responds with "BS Configuration Update Ack" message to acknowledge
that it successfully updated the configuration data.
ETSI
17 ETSI TR 102 907 V1.2.1 (2012-11)
Step 8: The central control point sends "Database Update Request" message including the updated configuration
parameters to the geo-location database. The database responds with "Database Update Ack" message to acknowledge
that it successfully updated the configuration data.
NOTE: The network may have some mechanisms to notify the UE about the current operating frequency of the
base station. For example, in-band CPC on another RAT can be utilized. In this case, the UE under the
coverage of the base station connects to the other RAT to obtain the operating TVWS frequency
information and accesses to the TVWS frequency band.
5.2.4.2 Incumbent protection (Switch from TVWS frequency band to licensed
TD-LTE frequency band or candidate TVWS frequency band)

Figure 8: Incumbent protection
Step 1: The central control point notifies the base station about the information of available TVWS frequency band(s) at
its location periodically or when it is triggered by the change of the information. Base station informs the UE(s) under
its coverage about the frequency usage status in order that Base Station and UE(s) maintain the same set of the
candidate frequency band(s) in the same order.
Step 2: During operation of the base station in TVWS bands, there may be situations where the secondary user has to
free spectrum because the incumbent user wants to use that spectrum. Examples of such operating parameters that
require decision are the switching time and the candidate frequency band. Two potential cases which trigger a HO are:
- Case A: Base station performs the spectrum sensing to monitor whether th
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