ETSI TR 102 947 V1.1.1 (2013-06)

Reconfigurable Radio Systems (RRS); Use Cases for building and exploitation of Radio Environment Maps (REMs) for intra-operator scenarios

DTR/RRS-01009

General Information

• Status: Published
• Publication Date: 23-Jun-2013
• Technical Committee: RRS 1 - RRS System Aspects & Cognitive functionalities
• Current Stage: 12 - Completion
• Due Date: 03-Jul-2013
• Completion Date: 24-Jun-2013

Standards Content (Sample)

ETSI TR 102 947 V1.1.1 (2013-06)






Technical Report
Reconfigurable Radio Systems (RRS);
Use Cases for building and exploitation
of Radio Environment Maps (REMs)
for intra-operator scenarios

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2 ETSI TR 102 947 V1.1.1 (2013-06)



Reference
DTR/RRS-01009
Keywords
CRS, radio, radio measurements
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3 ETSI TR 102 947 V1.1.1 (2013-06)
Contents
Intellectual Property Rights . 5
Foreword . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 Motivation, Goals . 8
5 Uses Cases . 9
5.1 Overview . 9
5.2 Detailed Use Cases . 9
5.2.1 In-band Coverage/Capacity Improvement by Relays . 9
5.2.1.1 General Use Case Description. 9
5.2.1.2 Stakeholders . 9
5.2.1.3 Scenario . 10
5.2.1.4 Information Flow . 11
5.2.1.5 Potential System Requirements . 12
5.2.2 Self-Configuration and Self-Optimization of Femto-Cells . 12
5.2.2.1 General Use Case Description. 12
5.2.2.2 Stakeholders . 12
5.2.2.3 Scenario . 12
5.2.2.3.1 Use of the REM to solve femto/macro interference . 13
5.2.2.4 Potential System Requirements . 16
5.2.3 System Optimization. 16
5.2.3.1 General Use Case Description. 16
5.2.3.2 Stakeholders . 16
5.2.3.3 Scenarios . 16
5.2.3.4 Information Flow . 17
5.2.3.5 Potential System Requirements . 18
5.2.4 Introduction of New Radio Access Technologies . 18
5.2.4.1 General Use Case Description. 18
5.2.4.2 Stakeholders . 18
5.2.4.3 Scenario . 19
5.2.4.3.1 Use of REM for interference mitigation . 19
5.2.4.4 Potential System Requirements . 21
5.2.5 Vertical Handovers Optimization . 21
5.2.5.1 General Use Case Description. 21
5.2.5.2 Stakeholders . 22
5.2.5.3 Scenario . 22
5.2.5.4 Information Flow . 23
5.2.5.5 Potential System Requirements . 24
5.2.6 Intra-System Handovers Optimization. 24
5.2.6.1 General Use Case Description. 24
5.2.6.2 Stakeholders . 24
5.2.6.3 Scenario . 25
5.2.6.4 Information Flows . 26
5.2.6.5 Potential System Requirements . 28
6 Technical challenges . 28
6.1 Collection of the REM information . 28
6.2 Processing and exploitation of the REM information . 28
6.3 Measurement overhead impact to interface capacity . 29
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4 ETSI TR 102 947 V1.1.1 (2013-06)
6.4 Impact on the MCD . 29
7 Conclusion . 29
History . 31

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5 ETSI TR 102 947 V1.1.1 (2013-06)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://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).
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6 ETSI TR 102 947 V1.1.1 (2013-06)
1 Scope
The present document intends to identify use cases and provide system level functionality for building and exploiting
evolutionary Radio Environment Maps (REMs) in a single or multi-RAT context in intra-operator scenarios.
Building the REM within an RRS context requires the enhancement of existing network entities, protocols and
interfaces accomplishing the tasks of requesting, storing and processing geo-located measurements related to the radio
environment.
It is expected that REMs will be exploited in an RRS context for network troubleshooting and radio resource
management optimization. The present document includes a general description of the use cases and associated
stakeholders as well as information flows and high level requirements. Technical challenges are also identified.
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
referenced 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] Report Recommendation ITU-R SM.2152 (2009): "Definitions of Software Defined Radio (SDR)
and Cognitive Radio System (CRS)".
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 as given in [i.1].
Reconfigurable Radio Systems (RRS): generic term for radio systems encompassing Software Defined and/or
Cognitive Radio Systems
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7 ETSI TR 102 947 V1.1.1 (2013-06)
Software Defined Radio (SDR): 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 as given in [i.1]
use case: description of a system from a user's perspective
NOTE 1: Use cases treat a system as a black box, and the interactions with the system, including system responses,
are perceived as from outside the system. Use cases typically avoid technical jargon, preferring instead
the language of the end user or domain expert.
NOTE 2: Use cases should not be confused with the features/requirements of the system under consideration. A use
case may be related to one or more features/requirements, a feature/requirement may be related to one or
more use cases.
NOTE 3: A brief use case consists of a few sentences summarizing the use case.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
BS Base Station
CAPEX CAPital EXpenditures
CR Cognitive Radio
FDD Frequency Division Duplex
GUI Graphical User Interface
HO HandOver
LTE Long Term Evolution
MCD Measurements Capable Device
MD Mobile Device
MDT Minimization of Drive Test
MME Mobility Management Entity
MNO Mobile Network Operator
NFC Near Field Communication
OFDM Orthogonal Frequency Division Multiplexing
PHY Physical Layer
QoS Quality of Service
RAN Radio Access Network
RAT Radio Access Technology
RBS Radio Base Station
REM Radio Environment Map
RF Radio Frequency
RFID Radio Frequency Identification
RNC Radio Network Controller
RRM Radio Resource Management
RRS Reconfigurable Radio System
RSRP Reference Signal Received Power
SDR Software Defined Radio
SINR Signal to Interference plus Noise Ratio
TR Technical Report
UMTS Universal Mobile Telecommunications Service
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4 Motivation, Goals
The cognitive radio concept offers, through radio environment awareness, opportunities for improving radio resource
management as well as for easing network monitoring and troubleshooting.
The Radio Environment Map (REM) defines a set of network entities and associated protocols that trigger, perform,
store and process geolocated radio measurements (received signal strength, interference levels, QoS measurements for
e.g. femto cell deployment scenario and related radio resources management) and network performance indicators.
Such measurements are typically performed by user equipments, network entities or dedicated sensors.
The REM uses a dynamic database capable of tracking changes in the radio environment and, as such, necessitates a
careful design depending on the scenarios of interest.
A generic description of the REM concept is provided in Figure 1. As shown in the Figure, Measurement Collection
Modules (one for each RAT domain) request geo-located measurements from,Measurements Capable Devices (MCDs),
such as Mobile Devices. The data collected from every RAT domain is stored and treated in the REM entity
(encompassing REM management and storage modules). The post-treated REM data is then provided to the RRM
entities for radio resources optimization purposes.
For MCDs, the following principles apply as far as MDs are concerned:
• The info in the REM is gathered by Mobile Devices that may not be the ones that benefit from the REM
information in a specific scenario.
• The Mobile Device making field strength measurement, can measure in a frequency band which is not the
band where the device is operating.
• As REM are, in principle, technology agnostic, measurements for the benefit of Mobile Devices operating on a
particular RAT may be performed by Measurement Capable Devices (MCD) operating in another RAT.
In this context the REM is a powerful technology agnostic tool that encompasses any compliant reconfigurable radio
access technology, which allows powerful cross-technology optimization algorithms to be implemented and provides a
synthesized view of the networks for monitoring purposes through dedicated Graphical User Interfaces (GUIs).
Radio
Resources
Optimisation

Figure 1: Generic REM description in intra-operator domain
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9 ETSI TR 102 947 V1.1.1 (2013-06)
5 Uses Cases
5.1 Overview
Use Cases according to the definition in clause 3.1 will describe the system behaviour according to the specific Scenario
considered. Use Cases and related Scenarios are then used for deriving the potential System Requirements. For this
purpose each Use Case described in the following clauses is documented in the same way by using the same structure:
• General Use Case Description
• Stakeholders
• Scenario
• Information Flow
Hereafter the list of Use Cases (described in detail in the next clauses) with the aim to serve as a short summary is
reported. The Use Cases considered in the present document are the following:
• In-band Coverage/Capacity Improvement by Relays
• Self-Configuration and Self-Optimization of Femto-Cells
• System Optimization
• Introduction of New Radio Access Technologies
• Vertical Handovers Optimization
• Intra-System Handovers Optimization
5.2 Detailed Use Cases
5.2.1 In-band Coverage/Capacity Improvement by Relays
5.2.1.1 General Use Case Description
In this scenario REM helps detecting and locating coverage and capacity problems by supplying geo-localized
information on the coverage/capacity indicators. As a remedy, it provides a means to dynamically adjust the transmit
power of the emitters (i.e. auto-configuration of relays).
Basically, the aim is to detect and solve coverage hole and traffic hotspot issues through introduction of relays. From
the operator perspective, the problem detection is a key issue since it appears when customers complain. One way
forward is then the necessity to perform specific measurement campaign to clearly understand the unsatisfying situation
before deciding on solution implementations to improve it. In some scenarios (e.g. LTE) MDT concept is also a
solution.
The relay solution appears to be efficient as it allows improving/extending the coverage zone, and at the same time also
helps to handle more traffic. However, relays are deployed inband with radio backhauling, hence generating potential
interference and also consuming radio resources. Their configuration has therefore to be optimized to avoid resource
wastage.
5.2.1.2 Stakeholders
Mobile Network Operator (MNO): operates and maintains an heterogeneous mobile network deployed using
reconfigurable radio nodes (e.g. RBSs) and provides mobile services (voice and data) to its customers.
User: performs voice and/or data traffic through his/her Mobile Device.
Base Station: The existing BSs provide the coverage and capacity foreseen by the network planning.
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10 ETSI TR 102 947 V1.1.1 (2013-06)
Relays: They are intended to improve coverage and capacity (low-cost solution to coverage/capacity adjustments).
REM: This entity stores geo-localized coverage/capacity information.
Mobile Device: MD reports measurements for the REM.
5.2.1.3 Scenario
Within a cellular network, areas that suffer from high shadowing receive the serving signal with strength much lower
than what the initial planning forecasted. This is commonly referred to as a dead zone or a coverage hole. Possible
causes are a hilly terrain or buildings of great dimensions. In these areas, the service quality is usually severely
impacted. However, depending on the size of a coverage hole and traffic needs, the deployment of a new base station
may not be a cost-effective solution.
On the other hand, some areas might have a significantly high traffic demand for short periods, which necessitates a
provision of capacity increase in order not to cause a notable degradation in the planned service quality. A cost-effective
solution to alleviate such problems is the use of relays, whose deployment is foreseen as one of the new features to be
included in LTE-Advanced. Relays are small base stations that use the radio access spectrum for backhauling and they
forward mobile messages to/from the Base Stations (BSs). Capacity/coverage improvement is obtained by properly
configuring the relays (adjusting the transmitting power, antenna parameters, etc.). In this context, REMs can be used to
reach the following objectives:
• Detect and locate the above mentioned situations that require coverage and capacity improvements.
• Trigger a cognitive engine to handle the issue.
• Help to configure and optimize the solution in a way that does not require a re-planning.
Figure 2 provides an example of a relay-based solution to coverage improvement. The figure depicts a situation where
the green area requires better coverage due to propagation issues or more capacity due to traffic issues. The left-hand
sub-figure highlights the weakness of a hand-made solution: the transmission power of the relay is not optimally
adjusted to cover the intended zone. The blue area that is due to the overshoot in relay coverage causes high
interference, degrading the QoS for the users in the vicinity. Besides, the relay coverage does not completely cover the
intended zone, leaving the initial problem partially unsolved. On the right-hand side, the solution tailored with REM can
be seen. The transmission power of the relay is optimally configured and its coverage matches the green area.

Figure 2: Relay scenario
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11 ETSI TR 102 947 V1.1.1 (2013-06)
5.2.1.4 Information Flow
This clause presents a high level information flow depicted in Figure 3 and Figure 4 for the Relay optimization
scenario. The information flow considers the following nodes:
• Base Station: The existing BSs provide the coverage and capacity foreseen by the network planning.
• Relays: They are intended to improve coverage and capacity (low-cost solution to coverage/capacity
adjustments).
• REM: This entity stores geo-localized coverage/capacity information.
• Mobile Device: MD reports measurements for the REM.
In the following, the situation has been split into the following main phases:
• Phase 1: REM helps detecting/identifying and locating coverage and/or capacity problems.
• Phase 2: A new relay is installed and commissioned at the appropriate location.
• Phase 3: REM helps optimizing the relay configuration parameters.
The phase 1 information flow is the following:
☺☺☺
REMREMREM BSBSBS MDMDMD
OOOppperereratatatororor
MMeeasasurureemmeennttss
MMeeasasurureemmenentt
FWFWDD
EvEveenntt R Reporeportt
(R(RLF) andLF) and
mmeeasasurureemmenenttss
DatDataa F Fuussiionon
AlarAlarmm

Figure 3: Phase 1 information flow
Phase 3 on Relay optimization takes place after the roll-out and initial configuration setting. MDs, BSs and Relays
continuously monitor events and carry on relevant measurements. Based on those reports, REM detects whether the
problem is solved or not and adjust the relay configuration, adjusting parameters related to e.g. remotely controllable
mechanical downtilt, electrical downtilt, beamforming, transmitted power, allocated bandwidth and allocated timeslots.
The corresponding high level information flow is given below.
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12 ETSI TR 102 947 V1.1.1 (2013-06)
MDMDMD REMREMREM BSBSBS MDMDMD
RelaRelayy
MMeeasasurureemmentent
MMeeasasuurreemmentent F FWWDD
MeMeasasurureemmenenttss
MMeeasasurureemmentent F FWWDD
EEvvent Rent Repoeporrtt
EveEvenntt R Reepoport rt aand nd
memeasasurureemmenenttss
ReReccoonnffiiggururatatiioon n
RRequeequestst

Figure 4: Phase 3 information flow
5.2.1.5 Potential System Requirements
From the Use Case presented above, the following system requirements can be derived:
REQ_01 Mobile Devices have the capability to perform geo-localized measurements.
REQ_02 Mobile Devices can report their location information with sufficient precision.
REQ_03 BSs and relays have a connection with the REM.
REQ_04 Relays are agile enough in configuration modifications (power adjustment, beamforming capability, etc.).
5.2.2 Self-Configuration and Self-Optimization of Femto-Cells
5.2.2.1 General Use Case Description
This clause addresses the use of REM to enable efficient self-configuration, self-optimization and self-healing of femto-
cells (transmission parameters, admission/mobility/congestion/interference control, etc.)
5.2.2.2 Stakeholders
Mobile Network Operator (MNO): operates and maintains an heterogeneous mobile network deployed using
reconfigurable radio nodes (e.g. RBSs) and provides mobile services (voice and data) to its customers.
User: performs voice and/or data traffic through his/her Mobile Device (MD).
5.2.2.3 Scenario
The aim of this scenario is to use REM information to ease self-configuration, self-optimization and self-healing of
femto-cells.
Femto-cells are very small base stations that are located in customers' premises and that are operated by the customers.
Backhauling is provided by the landline internet access of the customer (ADSL, fiber, etc.) and radio access is achieved
by the radio access technology that defines the femto-cell (3G or LTE). Since they are operated by the customers, they
are typically plug-and-play type devices.
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13 ETSI TR 102 947 V1.1.1 (2013-06)
Besides, since the operator has no role in their installation and their operation, the initial network planning process does
not exist in femto-cells. The operator does not exactly know how many femto-cells will be deployed and therefore
cannot carry out an initial dimensioning and planning of the femto-cell network. Being plug-and-play type devices,
femto-cells are completely autonomous in operations like transmission parameter settings (RF and antenna parameters,
power levels, etc.), neighbour list definition, admission/congestion control parameter adjustment, mobility management
(femto-femto as well as femto-macro), etc.
Furthermore, femto-cells are deployed in the same frequency band as the macro cells of the same radio access
technology (3G or LTE) and therefore interference mitigation with the neighbouring macrocells is a challenging issue.
Finally, systems involving femtocells are expected to be highly dynamic; as consumer equipment the rate of
deployment is uncertain, the devices might be powered down for substantial period of time, and devices might be
...