ETSI TR 103 103 V1.1.1 (2012-09)

Fixed Radio Systems; Point-to-point systems; ATPC, RTPC, Adaptive Modulation (mixed-mode) and Bandwidth Adaptive functionalities; Technical background and impact on deployment, link design and coordination

DTR/ATTM-04024

General Information

• Status: Published
• Publication Date: 06-Sep-2012
• Technical Committee: ATTM TM4 - Fixed Radio Systems
• Current Stage: 12 - Completion
• Due Date: 05-Oct-2012
• Completion Date: 07-Sep-2012

Standards Content (Sample)

Technical Report
Fixed Radio Systems;
Point-to-point systems;
ATPC, RTPC, Adaptive Modulation (mixed-mode)
and Bandwidth Adaptive functionalities;
Technical background and impact on deployment,
link design and coordination
2 ETSI TR 103 103 V1.1.1 (2012-09)

Reference
DTR/ATTM-04024
Keywords
adaption, DFRS, point-to-point, modulation
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ETSI
3 ETSI TR 103 103 V1.1.1 (2012-09)
Contents
Intellectual Property Rights . 4
Foreword . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions, symbols and abbreviations . 6
3.1 Definitions . 6
3.2 Symbols . 6
3.3 Abbreviations . 6
4 Impact of power control (ATPC and/or RTPC), mixed-mode and bandwidth adaptive operation
on spectrum mask and link design requirements . 7
4.1 ATPC and RTPC implementation background . 7
4.1.1 RTPC Impact . 8
4.1.2 ATPC impact . 9
4.1.2.1 ATPC not required as licensing/coordination conditions . 9
4.1.2.1.1 Use in bands where conventional coordination is applied . 9
4.1.2.1.2 Use in bands where no coordination or simpler self-coordination is applied . 10
4.1.2.2 ATPC required as licensing/coordination conditions . 11
4.2 Mixed-mode operation impact . 11
4.2.1 Basic concepts . 11
4.2.2 Link availability . 12
4.2.3 Link fade margin . 13
4.2.4 ATPC range . 14
4.3 Bandwidth adaptive operation impact . 18
4.3.1 Basic concepts . 18
4.3.2 Bandwidth (channel) occupancy . 18
4.3.3 Link availability and fade margin . 18
4.3.4 ATPC range . 18
5 Impact on frequency co-ordination . 19
6 Impact on Article 3.2 "essential" parameters and operating conditions . 20
History . 22

ETSI
4 ETSI TR 103 103 V1.1.1 (2012-09)
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 Access, Terminals, Transmission and
Multiplexing (ATTM).
ETSI
5 ETSI TR 103 103 V1.1.1 (2012-09)
1 Scope
The present document aims to facilitate the correct understanding of the use of the following functionalities widely used
in point-to-point fixed radio systems in the context of network coordination with a view to R&TTE Directive [i.1]
assessment procedures:
• Remote Transmit Power Control (RTPC).
• Automatic Transmit Power Control (ATPC).
• Mixed-mode (also known as Adaptive modulation) operation.
• Bandwidth adaptive operation.
The technical content has been derived from extensive technical background originally placed in EN 302 217-2-2 [i.5]
and subsequently improved and moved, as stand alone text, to the present document.
Therefore, the scope of the present document is also to assist the correct understanding of the requirements in
EN 302 217−2−2 [i.5] and their consequent assessment.
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] Directive 1999/5/EC of the European Parliament and of the Council of 9 March 1999 on radio
equipment and telecommunications terminal equipment and the mutual recognition of their
conformity (R&TTE Directive).
[i.2] ECC/REC(01)05: "List of parameters of digital point-to-point fixed radio links used for national
planning".
[i.3] ETSI EN 302 217-1: "Fixed Radio Systems; Characteristics and requirements for point-to-point
equipment and antennas; Part 1: Overview and system-independent common characteristics".
[i.4] ETSI EN 302 217-2-1 (V1.3.1): "Fixed Radio Systems; Characteristics and requirements for
point-to-point equipment and antennas; Part 2-1: System-dependent requirements for digital
systems operating in frequency bands where frequency co-ordination is applied".
ETSI
6 ETSI TR 103 103 V1.1.1 (2012-09)
[i.5] ETSI EN 302 217-2-2: "Fixed Radio Systems; Characteristics and requirements for point-to-point
equipment and antennas; Part 2-2: Digital systems operating in frequency bands where frequency
co-ordination is applied; Harmonized EN covering the essential requirements of Article 3.2 of the
R&TTE Directive".
[i.6] ETSI EN 302 217-3: "Fixed Radio Systems; Characteristics and requirements for point-to-point
equipment and antennas; Part 3: Equipment operating in frequency bands where both frequency
coordinated or uncoordinated deployment might be applied; Harmonized EN covering the essential
requirements of Article 3.2 of the R&TTE Directive".
[i.7] ETSI EN 302 326-2: "Fixed Radio Systems; Multipoint Equipment and Antennas; Part 2:
Harmonized EN covering the essential requirements of Article 3.2 of the R&TTE Directive for
Digital Multipoint Radio Equipment".
[i.8] ITU-R Recommendation P.530: "Propagation data and prediction methods required for the design
of terrestrial line-of-sight systems".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in EN 302 217-1 [i.3] apply.
3.2 Symbols
For the purposes of the present document, the following symbols apply:
dB deciBel
dBm deciBel relative to 1 mW
GHz GigaHertz
MHz MegaHertz
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ATPC Automatic Transmit Power Control
ATTM ETSI TC-Access Terminals, Transmission and Multiplexing
BER Bit Error Ratio
BPSK Binary Phase Shift Keying
C/I Carrier to Interference ratio
CEPT Conférence des administrations Européennes des Postes et Télécommunications
ECC Electronic Communication Committee of the CEPT
EHF Extremely High Frequency
EIRP Equivalent Isotropically Radiated Power
ERC European Radiocommunications Committee of the CEPT, presently become ECC
FM Fade Margin
ITU-R International Telecommunication Union - Radiocommunications standardization sector
MP MultiPoint
NFD Net Filter Discrimination
PMP Binary Phase Shift Keying
P-MP Point-to-Multipoint
PP Point to Point
P-P Point-to-Point
PSK Phase Shift Keying
QAM Quadrature Amplitude Modulation
QPSK Quadrature Phase Shift Keying
R&TTE Radio and Telecommunication Terminal Equipment
ETSI
7 ETSI TR 103 103 V1.1.1 (2012-09)
R&TTE Radio equipment and Telecommunications Terminal Equipment
RBER Residual BER
RF Radio Frequency
RSL Receiver Signal Level
RTPC Remote Transmit Power Control
RX Receive or Receiver
S/(N+I) Signal to Noise plus Interference Ratio
S/N Signal to Noise ratio
SW SoftWare
TC Technical Committee
TX Transmit or Transmitter
4 Impact of power control (ATPC and/or RTPC),
mixed-mode and bandwidth adaptive operation on
spectrum mask and link design requirements
4.1 ATPC and RTPC implementation background
It is worth explaining that, in most practical applications, ATPC and RTPC are realized by a single function SW
programmable system; therefore it is the supplier that should declare how the available range of attenuation should be
subdivided (and possibly limited) in order to meet the normative conditions contained in the relevant ETSI Harmonized
Standards and/or in other regulatory limits eventually defined by administrations in the licensing conditions. Those
conditions are summarized below.
It is important to understand that the total available range of attenuation is, in general, subdivided in two sub-ranges,
which, in principle, are independent from any "labelling" as RTPC or ATPC ranges:
• "Initial" Sub-range where the required spectrum mask is still fulfilled;
• "Final" Sub-range where the required spectrum mask is no longer fulfilled.
The ATPC sub-range may be used within two possible scenarios synthesised by table 1.
Table 1: ATPC operating modes versus licensing conditions
Coordination/licensing Effect on network Operational needs
conditions
No ATPC is imposed but the Interference impact on performance and availability is still No need for fulfilling the
user(s), under his (their) evaluated with power at nominal level (no ATPC attenuation spectrum mask (and NFD)
responsibility, apply an ATPC is considered in the coordination process); therefore: in the ATPC range, which
reduction in a homogeneous can indifferently use
• No improvement in the network density.
area for general improvement "initial" and/or "final"
• The user under his own responsibility might obtain
of the interference situation. sub-ranges of attenuation.
additional margin against the calculated performance and
availability objectives.
ATPC is imposed as Interference impact on performance and availability is Need for fulfilling the
pre-condition of evaluated with power reduced by an ATPC range; therefore: spectrum mask (and NFD)
coordination/licensing • Improvement in the network density could be obtained in the assumed ATPC
(note 1). range, which is supposed
(note 2).
to remain within "initial"
• No additional margin against the calculated performance
sub-range of attenuation.
and availability objectives (note 3).
NOTE 1: The ATPC range is link-by-link dependent, it is usually determined in order to fix the maximum RSL permitted
during unfaded periods.
NOTE 2: In general the use of ATPC pre-condition is possible for new links in a network; if existing links in already
dense networks were coordinated without any ATPC, the possible density improvement might be severely
reduced.
NOTE 3: However, in principle and if possible and practical, improvement might still be obtained using the residual
ATPC attenuation, under operator responsibility.

ETSI
8 ETSI TR 103 103 V1.1.1 (2012-09)
Therefore, from the point of view of equipment use in the network, the RTPC and ATPC "labelling" of the available
attenuation range is, in principle, different for the two cases considered in table 1; figure 1 summarises this aspect (see
note).
NOTE: The use of ATPC in the license conditions is foreseen in some countries on national basis; in addition, the
implementation of ATPC functionality is left, as an option, to manufacturer choice. Therefore, the ATPC
assessment for specific licensing conditions is not retained "essential" for R&TTE Directive [i.1] point of
view. Nevertheless, the supplier is recommended to define the RTPC/ATPC ranges possibly available for
that purpose.
Maximum nominal power
RTPC/ATPC range subdivision
(possibly depending on RTPC need for
obtaining the licensed e.i.r.p.)
Minimum power
Limitations when ATPC is not used as Limitations when
licensing/coordination condition ATPC is used as
Technical
(ATPC may still be used only under user responsibility licensing/coordination
limitations
for improving its own network density) condition

Figure 1: ATPC/RTPC ranges and licensing/coordination conditions
4.1.1 RTPC Impact
It should be considered that, when RTPC is used as alternative for conventional RF attenuators (used in the past for a
similar purpose) for setting the maximum power established in the network when planning for each single PP link in
order to restrict inter-system interference into other links, the NFD should be maintained (because it is used for
frequency planning and associated with a rated power). Therefore the mask should be met throughout the operating
range offered (supplier should limit the available range of RTPC accordingly).
NOTE: The above description might not be directly applicable to Multi-Point (MP) applications because RTPC
(if any) might be used in MP systems for different purposes, see EN 302 326-2 [i.7].
ETSI
Total range of power control
Range of power control not Maximum range of power control
fulfilling the spectrum mask fulfilling the spectrum mask
(“Final” sub-range) (“Initial” sub-range)
Range usable for ATPC only Range usable for RTPC and/or ATPC
(under user responsibility) (under user responsibility)
Maximum range usable for ATPC
(useable for licensing conditions)
Range usable for further
ATPC range
(under user responsibility)
Shorter hops reduced
ATPC range (useable for
Shorter hops
licensing conditions)
RTPC range
9 ETSI TR 103 103 V1.1.1 (2012-09)
4.1.2 ATPC impact
4.1.2.1 ATPC not required as licensing/coordination conditions
4.1.2.1.1 Use in bands where conventional coordination is applied
Figure 2 clarifies the technical background for the ATPC operations; it identifies the relevant power levels and their
relationship with the transmitter power density spectrum mask as required by EN 302 217-2-2 [i.5] (see note 1) in
relation to the Article 3.2 of R&TTE Directive [i.1].
NOTE 1: Presently, the large majority of licensing procedures in Europe do not impose an ATPC range; therefore,
it is not considered to be an essential requirement in accordance with the R&TTE Directive [i.1]; more
stringent spectrum usage scenarios (see next clause 4.2.1.2) are left to voluntary implementation of the
manufacturer.
In figure 2 different power levels, possible during ATPC operation, are identified as follows:
• Maximum Nominal Power (ATPC operating): This is coincident with the EIRP defined in the coordination
process for the required link availability (excluding the antenna gain).
• Minimum Power (ATPC operating): This is the lower power reached in unfaded (clear sky) propagation
conditions. This level is defined on the basis of a minimum receiver signal level (RSL) guaranteeing stable
"error free conditions" (including safeguard allowance for tolerances in both TX power setting and RX RSL
detection).
• Intermediate Power (ATPC operating): Any intermediate power condition adapted to the instantaneous
propagation condition.
• Maximum available power (ATPC overdrive): This is mentioned only for due background information of the
technical capability of an ATPC system in a network; however, the applicability and the benefits of this
"overdrive" feature in a multi-operator network are doubtful. It might be considered, with care, only when a
single operator can be responsible for all mutually interfering links in a certain area and can actively monitor
the network for possible unacceptable interference between links using this feature.
Rationale is that this higher power might be provided by the equipment when the nominal power defined by
the coordination process is lower than the equipment capability; in principle, this extra power might be
activated by the ATPC system when the RSL becomes even lower than the BER threshold used for the
required availability. This, still in principle, should happen for less than the unavailability time used for the
network coordination (e.g. less than 0,01 % of the time if availability of 99,99 % is sought); therefore, the
potential interference power increase towards other links in the area should happen only for a time percentage
lower than their nominal unavailability. However, a number of practical considerations (e.g. activation
threshold should be somehow higher than BER threshold for an "error free" operation, significant tolerance in
detecting very low RSL, etc.) suggest that the actual activation time could become sensibly higher than ideal
and the impact on other links nearby might no longer be negligible. Therefore, the applicability and benefit of
this "overdrive" feature in a multi-operator network are considered unpractical.
The Rationale for the requirement related to respecting or not the spectrum mask (see note 2) is that while the mask is a
"relative attenuation", the actual interference potential is given by the absolute power spill-over into adjacent channels.
Therefore the NFD should be guaranteed when transmitters operate at maximum nominal power or in the overdrive
region (i.e. when maximum absolute power is produced in adjacent channels), which are the conditions commonly used
for frequency planning. In all lower power conditions, even where the NFD may be degraded by the (apparent) increase
of the noise floor (due to the actual drop in carrier power), resulting in the mask level being exceeded (see figure 2),
however the absolute interference power on adjacent channels will in any case be equal to or less than that used for
planning (i.e. the planned C/I on adjacent channels will not be exceeded).
NOTE 2: In practice (see clause 4.2.2.1.1), if licensing conditions permits a limited EIRP increase for short periods,
only the ATPC operating in the range between "maximum nominal power" and "maximum available
power", including the relevant attenuation introduced by the RTPC function (if any) for setting the
licensed level of EIRP, is relevant for maintaining the spectral emission within the mask and
consequently the NFD.
ETSI
10 ETSI TR 103 103 V1.1.1 (2012-09)

Extra power exceeding
the EIRP used for the link
Max available power (ATPC overdrive)
coordination
Max nominal power
(ATPC operating)
ATPC “down range”
Intermediate levels
Mask to be met only in the
(ATPC operating)
range “maximum nominal”
to “maximum available”
Minimum power
power (if overdrive power is
(ATPC operating)
permitted
Mask possibly not met in the range
from “maximum nominal” to
“minimum” power
Figure 2: Relationship between spectrum mask requirement and ATPC operation
(ATPC not required by licensing conditions)
However, it has to be considered that, besides the inter-system operation guaranteed by the above behaviour of the
equipment, there is an intra-system constraints for maintaining a suitable RBER that should be taken into account in the
system design; under ATPC operation, the "noise floor" of the emission should remain sufficiently low for maintaining
a signal to noise ratio (S/N) suitable for RBER fulfilment. That S/N would depend on the proprietary implementation;
however, a conservative indication may be drawn assuming that the ratio between the in-band power density and the
noise density ("transmitter S/N") should be:
-6
Transmitter S/N (dB) > (Cochannel C/I@1dB) + (RSL@RBER - RSL@BER10 )
Where:
Cochannel C/I@1dB is defined in clause 4.2.3 and specified in relevant annexes.
-6
The factor (RSL@RBER - RSL@BER10 ) is defined as ≤ 10 dB in clause 6.5.1 of EN 302 217-2-1 [i.4].
4.1.2.1.2 Use in bands where no coordination or simpler self-coordination is applied
Besides the conventional use of ATPC for improving the network density and/or link quality described in previous
clauses, a further use for ATPC, in bands where no coordination is applied or simpler procedures implying self-
coordination under user's responsibility (sometime called light licensing) is required, is identified in EN 302 217-3 [i.6].
In this case the ETSI EN autonomously poses EIRP and/or Pout limitations, function also of the actual antenna gain, for
easing the coexistence of different links in the same area; those limits are in any case equal or lower than any specific
regulatory limit posed by relevant ECC rules (see note 1).
NOTE 1: Only equipment assessing R&TTE Directive [i.1] essential requirements through EN 302 217-3 [i.6] are
subject to those limits; other equipment may follow alternative assessment route foreseen by the
Directive.
In some cases of EN 302 217-3 [i.6] equipment are permitted to exceed those EIRP/Pout limits when ATPC is
implemented as permanent feature (see note 2) and corresponding minimum ATPC attenuation (see note 2) is provided
for not exceeding, in normal clear sky (unfaded) conditions, the maximum required to all equipment. In such a way,
with higher ATPC emission, during deep fading periods, the user may enhance either the maximum hop length and/or
the expected links quality, permitted with certain limited antenna gain (with the desirable corresponding limited antenna
size), still keeping the foreseen reduced interference scenario.
ETSI
11 ETSI TR 103 103 V1.1.1 (2012-09)
The ATPC activation is intended as linearly activated by the drop of RSL in the corresponding far end receiver, so that
the normal limits of EIRP/Pout, otherwise required to "non ATPC operated" equipment, can be exceeded only during
the very limited time of rain induced deep fading, when also interfering paths towards nearby links are likely to be
affected as well for fading correlation.
NOTE 2: With the term "permanent feature" it is intended that ATPC cannot be disabled by the user or, whenever it
is possible, the maximum output power delivered, in any conditions, cannot be set to a value exceeding
the limits for equipment without ATPC. Obviously, an ATPC range larger than the minimum required for
the desired hop length/quality may still be used for enhancing the network density whenever some form
of coordination is in place among links in the same area (e.g by mutual agreements between users, by the
national regulatory authorities, or when blocks of frequencies have been auctioned).
4.1.2.2 ATPC required as licensing/coordination conditions
When it is required to use ATPC for a real increase of the density of networks subject to conventional link-by-link
coordination, the following steps should be considered:
• When existing links in an already relatively dense network do not implement any ATPC, the density
improvement of imposing ATPC for new links is very limited, unless, very unlikely, an investment for ATPC
retrofit and new re−coordination is planned.
• Take into account that links of different length would require different fade margin; consequently, the ATPC
range would also possibly be different; the ATPC range should be calculated on the basis of a suitable fixed
RSL in "clear sky" conditions (often enhanced by other link quality requirements) valid for any link, rather
than considering a fixed transmitter attenuation. Sufficient margin between RSL BER threshold and the
required "clear sky" RSL in ATPC conditions should also be provided for guaranteeing "error free" condition;
relatively short links might not permit any ATPC range but would rather require some "extra margin" in term
of EIRP higher than that calculated for availability.
• In order to guarantee the NFD also in the minimum ATPC power condition, used for coordination, the spectral
density mask should be respected in the range of ATPC assumed for coordination (see note).
• The links coordination of new links for the desired performance and availability objectives would be done with
transmitter output power reduced by the link-specific ATPC range necessary for the link to reach the desired
fixed RSL in "clear sky" conditions.
• Existing links with no ATPC can still be coordinated with their nominal output power.
• A practical ATPC range should be defined considering also the possible implementation limitation described
in clause 4.1.
• When "mixed-mode" systems are used, further constraint to ATPC range might be taken into account. See
clause 4.2.1.3 for more details.
NOTE: It should be considered that ATPC is not a mandatory feature for the equipment in the scope of
EN 302 217-2-2 [i.5]. For this reason, the RTPC/ATPC ranges subdivision, formally aligned only with
the general case considered in clause 4.1.1.1 (where the spectrum mask matching is not required in the
ATPC range), should be specifically re−defined by the manufacturer, as function of the minimum ATPC
range, when it is required by the licensing conditions.
4.2 Mixed-mode operation impact
4.2.1 Basic concepts
Mixed−mode systems (see note) can dynamically (on the basis of RSL and other built-in quality parameters) smoothly
switch between different modulation formats, increasing/decreasing the payload capac
...