ETSI TR 102 581 V1.2.1 (2015-11)

Speech Processing, Transmission and Quality Aspects (STQ); A Study on the Minimum Additional Required Attenuation on the Antenna Path of the Field Test Equipment

RTR/STQ-00200m

General Information

• Status: Published
• Publication Date: 16-Nov-2015
• Technical Committee: STQ MOBILE - STQ Mobile
• Current Stage: 12 - Completion
• Due Date: 20-Oct-2015
• Completion Date: 17-Nov-2015

Standards Content (Sample)

ETSI TR 102 581 V1.2.1 (2015-11)






TECHNICAL REPORT
Speech Processing, Transmission and Quality Aspects (STQ);
A Study on the Minimum Additional Required Attenuation
on the Antenna Path of the Field Test Equipment

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2 ETSI TR 102 581 V1.2.1 (2015-11)



Reference
RTR/STQ-00200m
Keywords
3G, antenna, GSM, MIMO, network
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3 ETSI TR 102 581 V1.2.1 (2015-11)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Abbreviations . 5
4 Typical measurement scenario . 6
5 Real life scenario versus measurement scenario . 6
5.1 Introduction . 6
5.2 Case 1 of the Measurement Scenario . 7
5.3 Case 2 of the Measurement Scenario . 7
6 Estimation of additional required attenuation based on the measurement model . 8
7 Generally recommended additional attenuation values . 10
8 Conclusions . 11
Annex A: In car simulation test . 12
A.1 Introduction . 12
A.2 Problem definition . 12
A.3 Test set up . 12
A.4 Test description . 12
A.5 Results . 12
Annex B: In car simulation test in MIMO environment . 14
B.1 Introduction . 14
B.2 Problem definition . 14
B.3 Test set up . 14
B.4 Test description . 14
B.5 Results . 14
Annex A (informative): Bibliography . 17
History . 18

ETSI

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4 ETSI TR 102 581 V1.2.1 (2015-11)
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 Speech and multimedia Transmission
Quality (STQ).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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5 ETSI TR 102 581 V1.2.1 (2015-11)
1 Scope
The present document presents a theoretical model to be used for the estimation of the minimum required additional
attenuation on the antenna path of the field test equipment in order for this to emulate the real life scenarios.
The model takes into consideration propagation within different environments, such as dense or spread urban areas, as
well as in car and pedestrian scenarios. In addition, in order to provide the estimator, the model uses previously
determined and known values for a set of parameters such as measurement and phone antenna gain, cable loss, car
penetration, body loss.
The model is not applicable in the HSPA environments requiring MIMO technology and in the LTE environment.
2 References
2.1 Normative 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.
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative 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.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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.
3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
CDMA Code Division Multiple Access
HSPA High Speed Packet Access
LTE Long Term Evolution
ME Measurement Equipment
MIMO Multiple Input Multiple Output
PCS Personal Communication System
RF Radio Frequency
RSSI Received Signal Strength Indicator
ETSI

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6 ETSI TR 102 581 V1.2.1 (2015-11)
4 Typical measurement scenario
To ensure accurate network monitoring and testing, the field equipment needs to be set up to emulate real-life mobile
phone utilization scenarios as closely as possible. The complexity of this emulation increases with the number of
elements present in the mobile phone antennas which use e.g. dual-polarized MIMO and automatic band switching
techniques or other smart functions.
Generally, non-MIMO equipment uses a single external antenna mounted on the roof of the drive test vehicle. This
external antenna is connected to the RF input of the equipment box, which then connects to the RF input of the phone
that is found inside the equipment box (see figure 4.1).

Figure 4.1: Measurement equipment
This set-up is beneficial to the signal strength (the RF power) that the phone receives and generates more optimistic
results than a normal subscriber would experience. Therefore, an additional attenuator, characterized by the appropriate
attenuation value, is required to ensure that the measurement configuration reproduces as closely as possible the real-
life scenario. It should be noted, however, that there are a set of RF and electrical components involved in the
measurements that compensate for the measurement's imperfections to a certain extent.
This is why a proper measurement set up requires the evaluation of the impact of these components (such as
measurement antenna gain, cable loss, phone antenna gain, car penetration, and body loss) in order to estimate the
minimum required additional attenuation to be inserted on the measurement path.
5 Real life scenario versus measurement scenario
5.1 Introduction
While the values of the RF and electrical characteristics are generally specified by the manufacturers of the
measurement equipment's parts, the required additional attenuation value needs to be determined based on a
measurement model designed to best emulate the real-life scenario. The model is based on the required equivalency
between the real-life conditions and the measurement scenarios.
ETSI

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7 ETSI TR 102 581 V1.2.1 (2015-11)
In a real-life scenario, which considers a subscriber using the phone inside the car, the power received by the phone's
antenna is given by equation (1) below:
Pin,phone = Prf 1 + Atten(car) + Atten(human head) + Gain(antenna phone) [dB] (1)
where Prf1 is the RF power at the phone's location. The power is dependent on the path loss of the RF signal. The path
loss depends on a set of environmental factors (such as the nature of the landscape, the type and the morphology of the
measurement location, the geography of the location) described by the function F and the receiving antenna's height h
(see equation (2) below):
PathLoss(h) = F(landscape, morphology, geography) + A(h) [dB] (2)
The A(h) factor is also called the correction factor and an approximate value of this factor can be calculated using
Hatta's equation for dense cities covered by micro cells with a small radius (about 1km) (see equation (3) below):
A (h) = (1,1 × lg (f) -0,7) × h -1,56 × lg (f) + 0,8 [dB] (3)
where f(MHz) represents the carrier frequency. For spread cities covered by macro cells with radius larger than 1 km,
the A(h) does not depend on the frequency anymore (see equation (4) below):
A (h) = 3,2 × (lg (11,75 × h)^2 - 4,97 [dB] (4)
In the measurement's scenario, the received power by the phone comes through the external antenna mounted on the
drive test vehicle's roof and is given by (equation (5) below):
Pin,phone = Prf 2 + Gain(external antenna) + Atten(ext antenna cable) +
Atten(ME) + Atten(add atten) [dB] (5)
where Prf2 represents the RF power at the external antenna location, and the measurement equipment is denoted ME.
The term Atten(ME) denotes the attenuation inserted by the path between the RF input of the ME box to the RF input of
the phone, and includes connectors and cable loss.
The measurement scenario emulates the real-life condition if the Pin,phone given in the both scenarios is the same.
The term Atten(add atten) represents the attenuation that is required in the measurement chain in order to ensure that the
measurement scenario emulates the real live scenario.
5.2 Case 1 of the Measurement Scenario
If the measurements are performed using a car, then the antenna height is considered to be 1,5 meters and the
equality 6 (6) takes place:
Prf1 = Prf2 (6)
The value of the required additional attenuation can be therefore calculated using equations (1) and (5) and the
equality (6) (see equation (7) below):
Atten(add atten) = - Gain(external antenna) - Atten(ext antenna cable) - Atten(ME) +
Atten(car) + Atten(human head) + Gain(antenna phone) (7)
5.3 Case 2 of the Measurement Scenario
If the measurements are performed using a van, mini truck, or bus, then the antenna is higher than 1,5 meters. Assuming
that the environmental factors remain unchanged and using equation (2), the following equality (8), takes place.
Prf2 = Prf1 + PathLoss(h) - PathLoss(1,5 m) = Prf1 + (A(h) - A(1,5 m)) (8)
The equation (8) is equivalent to a correction of the external antenna gain as it is described by equation (9), below:
Gain(external antenna)_corrected = Gain(external antenna) + (A(
...