Report-DAS and Mobile Transmission Power

The Impact of a DAS system on
the transmitted power of Mobile
Telephony equipment and Mobile
Phones
Version: 1.1
Date: May 13th
2015
Authors:
Nyoka de Wert
MSc Renzo Hardy
Commissioned by:
Erasmus University Medical Center: Antoine van Kempen
RadioAccess : Maurits Zandbergen

Version: 1.1 20150602 report-das and mobile transmission power _incl. handtekeningen.docx Page 2 of 31
Contents
1 General ........................................................................................................................3
1.1 Purpose of this document ........................................................................................................ 3
1.2 Version Control ........................................................................................................................ 3
1.3 Approval................................................................................................................................... 3
2 Abstract .......................................................................................................................4
2.1 In English................................................................................................................................. 4
2.2 In het Nederlands..................................................................................................................... 5
2.3 Regulations relevant to Hospital environments ........................................................................ 6
2.3.1 Equipment......................................................................................................................... 6
2.3.2 Public ................................................................................................................................ 6
3 Research Definition....................................................................................................7
3.1 Introduction .............................................................................................................................. 7
3.2 Assignment .............................................................................................................................. 7
3.3 Problem Definition.................................................................................................................... 7
3.4 Hypothesis............................................................................................................................... 8
3.5 Research Question .................................................................................................................. 8
3.6 Demarcation ............................................................................................................................ 8
4 Research Method........................................................................................................9
4.1 Method of measurements ........................................................................................................ 9
4.1.1 Equipment......................................................................................................................... 9
4.1.2 Location ............................................................................................................................ 9
4.1.3 Method.............................................................................................................................. 9
4.1.4 Active DAS........................................................................................................................ 9
4.1.5 Operator............................................................................................................................ 9
4.2 Information on Measured Data............................................................................................... 10
4.2.1 Signal Strength................................................................................................................ 10
4.2.2 Signal Strength – Transmit Power User Equipment ........................................................ 10
4.2.3 Signal Strength - Received.............................................................................................. 10
4.2.4 Relation User Equipment Received Signal Strength and Transmitted Power.................. 11
4.2.5 Signal Quality GSM......................................................................................................... 12
4.2.6 Signal Quality UMTS....................................................................................................... 12
4.2.7 Conversion to V/m........................................................................................................... 12
4.3 Results – GSM....................................................................................................................... 14
4.3.1 Time Graphs ................................................................................................................... 14
4.3.2 Distribution Graphs ......................................................................................................... 16
4.3.3 Summary......................................................................................................................... 17
4.3.4 Electric Field Strength ..................................................................................................... 18
4.3.5 Conclusions..................................................................................................................... 19
4.4 Results – UMTS..................................................................................................................... 20
4.4.1 Time Graphs ................................................................................................................... 20
4.4.2 Distribution Graphs ......................................................................................................... 23
4.4.3 Summary......................................................................................................................... 24
4.4.4 Electric Field Strength ..................................................................................................... 25
4.4.5 Conclusions..................................................................................................................... 25
5 Conclusions & Recommendations .........................................................................27
5.1 Recommendation................................................................................................................... 28
5.2 Future Research .................................................................................................................... 28
6 Annex A: Abbreviations & Acronyms.....................................................................29
7 Annex B: References................................................................................................30
8 Annex C: Detailed Measurements...........................................................................31

1 General
1.1 Purpose of this document
This document outlines the results and conclusions from a joint research project between Erasmus
University Medical Center and RadioAccess BV. The project has been outlined in the document
“Research plan to the effects of the Distributed Antenna System” (original title: “Onderzoeksplan naar
de effecten van het Distributed Antenna System”, dated May 2013, written by Nyoka de Wert).
This document starts with an English and Dutch abstract. In the first chapter (chapter 3) the research
definition will be illustrated, after which the research methods are explained in chapter 5. Chapter 5
contains conclusions and recommendations. All definitions, abbreviations and acronyms are explained
in Annex A. Finally annex B contains all references and Annex C the detailed measurements.
1.2 Version Control
Version
Nr.
Date Author Change
0.6 09-07-2014 Nyoka de Wert
MSc. Renzo Hardy
Intermediate Draft
0.7 19-08-2014 MSc. Renzo Hardy First review adjustments
0.9 10-09-2014 MSc. Renzo Hardy Further first review adjustments
0.91 24-09-2014 Leo Verstaeten Reference to study Prof. van Rhoon
0.96 25-09-2014 MSc. Renzo Hardy Adding electrical field strengths
0.97 07-10-2014 Nyoka de Wert Abstract and Review
0.98 01-12-2014 Nyoka de Wert Review by Peer reader Prof. van Rhoon
1.0 21-01-2015 Nyoka de Wert
MSc. Renzo Hardy
First complete version
1.1 13-05-2015 Nyoka de Wert Final version
1.3 Approval
This document has been peer reviewed and approved by;

2 Abstract
2.1 In English
The Erasmus University Medical Center has invested in a Distributed Antenna System (DAS) in the
new building to guarantee an optimal indoor coverage for mobile devices (GSM and smartphones) to
the new building an important effect of the DAS. With this research the Erasmus University Medical
Center together with RadioAccess aims to demonstrate that the transmitting power of the mobile
devices reduces, while the mobile coverage increases. For that reason, the research question will be
answered; ‘What is the effect of an indoor DAS on the transmission power of GSM and UMTS devices
which are connected to this DAS?
Together with RadioAccess the Erasmus University Medical Center has carried out measurements to
determine the effect of the DAS. The measure equipment, Nokia type 6720c measurement phone,
Zadako UMTS Modem, a HP Elitebook pen tablet computer and JDSU E6474A Wireless Network
Measurement Software v.16.1 were used to determine the signal strength on 6 locations with the DAS
on and off. Four were in a high rising tower Na- on floors 3, 6, 12 and 28. The other two were in an
adjacent building part on floor 6 and 12.
In the findings several differences can be noticed when it comes to GSM Signal:
 With the DAS on, the average received signal strength is higher and the transmitted power is lower
than with the DAS switched off;
 With the DAS switched off, the mobile phone was transmitting at maximum powermore than 60% of
the time and is regularly switching between 900 MHz and 1800 MHz. With the DAS switched on the
transmitted time on maximum power is less than 1%;When the DAS is switched on, the average
measured RxLev (Received power level) improves by 18.4 dB;
 The transmitted power from the user equipment decreases by 9 dB.
This means that received signal level is almost 70 times stronger with the DAS switched on compared
to the DAS switched off. The transmitted power reduced from on average 0.53 Watt to 0.06 Watt, i.e. a
factor 8.
In measurement results for UMTS the following is notable:
 With the DAS on, the average received signal strength RSCP (Received Signal Code Power) is
higher and the transmitted power TxLev (Transmitted power level) is lower than with the DAS
switched off:
 With the DAS switched off, 5.2% of the time the mobile was transmitting at maximum power. With
the DAS switched on, the transmitted power only got above 1% of maximum power during the
measurement where the mobile temporarily went to the macro network ;
 The difference in transmitted power is 30.0 dB.
This means that the RSCP improves a factor 75 with the DAS switched on compared to the DAS
switched off. The decrease of transmitted power from the user equipment by 30 dB means that the
transmitted power level is a factor 1000 lower with the DAS on compared to the measurements when
the DAS was switched off, dropping it from 4 milliWatt to 0.004 milliWatt. Comparing it to GSM with the
DAS switched on, then the difference is 42.2 dB or a factor 16.000, 67 milliWatt for GSM vs 0.004
milliWatt for UMTS.
The hypothesis ‘When GSM/UMTS user equipment operates in a Distributed Antenna System (DAS)
coverage area, the transmission power of this user equipment decreases’ has been proven to be right.
It can be concluded that an indoor DAS reduces the transmitted power of user equipment, in which
reduction for UMTS is larger than for GSM. This means that the use of mobile devices is safer with a
DAS than in situations without a DAS, while the quality of communications facilities improves.
The differences in transmitted power for GSM and UMTS with DAS on and off are significant.
The electric field strength at the edge of the far field decreases by 7 for both GSM and UMTS when
the DAS is switched on. In addition, UMTS performs 16.000 times better than GSM.

2.2 In het Nederlands
Het Erasmus Universitair Medisch Centrum heeft geïnvesteerd in een Distributed Antenna System
(DAS) in de nieuwbouw om een optimale indoor dekking voor mobiele gebruikersapparatuur (GSM en
smartphones)in het nieuwe gebouw te kunnen garanderen. Met dit onderzoek wil het Erasmus
Universitair Medisch Centrum samen met RadioAccess B.V. aantonen dat het zendvermogen van de
mobiele apparaten vermindert, terwijl de mobiele dekking toeneemt. Om die reden zal de
onderzoekvraag moeten worden beantwoord: 'Wat is het effect van een indoor DAS op het
zendvermogen van GSM- en UMTS- gebruikersapparatuur die met dit DAS zijn verbonden?
Samen met RadioAccess heeft het Erasmus Universitair Medisch Centrum metingen verricht om het
effect van het DAS te bepalen. De meetapparatuur, een Nokia 6720c, Zadako UMTS modem, een HP
Elitebook pen tablet computer en JDSU E6474A Draadloos Netwerk metingen Software v.16.1 werden
gebruikt om de signaalsterkte op 6 locaties met het DAS aan en uit te bepalen. Vier metingen waren in
de hoogbouw toren Na- op de verdiepingen 3, 6, 12 en 28. De andere twee metingen in een
aangrenzend bouwdeel op verdieping 6 en 12.
Uit de bevindingen kunnen een aantal verschillen worden opgemerkt wat betreft het GSM signaal:
• Met het DAS aan is de gemiddelde signaal sterkte bij de ontvanger hoger en is het uitgezonden
vermogen lager dan wanneer het DAS is uitgeschakeld;
• Met het DAS uitgeschakeld, zendt de mobiele telefoon 60% van de tijd op maximaal vermogen uit en
wordt er regelmatig geschakeld tussen 900 MHz en 1800 MHz. Wanneer het DAS is ingeschakeld is
zendt de mobiele telefoonminder dan 1% % van de tijd op maximaal vermogen uit;
• Als het DAS wordt ingeschakeld, verbetert de gemiddeld gemeten RxLev (Received power level) met
18,4 dB;
• Het uitgezonden vermogen van de gebruikersapparatuur daalt met 9 dB.
Dit betekent dat de ontvangst signaalsterkte bijna 70 keer sterker is met het DAS ingeschakeld in
vergelijking met het DAS uitgeschakeld.
Het uitgezonden vermogen wordt gereduceerd met een factor 8 van gemiddeld 0,53 Watt tot 0,06
Watt.
In de meetresultaten voor UMTS is het volgende opmerkelijk:
• Met het DAS aan is de gemiddelde sterkte van het ontvangen RSCP (Received Signal Code Power)
signaal hoger en is het uitgezonden vermogen in TxLev (Transmitted power level) lager dan bij een
uitgeschakeld DAS;
Met het uitgeschakelde DAS werd 5,2% van de tijd op het maximum vermogen uitgezonden. Met het
DAS aan kwam het uitgezonden vermogen slechts boven 1% van het maximum vermogen tijdens de
metingen wanneer het mobiele toestel tijdelijk over schakelde naar het macro netwerk; het verschil in
uitgezonden vermogen is 30,0 dB.
Dit betekent dat de RSCP 75 maal beter is wanneer het DAS ingeschakeld in vergelijking met een
uitgeschakeld DAS. De afname van het uitgezonden vermogen van de gebruikersapparatuur met 30
dB betekent dat het uitgezonden vermogen 1000 maal lager is met het DAS aan, in vergelijking met
de metingen bij een uitgeschakeld DAS, van 4 milliwatt tot 0,004 milliwatt. Wanneer dit voor GSM
wordt vergeleken met een aangeschakeld DAS is het verschil 42,2 dB of een factor 16.000; 67
milliwatt voor GSM versus 0,004 milliwatt voor UMTS.
De hypothese: 'Wanneer een GSM / UMTS gebruikersapparaat zich binnen de dekking van het DAS
bevindt, daalt het zendvermogen van dit gebruiksapparaat’ is hiermee bewezen. Hiermee kan worden
geconcludeerd dat met een indoor DAS het uitgezonden vermogen van de gebruikersapparatuur
gereduceerd wordt, waarbij de afname voor UMTS groter is dan voor GSM. Dat betekent dat het
gebruik van mobiele gebruikersapparaat veiliger is met een DAS dan in een situatie zonder DAS,
terwijl de kwaliteit van de communicatiemogelijkheden verbetert. .
De verschillen in het zendvermogen voor GSM en UMTS met het DAS aan en uit zijn significant
De elektrische veldsterkte aan de rand van het stralingsgebied neemt met factor 7 af voor zowel GSM
als UMTS wanneer het DAS is ingeschakeld. Bovendien presteert UMTS 16.000 maal beter dan
GSM.

2.3 Regulations relevant to Hospital environments
There are two kinds of regulations that are important with regard to safety and mobile telephony. One
is with regard to equipment and the other is with regard to people. Standards of equipment are more
stringent than standards for humans. Because the Erasmus University Medical Center and
RadioAccess B.V. already meet the standard for humans it is disregarded in this research.
2.3.1 Equipment
Regulations with regard to equipment come down to an international standard for electromagnetic
compatibility (EMC): “IEC 61000-4-3:2006+A1:2007+A2:2010”. There are several test levels. It
depends on the type of equipment what test level has to be used.
Table 1: Equipment test levels
Test Level
Carrier field strength
(V/m)
1 1
2 3
3 10
4 30
2.3.2 Public
For people guidelines have been created by the International Commission on Non-Ionizing Radiation
Protection: “Guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic
fields (up to 300 GHz) – 1998”. Differentiation has been made for occupational exposure and for the
general public, where the occupational allow higher exposure levels. For hospitals, the guidelines for
general public will be applied. The following equations apply:
Emax = 1.375 * f 400 MHz < f < 2000 MHz (equation 3.1)
Emax = 61 V
/m 2000 MHz < f < 300000 MHz (equation 3.2)
When applying equation 3.1 and 3.2 on the GSM and UMTS frequencies the following values are
obtained:
Table 2: ICNIRP guidelines, electrical field strength per frequency band
Frequency band
(MHz)
Mobile Transmit
Frequency
(MHz)
Emax
(V
/m)
GSM
900 MHz 897.5 41.2
1800 MHz 1747.5 57.5
UMTS 2100 MHz 1950.0 60.7
As these guidelines are far less strict than for equipment, they will not be taken into account in this
document.

3 Research Definition
Since the introduction of the new generation of digital mobile telephony, GSM, in the mid 90’s, there
has been discussion around the impact of the signals on equipment and people in the vicinity of
mobile phones and base stations. Many people remember the sounds on transistor radios when
phones received calls or text messages. The fear of impact was likely also fed by a lack of knowledge
and a lack of relevant research into this topic.
In most hospitals around the world, the use of mobile phones was prohibited. Over the last few years
however, this ban on mobile telephony in hospitals has been lifted or the usage of mobile phones is
tolerated. Experience has shown that the impact is small or even negligible. Research has shown
similar results, as indicated by the referenced studies in Annex B: References Furthermore; medical
equipment has been replaced by newer generations, which have better shielding against possible
effects by external signals. Formally though, till today the Erasmus University Medical Center does not
allow usage of mobile phones.
Based on preliminary research studies interference of mobile devices on medical equipment rarely
happens and the effect is minimal, but it does occur and cannot be considered 100% safe. Based on
current practice, there seems to be no strong indications to restrict usage in hospitals of mobile
devices, operating under normal conditions within the normal standards of mobile telephony.
As long as there are questions to be answered and topics to be studied in this field, it still makes
sense to have a conservative attitude towards the impact of mobile telephony on medical equipment,
especially in high risk environments such as the intensive care areas and the operating rooms. The
research described in this document focusses on the question how to minimize mobile phone signals
in the building while still maintaining a good communication level. More particular the study
investigates the difference in radiation levels when relying on network signals from outside the building
to those when using an internal antenna system, a so-called Distributed Antenna System (DAS).
Based on the results, the Erasmus University Medical Center may change its’ policy towards the
usage of mobile phones in their hospital.
3.1 Introduction
A conservative attitude towards the usage of mobile telephony in sensitive environments such as
hospitals remains wise. Prohibiting the use of modern mobile telephony technologies not effective,
hence it is better to try to minimize the power levels of the signals on both network side (base stations)
as well as user equipment side (telephone, tablets etc.) to reduce risks.
This research focusses on the differences in transmitted power of a mobile phone in areas where the
base station signals are good and poor. To simulate this, measurements were performed in several
places in the same building with an in active Distributed Antenna System (DAS) switched on and off.
3.2 Assignment
The document as referenced in chapter 1.1 details the assignment and the methods of performing the
measurements. The chapter concerning the definition of the research is repeated below for the sake of
completeness of this document.
3.3 Problem Definition
Signals that are being generated by GSM/UMTS/LTE user equipment may cause interference on
sensitive equipment in the operating rooms, intensive care and other areas with medical equipment. In
poor coverage areas, user equipment must transmit at high power to get their signals back to the base
stations. This increases the risk of above mentioned interference. Hospitals are often large and deep
buildings, and subsequently the signal strength from outdoor base stations in many areas is often
weak. In addition, modern construction materials reflect much of the GSM/UMTS signals, thus

significantly decreasing the signal strength in buildings and increasing the transmit power of mobile
phones.
3.4 Hypothesis
When GSM/UMTS user equipment operates within an area where there is good coverage, like in the
coverage area of a Distributed Antenna System (DAS), the required transmission power decreases.
3.5 Research Question
What is the effect of an indoor DAS on the transmitted power of GSM and UMTS user equipment that
operates within the coverage area?
3.6 Demarcation
In scope:
In scope is all equipment that has yet been installed by RadioAccess B.V. for the DAS in tranche 1 of
the new area of the Erasmus University Medical Center. 2G and 3G are included (C2000 is not
possible).
Out of scope:
Out of scope are all networks that have not yet been realized, such as 4G/LTE, WiFi and PMR

4 Research Method
4.1 Method of measurements
4.1.1 Equipment
The following equipment has been used:
 Nokia type 6720c measurement phone
 Zadako UMTS Modem
 HP Elitebook pen tablet computer
 JDSU E6474A Wireless Network Measurement Software v.16.1
4.1.2 Location
Six measurement locations had been selected. Four were in a high rising tower on floors 3, 6, 12 and
28. The other two were in an adjacent building part on floor 6 and 12.
4.1.3 Method
Both the Zadako and Nokia measurements phones were connected to the tablet computer at the
same time to allow simultaneous measurement of the GSM and UMTS signals. The Zadako was used
for UMTS and the Nokia for GSM. The floor plans for the measurements were imported into the JDSU
software. During measurement, the location was pinpointed on the floor plans regularly allowing the
software to relate the measured data to a position on floor plan. When a measurement was
completed, the log file was saved. Back in the office, exports were made from the log files with all the
relevant data. Using Excel, the data was processed.
4.1.4 Active DAS
In both building parts, there was an active DAS using ZinWave equipment. The DAS has been
configured using primary or main hubs in a central location, with secondary or slave hubs in the MERs
in different building parts and remote units spread across the building. The connection between the
primary and secondary hubs and between the secondary hubs and remote units is by optic fibre.
Connected to each remote unit are three sets of antennas. In ZinWave, there is a separate path for
signals going from the base station.
The DAS is ultra wide band and can support frequencies from 300 MHz to 2200 MHz. At the time of
the measurements, C2000 (emergency services), and two mobile operators were connected to the
DAS. As the measurements were performed in a live hospital, the DAS could not be completely
switched off. For each measurement, the public operator frequencies were switched off in the remote
units in the area of the measurement as well as in the remote units on the floor above and below the
measurement.
4.1.5 Operator
At the time of the measurement, T-Mobile was the only operator that had GSM and UMTS base
stations connected to the DAS. As the GSM base station had just been swapped, the input signal
going into the DAS had not yet been properly configured and was too low. This can be seen in the
GSM measurements with the DAS switched on. The received signal strength (RxLev) was 10 dB lower
than it was during verification measurements following the installation of the original equipment.

4.2 Information on Measured Data
4.2.1 Signal Strength
For GSM and UMTS, signal strengths are measured in dBm. DBm is an abbreviation for the power
ratio in decibels (dB) of the measured power referenced to one milliWatt (mW). It is used in radio,
microwave and fibre optic networks as a convenient measure of absolute power because of its
capability to express both very large and very small values in a short form. Since it is referenced to
one milliWatt, it is an absolute unit, used when measuring absolute power.
Operator base stations in the macro network transmit between 40 and 49 dBm per carrier, which
equals to 10 to 80 Watt. By comparison, the remote units in the active DAS at Erasmus have a
maximum composite transmit power of 18 dBm (63 milliWatt = 0.063 Watt). For UMTS, signals
strengths as low as -115 dBm (≈3*10-15
Watt) can be measured and used for speech communication.
4.2.2 Signal Strength – Transmit Power User Equipment
The transmitted power of user equipment varies per technology and per frequency band. Here is a
short table with maximum values.
Bandwidth
(MHz)
Freq band
(MHz) Service
Peak
(dBm)
Peak
(Watt)
Note
GSM 0.2 MHz
900 MHz
Speech 33 2 Transmits ⅛ of the time
Data 33 2 Multislot transmission
1800 MHz
Speech 30 1 Transmits ⅛ of the time
Data 30 1 Multislot transmission
UMTS 5 MHz 2100 MHz
Speech 24 0.25 Continuous transmission
Data 24 0.25 Continuous transmission
GSM is a TDMA (Time Division Multiple Access) technology where each carrier has 8 timeslots that
can be used for speech or data. Each user gets one or more timeslots, depending on the requested
service and possibilities of the network and user equipment. Speech requires only one timeslot, and
thus the mobile will transmit only ⅛th
of the time. The peak power depends on the frequency band and
the average is ⅛th
of that. Data gets 1 to 4 timeslots, so the average power equals ⅛th
to ½ of the peak
power.
UMTS is rather straightforward as only one frequency band is used, the maximum transmitted power
is the same regardless of service, and the average is the same as the peak because of continuous
transmission.
4.2.3 Signal Strength - Received
The received signal strength of a mobile phone for GSM is expressed as RxLev and normally varies
between -40 and -100 dBm (10-7
and 10-13
Watt). The signal strength measured is all the power in a
single carrier that has a bandwidth of 200 kHz. Table 3 is used by RadioAccess to describe the quality
of signal strength.

Table 3 : Legend GSM - signal strength (RxLev)
-60 t/m 0 dBm Very good
-70 t/m -61 dBm Good
-80 t/m -71 dBm Sufficient to good
-85 t/m -81 dBm Sufficient
-90 t/m -86 dBm Acceptable
-100 t/m -91 dBm Insufficient
-110 t/m -101 dBm Bad
The received signal strength of a mobile phone for UMTS is expressed as RSCP (Received Signal
Code Power) and normally varies between -50 and -110 dBm (10-8
and 10-14
Watt). The signal
strength measured is the power of a pilot signal in the serving carrier which usually is 10% of the
maximum power of a carrier. A measured RSCP above -80 dBm is strong and below -100 dBm weak.
In addition to RSCP, RSSI is measured as well in UMTS. This is total amount of power measured in a
UMTS carrier, which has a bandwidth of 5 MHz. Table 4 is used by RadioAccess to describe the
quality of the signal strength for UMTS.
Table 4 : Legend UMTS - signal strength (RSCP)
-65 t/m 0 dBm Very good
-75 t/m -66 dBm Good
-85 t/m -76 dBm Sufficient to good
-90 t/m -86 dBm Sufficient
-100 t/m -91 dBm Acceptable
-110 t/m -101 dBm Insufficient
-115 t/m -111 dBm Bad
4.2.4 Relation User Equipment Received Signal Strength and Transmitted Power
The received signal strength Prx and transmitted power Ptx are related to the path loss Lpath:
Lpath = Ptx - Prx (equation 5.1)
In radio networks, there are two paths. The first path is where the base station is the transmitter and
the mobile phone the receiver. This is called the downlink (dl or DL). The second is where the mobile
phone is the transmitter and the base station the receiver. This is called the uplink (ul or UL). The
relation between the downlink and uplink path loss can be defined as:
Lpath_dl - Lpath_ul = α (equation 5.2)
Where α is a small constant that is mainly influenced by the differences in frequency for the uplink and
downlink. Combining equation 5.1 and 5.2 results in:
(Ptx_dl – Prx_dl) – (Ptx_ul – Prx_ul) = α (equation 5.3)
For the downlink, transmitted power of the base station (Ptx_dl) is fixed. For the uplink, received power
at the base station (Prx_ul) is kept within in pre-set bandwidth. This latter is done to ensure that the
received powers from all user equipment have the same level for optimal performance of the system.
The following can be defined:
Ptx_dl + Prx_ul = β (equation 5.4)
Where β is a variable that can change depending on the tolerance allowed for Prx_ul. For GSM the
bandwidth is larger than for UMTS. Combining equation 5.3 and 5.4 results in:
Prx_dl + Ptx_ul = β – α (equation 5.5)
As α and β show little variation, there is an almost linear relation between Prx_dl and Ptx_ul. If the
received signal strength at the mobile phone increases, the transmitted power of the mobile phone
decreases. The relation fails when the mobile phone should regulate it’s transmit power below
minimum or above maximum allowed. In addition, for GSM, during call setup, the mobile phone

always transmits at maximum power. Subsequently this is regulated to a level where Prx_ul is within the
pre-set bandwidth.
Two remarks must be made with regard to the relation as described in equation 5.5:
 The transmitted power of the mobile phone (Ptx_ul) is also regulated by the uplink signal quality.
When the signal quality degrades, the mobile phone will be instructed to increase the transmitted
power in an effort to improve the uplink signal quality. When this happens, the relation between
Prx_dl and Ptx_ul will disappear.
 The active system has separated uplink and downlink antennas that have a spacing of four meters.
Therefore, when the DAS is switched on, the relation will not be very evident because uplink and
downlink follow different paths. When the mobile phone is under a transmitting antenna, the Prx_dl
will be at its strongest while the mobile phone is still four meters from the receiving antenna and
thus will Ptx_ul not be at its lowest.
4.2.5 Signal Quality GSM
The received signal quality of a mobile phone for GSM is expressed as RxQual. This is an integer
value which can vary between 0 and 7 and reflects the quality of voice. Each RxQual value
corresponds to an estimated number of bit errors. Values of 2 or lower are considered good and 5 or
higher insufficient.
4.2.6 Signal Quality UMTS
The received signal quality of a mobile phone for UMTS is expressed as EcNo. This is the signal to
noise ratio in dB, where RSCP is the signal and RSSI the noise. The value of EcNo varies between 0
and -20 dB. An EcNo of -10 dB means that the pilot signal RSCP is a factor 10 weaker than the noise,
RSSI. A negative signal to noise ratio is normal for UMTS as it a WCDMA technique. Values of -6 dB
or higher are considered good and below -10 dB insufficient.
4.2.7 Conversion to V/m
When measurements are performed on GSM and UMTS networks, it is always the power that is
measured expressed in dBm. The actual electric field strength can be calculated when the power is
known. The equation that is commonly used for conversion from measured signal strength in dBm to
electric field strength in V/m is in equation 5.6. The electric field strength depends on the power and
the frequency and a constant. As the power is expressed in dBm and electric field strength in V/m, a
conversion needs to made from the logarithmic domain to the real domain, which is done using the
10^(…).
E<V/m> = 10^ ((P<dBm> + 20 * log (f<MHz>) – 42.8)/20) (equation 5.6)
In equation 5.6 there is a relation between the received signal power and the electric field strength.
What is needed is a relation between the electric field strength and the transmitted power of the
source and the distance to the source. When there are no obstacles between the sending and
receiving antenna and the antennas are aligned correctly, the free space equation can be used to
calculate the losses from a sending antenna to a receiving antenna in the far field.
Prx = Ptx – (20 * log (d<m>) + 20 * log (f<MHz>) -27.55) (equation 5.7)
Combining equation 5.6 and 5.7 yields:
E<V/m> = 10^ ((Ptx - 20 * log (d<m>) – 15.25)/20) (equation 5.8)
The far field for antennas that are electrically small begins at two times the wavelength (λ). Examples
of these antennas are the ones used on mobile phones. Table 5 displays the far fields for various
frequency bands.

Table 5 : Far fields for various frequencies
Frequency
Band
UL Frequency
(MHz)
Wavelength
(m)
Far field
(m)
900 MHz 897.5 0.334 ≥ 0.668
1800 MHz 1747.5 0.172 ≥ 0.344
2100 MHz 1950.0 0.154 ≥ 0.308
For distances close to the antenna, other more complex equations apply to calculate the electric field
strength that is beyond the scope of this report.

4.3 Results – GSM
The results of all the individual measurements can be found in Annex C.
4.3.1 Time Graphs
The exports from all six measurements have been put in a single file and the graphs are displayed in
figures Figure 1 to Figure 8 . There is a small white gap between two measurements. The individual
results can be found in annex C. The data as measured through time has been plotted.
Figure 1 : RxLev & TxLev - DAS on - all measurements files combined
Figure 2 : RxLev & TxLev - DAS off - all measurement files combined
Between the Figure 1 and Figure 2 several differences can be noticed
 With the DAS on, the average received signal strength is higher and the transmitted power is lower
than with the DAS switched off.
 With the DAS off, the mobile phone is often transmitting at maximum power and is regularly
switching between 900 MHz and 1800 MHz. This does not happen with the DAS switched on
 The difference in received signal level is 18.4 dB while the difference in transmitted power is 9.0
dB.
In Figure 3 and Figure 4, a more detailed view on the first measurement (floor Na-03) is given. With
the DAS switched on, the different peak where antennas were passed can be identified. In addition,
peaks for downlink and uplink are shifted in time which is explained by the fact that antennas for uplink
and downlink have a spacing of four meters.

Figure 3 : RxLev & TxLev - DAS on – measurement Na-03
Figure 4 : RxLev & TxLev - DAS off - measurement Na-03
Based on equation 5.5, the RxLev and TxLev have been added in Figure 5 and Figure 6. With DAS
on, the peaks and valleys are caused by the antenna separation. With DAS off, there is no relation
between RxLev and TxLev.
Figure 5 : RxLev + TxLev - DAS on – measurement Na-03
Figure 6 : RxLev + TxLev - DAS off – measurement Na-03

In Figure 7 and Figure 8 the downlink signal quality, RxQual, is displayed. With the DAS switched on,
the measurements look very good except on one location. This is the 28th
floor where too many strong
macro signals interfere with the indoor DAS.
Figure 7 : RxQual & TxLev - DAS on - all measurements files combined
Figure 8 : RxQual & TxLev - DAS off - all measurement files combined
4.3.2 Distribution Graphs
The colours correspond to the legend in Table 3.
Figure 9 : RxLev – DAS on - all measurements Figure 10 : RxLev – DAS off - all measurements
Figure 11 : TxLev – DAS on - all measurements Figure 12 : TxLev – DAS off - all measurements
Figure 13 : RxQual – DAS on - all measurements Figure 14 : RxQual – DAS off - all measurements

In Figure 15 the percentage of measurement points is plotted where the mobile phone transmitted at
either maximum power, greater than or equal to 25% or 10% of the maximum power. For each floor
the percentages are plotted with the DAS on and the DAS off. With the DAS switched off, more than
60% of the time the mobile phone was transmitting at maximum power versus less than 1% with the
DAS switched on.
Figure 15 : Percentage TxLev = max, TxLev ≥25% max and TxLev ≥10% max per floor with DAS off and on
4.3.3 Summary
Table 6 : Summary of GSM measurements
Area DAS
Avg RxLev
(dBm)
Avg
RxQual
Avg TxLev
(dBm)
Percentage
Tx = Max
Percentage
Tx ≥ 25%
Max
Percentage
Tx ≥ 10%
Max
Na-03
On -72.1 0 17.7 0.0% 5.5% 23.6%
Off -91.8 2.5 28.5 75.3% 84.0% 100.0%
Difference -19.7 dB 2.5 10.8 dB 75.3% 78.5% 76.4%
Na-06
On -72.6 0 17.1 0.0% 1.0% 20.0%
Off -94.4 3 26.5 54.3% 58.0% 89.9%
Difference -21.8 dB 3.0 9.4 dB 54.3% 57.0% 69.9%
Na-12
On -73.8 0 17.8 0.0% 7.5% 36.1%
Off -92 3.2 23.7 10.9% 12.6% 100.0%
Difference -18.2 dB 3.2 5.9 dB 10.9% 5.1% 63.9%
Na-28
On -72.6 1.1 18.3 3.3% 7.4% 38.8%
Off -94.7 4.9 30 100.0% 100.0% 100.0%
Difference -22.1 dB 3.8 11.7 dB 96.7% 92.6% 61.2%
Nb-061
On -75.2 0.1 22.2 2.5% 49.4% 83.5%
Off -87.4 2.4 28 69.6% 85.9% 100.0%
Difference -12.2 dB 2.3 5.8 dB 67.0% 36.5% 16.5%
Nb-12
On -73.4 0.3 17.9 0.0% 2.8% 44.0%
Off -89 2.4 24.8 37.3% 39.5% 83.1%
Difference -15.6 dB 2.1 6.9 dB 37.3% 36.8% 39.0%
All
On -73.2 0.3 18.3 0.9% 10.3% 38.7%
Off -91.6 2.9 27.3 63.0% 67.5% 95.4%
Difference -18.4 dB 2.6 9.0 dB 62.1% 57.1% 56.7%
1
This area is most relevant, because of the presence of ORs and the Central Sterilization Department

With DAS switched off, the average RxLev indoors equals -91.6 dBm, which is insufficient. More than
60% of the time, the mobile phone was transmitting at maximum power. The average TxLev for the
mobile phone is 27.3 dBm.
When the DAS is switched on, the average measured RxLev improves by 18.4 dB. This means that
the received signal level is almost 70 times stronger with the DAS switched on compared to the
DAS switched off. The transmitted power from the user equipment decreases by only 9 dB. This is
still a factor 8, reducing the transmitted power from on average 0.53 Watt to 0.06 Watt. The average
reduction in transmitted power may not be great, but the amount of time the mobile phone was
transmitting at maximum power was reduced to less than 1% versus 63% with the DAS switched off.
For transmitted powers up to 6 dB below maximum, the reduction was 10.3% of the time versus
67.5% which is still significant.
The reduction in transmitted power is significantly less than the difference in RxLev. This is primarily
caused by the fact that the mobile phone should be transmitting at higher powers when the DAS is
switched off to keep Prx_ul in equation 5.3 within its pre-set bandwidth, but is unable to do so because
the mobile phone is already transmitting at maximum power.
Floor Nb-06 is of especial interest to Erasmus University Medical Center because some operation
chambers are located in that area. There, the amount of time the mobile phone was transmitting at
maximum power was reduced from almost 70% to 2.5%, but the transmitted power still stayed high
with DAS on as it was at 25% of maximum power or higher for almost 50% of the time. This was the
worst floor with regard to transmitted power with the DAS switched on when compared to all the other
measurements. Should there occur any complaints from employees about bad reception, it will be
tested whether this can be solved by placing additional PICO cells, to decrease the density of the
antenna network.
4.3.4 Electric Field Strength
The average of the 5% strongest transmit levels will be used to get an impression of the electrical field
strength. The top 5% were used for worst case scenario. The equations in chapter 4.2.7 are used,
taking into account that they can only be used in the far field.
Table 7 : Summary of GSM measurements
Area DAS
Avg TxLev
Strongest 5%
(dBm)
E at 35 cm
(V/m)
d where
E = 3 V/m
(m)
d where
E = 10 V/m
(m)
Na-03
On 24.5 8.4 0.97 <0.35
Off 33.0 22.1 * 2.57 0.77
Na-06
On 20.5 5.2 0.61 <0.35
Off 30.0 15.6 1.82 0.55
Na-12
On 24.1 8.0 0.92 <0.35
Off 30.5 16.5 * 1.93 0.58 *
Na-28
On 28.3 12.8 1.50 0.45
Off 30.0 15.6 1.82 0.55
Nb-062 On 28.2 12.8 1.48 0.44
Off 30.0 15.6 1.82 0.55
Nb-12
On 22.5 6.6 0.77 <0.35
Off 30.0 15.6 1.82 0.55
All
On 25.1 8.9 1.04 <0.35
Off 30.1 15.8 * 1.84 0.55 *
2

*) Part or all of the measurements were done in the GSM 900 band. This means that the calculations
are an approximation
With DAS switched off, the strongest 5% transmit levels are always at maximum power in the
frequency band that is being used. This is lower when the DAS is switched on, but on average no
more than 5 dB.
With regard to electrical field strength, all values are well below the ICNIRP guidelines for human
safety. At a distance of 35 cm, with the DAS off, the electric field strength is above Test Level 3 (10
V/m) from Table 1. With the DAS switched on this improves but all values still remain 3 V/m (Test
Level 2).
Regardless if the DAS is switched on or off, GSM user equipment will always transmit at the maximum
allowed power for the device at call setup. Unless the operator has changed parameters that reduce
the maximum allowed power, which he can do on a per cell base like for example for indoor hospital
cells, the maximum allowed power always equals the maximum user equipment can transmit. This
means that a minimum safe distance of 2.57 meter must be applied to reach 3 V/m for GSM and 0.77
meter for 10 V/m (worst case scenario where mobile transmits at 33 dBm in the 900 MHz band)
4.3.5 Conclusions
 The difference in received signal level is 18.4 dB while the difference in transmitted power is
9.0 dB. This indicates that with the DAS on, the average received signal strength is 25%
higher and the transmitted power is 49% lower than with the DAS switched off.
 With the DAS off, the mobile phone is transmitting 60% of the time at maximum power and
is regularly switching between 900 MHz and 1800 MHz. This does not happen with the DAS
switched on

4.4 Results – UMTS
The results of all the individual measurements can be found in Annex C.
4.4.1 Time Graphs
The exports from all six measurements have been put in a single file and the graphs are displayed in
Figure 16 and Figure 17. There is a small white gap between two measurements. The individual
results can be found in annex C. The data as measured through time has been plotted.
Figure 16 : RSCP, RSSI & TxLev - DAS on - all measurements files combined
Figure 17 : RSCP, RSSI & TxLev - DAS off - all measurement files combined
Between Figure 16 and Figure 17 several differences can be noticed
 With the DAS on, the average received signal strength RSCP is higher and the transmitted power
TxLev is lower than with the DAS switched off.
 During the last measurement with the DAS switched on, the RSCP is rather weak in the middle.
For unknown reasons, there was a handover to the outdoor cell which is significantly weaker. The
active DAS was still working because GSM was measured at the same time and that measurement
was according to expectations.
 The difference in received signal level is 18.8 dB while the difference in transmitted power is 30.0
dB. Most likely this difference is caused by uplink signal quality and cell load. The signal quality
plots can be seen in Appendix D.
In Figure 18 and Figure 19, a more detailed view on the first measurement (floor Na-03) is given. With
the DAS switched on, the different peaks where antennas were passed can be identified. In addition,
peaks for downlink and uplink are shifted in time which is explained by the fact that antennas for uplink
and downlink have a spacing of four meters.

Figure 18 : RxLev & TxLev - DAS on – measurement Na-03
Figure 19 : RxLev & TxLev - DAS off - measurement Na-03
Based on equation 5, the RSCP and TxLev have been added in Figure 20 and Figure 21. With DAS
on, there seems to be no relation which is most likely caused by the antenna separation. With DAS off,
there seems to be a relation when looking at the standard deviation. To better visualise that, RSCP
and TxLev have been plotted in a different way in Figure 22. Between RSCP values of -115 dBm and -
75 dBm, the TxLev degrades almost linearly from 20 dBm to -20 dBm.
Figure 20 : RSCP + TxLev - DAS on – all measurements
Figure 21 : RSCP + TxLev - DAS off – all measurements

Figure 22 : RSCP vs TxLev - DAS off - all measurements
In Figure 23 and Figure 24 the downlink signal quality, EcNo, is displayed. With the DAS switched on,
the measurements look very good except on one location where a significant drop in signal quality can
be seen. This is where the handover took place to the outdoor network. With this signal quality high
data speeds can be achieved almost everywhere in the DAS. With the DAS switched off, the signal
quality is mostly below -10 dB, which means that only speech and low speed data are possible.
Figure 23 : EcNo & TxLev - DAS on - all measurements files combined
Figure 24 : EcNo & TxLev - DAS off - all measurement files combined

4.4.2 Distribution Graphs
The colours correspond to the legend in Table 4.
Figure 25 : RSCP & RSSI – DAS on - all measurements Figure 26 : RSCP & RSSI – DAS off - all measurements
Figure 27 : TxLev – DAS on - all measurements Figure 28 : TxLev – DAS off - all measurements
Figure 29 : EcIo – DAS on - all measurements Figure 30 : EcIo – DAS off - all measurements
In Figure 31 the percentage of measurement points is plotted where the mobile transmitted at either
maximum power, greater than or equal to 10% or 1% of the maximum power. For each floor the
percentages are plotted with the DAS on and the DAS off. With the DAS switched off, 5,2% of the time
the mobile was transmitting at maximum power, almost 25% of the time at 10% of the maximum
power or greater and 63% of the time at 1% of the maximum power or greater. The best floor was Nb-
06 where the macro network performed exceptionally well and the mobile never transmitted at 10% of
maximum power or higher. The worst was the 28th
floor.
With the DAS switched on, the transmitted power only got above 1% of maximum power during the
measurement where the mobile temporarily went to the macro network. During all the other
measurements, the transmitted power was always less than 1% of the maximum.
Figure 31 : Percentage TxLev = max, TxLev ≥10% max and TxLev ≥1% max per floor with DAS off and on

4.4.3 Summary
Table 8 : Summary of UMTS measurements
Area
DAS
Avg
RSCP
(dBm)
Avg
Ec/Io(dB)
Avg
TxLev
(dBm)
Percentage
Tx = Max
Percentage
Tx ≥ 10%
Max
Percentage
Tx ≥ 1%
Max
Na-03
On -82.1 -2.7 -26.3 0.0% 0.0% 0.0%
Off -108.8 -11.3 6.8 2.8% 25.2% 66.7%
Difference -26.7 -8.6 33.1 2.8% 25.2% 66.7%
Na-06
On -82.1 -3.1 -24.7 0.0% 0.0% 0.0%
Off -104.6 -12.8 7.9 1.3% 22.6% 74.1%
Difference -22.5 -9.7 32.6 1.3% 22.6% 74.1%
Na-12
On -84.3 -4.7 -27.2 0.0% 0.0% 0.0%
Off -101.8 -13.6 6 2.7% 18.3% 66.1%
Difference -17.5 -8.9 33.2 2.7% 18.3% 66.1%
Na-28
On -79.2 -2.5 -26.5 0.0% 0.0% 0.0%
Off -107.8 -16.1 12.8 15.3% 53.0% 89.1%
Difference -28.6 -13.6 39.3 15.3% 53.0% 89.1%
Nb-063
On -83.7 -5.4 -18.9 0.0% 0.0% 0.0%
Off -93.3 -10.5 -5 0.0% 0.0% 24.5%
Difference -9.6 -5.1 13.9 0.0% 0.0% 24.5%
Nb-12
On -88.1 -12.9 -16.8 0.0% 0.0% 21.0%
Off -97.7 -15.1 3.4 2.6% 12.8% 42.9%
Difference -9.6 -2.2 20.2 2.6% 12.8% 21.9%
All
On -83.5 -5.6 -23.9 0.0% 0.0% 3.4%
Off -102.3 -13.8 6.1 5.2% 24.8% 63.0%
Difference -18.8 -8.2 30.0 5.2% 24.8% 59.6%
The average RSCP with the DAS switched off equals -102.3 dBm, which is insufficient. Just over 5%
of the time the mobile was transmitting at maximum power which is less than GSM where that
occurred 65% of the time. Just less than 25% of the time the mobile transmitted at equal to or higher
than 10% of the maximum power. The average TxLev for the mobile phone is 6.1 dBm. Compared to
GSM with the DAS switched off, this is a factor 131 weaker. The average transmitted power for GSM
was 537 milliWatt and for UMTS 4 milliWatt.
When the DAS is switched on, the average measured RSCP improves by 18.8 dB to -83.5 dBm,
which is a factor 75. The transmitted power from the user equipment never rises above 10% of its
maximum and only became higher than 1% of the maximum in when the mobile temporarily switched
to the macro network. The average transmitted power decreases by 30 dB. This means that the
transmitted power level is a factor 1000 lower compared to the measurements when the DAS was
switched off, dropping it from 4 milliWatt to 0.004 milliWatt. Comparing it to GSM with the DAS
switched on, then the difference is 42.2 dB or a factor 16 thousand, 67 milliWatt for GSM vs 0.004
milliWatt for UMTS.
Looking at floor Nb-06 with the operation chambers, it was significantly better than any other floor with
the DAS off, with user equipment never transmitting at 10% max power or higher. With the DAS on,
the coverage became better and the transmitted power never reached 1% of the max power. Since
3

the reduction is larger for UMTS than GSM, it can be recommended to only use UMTS mobile phones
in order to reduce risks,
4.4.4 Electric Field Strength
The average of the 5% strongest transmit levels will be used to get an impression of the electrical field
strength. The top 5% were used for worst case scenario. The equations in chapter 4.2.7 are used,
taking into account that they can only be used in the far field.
Table 9 : Summary of UMTS measurements
Area DAS
Avg TxLev
Strongest 5%
(dBm)
E at 31 cm
(V/m)
d where
E = 3 V/m
(m)
d where
E = 10 V/m
(m)
Na-03
On -15.7 0.09 <0.31 <0.31
Off 22.5 7.43 0.77 <0.31
Na-06
On -11.9 0.14 <0.31 <0.31
Off 21.1 6.33 0.65 <0.31
Na-12
On -11.6 0.15 <0.31 <0.31
Off 21.1 6.33 0.65 <0.31
Na-28
On -2.7 0.41 <0.31 <0.31
Off 24.2 9.04 0.93 <0.31
Nb-064 On -11.8 0.14 <0.31 <0.31
Off 10.4 1.85 <0.31 <0.31
Nb-12
On 9.5 1.66 <0.31 <0.31
Off 21.8 6.86 0.71 <0.31
All
On 4.8 0.97 <0.31 <0.31
Off 23.1 7.96 0.82 <0.31
With DAS switched off, the strongest 5% transmit levels are often close to maximum power. This is
almost 20 dB lower when the DAS is switched on.
With regard to electrical field strength, all values are well below the ICNIRP guidelines for human
safety. At a distance of 31 cm, with the DAS off, the electric field strength is between Test Level 3 (10
V/m) and Test Level 2 (3 V/m) from Table 1. With the DAS switched on this drops to less than 1 V/m
on average.
With the DAS switched off, the distance to the mobile phone must approximately 80 cm in order to
reach the 3 V/m, and with the DAS switched on this is always less than 31 cm, the shortest distance
where the equations are valid.
User equipment which is in UMTS mode will not transmit at maximum power when a connection is
made to the network, which is a sharp contrast to when it is in GSM mode.
4.4.5 Conclusions
 The difference in received signal level is 18.8 dB, which is an improvement of a factor 75,
while the difference in transmitted power , 30.0 dB, is (1000 times lower) compared to when
the DAS is switched off. Most likely this difference is caused by uplink signal quality and
cell load. The signal quality plots can be seen in Appendix D.
4

 The average TxLev for the mobile phone is 131 times weaker compared to GSM with the
DAS switched off.
 With the DAS on, the average received signal strength RSCP is 32% higher and the
transmitted power TxLev is almost 4 times lower than with the DAS switched off.
 During the last measurement with the DAS switched on, the RSCP is rather weak in the
middle. For unknown reasons, there was a handover to the outdoor cell which is
significantly weaker. The active DAS was still working because GSM was measured at the
same time and that measurement was according to expectations.
 The transmitted power from the user equipment never rises above 10% of its maximum and
only became higher than 1% of the maximum in when the mobile temporarily switched to
the macro network.

5 Conclusions & Recommendations
User equipment is most dangerous when transmitting at high power. Table 10 shows the differences
between GSM and UMTS with the DAS on and off in how much of the time the user equipment is
transmitting at maximum or high power.
Table 10 : Transmit power per technology with different states of DAS
Avg Tx Power Percentage of time Tx =
Technology DAS (dBm) (mWatt) max ≥ 25% max ≥ 10% max ≥ 1% max
GSM
Off 27.3 537 63.0% 67.5% 95.4%
On 18.3 67 0.9% 10.3% 38.7%
UMTS
Off 6.1 4.1 5.2% 24.8% 63.0%
On -23.9 0.004 0.0% 0.0% 3.4%
The effect of an indoor DAS on the transmitted power of user equipment is that the transmitted power
is reduced. This means that the hypothesis has been proven. Thus, with a DAS switched on, the
signals transmitted by user equipment are at lower power, reducing the strength of the
electromagnetic field, which is safer, while improving the quality of communication facilities. With the
DAS switched off, more than 60% of the time the mobile phone was transmitting at maximum power
versus less than 1% with the DAS switched on. With the DAS switched off, more than 60% of the time
the mobile phone was transmitting at maximum power versus less than 1% with the DAS switched on.
The reduction for UMTS is larger than for GSM. Even when taking out the possible effects of
optimization of the GSM network, the reduction in UMTS would still be greater. With the DAS switched
off, 5,2% of the time the mobile phone was transmitting at maximum power, almost 25% of the time at
10% of the maximum power or greater and 63% of the time at 1% of the maximum power or greater.
With the DAS switched on, the transmitted power only got above 1% of maximum power during the
measurement where the mobile phone temporarily went to the macro network. The power control
bandwidth for GSM is only 30 dB between maximum and minimum power and power up and down
commands being sent 2 times per second. For UMTS the bandwidth is more than 70 dB and power up
and down commands are sent 1600 times per second. The reason for this difference is that for UMTS
networks it is of vital importance that the transmitted power of user equipment is kept to the lowest
possible for good reception at the base station as all mobile phones are transmitting at the same
frequency. Should one mobile phone be received at a higher power than the rest, than the noise for
the other mobile phones increases which might result in reduced data speeds and dropped calls for
the other mobile phones.
.
Table 11 : Electric field strength per technology with different states of DAS for 5% strongest transmit powers
Technology DAS E at edge far field
(V/m)
d where
E = 3 V/m
(m)
d where
E = 10 V/m
(m)
GSM
Off 15.8 * at 35 cm 1.84 0.55 *
On 8.9 at 35 cm 1.04 <0.35
UMTS
Off 7.96 at 31 cm 0.82 <0.31
On 0.97 at 31 cm <0.31 <0.31
*) Part or all of the measurements were done in the GSM 900 band. This means that the calculations
are only an approximation as the far field for the 900 MHz band starts at 66 cm
The electric field strength at the edge of the far field decreases by 7 for both GSM and UMTS when
the DAS is switched on. In addition, UMTS performs better than GSM. Relevant test levels for
equipment are significantly closer to the mobile device when the DAS is switched on. In this test case
in areas of weak coverage, a GSM mobile device with a DAS off is safe at 1.84 m from equipment at
test level 2 and this reduces to less than 31 cm for UMTS mobile phones with a DAS on.

Operators are migrating from GSM (2nd
generation) to UMTS (3rd
generation) and have started
deploying LTE (4th
generation). This has a positive effect on the transmitted power of user equipment.
No measurements have been done for LTE, but power control for LTE resembles UMTS more than it
does GSM, which makes it likely that transmitted power will be less for LTE than for GSM.
5.1 Recommendation
It is advised to use mobile phones that support 3G (UMTS or HSPA) instead of 2G (GSM, GPRS or
EDGE), such as the Nokia 113 and Nokia 220.
5.2 Future Research
This report was limited to 2G and 3G on an active DAS using ZinWave equipment. Future research
can be done on 4G, but it is wise to wait with that until VoLTE (Voice over LTE) has been deployed by
the operators. This is necessary to make a comparison with this report. Also data instead of speech
can be investigated.
During regular measurement sessions by RadioAccess technicians to map the transmission density
finding was that the EMV round fluorescent tube lamps were increased. It is advisable to investigate
the influence of radiation from fluorescent lamps on a DAS and transmitted power of mobile phones.

6 Annex A: Abbreviations & Acronyms
Term Description
DAS Distributed Antenna System. A system that allows the distribution of
signals (typically for various communication purposes) in buildings through
a series of antennas spread over the buildings’ floors and rooms. These
antennas are connected using passive elements, such as coaxial cables,
and sometimes active elements, such as signal boosters and generators,
typically connected through fibre optic cabling.
GSM Global System for Mobile communication. Second generation digital
Mobile phone standard, widely used across the world since 1995. Also
referenced as 2G.
UMTS Universal Mobile Telecommunication System, also known as 3G.
Successor of GSM.
WiFi Wireless Technology based on IEEE 802.11 standard, also referenced as
Wireless LAN
CDMA Code Division Multiple Access; Mobile phone standard (comparable to
GSM) typically used in North and South America
LTE Long Term Evolution. Fourth generation of Mobile Telephony standard
also referenced as 4G. Successor of UMTS.
C2000 Digital network used by the Dutch police, emergency services etc.
ZinWave Brand of active DAS equipment
RSCP Received Signal Code Power – Indication of signal strength in a UMTS
network, as received by the mobile phone
RSSI Received Signal Strength Indicator -
TxLev Transmitted power Level – power transmitted by the mobile phone
Ec/Io This is the ratio of the received energy per chip (= code bit) and the
interference level, usually given in dB
RxLev Received power Level – indication of the signal strength in a GSM
network, as received by the mobile phone
RxQual Received network Quality – indication of the quality of the signal received
by the mobile phone in a GSM network

7 Annex B: References
1. Giovanni Calcagnini, Federica Censi, Michele Triventi, Eugenio Mattei and Pietro Bartolini,
“Electromagnetic immunity of infusion pumps to GSM mobile phones: a systematic review”,
Ann Ist Super Sanità 2007 | Vol. 43, No. 3: 225-228
2. Jeffrey l. Tri, MSEE; Rodney P. Severson, CBET; Linda K. Hyberger, MA, CCRC; and David
L. Hayes, MD, “Use of Cellular Telephones in the Hospital Environment”, Mayo Clinic
Proceedings 2007; 82(3):282-285
3. Tri JL, Hayes DL, Smith TT, Severson RP, “Cellular phone interference with cardiopulmonary
monitoring devices.”, Mayo Clinic Proc. 2001;76:11-15.
4. Fung, HT, Kam CW, Yau HH., “A follow-up study of electromagnetic interference of cellular
phones on electronic medical equipment in the emergency department”, Emerg Med
(Fremantle). 2002;14:315-319
5. JUSTIN BOYLE, Ph.D., “Wireless Technologies and Patient Safety in Hospitals”,
TELEMEDICINE AND e-HEALTH, Volume 12, Number 3, 2006; 373-382
6. Giovanni Calcagnini, Federica Censi, Michele Triventi, Eugenio Mattei and Pietro Bartolini’,
“Electromagnetic immunity of infusion pumps to GSM mobile phones: a systematic review”,
Ann Ist Super Sanità 2007 | Vol. 43, No. 3: 225-228
7. Lieshout E.J. van, Veer S.N. van der, Hensbroek R., Korevaar J.C., Vroom M.B. and Schultz
M.J. “Interference by new-generation mobile phones on critical care medical equipment”
Critical Care, 11 R98
8. Togt R. van der, Lieshout E.J. van, Hensbroek R., Beinat E., Binnekade J.M. and Bakker
P.J.M. “Electromagnetic interference from radio frequency identification inducing potentially
hazardous incidents in critical care medical equipment” JAMA - Journal of the American
Medical Association, 24, 299, 2884-2890
9. G.C. van Rhoon, Erasmus MC, Faculty of the Erasmus University Rotterdam,
“Elektromagnetische velden: geen ontkomen aan”, translated to “Electromagnetic Fields:
There is no escape”, November 2011.
10. ICNIRP; www.ICNIRP.org

8 Annex C: Detailed Measurements
Due to the size, this Annex has been documented separately. Please sent your request to Nyoka de
Wert; n.dewert@erasmusmc.nl.

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