Post on 27-Mar-2018
International Telecommunication Union
V K Roy ITU Expert
COMPLIANCE TESTING
of
Mobile Base Station/Broadcast Station
(CT:MBS/BS)
Theoretical Perspectives
2nd November 2016
Thimpu Bhutan
International Telecommunication Union
Agenda
EMF landscape @ Bhutan
Compliance with International Standard : Exposure limits of
ICNIRP
Activities associated with compliance testing
ICNIRP POSTULATES for Measurement
Measurement Method based on GSM/UMTS/LTE and Broadcast
signal structure
Measurement equipment
Exposure determination
Safety signage
Mitigation Techniques
Discussion
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Measurement of radio
frequency
electromagnetic fields
to determine
compliance with
human exposure limits
FOCUS :
On Measurement Process and Techniques for HANDS-ON TRAINING
with Measurement Equipment: Request by BICMA
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EMF Landscape @Bhutan
:Growing Wireless Infrastructure
Unprecedented increase in mobile voice & data traffic in last
decade.
Exponential increase in a number of cellular towers in Bhutan and
more & more towers erected each year.
Almost 99% of total towers are GBT in Bhutan.
0
100
200
300
400
500
600
Mobile Towers
Mobile Wireless
Infrastructure
2012 2013 2014 2015 2016
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More number of Towers
RAISES PUBLIC CONCERN:EXPOSURE TO EMF?
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Reason of Concerns
LACK OF
Communication to
Citizens
Lack of
Trust and
Concern
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KuenselOnline Archives http://kuenselonline.com/archive/motithang-
residents-want-cell-phone-tower-relocated/ 2/2
Motithang residents want
cell phone tower relocated
| KuenselOnline Archives
01/09/2014 Featured, News 54 Views They fear the close proximity of emissions
may have an ill effect on their health.
Tashi Cell has almost 20 towers in the Thimphu valley, up till
Chuzom.
It is not known if there is a maximum level of radiation set by the
Bhutan InfoComm and Media Authority (BICMA) or the health
ministry.
“I’m not aware of rules or regulations concerning radiation
exposure limits from either health or BICMA,” said Mr
Dhungyel,GM,Tashi Cell.
International Telecommunication Union
KuenselOnline Continued….
BT B-Mobile general manager, Pushpa M Pradhan,
said that the amount of radiation emitted by BT cell phone
towers are within safe limits followed internationally.
“However, he did not provide a figure of measurement.”…
“Seeing is believing”……… a matter of perception
“EVERYONE believes a measurement ”
?
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Possible Options?
BICMA and Mobile/Broadcast Service Providers
are encouraged to work in a collaborative
manner to ensure coverage of the signal as well
as balancing the concerns of consumers towards
potential effects of exposure.
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Compliance with International Standard
&
Reporting Mechanism
Assures the Citizens
That regulators and network operators
have complied with international
best practices in deploying base stations
Thereby Safeguarding their lives
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Measurement
advantages
• It can be done with little knowledge about radiating sources (initial measurement of the occupied spectrum is required only)
• Good quality measurement equipment is accessible in the market
• On site demonstration of the measurement to the interested people is possible
• It takes into account all radiating sources with real
parameters, real environment (reflections, antenna
supporting hardware, obstacles), simultaneous
exposure in the real way (phase differences of the
different waves are taken into account)
Source: NARDA
International Telecommunication Union
Organizations referring to EMF on health hazard of NIR exposure
WHO and ICNIRP are the most recognized and accepted International research
organizations referring to EMF on the health hazards of non-ionizing radiation exposure.
The ICNIRP is a non-governmental organization which has official relations with the WHO.
FCC guideline has been
based on the ANSI/IEEE
C95.1-1992 standards
EMF standards and limit values
Evaluation of testing instrumentation and methods
of measuring EMF associated with human
exposure.
Europe: CENELEC (Comite
Europeen de Normalisation
Electrotechnique) :Standards for
EMF in the human environment
USA
International Telecommunication Union
■ independent group of experts, independent scientific organization
■ emanated from IRPA/INIRC in May 1992, continues the Non-Ionizing-
Radiation sector of IRPA
■ members are not affiliated with commercial or industrial enterprises
■ multidisciplinary
■ balanced in terms of geography and gender
■ formally recognized cooperation with WHO, ILO, and others
■ registered not-for-profit
co-ordinates the research projects worldwide
aim: guidelines and recommendations for the safety of people exposed
to EMF
ICNIRP developed exposure limits which are supported and accepted by
the WHO , also endorsed by ITU
their recommendations are widely accepted
many countries consider ICNIRP recommendations as a basis for their
national regulation
ICNIRP (International Commission for Non-Ionizing Radiation Protection
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Electromagnetic
Radiation Sources
Wi-Fi & Wi-Max
AM Tower
TV
Tower
Cell Phone
Cell
Tower
FM
Tower
Un
-in
ten
tio
na
l R
F
Em
iss
ion
So
urc
es
R.F .
Source
Operating
Frequency
Transmission
Power
AM/FM
Tower
540 KHz-108
MHz 1 KW-300 KW
TV Tower 48 MHz- 814
MHz 10-500Watt
Wi-Fi 2.4-2.5 GHz 10-100mW
Wi-Max 2.3, 2.5 GHz
and 3.5 GHz 20W
Cell
Towers
700,800,900,
1800,2100,23
00 MHz
20W,40 W
Mobile
Phones
GSM-1800
GSM-900
UMTS-1800
etc.
1W
2W
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NIR vs. IR
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International Exposure Limit(0-300 GHz)
In 1998, ICNIRP published guidelines for limiting exposure
to time varying electromagnetic fields in the frequency range
up to 300 GHz.
The WHO encourages the adoption of exposure limits that
provide similar levels of health protection for all people.
The ICNIRP guidelines form the basis of WHO and ITU
Recommendations to governments and have been widely
adopted around the world.
ITU recommends the exposure limits for EMF developed by
ICNIRP where no national limits exist. National EMF
exposure limits based on the ICNIRP guidelines provide a
global reference, an internationally harmonized approach
and a global consistency of exposure protection.
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The basis of the ICNIRP guidelines :Established biological effects that are to
temperature rise (i.e., thermal effects).
ICNIRP states that non-thermal effects have not been established and their relevance to human
health is uncertain. Therefore, ICNIRP states that it is impossible to use reports of such effects
as a basis for setting limits on human exposure to these fields.
The reduction factors for the general public and workers are designed to account for any
scientific uncertainties, variations in the population health and environmental conditions.
Specified by Current Density, SAR, Power
Density
Source: ICNIRP presentation: EMF Safety Guidelines - The ICNIRP View presented at the ITU Workshop on Human Exposure to Electromagnetic Fields, Turin, 9 May 2013 available at
http://emfguide.itu.int/pdfs/ITU-EMF-Workshop-Turin2013-ICNIRP-Matthes.pdf
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How do limits for EMF come about?
RREstablished Health Effects
BBBBASIC LIMITS(
Expressed in Current
density, SAR inside the
body)
Derived Limits(Reference
level for measurement
outside the body)
Research
What are the effects of
Exposure?
There are two types of
limits:
(A) the basic restrictions
and
(B) the reference levels.
The basic restrictions are
directly related to the
biological effects but they
are sometimes expressed
in quantities, which are
difficult to measure (e.g.
current density in the
human body).
The reference levels are
derived from the basic
restrictions and are
formulated in easily
measurable quantities.
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ICNIRP Exposure Limit
Type of Exposure
Frequency Range
Electric Field Strength E(V/m)
Magnetic Field Hm(A/m)
Equivalent Plane wave Power Density Sev (W/m2)
General
Public
10-400 MHz
28
0.073
2
400-2000MHz
1.375f1/2
0.0037f1/2
f/200
2-300GHz
61
0.16
10
Occupational
10-400 MHz
61
0.16
10
400-2000 MHz
3f1/2
0.008f1/2
f/40
2-300 GHz
137
0.36
50
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ICNIRP electric field strength reference levels for public and
occupational exposures
Source: Mazar, ‘International, Regional and National Regulation and Standardisation’ [forthcoming].
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2 2
10 10 10 10
50 50
1
10
100
10 100 1,000 10,000 100,000 1,000,000
Po
wer
D
ensi
ty (
W/m
2)
Frequency (MHz)
public exposure
occupational exposure
ICNIRP power density reference levels above 10MHz for public and
occupational exposures
Source: Mazar, ‘International, Regional and National Regulation and Standardisation’ [forthcoming].
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Activities during Exposure level Assessment
Ref: ITU K.91
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In general, the inner boundary of the far-field is considered to be at a radius of about 3 λ from the emitter site (or 2D 2/ λ
if the size of the antenna is large compared with the wavelength λ).
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EXCEDENCE ZONE Occupational limits exceeded
OCCUPATIONAL ZONE Public limits exceeded
COMPLIANCE ZONE
The ICNIRP EMF guidelines are based on a
threshold level of exposure above which health
effects have been established.
A reduction factor is then applied to establish a safe
exposure level for workers (occupational exposure,
factor of 10) and the general public (factor of 50).
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The Standard (ICNIRP)postulates…..Measurement
Worst Emission Conditions: Measurements must be done during times
of maximum operational state of the exposure EMF source. If this is not
possible, the results have to be extrapolated.
Note: The radiated power of (e.g. GSM, UMTS, LTE) mobile phone
base station antennas is not constant over time, it is depending on the
actual traffic! Therefore special measurement and extrapolation
techniques are necessary for a correct exposure Determination.
The transmitted power is time invariant, extrapolation is not required for
broadcasting systems.
If more than one signal is present at the measurement point, a
summation of the exposure has to be performed (f > 10 MHz:
Summation relative to the power).
Measurements must be done at places with maximum exposure.
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ICNIRP Postulates….
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Following measurement methods can be used to
determine compliance of the EUT:
Broadband Method
Frequency Selective Method
Measurement Methods
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Measured quantity
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General exposure assessment : Broadband
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Comprehensive assessment :Narrow Band/ Frequency selective
equipment
For mobile communications systems using adaptive power control,
including GSM, WCDMA and LTE, the BS does not transmit at a
constant power level; the emitted power varies with time depending
on factors such as traffic variation and dynamic power control .In
particular, it has been shown that the typical BS output power levels
for mobile communication technologies are well below the available
maximum power.
To extrapolate time variant signals to either realistic or theoretical
maximum output power conditions, a time invariant component of the
signal is evaluated. This component is transmitted at constant power
level for specific frequencies within a certain band.
To measure this signal, a frequency selective equipment, and in
some cases a specific decoder, is needed
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Determination of the total exposure ratio
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Measurement Instrument
Electric field strength measurement:
Broad band Meter:
Used for general assessment of Exposure
Narrow Band/frequency selective radiation meter– Used for comprehensive assessment, more expensive,
time consuming, requires post processing. Also used for broadband measurement.
Different Modes: Spectrum Analysis, ,Safety Evaluation, Level recorder, Specific decoder mode
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Frequency Selective radiation meter
=
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1.
2.
3.
4.
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Isotropic Probe
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39
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k
kTOT EE 2 )(lim fE
12
lim
2
k
kE
kE
E
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Measurement(Broadband measurement by Selective radiation
meter)
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Spectrum Analysis of band 0-3 GHz
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“Identification of time invariant
component of the signal ”
Having constant power level in specific frequencies within a certain band
for SPECIFIC TECHNOLOGY”
• GSM (900 / 1800 MHz)
• UMTS (WCDMA; 2100 MHz; 900
MHz)
• CDMA (CDMA-2000; CDMA One)
• LTE (FDD, TDD; different bands)
Time Invariant Component of signal…
GSM……BCCH
UMTS….C-PICH
LTE…….RS/PBCH
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GSM: Signal structure
Signal bandwidth ≈ channel spacing = 200 kHz.
The signal of one transmitter is divided into 8 time slots (duration:
577 μs). For the data transmission to the telephone minimum one
time slot is used. Therefore theoretically maximum 8 telephones can
be served by one transmitter frequency(TDMA = time division
multiple access).
Because of the high number of subscribers, it is necessary to serve
one cell with more than one frequency. The additional installed
frequency channels are called "Traffic channels" (TCH's). If the
additional TRX-Modules are installed, they will be activated
automatically, if the traffic makes it necessary.
Therefore the total power, transmitted by one antenna depends on
the actual traffic.
Worst case: All installed frequency channels are on air and all time
slots are used
(and maximum transmitter power is used).
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GSM: Signal structure in time domain
1st frequency:
"Broadcast Control Channel"(BCCH)
The BCCH channel is transmitted with
constant power, regardless of the
present traffic.
Additional frequencies (No. 2,3,4...):
"Traffic channels"(TCHs)
The TCH channels are transmitted with
variable power dependent on the
connection quality (transmit power
control).
Some time slots may even be empty
(no user)
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GSM
• TRX 1 (BCCH) permanently on air with maximum power
• TRX 2.....n (TCH) not on air or on air with permanently changing power.
• Consequence: Maximum transmitted power = n · Power of TRX 1.
Maximum exposure = n · Exposure generated by TRX 1 (power density)
Maximum exposure = SQRT(n) · Exposure generated by TRX 1 (field
strength)
TRX 1
TRX2
TRX3
TRX4
Antenna
RF radiation
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Spectrum Analyzer mode
• Use the "Spectrum Analyzer" mode of the SRM-3006.
• Measure the field strength EBCCH of BCCH signals of each sector
antenna.
• Extrapolate their exposure to maximal channel number n (this
information must be delivered by the network operator).
• Ignore TCH exposure.
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Spectrum Analyzer Mode
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SERVICE TABLE CREATION
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Exposure ratio
Finally calculate the sum exposure IE of all antennas.
Emax,n: Extrapolated field strength for the signal with frequency n
Eln: Limit value (electric field strength) to be applied to this frequency (or
for the lowest frequency of the relevant GSM band)
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Additional information: GSM base stations with software defined
radio transmitters.
• More and more often the network operators do not use individual
radio TRX modules for each GSM channel.
• Modern systems only have one output connector. The number of
RF channels which are present at this connector will be defined by
software.
Classical configuration:
• Operator uses individual TRX modules (e.g. n = 4).
• Then the extrapolation factor K is:
K = n = 4 (in dB: K = 10·log 4 = 6 dB).
Modern configuration:
• Example: Actual power of the BCCH signal adjusted by the
software to a value of 20 W; Maximum output power of the TRX
module = 150 W.
• Then the extrapolation factor K is:
K = 150/20 = 7.5 (in dB: K = 10·log 7.5 = 8.8 dB).
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GSM: EXCEL evaluation sheet
GSM: EXCEL evaluation sheet
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1
2
3
4
5
6
7
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UMTS Base Station Sites
Frequency range
(Downlink; Bhutan) :
(i) 869 - 870 MHz (2 channels)
(ii) 2110-2120 MHz(2 channels)
Signal bandwidth: ≈ 4.6 MHz (WCDMA;
"3G")
The power of CPICH signal of each antenna is distributed over the full signal
bandwidth of ≈5 MHz and coded by the individual scrambling codes.
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WCDMA/UMTS
Scrambling
code 155 Scrambling
code 298
Scrambling
code 178
• Different sectors are separated by "scrambling codes".
• P-CPICH "Primary common pilot channel" ("CPICH") is a permanent
signalling channel.
• P-CPICH transmits with constant power (typ. ≈10 dB below Pmax)
and can be used for precise extrapolation.
• Measure exposure to P-CPICH and extrapolate by Pmax/PCPICH
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WCDMA/UMTS: Code Selective Measurement
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GSM+UMTS: EXCEL evaluation sheet
WCDMA/UMTS: Code Selective Measurement
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UMTS Mode
Perform the same measurements and extrapolation , If more than the one frequency channel is radiated by the antenna system.
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Mode: UMTS P-CPICH demodulation (UMTS) Smax= Scpich * Nciph
•The parameter Ncpich is set by the TSP.A typical value is 10(i.e. 10% of the total power
allocated to Cpich)
Mode: UMTS P-CPICH demodulation (UMTS)
• Result Type: MAX (and ACT)
• Center frequency: Center frequency of the UMTS signal; may be slightly different to the
center frequency of the channel
• Resolution bandwidth (RBW): 5 MHz (automatically set by the instrument, can not be
changed).
Also RMS detection is automatically switched on.
• Measurement range: Depends on field strength of the strongest signal (Should be
minimum 20 dB above the strongest measured CPICH signal)
• Antenna: 3-axis
• Worst case approach: Measuring of CPICH-signals + extrapolation by using a factor,
based on the power of the CPICH signal relative to the
maximum power radiated by the antenna.
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• LTE can be utilized in the frequency ranges 700 MHz, 900 MHz, 1.8 GHz, 2.1 GHz and
2.6 GHz.
• As with UMTS, LTE uses individual cells, which are differentiated by their cell numbers
(cell ID, 0 to 503).
• Each cell can also use one, two or four antennas (multiple input – multiple output,
MIMO).
• LTE uses a special method of modulation called orthogonal frequency domain
modulation access (OFDMA). This distributes the information across many sub-carriers
spaced at intervals of 15 kHz, each of which is modulated by QPSK, 16 QAM or 64
QAM. Frequency division duplex (FDD) is generally used to separate the uplink and
downlink directions (from the subscriber to the base station and vice versa), although
time division duplex (TDD) is also possible.
The LTE option(Dedicated Decoder) equips users for all the crucial measurement tasks on
LTE systems with FDD.
The Measurement equipment should support
• all LTE channel bandwidths from 1.4 MHz to 20 MHz
• automatically determine the cell ID and number of antennas used
• Measure the average power values of the PSS and SSS
• measure the average power values of the Reference Signal, separately for each
antenna, or as average power of all antennas used, or as maximum power of all
antennas used
• offers automatic extrapolation using factors up to 10,000
LTE
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LTE: Important technical parameters
Frequency range (depends on national
situation) :
- 700/800 MHz (Digital Dividend, rural areas)
- 1.8 / 2 / 2.6 GHz (urban areas)
Modulation: Multi carrier modulation :
Concurrent Transmission of multiple
subcarriers with 15 KHz spacing
- OFDM (downlink):A modulation and
multiplexing technique, SC-FDMA (uplink)
Duplex:- FDD or TDD;
Channel bandwidth (CBW):
- 1.4 / 3 / 5 / 10 / 15 and 20 MHz,
- Selectable channel bandwidth between 1
and 20 MHz (variable)
Signal ("transmission") bandwidth (TBW):
- 1.08 / 2.7 / 4.5 / 9.0 / 13.5 / and 18.0 MHz (<
channel bandwidth)
Transmitter power (Base Station):
- typ. 20 - 50 W/Channel (often 2 channels
are radiated by one antenna → MIMO
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LTE: Basic measurement strategy for maximum exposure
determination
1. Identification of a signal, which will be transmitted with traffic
independent, constant power.
2. Measuring the exposure, caused by this signal.
3. Extrapolation to maximum power of the antenna.
4. Applying an additional reduction factor on TDD signals
(depending on DL / UL configuration)
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• Cell specific signals (Signal) PSS (Primary Sync Signal)
SSS (Secondary Sync Signal)
RS Avg. (Reference Signal Average)
RS Sum (Reference Signal Sum)
RS Max (Reference Signal Maximum)
RS 0 (Reference Signal antenna 0)
RS 1 (Reference Signal antenna 1)
RS 2 (Reference Signal antenna 2)
RS 3 (Reference Signal antenna 3)
• PBCH: Physical Broadcast Channel:±3 resource blocks (±36
subcarriers; 1.08 MHz) symmetric to center frequency. Duration:
4symbols; appears each radio frame in Slot no. 1; carries cell specific
system info and access -control parameters.
• P-SS, S-SS, PBCH (and RS) are transmitted independent from actual
traffic with constant power.
LTE : Signals
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Step 1: Signals with constant power
RS signals : RS signals are distributed over whole frame (time vs
frequency)and are typically transmitting max. power in SISO or MIMO
configuration, same position of RS(freq. vs time) is not reused , all RSx are
interleaved, only RS & traffic signals are transmitted by all antenna and over
whole Band, hence ideal for testing.
Ideal for extrapolation to total power and offering minimal effect from fading on
measurement uncertainty when decoding whole band(CBW
R0 R0
R0 R0
R0 R0
R0 R0
R1 R1
R1 R1
R1 R1
R1 R1
MIMO: Two Antenna Ports
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Code selective LTE measurements: Basic principle
At LTE base stations, the signals P-SS, S-SS and RS are
coded cell specific.
Most important: Measurement of RS signals (because RS
signals can be separated rel. to the MIMO antenna
channels).
With the code selective measurement you can determine
the field strength, which is generated per Resource Element
(i.e. per subcarrier) by the RS signals.
The measurement is done by averaging over a defined part
of the spectrum.
With an extrapolation factor the maximum exposure can be
calculated from the measurement values.
Not very much information about the site configuration must
be delivered by the network operator.
Sector 1,Cell Id 261 Sector 2,Cell Id 263
Sector 3, Cell Id 262
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Extrapolation Factor
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CBW TBW(SBW) Number of
Sub
Carriers
Extrapolatio
n Factor
Ki(linear)
Extrapolatio
n Factor
Ki(dB)
Extrapolatio
n Factor If
RS has
power
boost of
3dB Ki
1.4 MHz 1.08 MHz 72 72 18.57 36
3 MHz 2.7 MHz 180 180 22.55 90
5 MHz 4.5 MHz 300 300 24.77 150
10 MHz 9.0 MHz 600 600 27.78 300
15 MHz 13.5 MHz 900 900 29.54 450
20 MHz 18.0 MHz 1200 1200 30.79 600
Information required from Operator: No boosting or 3 dB boosting of RS signals
LTE : Extrapolation Factor
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LTE: Measurement Report
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Spectrum analysis(Level recorder Mode)
Particularly suitable for this are the primary and secondary
synchronization signals (P-SS and S-SS) and the physical broadcast
channel (PBCH), that are radiated at regular intervals every 5 or 10 ms
with constant power and take up a tenth of the signal spectrum with a
bandwidth of approx. one MHz
If all subcarriers are radiated with the same power, the extrapolation
factor K is identical with the number of subcarriers of the LTE signal
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ANNEX-
Measurement Location =
BTS Technology BCCHn/Scrambling Code/Cell Id+Rsi MIMO antenna path path
Frequency
Measured Value
Extrapolation Factor
Extrapolated Field strength
Limit vale of field strength
Over all exposure Ratio
GSM BTS using TDMA Technology (add row for each such BTS)
BCCH1
BCCH2
BCCH3
UMTS Node-B using WCDMA Technology( add row for each such BTS)
178
298
155
LTE eNode-B using OFDM Technology (add row for each such BTS)
280_0
280_1
REPORT FORMAT FOR CERTIFICATION OF BTS FOR COMPIANCE OF
THE EMF EXPOSURE LIMITS
BTS name; if shared name of all i.e. site Id
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Broadcast signals
• Broadcast transmitters do not have
utilization-dependent fluctuations in the power output
so that the processes for extrapolation
to maximum possible base station utilization do not apply.
• It is therefore sufficient to know
the correct configuration parameters on the measuring
equipment,
• The additional application of
special formulae for extrapolation to maximum power is
not necessary.
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Frequency range (span):
Use
87.5 - 108.0 MHz (band II)
Analog audio broadcast (FM radio)
174 - 230 MHz (band III)
DAB
470 - 790 MHz (bands IV + V)
DVB-T
1,452 - 1,480 MHz (L band)
DAB
BROADCAST SIGNALS
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Typical spectrum in Band IV (UHF) with analog TV channels (PAL) and
DVB-T channels directly adjacent to each other.
1.Video
carrier
3.Sound carrier
2.Chrominance
Carrier
Analog TV channel
DVB-T
signal
• Channel bandwidths of Analog TV= between 6 MHz and 8 MHz; e.g. 7 MHz in the VHF
band and 8 MHz in the UHF band
• The transmission power is quoted in terms of the synch peak power, which is the power
at which the line synchronization pulse is broadcast. The rest of the power depends
greatly on the program content, with the greatest possible average broadcast
power being some 2.3 dB below the synch peak power. The spectrum is unevenly
distributed, with strong components around the video carrier
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Analog TV signal
Analog TV channel : RBW=300 KHz
Test equipment settings for measuring
analog TV signals:
Operating mode: Spectrum
Analysis
Alternatively: Safety Evaluation
with a prepared service table
Span: in this case 670 - 702 MHz
as channels 46 and 49 are
active
Resolution bandwidth RBW: 300
kHz
To determine the maximum field
strength value from the
measured value of the analog
TV signal , a factor of 2.3 dB
must be added to the maximum
measured field strength.
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DVB-T signal
DVB-T involves multi-carrier modulation in accordance with the OFDM
procedure (Orthogonal Frequency Division Multiplexing). This results in a
very wide
1.Test equipment settings
for measuring DVB signals: 1. Operating mode:
Safety Evaluation
2. Span: in this case
channel 31 at 550
MHz was active
3. Resolution
bandwidth RBW:
50 kHz
Figure 2 clearly
shows that
channel 31 was
the only active
DVB channel,
thanks to noise
suppression.
Four DVB-T signal in Band V Detailed Measurement of a
DVB-T signal
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Typical spectrum of a FM radio stereo transmission signal
(carrier frequency: 96 MHz; frequency deviation: 75 kHz;
Modulated with a stereo noise signal in accordance with ETS 300 384).
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Signal structure, modulation procedure, transmission bandwidths:
Analog (FM) radio
Test equipment settings
for measuring in the FM
band:
Operating mode:
Spectrum Analysis
Alternatively: Safety
Evaluation with a
prepared service table
Span: 75 MHz – 108
MHz
Resolution bandwidth
RBW: 200 kHz ;
Level recorder Mode is
also used.
For the entire VHF band, a constant limit value (28 V/m, 0.073
A/m or 2 W/m2) applies in accordance with EU / ICNIRP.
International Telecommunication Union
Detailed evaluation table for the determination of sum emissions caused by FM
radio as well as DAB and DVB-T signals.
International Telecommunication Union
Uncertainty
Uncertainty for NIR measurement can be divided in two parts:
• uncertainty due to the environment
• and uncertainty due to the instruments.
Uncertainty due to the environment:
there are uncertainties inherent to on site measurement, due to various parameters
(fading, multipath....).
This value can be reduced with the spatial averaging method.
One can consider that the uncertainty due to the environment is reduced to 3 dB
with 3 measurement points and 2 dB with 6 points.
More detailed information about the application of time and space averaging can be
found on ITU-T Recommendation K.61.
Uncertainty due to the equipment will be intrinsic for each instrument and as such,
should be provided by the manufacturer.
Care should be taken whenever buying such equipment that all necessary
information for the computation of the uncertainty is provided, including calibration
certificates and uncertainty propagation functions that allows the proper use of the
information provided on such certificate to determine the final measurement result
uncertainty.
It is preferable to maintain the overall uncertainty below an acceptable level.
As an example, the European standard EN 50 492 recommends a value of 4 dB as
the maximum uncertainty.
International Telecommunication Union
REPORTING
The measurement results for each location should be
documented on a report, preferably using tables. A
comprehensive report expects: • Purpose and objectives of the measurements;
• Date, start and stop time;
• Geographic co-ordinates, altitudes above ground level, and particular
characteristics of the measurement sites;
• List of identified transmitters;
• Temperature;
• The used equipment and its serial numbers;
• Uncertainty of the measurements.
• Additionally, in order to improve the intelligibility of the report is
desirable to use graphical representation of the results in the form of
maps, diagrams and photos.
International Telecommunication Union
CERTIFICATION OF BTS FOR COMPLIANCE OF THE EMF EXPOSURE LEVELS (MEASUREMENT USING BROADBAND RF METERS)
(A) SITE DATA & TECHNICAL PARAMETERS
Name of the BTS :
Sidhi Vinayak Chamber
System Type:
GSM Idea
SIT
E D
AT
A
Item Units IDEA
Site ID
Name Sidhi Vinayak
Chamber
Address Opp. MIG Club, Bandra East, Kalanagar Mumbai
Lat / Long 19 03 26.7 N 72 50 52.5 E
RTT / GBT RTT
Building Height AGL (m) NA
Antenna Height AGL (m) 24m
Base Channel Frequencies (MHz) 1805.2–1879.8 935
- 960 MHz
Carriers / Sector 4 4 4
Tx Power (dBm) 43 dbm 43 dbm 43 dbm
(B) MEASUREMENT OF ELECTRIC FIELD STRENTH
M
easu
red
valu
e o
f E
lectr
ic f
ield
(V
/m
) a
t ad
jacen
t b
uil
din
gs/
co
nsp
icu
ou
s
locati
on
s w
ith
in 1
00
mete
rs r
ad
ius.
Building 0 (B0) Own Building Top Corners / Points
C1 C2 C3 C4 C5 C6 C7
Dis. From Tower Base (m) 5m 3m 2m
ICNIRP Limit (V/m) * 4.2 4.2 4.2
Measured Value (V/m)
Ratio (Measured / ICNIRP) 0.2353926 0.36 0.27819123
OT
HER
CO
NS
PIC
UO
US
LO
CA
TIO
NS
ON
TH
E
GR
OU
ND
SPOT LANDMARK Near
Dhamkanta
Near Glass Showroom
Spot 3 Spot 4 Spot 5 Spot 6 Spot 7
Azimuth 230 350
Distance from BTS 17m 16m
ICNIRP Limit (V/m) *
4.20574 4.206
Measured Value (V/m)
2.15 1.32
Ratio (Measured / ICNIRP Limit)
0.5112061 0.31
RE
SU
LT
COMPLIANT (YES/ NO) YES
Note : * ICNIRP Limit will be for the worst case among all the bands present on the Site
International Telecommunication Union
Measu
red
valu
e o
f E
lectr
ic f
ield
(V
/m
) a
t ad
jacen
t b
uil
din
gs/
co
nsp
icu
ou
s
locati
on
s w
ith
in 1
00
mete
rs r
ad
ius.
Building 0 (B0) Own Building Top Corners / Points
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11
Dis. From Tower Base (m)
Operator 1
Operator 2
Operator 3
RMS of Relative Values
Building 1 (B1) Adjacent Building at various Heights (m)
Azimuth Distance from BTS 3 6 9 12 15 18 21 24 27 30 33
Operator 1
Operator 2
Operator 3
RMS of Relative Values
OT
HER
CO
NS
PIC
UO
US
LO
CA
TIO
NS
ON
TH
E
GR
OU
ND
SPOT LANDMARK
Spot 1 Spot 2
Spot 3 Spot 4
Spot 5 Spot 6
Spot 7 Spot 8 Spot 9 Spot 10 Spot 11
Azimuth
Distance from BTS
Measured value of Electric Field
(V/m) OPERATOR 1
Measured value of Electric Field
(V/m) OPERATOR 2
Measured value of Electric Field
(V/m) OPERATOR 3
RMS of Relative Value
RE
SU
LT
COMPLIANT (YES/ NO)
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International Telecommunication Union
3.
4.
International Telecommunication Union
International Telecommunication Union
International Telecommunication Union
International Telecommunication Union
Low Power BTS Annexure-II
Restriction on minimum height of lowest radiating part of Antenna and minimum distance to areas accessible to general public in the main lobe direction for Low Power
BTS
Sl. No. EIRP(in Watts)
Minimum Height(in metres)as per different Antenna Tilts in degrees Minimum Distance(in
metres)for publically accessible area in the main lobe direction
Minimum Distance(in
metres)for other Emitters(≥10
Watts) in the main lobe direction 0ᵒ 5ᵒ 10ᵒ 15ᵒ
1 ≤2 No specific criteria .According to (ITU-T K.52) emitters with a
maximum EIRP of 2W or less are inherently compliant
2 ≤10 2.5 2.7 2.8 3.0 1.9 9
3 ≤20 2.8 3.0 3.2 3.4 2.6 13
4 ≤30 2.9 3.2 3.5 3.7 3.2 16
5 ≤40 3.1 3.4 3.7 4.0 3.7 19
6 ≤50 3.2 3.5 3.9 4.2 4.2 21
7 ≤60 3.3 3.7 4.1 4.4 4.6 23
8 ≤70 3.4 3.8 4.2 4.6 4.9 25
9 ≤80 3.5 4.0 4.4 4.8 5.3 26
10 ≤90 3.6 4.1 4.5 4.9 5.6 28
11 ≤100 3.7 4.2 4.7 5.1 5.9 29
Compliance Testing :LOW POWER BTS
International Telecommunication Union
• Recommendation ITU-T K.52 (2004), Guidance on complying with limits for human exposure to electromagnetic
fields.
• Recommendation ITU-T K.61 (2003), Guidance to measurement and numerical prediction of electromagnetic fields
for compliance with human exposure limits for telecommunication installations.
• Recommendation ITU-T K.70 (2007), Mitigation techniques to limit human exposure to EMFs in the vicinity of
radiocommunication stations.
• Recommendation ITU-T K.83 (2011), Monitoring of electromagnetic field levels. Recommendation ITU-T K.91
(2012), Guidance for assessment, evaluation and monitoring of human exposure to radio frequency
electromagnetic fields.
• ITU-R Handbook (2011). Handbook on Spectrum Monitoring.
• CENELEC EN 50383:2010, Basic standard for the calculation and measurement of electromagnetic field strength
and SAR related to human exposure from radio base stations and fixed terminal stations for wireless
telecommunication systems (110 MHz - 40 GHz).
• Rec. ITU-T K.100 (12/2014) 1 Measurement of radio frequency electromagnetic fields to determine compliance
with human exposure limits when a base station is put into service
• CENELEC EN 50400:2006, Basic standard to demonstrate the compliance of fixed equipment for radio
transmission (110 MHz~40 GHz) intended for use in wireless telecommunication networks with the basic restriction
or the reference levels related to general public exposure to radio frequency electromagnetic fields, when put into
service.
• CENELEC EN 50401:2006, Product standard to demonstrate the compliance of fixed equipment for radio
transmission (110 MHz~40 GHz) intended for use in wireless telecommunication networks with the basic restriction
or the reference levels related to general public exposure to radio frequency electromagnetic fields, when put into
service.
• CENELEC EN 50492:2008, Basic standard for the in-situ measurement of electromagnetic field strength related to
human exposure in the vicinity of base stations.
• IEC 62232 ed. 1.0 (2011), Determination of RF field strength and SAR in the vicinity of radiocommunication base
stations for the purpose of evaluating human exposure.
• Other ITU Resources
• NARDA SAFETY SOLUTIONS RESOURCES
References:
International Telecommunication Union
Discussion…………
International Telecommunication Union
THANK YOU
International Telecommunication Union
EMF Standards, Acts, Norms
IEEE
ICNIRP
FCC
AS, NZS
WHO IEC
EU:
CENELEC
PPT
UK: NRPB D:
DIN/VDE
NHWM
The transmitters of RF services produce electromagnetic emissions people may be exposed to. For
assessing people’s safety, the exposure must be measured and compared with limits. Complying with
relevant standards demonstrates a commitment to protect the health of staff and the public community
and satisfies the legal safety requirements
Source:NAR
DA
International Telecommunication Union
NIR vs. IR with Photon energy
International Telecommunication Union
Item Mobile Handset Cellular BTS
Field Region Reactive Near Field Region Far Field Region
Radiation Range within λ. (1 to 2 cms from user
body)
beyond > 3λ and up
to several KMs
Propagation of
Electromagnetic
waves
Scattered Transplaner
Field Distribution
The field strength and field
distributions are highly dependent
on the location, orientation and
electromagnetic characteristics of
adjacent objects, such as the
user’s body.
Electric Field and
Magnetic Fields are
related :
E/H = 377
International Telecommunication Union
Broadband Isotropic Probes and Meters
Provide fast reading, usually in the order of 1/3 of a
second or less, reducing the exposure of the
personal handling the equipment and allowing the
use of techniques for quick overviews or mobile
monitoring.
Usually are harnessed against strong EMF,
allowing its operation near radio frequency sources,
places of interest for NIR measurements. Also the
upper limit of the measurement scale is usually
high, more than 70V/m and in some cases up to
hundreds (V/m), allowing the evaluation of
extremely hazardous RF environment, activity that
might be necessary to solve a dispute about
occupational hazard.
Simple to operate.
Limitation: Increased uncertainty under modulated
signals and places with multiple sources at various
frequencies, whenever the probe uses Schottky
diode detectors ,generally gives overestimation
International Telecommunication Union
Item Mobile Handset Cellular BTS
Compliance
parameter
With respect to evaluating EMF
exposure from Mobile Phones and
portable devices, SAR value is an
appropriate measure for the
purpose of determining EMF
compliance
It is necessary to measure only E-field in order to determine the power density and Exposure Ratio.
Special
Feature
Maximum energy absorption is
usually expected in the more
absorptive high water content
tissues near the surface of the
head or body.
Comparison of Radiation characteristics
Mobile Handset vs. Cellular BTS…
International Telecommunication Union
International Telecommunication Union
GSM: EXCEL evaluation sheet
Column 1: Frequency of BCCH-signals [MHz].
Column 2: Number of the measurement point; Name of the operator.
Column 3: Limit acc. National legislation (value of the lowest frequency of the
GSM-900/-1800 band).
Column 4: Measured field strength of BCCH signals [dBμV/m].
Column 5: Measuring uncertainty (uncertainty will be added, if value is ≠ 0
dB).
Column 6: Extrapolation factor for this antenna
Column 7: <Column 7> = <Column 4> + <Column 5> + 10 log <Column 6>
Column 8: Conversion from dBμV/m to V/m.
Column 9: <Column 9> = <Column 8> / <Column 3> in %
Column 10: Conversion from V/m to mW/m².
Yellow fields: Summation of all signal values (Column 8+9: RSS-summation;
Column 10: Linear summation)
International Telecommunication Union
UMTS: EXCEL evaluation sheet
Column 1: Center frequency of UMTS signal [MHz] + Scrambling code of CPICH signals
Column 2: Name of operator
Column 3: Limit acc. Indian legislation
Column 4: Measured field strength value of UMTS-CPICH signal [dBμV/m]
Column 5: Measuring uncertainty (uncertainty will be added, if value is ≠ 0 dB)
Column 6: Extrapolation factor for this antenna
Column 7: <Column 7> = <Column 4> + <Column 5> + 10·log <Column 6>
Column 8: Conversion from dBμV/m to V/m
Column 9: <Column 9> = <Column 8> / <Column 3> in %
Column 10: Conversion from V/m to mW/m²
Yellow fields: Summation of all signal values (Column 8+9: RSS-summation; Column 10:
Linear summation)
Yellow fields: Total summation over all operators
International Telecommunication Union
LTE Frame Structure
• The LTE frame structure are of two types based on topology either FDD or TDD.
• Total Frame duration is about 10ms.
• There are total 10 subframes in a frame.
• Each subframe composed of 2 time slots.
Type 1, LTE frame structure is applicable to FDD system. As shown in the figure below, an LTE frame is made of total 20 slots, each of 0.5ms.
Two consecutive time slots will form one subframe.
10 such subframes form one radio frame.
One subframe duration is about 1 ms.
Hence LTE radio frame will have duration of about 10ms.
Each radio frame will have 307200 Ts. Where in one Ts equals 1/(15000 x 2048) seconds.
International Telecommunication Union
LTE Frame Structure
Type 2, LTE frame structure is application to TDD system.
• As shown in the figure, here radio frame composed of two half frames, each of 5ms duration resulting in total frame duration of about 10ms.
• Each radio frame will have total 10 subframes, each subframe will have 2 time slots.
• Subframe configuration is based on Uplink downlink configuration(0 to 6). Usually in all the cases, subframe #0 and subframe#5 is always used by downlink.
• The Special subframe carry DwPTS(Downlink Pilot Time Slot),GP(Guard Period) and UpPTS(Uplink Pilot Time Slot).
• For the 5ms DL to UL switch point periodicity case, SS(Special subframe ) exists in both the half frames.
• For the 10ms DL to UL switch point periodicity case, SS exists only in first half frame.
International Telecommunication Union
LTE
LTE is a single frequency network (SFN).
Signals of the different cells can not be separated by spectral
measurements (both in frequency and in time domain). → You may not
notice, if one of the three sector antennas or some MIMO channels
do not radiate during the measurement!!!
Extrapolation can not be done with full precision, if extrapolation factor
differs from antenna to antenna.
Significant overestimation is possible, if P-SS, S-SS, PBCH have higher
power level, than the other parts of the spectrum ("boosting").
Extrapolation to maximum power is also depending on MIMO mode
(synch radiation pattern). Significant underestimation is possible!!
More reliable approach: Measuring the also stable signaling RS signals
with a code selective technique (similar to UMTS). Each cell (antenna)
has an individual identification (Cell ID). Therefore the signals can be
separated.
Code selective option is available for the SRM-3006 (but only for FDD mode).
International Telecommunication Union
2 Resource blocks,1msx180KHz
Depending on the required data rate , each UE can be assigned an individual number of
Resource Blocks(OFDMA).The number of assigned resource blocks can be changed
each subframe (1ms).
LTE: Assigning resource blocks to the user equipment (UE)
International Telecommunication Union
Resource Block for UE
1 Radio Frame (10
ms),
1 Sub-frame(1.0
ms),
1 Slot(0.5 ms)= 7
symbols
1 Symbol (≈70 μs) x
1 subcarrier (15 kHz)
= 1 Resource
Element (RE)
7 symbols x 12
subcarriers = 0.5 ms
x 180 kHz = 1
Resource Block (RB)