COMPLIANCE TESTING of Mobile Base Station/Broadcast ... · PDF filemay have an ill effect on...

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


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


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


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


More number of Towers

RAISES PUBLIC CONCERN:EXPOSURE TO EMF?


Reason of Concerns

LACK OF

Communication to

Citizens

Lack of

Trust and

Concern


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.


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 ”

?


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.


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


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


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


■ 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


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


NIR vs. IR


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.


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














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.


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


ICNIRP electric field strength reference levels for public and

occupational exposures

Source: Mazar, ‘International, Regional and National Regulation and Standardisation’ [forthcoming].


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].


Activities during Exposure level Assessment

Ref: ITU K.91


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).


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).


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.


ICNIRP Postulates….


Following measurement methods can be used to

determine compliance of the EUT:

Broadband Method

Frequency Selective Method

Measurement Methods


Measured quantity


General exposure assessment : Broadband


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


Determination of the total exposure ratio


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


Frequency Selective radiation meter

=


1.

2.

3.

4.


Isotropic Probe


39


k

kTOT EE 2 )(lim fE

12

lim

2

k

kE

kE

E


Measurement(Broadband measurement by Selective radiation

meter)


Spectrum Analysis of band 0-3 GHz


“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


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).


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)


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


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.


Spectrum Analyzer Mode


SERVICE TABLE CREATION


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)


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).


GSM: EXCEL evaluation sheet



1

2

3

4

5

6

7


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.


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


WCDMA/UMTS: Code Selective Measurement


GSM+UMTS: EXCEL evaluation sheet

WCDMA/UMTS: Code Selective Measurement


UMTS Mode

Perform the same measurements and extrapolation , If more than the one frequency channel is radiated by the antenna system.


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.


• 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


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


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)


• 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)




• 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


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


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


Extrapolation Factor


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


LTE: Measurement Report


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


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


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.


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


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


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.


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


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).


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.


Detailed evaluation table for the determination of sum emissions caused by FM

radio as well as DAB and DVB-T signals.


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.


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.


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

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(V

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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

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PIC

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LO

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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


Measu

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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

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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


(V/m) OPERATOR 2


(V/m) OPERATOR 3

RMS of Relative Value

RE

SU

LT

COMPLIANT (YES/ NO)


3.

4.


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


• 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:


Discussion…………


THANK YOU


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


NIR vs. IR with Photon energy


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


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


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…



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)


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


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.


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.


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).


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)


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)

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