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EMF ASSESSMENT BY MESEAREMENTS AND CALCULATION
(IVORIAN CASE)
Guy-Michel KOUAKOU,Vice-chair of study group 5 (ITU-T)Deputy-Director of Quality (ATCI)
ITU-T Workshop on Delivering Good Quality Telecommunication
Service in a Safe Environment in Africa (Nairobi, Kenya, 26 July – 27 July 2010 )
Nairobi, Kenya, 28-29 Juillet 2010
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PLAN
National context
EMF assessment
Flowchart for measurement procedure
Measuring equipment
Post-processing analysis
Some statistics
Conclusion
Nairobi, Kenya, 28-29 Juillet 2010
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NATIONAL CONTEXT (1/2)
public concern about the likely effects of electromagnetic fields on health.
Many people are against the deployment of base stations in their neighbourhoods.
No legal protection framework in place for EMF related health issues.
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NATIONAL CONTEXT (2/2)
the ATCI which assists the state regarding the protection of property and persons has adopted international standards such as:
ITU-T recommendations for compliance and estimation of EMF (K.52, K.70)
ICNIRP (International Commission on Non-Ionizing Radiation Protection) recommendation for exposure limits
CEPT recommendation for measurement procedures (ECC(02) 04 revised)
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EMF ASSESSMENT (1/2)
Measurements campaign was achieved in Abidjan and carried out in the frequency band from 10 KHz to 6 GHz
First step: 105 locations were identified and made a general field assessment
Second step: The whole procedure was executed in the 43 points with the highest level (decision level of 0,3 V/m).
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EMF ASSESSMENT (2/2)
In situ measurement duration: almost 3 hours per location (1 month for all locations)
some words about measurement protocol:Based on three cases;
Case 1 for quick overview to find the point where the field is higher (1.1, 1.5, 1.7)
Cases 2 & 3 for detailed investigation which allow to scan variable frequency band to deal with specific services
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FLOW CHART
Exigences de protection de la santé respectée
Exigences de protection non respectée
Résultats> limites CIPRNI
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MEASURING EQUIPMENTSFor case 1: RF radiation meters with isotropic field probes and a dosimeter
ANTENNESA EME SPY 120 (88Mhz - 3Ghz)
Cases 2 & 3: Spectrum Analyser
x
y
z
Champ EM émis par plusieurs services(TV, FM, GSM …)
Sonde tri axe Boîtier de
commutation
Analyseur de spectre Anritsu
MS2721B
y
z
x
Nairobi, Kenya, 28-29 Juillet 2010
Campmetre large bande
Sonde isotropique
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POST-PROCESSING (1/2)Measurement uncertainty estimation according to IEC guide:
Nairobi, Kenya, 28-29 Juillet 2010
Source d'erreurValeur
d'incertitude (%)Distribution de
probabilitéDiviseur Ci
Incertitudestandard (%)
Appareillage de mesure
Isotropie 21,62% Normale 2 1 0,85
Linéarité 12,20% Rectangulaire 1,73 1 0,58
Platitude en fréquence Normale 1
Température Normale 1
câble 2,33% Normale 2 1 0,10
Facteur d'antenne 18,85% Normale 2 1 0,75
Incertitude standardcombinée
15,88%
Incertitude étendue(intervalle de confiance de 95%) 31,76% Normale ue = 2* uc
Uncertainty table for case 2 and 3 (for f<3GHz)
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POST-PROCESSING (2/2)
Measurements in GSM were done only for the permanent control channel (BCCH). Results have been extrapolated taking into account the case where the trafic is maximum.
This extrapolation to the maximum traffic is calculated by the following formula Emax = E Control Channel x sqrt (n Transmitters)
n=3 in GSM 900 and n=4 in GSM 1800. These values represent the number of Transmitters generally used in rural areas
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RESULT
Every measurement was found to have been in compliance
with ICNIRP limits.
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SOME STATISTICS (1/3)Average field level per service
The average field level per service was low (under 0,3 V/m) except for GSM service where the average levels were 1.933 V/m for GSM 900 and 1.608 V/m for GSM 1800
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Ratio between average value and ICNIRP limits
SOME STATISTICS (2/3)
According to ICNIRP limits. GSM 900 represent 4.81% GSM 1800 represent 2.83%Nairobi, Kenya, 28-29 Juillet 2010
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SOME STATISTICS (3/3)Field level distribution per service
For GSM 900 : 93,02 % of field levels was less than 10% of limits value (4,18 V/m) ;
For GSM 1800 : 97,67 % of EM field was less than 10% of limits value (5.68 V/m);
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CONCLUSIONATCI will work with GSM operators to reduce the level of exposure (mitigation techniques proposed by recommendation ITU-T K.70).
Use of EMF estimator to assess the compliance of base stations before their installation.
Ongoing works:
Assessment of base stations compliance by measurements in each sensitive location;
Approval of a gentlemen agreement between operators, population and local authorities for base stations deployment;
Data base link to an automatic system for spectrum management .