Mladen Koprivica

STATISTICAL ANALYSIS OF ELECTROMAGNETIC RADIATION MEASUREMENTS IN THE VICINITY OF GSM/UMTS BASE STATION ANTENNA MASTS

As a result of dense installations of public mobile base station, additional electromagnetic radiation occurs in the living environment. In order to determine the level of radio-frequency radiation generated by base stations, extensive electromagnetic field strength measurements were carried out for 664 base station locations. Base station locations were classified into three categories: indoor, masts and locations with installations on buildings. Having in mind the large percentage (47 %) of sites with antenna masts, a detailed analysis of this location category was performed, and the measurement results were presented. It was concluded that the total electric field strength in the vicinity of base station antenna masts in no case exceeded 10 V m(-1), which is quite below the International Commission on Non-Ionizing Radiation Protection reference levels. At horizontal distances >50 m from the mast bottom, the median and maximum values were <1 and 2 V m(-1), respectively.

Improving the efficiency of measurement procedures for assessing human exposure in the vicinity of mobile phone (GSM/DCS/UMTS) base stations

Standards stipulate 6-min time interval of averaging for measurements of radio-frequency electromagnetic fields to assess human exposure to non-ionising radiation. Having in mind the base stations of public land mobile systems, the time interval defined in such a way noticeably limits the number of measuring points in practical applications. In this paper, based on the results of measurements in the vicinity of a multisystem base station (Global System for Mobile Communications [GSM], Digital Communication System [DCS] and Universal Mobile Telecommunications System [UMTS]), it was shown that the measurement process can be significantly accelerated by using shorter time intervals of averaging--15 s, 30 s and 1 min. It was found that measurement results differed from the 6-min root-mean-square mean by 10.5 %, 15.9 and 19 %, respectively, while the uncertainty of the measurements was increased by 3.0 %, 3.8 and 4.4 %, respectively. Shorter time-averaging intervals would reduce the total duration of the exposure assessment survey, while not compromising too much on measurement quality.

Statistical analysis of electromagnetic radiation measurements in the vicinity of GSM/UMTS base station installed on buildings in Serbia

As a result of dense deployment of public mobile base stations, additional electromagnetic (EM) radiation occurs in the modern human environment. At the same time, public concern about the exposure to EM radiation emitted by such sources has increased. In order to determine the level of radio frequency radiation generated by base stations, extensive EM field strength measurements were carried out for 664 base station locations, from which 276 locations refer to the case of base stations with antenna system installed on buildings. Having in mind the large percentage (42 %) of locations with installations on buildings, as well as the inevitable presence of people in their vicinity, a detailed analysis of this location category was performed. Measurement results showed that the maximum recorded value of total electric field strength has exceeded International Commission on Non-Ionizing Radiation Protection general public exposure reference levels at 2.5 % of locations and Serbian national reference levels at 15.6 % of locations. It should be emphasised that the values exceeding the reference levels were observed only outdoor, while in indoor total electric field strength in no case exceeded the defined reference levels.

Statistical analysis of electromagnetic radiation measurements in the vicinity of indoor microcell GSM/UMTS base stations in Serbia

To determine the level of radiofrequency radiation generated by base stations of Global System for Mobile Communications and Universal Mobile Telecommunication System, extensive electromagnetic field strength measurements were carried out in the vicinity of 664 base station locations. These were classified into three categories: indoor, masts, and locations with installations on buildings. Although microcell base stations with antennas installed indoors typically emit less power than outdoor macrocell base stations, the fact that people can be found close to antennas requires exposure originating from these base stations to be carefully considered. Measurement results showed that maximum recorded value of electric field strength exceeded International Commission on Non-Ionizing Radiation Protection reference levels at 7% of indoor base station locations. At the same time, this percentage was much lower in the case of masts and installations on buildings (0% and 2.5%, respectively).

Comparison of average global exposure of population induced by a macro 3G network in different geographical areas in France and Serbia.

This article is the first thorough study of average population exposure to third generation network (3G)-induced electromagnetic fields (EMFs), from both uplink and downlink radio emissions in different countries, geographical areas, and for different wireless device usages. Indeed, previous publications in the framework of exposure to EMFs generally focused on individual exposure coming from either personal devices or base stations. Results, derived from device usage statistics collected in France and Serbia, show a strong heterogeneity of exposure, both in time, that is, the traffic distribution over 24 h was found highly variable, and space, that is, the exposure to 3G networks in France was found to be roughly two times higher than in Serbia. Such heterogeneity is further explained based on real data and network architecture. Among those results, authors show that, contrary to popular belief, exposure to 3G EMFs is dominated by uplink radio emissions, resulting from voice and data traffic, and average population EMF exposure differs from one geographical area to another, as well as from one country to another, due to the different cellular network architectures and variability of mobile usage. Bioelectromagnetics. 37:382-390, 2016.

Intuitive exposure and risk perception of RF EMF: Case studies Serbia and Montenegro

Results of case studies describing peoples different intuitive risk perceptions of various exposure sources from telecommunication technologies in Serbia and in Montenegro are presented. Furthermore the cognitive link between risk perception and exposure perception of radio frequency electromagnetic fields is analysed. The knowledge about possible exposure features is evaluated and tested in a regression analysis to investigate the impact on lay peoples estimation of the dangerousness of several exposure situations. The results show that participants are more concerned about base stations than about all other RF EMF sources. Moreover, it seems that the knowledge about exposure characteristics is source specific. All in all the results raise doubts whether the knowledge about exposure features plays a crucial role in EMF risk perception.

Improving the efficiency of methods for measurement of electric field strength in the vicinity of public mobile system base stations

The aim of this paper was the efficiency improvement of methods for measurement of electric field strength in the vicinity of base stations, which was achieved in two areas: procedure for using shorter time intervals of averaging (comparing to 6min that standards stipulate) and model for the conversion from mono-axial measurements to isotropic case.

Long-term variability of electromagnetic field strength for GSM 900MHz downlink band in Belgrade urban area

The long-term variability of electric field strength, obtained by band selective measurements for GSM 900 MHz DL band in real mobile network environment, is considered in this paper. Intensive measurements were carried out for 7 days at each of 7 different locations in urban area of Belgrade. The measurement results show that each day can be divided in two distinctive periods: one with the higher levels and (9h-23h) and one with the lower ones (23h-9h). Regarding the days of the week, the results show that the weekend days are slightly different from the working days. Having in mind the need for determination of values averaged over the defined time period, additional uncertainty stemming from telecommunication traffic and transmitter functionalities must be taken into account. Mentioned uncertainty was determined for different time intervals of averaging: 10s, 30s, 1min, 6min, 15min, 30min, 1h, 3h, 5h, 10h, 14h and 24h. Results show that the uncertainty is in the range 3.57 - 12.11% for 6 different categories defined with regards to the days of the week and the specific day periods.

Experimental evaluation of IEEE 802.11e EDCA QoS mechanism for voice over WLAN

Experimental evaluation of QoS mechanism defined in IEEE 802.11e standard is presented in this paper. Measurements were carried out in controlled laboratory conditions, with and without configured QoS. Mean and maximum delay, jitter and packet loss are measured in voice communications between two clients, competing with other voice clients. The results show that QoS mechanism brings significant improvements in the transmission of voice, which is especially significant in the case of highly loaded network.

An analysis of passive relay station with back-to-back antenna for radio coverage improvement inside the buildings

The passive relay station implemented with two back-to-back antennas presents a possible, simple and cost-effective solution to achieve better radio-coverage quality inside the buildings. This paper presents theoretic analysis of the back-to-back solution for such application, followed by the experimental testing of one practical solution through the extensive measurement of achieved radio-coverage characteristics of an existing PMR network inside several electrical transformer station buildings. The measurement results confirmed, to a large extent, the results of the theoretical analysis, and it is concluded that the given solution, under the certain conditions, can be successfully applied for radio-coverage improvement inside the observed and similar type of buildings.