Empirical Analysis of Electric Field Strength Long-Term Variability for GSM/DCS/UMTS Downlink Band

Abstract

The long-term variability of electric field strength, obtained by band selective measurements for GSM 900MHz, DCS 1800MHz and UMTS 2100MHz downlink band in realistic mobile network environment, is considered in this paper. Intensive measurements were carried out for 7 days at each of 7 different locations in an urban area of Belgrade. The measurement results show that each day can be divided into two distinctive periods: one with higher levels of electric field (9h-23h) and one with 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 falls within a range of 4.04 – 12.11% (GSM), 2.71 – 7.92% (DCS) and 4.69 – 14.69% (UMTS), for 6 different categories defined with regard to the days of the week and the specific day periods.

Keywords

• electromagnetic fields
• GSM
• DCS
• UMTS
• base station
• human exposure
• long-term variability
• measurement uncertainty