GSM standard (Global System for Mobile Communication) is, at the present, the most extended public mobile communication system of the second generation (2G), which has almost global coverage [28], [29]. GSM standard uses for creation of multiple accesses the combination of FDMA and TDMA technology (frequency division and time division multiple access) where one carrier signal is divided in time domain to eight time slots. Combination of frequency duplex and time duplex (FDD/TDD) is used for assurance of the duplex transmission and for uplink (from mobile to base station) and downlink (reversal way) directions separation. The width of channels is 200 kHz. Two frequency bands are devoted to GSM system, with width of 25 MHz (890 – 915 MHz for downlink and 935 – 960 MHz for uplink), i.e. the system provides up to 124 FDMA channels or 992 transmission channels. Between upper and lower band is the guard band, but this band is usually not used. Besides GSM 900 standard, the standard called GSM 1800 (before DCS 1800) is also used in Europe. GSM 1800 is a derivate of GSM 900 standard and it is used as a complement system of GSM 900 for providing the huge intensity traffic in hot spots (shopping centers, administrative centers, bus and railway stations, airports and moreover).