Global System for Mobile Communications (GSM or also called 2G Network), historically “Mobile Special Group” is the second-generation standard for mobile telephony and the first one where is introduced Data Networking.
The cellular concept originates from the first-generation networks commissioned by the beginning of the 80’s. Each coverage area was a circle of 30 to 50 kilometers as hexagonal area, with a relay antenna localized in the center of each area. Each user in the coverage area had a frequency band allocated to their phone, with a dedicated communication in progress or in idle mode.
Two types of networks are found in Europe, particularly in Belgium, Spain, France, Germany, Italy and Switzerland based on 900 uses the 880-915 MHz band for sending voice or data from the mobile and the 925-960 MHz band for receiving information from the network. In the same context, 850 and 1800 Mhz are used in Ameria and Canada to introduce their first mobile network. The GSM using the 1800 Mhz is called DCS 1800 (Digital Communication System).