Harmonised technical parameters help wireless communications access radio spectrum, unlocking the full potential of 3G and 4G systems. Technical rules enable 2G (GSM mobiles), 3G (UMTS mobile internet) and 4G (LTE/WiMAX high speed broadband) services to coexist in the 900 and 1800 MHz bands.
In 2009, technical studies showed that LTE and WiMAX could safely coexist with the other systems already using the same bandwidth. These studies also clarified the technical conditions under which the systems using the 900 and 1800 MHz bands could protect systems in neighbouring frequency bands, such as GSM for railways and aeronautical services, from interference. Member States are obliged to give appropriate protection to systems in adjacent frequency bands