The Global System for Mobile Communications (GSM) which is a standard for 2G (second
generation) cellular networks has created an avenue for the development of 3G (third generation) and
4G (fourth Generation) cellular network standards such as Universal Mobile Telecommunications
System (UMTS) and long term evolution (LTE). With the deployment of new technologies still on the
way, the era beyond 3G and 4G requires that cellular and radio technologies need to work together
forming highly heterogeneous networks, therefore this paper analyses already existing cellular
network technologies such as LTE, GSM and UMTS in order to give a general understanding of their
architectures, functional and evolutional dependencies and also to provide an evolutionary trend and a
clear overview of the support provided for other telecommunications infrastructure.