RAN (Radio Access Network) is a domain in cellular telecommunications that deals with how a mobile device or UE (User Equipment) connects back to the Core Network (CN) which manages subscriber information, authentication, location, session and more. The RAN uses RF (Radio Frequency) to connect the UE via a fiber or wireless backhaul to the core network. The RAN is made up of several key elements: antennas, radios and baseband units (BBUs), each playing a significant function. The RAN has evolved from 1G, through 2G, 3G, 4G (LTE) to 5G. LTE and 5G has seen major improvements in the RAN like C-RAN (Centralized-RAN) and MIMO. There are different types of RANs and these include; O-RAN (open radio access network), C-RAN (cloud or centralized radio access network), GRAN (GSM radio access network), GERAN (which specifies the inclusion of EDGE packet radio services), UTRAN (universal mobile telephone system RAN), E-UTRAN (evolved universal terrestrial RAN).
