The cellular or mobile network differs from a communication network in that it uses radio signals as opposed to wires or cables.
It broadly consists of the following elements:
A Baseband Processor is a device in a network interface, such as a mobile phone or a tablet, which manages all the radio functions.
A Cell Site is a cellular telephone site where antennae and electronic communications equipment are placed, usually on a mast, tower or other high place, to create a cell or adjacent cells in a cellular network.
The Backhaul portion of the network comprises the intermediate links between the core network and the small sub-networks.
Radio Network Controller
The Radio Network Controller oversees controlling radio resource and the mobility of the handset. It carries out radio resource management, some of the mobility management functions and is the point where encryption is done before user data is sent to and from the mobile. GSM does not use Radio Network Controllers but Base Station Controllers. Base Station Controllers are network nodes that control the Cell site, manage radio resource, and control the mobility of handset.
The Core Network provides paths for the exchange of information between different sub-networks. It handles voice calls and texts. The packet switched network, on the other hand, handles mobile data.
The Gateway is an entrance point for one network to another network, a network node equipped for interfacing with another network that uses different protocols.
External Networks include the Public Switched Telephone Network, or PSTN, which connects subscribers to the wider telephony network. The Public Land Mobile Network, or PLMN, is a network that is established and operated by an administration or by a recognized operating agency (ROA) for the specific purpose of providing land mobile telecommunications services to the public. The Internet is also an External Network.