Editing Mobility management (section)

==Roaming==
[[Roaming]] is one of the fundamental mobility management procedures of all [[cellular network]]s. Roaming is defined<ref>{{Cite book |title=GSM Association Permanent Reference Document AA.39}}</ref> as the ability for a cellular customer to automatically make and receive voice calls, send and receive data, or access other services, including home data services, when travelling outside the geographical coverage area of the home [[Telecommunications network|network]], by means of using a visited network. This can be done by using a communication terminal or else just by using the subscriber identity in the visited network. Roaming is technically supported by a mobility management, [[authentication]], [[authorization]] and [[invoice|billing]] procedures.