The wireless market has experienced a phenomenal growth since the first second-
generation (2G) digital cellular networks, based on global system for mobile
communications (GSM) technology, were introduced in the early 1990s. Since then,
GSM has become the dominant global 2G radio access standard. Almost 80% of today’s
new subscriptions take place in one of the more than 460 cellular networks that use
GSM technology. This growth has taken place simultaneously with the large experienced
expansion of access to the Internet and its related multimedia services.
