Các mạng UTMS và công nghệ truy cập vô tuyến P1

EVOLVING MOBILE NETWORKS While the history of mobile communications is long [1–3], and the background of mo bile networks therebyx is also long, in this chapter we focus on the historic evolution in terms of network architecture and services starting with 2nd generation (2G) mobile systems. In particular we consider the development of the architecture of Global Systems for Mobile Communications (GSM), since it is by far the most widespread mobile system in the world today.