tailieunhanh - Radio System

As stated in Chapter 1, Section , requirements for International Mobile Telecommunications-2000 (IMT-2000) include system flexibility, economy and conditions on data transmission speed defined in numerical terms. The minimum performance requirement in terms of transmission speed is 2 Mbit/s in an indoor environment, 384 kbit/s in a pedestrian mode and 144 kbit/s in a vehicle mode. For the radio system, Wideband Code Division Multiple Access (W-CDMA), which outperforms the stated requirements, was proposed as the air interface, which led to efforts in standardization and system development | W-CDMA Mobile Communications System. Edited by Keiji Tachikawa Copyright 2002 John Wiley Sons Ltd. ISBN 0-470-84761-1 3 Radio System Seizo Onoe Takehiro Nakamura Yoshihiro Ishikawa Koji Ohno Yoshiyuki Yasuda Nobuhiro Ohta Yoshio Ebine Atsushi Murase and Akihiro Hata Radio System Requirements and Design Objectives As stated in Chapter 1 Section requirements for International Mobile Telecommuni-cations-2000 IMT-2000 include system flexibility economy and conditions on data transmission speed defined in numerical terms. The minimum performance requirement in terms of transmission speed is 2 Mbit s in an indoor environment 384 kbit s in a pedestrian mode and 144 kbit s in a vehicle mode. For the radio system Wideband Code Division Multiple Access W-CDMA which outperforms the stated requirements was proposed as the air interface which led to efforts in standardization and system development. IMT-2000 is noteworthy for its global nature more than anything else and strong efforts were made to harmonize multiple competing systems that had been proposed in the standardization process as it was regarded important to develop a globally common air interface to assure the sharing of terminal hardware. As mentioned in Section in Chapter 1 W-CDMA was approved as one of the interfaces in a recommendation by the International Telecommunication Union ITU under which it is referred to as IMT-2000 CDMA Direct Spread. In fact the technology is expected to spread widely in North America Europe and Asia. As for the services one of the major objectives is to provide full-fledged multimedia in the world of mobile communications. The high-speed transmission capability referred to earlier will make this possible. Under IMT-2000 the air interface and the radio system must be able to accommodate various data speeds provide multiple services simultaneously and render efficient Packet-Switched PS services as well as Circuit-Switched CS services. W-CDMA is an effective way to meet