Asynchronous Wideband CDMA for IMT-2000

This paper presents an overview of the wideband CDMA concept which was chosen in ETSI (European Telecommunications Standards Institute) in January 1998 as a basis for UMTS air interface for FDD (Frequency division duplexing) operation. UMTS is the 3rd generation mobile communication system specified within ETSI. This paper is organized as follows. First, the background of WCDMA is presented in Section II. An overall description of WCDMA physical layer is given in Section III. Logical channels and dedicated physical channels are described in Sections IV and V. Service multiplexing and coding is introduced in Section VI. Common physical channels are presented in Section VII. Asynchronous base station operation is described in Section VIII. Inter-frequency handovers for utilizing hierarchical cells are presented in Section IX followed by an introduction of packet access solution in Section X. In Section XI support for adaptive antennas is considered and conclusions are drawn in Section XII.