Asynchronous Wideband CDMA for IMT-2000
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This paper presents an overview of the wideband CDMA concept that was chosen in ETSI (European Telecommunications Standards Institute) in January 1998 as a basis for the UMTS Terrestrial Radio Access (UTRA) air interface for FDD(Frequency division duplexing) operation. WCDMA is based on the long term European research work and it is developed by contributions from a large number of companies from Europe, Japan and US. The air interface solution is able to offer speech and multimedia services with different transmission rates and service quality requirements. The WCDMA physical layer offers flexible multirate transmission capabilities, service multiplexing scheme and an efficient support of packet access. Continuous transmission is used in the uplink to avoid audible interference problems to other equipment. The physical layer solutions for supporting future multimedia services are presented in this paper. The asynchronous operation of base stations and its consequences on the system design are discussed. Inter-frequency handovers are needed for taking an advantage of hierarchical cell structures and for utilizing the existing 2nd generation cellular networks with a dual mode mobile. In this paper inter-frequency handovers between WCDMA carriers and between WCDMA and 2nd generation systems are presented and utilization of operator’s frequency band is discussed.
Abstract
This paper presents an overview of the wideband CDMA concept that was chosen in ETSI (European Telecommunications Standards Institute) in January 1998 as a basis for the UMTS Terrestrial Radio Access (UTRA) air interface for FDD(Frequency division duplexing) operation. WCDMA is based on the long term European research work and it is developed by contributions from a large number of companies from Europe, Japan and US. The air interface solution is able to offer speech and multimedia services with different transmission rates and service quality requirements. The WCDMA physical layer offers flexible multirate transmission capabilities, service multiplexing scheme and an efficient support of packet access. Continuous transmission is used in the uplink to avoid audible interference problems to other equipment. The physical layer solutions for supporting future multimedia services are presented in this paper. The asynchronous operation of base stations and its consequences on the system design are discussed. Inter-frequency handovers are needed for taking an advantage of hierarchical cell structures and for utilizing the existing 2nd generation cellular networks with a dual mode mobile. In this paper inter-frequency handovers between WCDMA carriers and between WCDMA and 2nd generation systems are presented and utilization of operator’s frequency band is discussed.