In January 1998, the European standardisation body for third generation mobile radio systems, the European Telecommunications StandardsInstitute - Special Mobile Group (ETSI SMG), agreedupon a radio access schemefor third generation mobile radio systems, referred to as the Universal Mobile Telecommunication System (UMTS) [ 11,321. | Third-Generation Systems and Intelligent Wireless Networking . Blogh L. Hanzo Copyright 2002 John Wiley Sons Ltd ISBNs 0-470-84519-8 Hardback 0-470-84781-6 Electronic Chapter UTRA Network Performance Using Adaptive Arrays and Adaptive Modulation Introduction In January 1998 the European standardisation body for third generation mobile radio systems the European Telecommunications Standards Institute - Special Mobile Group ETSI SMG agreed upon a radio access scheme for third generation mobile radio systems referred to as the Universal Mobile Telecommunication System UMTS 11 32 . Although this chapter was detailed in Chapter 1 here we provide a rudimentary introduction to the system in order to allow readers to consult this chapter directly without having to read Chapter 1 first. Specifically the UMTS Terrestrial Radio Access UTRA supports two modes of duplexing namely Frequency Division Duplexing FDD where the uplink and downlink are transmitted on different frequencies and Time Division Duplexing TDD where the uplink and the downlink are transmitted on the same carrier frequency but multiplexed in time. The agreement recommends the employment of Wideband Code Division Multiple Access W-CDMA for UTRA FDD and Time Division - Code Division Multiple Access TD-CDMA for UTRA TDD. TD-CDMA is based on a combination of Time Division Multiple Access TDMA and CDMA whereas W-CDMA is a pure CDMA-based system. The UTRA scheme can be used for operation within a minimum spectrum of 2 x 5 MHz for UTRA FDD and 5 MHz for UTRA TDD. Both duplex or paired and simplex or unpaired frequency bands have been identified in the region of 2 GHz to be used for the UTRA third generation mobile radio system. Both modes of UTRA have been harmonised with respect to the basic system parameters such as carrier spacing chip rate and frame length. Thereby FDD TDD dual mode operation is facilitated which provides a basis for the development of low cost terminals. Furthermore the interworking of .
