Spectrum efficiency in universal mobile telecommunication system (UMTS)

This paper addresses some key issues concerning: the efficient use of the spectrum for the Third Generation system. It covers some results of the ongoing work in European fora- in particular UMTS Forum Spectrum Aspect Group - to determine how to make the best use of the UMTS/IMT-2000 spectrum allocated by WARC-92 and how to estimate the additional spectrum needed which could be allocated by the next World Radiocommunication Conference (WRC-99). The Extension ion Bands should be identified to meet the predicted increase in traffic demand by 2010. The Third Generation mobile system will deliver an extensive range of high-performance wide-band wireless and personalised multimedia sen,ices with a better spectral efficiency than the Second Generation mobile systems. UTRA - UMTS Terrestrial Radio Access - the new European radio interface confirms the possibility of better use of the spectrum resources and guarantee the quality of services provided. The increase of the spectrum efficiency could be found in the improvements of the radio transceiver technology, the applications and services technology, the traffic management and the radio channel access management. Some other factors such as: wider channels. Adaptive Antenna Arrays, Hierarchical Cell Structure, Multi-User Detection, fast Power Control are crucial too. Although the technical improvements are essential, if the spectrum is to be used efficiently, it is also critical to ensure the best frequency allocation (high flexibility for operators) and the frequency management at both international and national level.