ESA satellite wideband CDMA radio transmission technology for the IMT-2000/UMTS satellite component : features and performance

The recent European Telecommunications Standards Institute (ETSI) decision to endorse for the Universal Telecommunication Radio Access ??? (UTRA) techniques based upon wideband-CDMA approaches for terrestrial UMTS (T-UMTS) paired frequency duplexing band will certainly constitute an important driver to orientate the corresponding choice for the satellite UMTS (S-UMTS) component. In this paper it is shown how a similarity in the S-UMTS access solution not only contributes to making dual-mode user-terminals more cost-effective but also represents a good technical choice. This is despite the fact that the satellite UMTS component faces a number of unique challenging requirements, such as very scarce RF power resources compared to T-UMTS, significant propagation delay, high frequency variations due to Doppler shift (especially for the Low-altitude Earth Orbit (LEO) case), larger cell size. This paper describes the main ETSI UTRA modifications required to obtain an efficient S-UMTS air interface capable of suiting the above listed constraints, while keeping maximum commonality with the T-UMTS. The proposed W-CDMA air interface implements satellite path diversity in both forward and reverse link, burst forward link pilot, blind MMSE forward link interference mitigation, pilot-aided coherent uplink demodulation. The main W-CDMA performance simulation results both at physical and system level are shortly reviewed.