Comparison of SC-FDMA and HSUPA in the Return-Link of Evolved S-UMTS Architecture

Single carrier frequency division multiple access (SC-FDMA), a multiple access technique similar to orthogonal frequency division multiple access (OFDMA), presently features as a strong candidate in the return link of the long time evolution (LTE) of T-UMTS. In the satellite domain there is an emerging research interest in extending mobile broadcasting system architectures that include complementary ground components, in providing bi-directional data services to mobile users. In such ´evolved S-UMTS´ architecture, compatibility with current (CDMA based) and future (OFDMA/SC-FDMA) based) T-UMTS physical layer techniques is of high relevance, if satellite networks are to assume a complementary role to terrestrial ones. In this paper, we first give an overview of SC-FDMA and then compare, via simulations, the performance of the technique with that of the WCDMA-based high speed uplink packet access (HSUPA) that has been defined in release 6 of T-UMTS. The performance evaluations are performed over channels that are representative of the evolved S-UMTS architectures. Emphasis in the study is also given to realistic channel estimation and taking into account the effects of the amplifier´s non-linearity. Other elements addressed in this paper are the impact of linearization techniques, and the pilot channel design in order to achieve robust estimation in the presence of non-linear channels.