Multiuser Detection for S-UMTS and GMR-1 Mobile Systems

Application of multiuser detection (MUD) techniques to current and to-be deployed mobile communication systems is currently under study within the scientific and industrial communities. In this paper, we dwell on the applicability of successive interference cancellation (SIC) and turbo spatial minimum mean squared error-interference cancellation (turbo SMMSE-IC) to a CDMA and a TDMA mobile satellite system (MSS), i.e. S-UMTS and GMR-1, which provide seamless service and coverage extension to their terrestrial counterparts: UMTS and GSM. The adoption of MUD techniques for these two systems turns out to be instrumental for achieving the required high spectral efficiency, but also very challenging due to the peculiarities of the MSS environment. Performance of the two techniques is evaluated considering correlated Rician fading, non-linear distortion introduced by high power amplifiers, and residual parameter estimation errors. Our results show that MUD techniques allow to largely increase MSS throughput: in S-UMTS a number of users as large as twice the spreading factor can be sustained, while a full frequency reuse can be adopted in GMR-1