Abstract
This thesis considers the physical layer performance of the Satellite High Speed Downlink Packet Access (S-HSDPA) system via ground based relays or intermediate Module Repeaters (IMRs). The work evaluates the modifications needed for the terrestrial HSDPA system to a satellite architecture by change of certain significant parameters within a high dispersive IMR environment to deliver high data throughput to satellite mobile terminals. Initial results for S-HSDPA with different terminal capabilities and modulation formats have been obtained. Two diversity techniques, namely receive antenna diversity and space time transmit diversity (STTD) were also investigated. The impact of increasing the number of multicodes transmission for the S-HSDPA system has also been considered. In all of these results, we have shown the capacity to be insufficient to support an economic operational system. In order to investigate improved capacity we have analyzed two advance receiver techniques using channel equalizers and multipath interference cancellers. The performances of two low complexity chip-level adaptive equalizers (CPICH NLMS equalizer and Griffiths' equalizer) equalizer) and the multipath interference canceller (MPIC) have been compared with the conventional RAKE receiver for the S-HSDPA system in an IMR environment. It has been shown that the equalizers can increase the throughput in comparison to the conventional Rake receiver while incurring minimum additional complexity. Thus it is concluded that advanced terminal receivers will be necessary in any practical satellite system. Finally, a study of the orthogonality factor (which parameterizes the intracell interference), as a crucial parameter in the calculation of downlink satellite power has been performed in the IMR environment. Results of the orthogonality factor are presented for multicode S-HSDPA transmission for simple receivers and the use of receive antenna diversity. Using the equalizer based receivers it is shown that the orthogonality factor statistics can be significantly lowered as compared to the conventional matched filter receiver.