A. Papathanassiou et al., A comparison study of the uplink performance of W-CDMA and OFDM for mobilemultimedia communications via LEO satellites, IEEE PERS C, 8(3), 2001, pp. 35-43
This article presents a comparison study of the uplink performance of two w
ell-known transmission schemes, W-CDMA and OFDM, for mobile multimedia comm
unications via LEO satellites. In order to provide a framework for a fair c
omparison we have considered for both schemes common parameters. including
identical channel bandwidth, coding/decoding algorithms and similar net dat
a rate. The values of these parameters have been appropriately selected in
accordance with the corresponding UMTS system specifications. For W-CDMA, w
e propose a receiver structure that eliminates ISI for both channel estimat
ion and equalization at the LEO satellite. For OFDM, we propose a system th
e design of which is based upon the parameters of W-CDMA for UMTS. For both
schemes appropriate transceiver structures are proposed and analyzed and t
heir performance is evaluated in terms of computer simulation. The design o
f these transceiver structures effectively takes into account the statistic
al characteristics of the LEO satellite channel, so that the overall system
performance is improved. The simulation results evaluating the uplink BER
performance for a single user indicate that, although the BER performance o
f W-CDMA is slightly better than that of OFDM, the performance differences
are rather small. Furthermore, these differences in performance become even
smaller when channel coding is applied and when LOS conditions between the
mobile terminal and the LEO satellite exist. Since these results have not
shown a clear-cut winner, further comparative studies are required in order
to identify the most appropriate transmission scheme for applications supp
orting global mobile multimedia communication via LEO satellite networks. S
uch studies should include determination of the downlink EER performance as
well as spectrum efficiency and capacity performance evaluations fur both
up and down satellite communication links.