S-MIM offers a low cost though very bandwidth and power efficient solution to send short messages (300, 600, 1200 bits at a user rate of 5 or 10 kbps) via GEO S-Band Satellite with modest power requirements on the terminal side (as low as 0 dBW EIRP). In the FWD link, S-MIM allows reusing any standardised (broadcast) radio interface such as DVB-SH, DVB-NGH, DVB-S/S2, ETSI SDR. The RTN link relies on Enhanced Spread Spectrum Aloha Random Access (E-SSA) derived from 3GPP Wideband Code Division Multiple Access (W-CDMA) technology, properly adapted to the scope. This approach has the twofold advantage of keeping the sender in the terminal very simple whilst ensuring an aggregate MAC Throughput up to ca. 5,5 Mbps per 5 MHz channel thanks to a successive interference cancellation algorithm applied in the demodulator. Moreover, DLR designed a suitable load control algorithm, allowing to maintain the RTN link operational point in the maximum throughput region.
The S-MIM technology is therefore suitable for many application scenarios, including e.g. professional and consumer handhelds, sensor networks and vehicular applications. Within the SafeTRIP project, an early prototype of the S-MIM system was implemented. Besides the validation of the communication subsystem, end-to-end trials and demonstrations involving real applications for the automotive market such as Live TV, Multimedia Datacast, Stolen Vehicle Tracking, Road Safety Alerts, Real Time Tracking of Coaches and many others are currently taking place.