A FLEXIBLE MF-TDMA MODEM FOR AN IP-BASED SATELLITE COMMUNICATIONS SYSTEM
- Paper ID
IAC_03_M_2_07
- author
- company
Joanneum Research
- country
Austria
- year
2003
- abstract
In the framework of ESA‘s ARTES-5 program the Institute of Applied Systems Technology (Joanneum Research) in cooperation with the Department of Communications and Wave Propagation has developed a novel meshed satellite communications system which is optimised for Internet traffic and applications. Both symmetrical and asymmetrical connections are supported. Bandwidth on demand and guaranteed quality of service are key features of the system. For the transmission subsystem an MF-TDMA modem using Field Programmable Gate Arrays (FPGAs) was developed. A “software radio” approach was adopted minimising the hardware requirements and offering the potential for reconfigurable and adaptive transmission systems. Advanced synchronisation algorithms have been successfully developed and implemented which allow to operate at low signal-to-noise ratio, even with short synchronisation sequences. Thus, the availability of the system is significantly improved without increasing the EIRP or G/T parameters. A powerful forward-error correction system based on low-complexity Turbo codes was implemented entirely in software, allowing to adapt the parameters easily. The system architecture of the MF-TDMA modem and results of the simulations of the system, in particular the enhanced synchronisation, are presented.