Software defined radio-based multi-mode DVB-RCS terminals

The recent increase of multimedia applications lead to the design of new terminals capable of working with different technologies. Software defined radio (SDR), a collection of hardware and software technologies that allows reconfigurable system architectures, should he the solution to the described problems. The new types of terminals that use the SDR technique are called multi-mode terminals. In our study, we intend that a multi-mode terminal is a terminal capable of communicating both with a Bent Pipe (BP) satellite and with an On Board Processor (OBP) satellite. The goal of our work is to plan a satellite system based on the DFB-RCS standard in which the RCSTs are able to adapt itself to the channel state, configuring the transmission chain via software, respecting a QoS constraint on the PER. These considerations bring us to introduce the Supervisor (SPV) element: on the basis of inputs coming from upper layer and from the information on the channel noise power level provided by an estimator, the SPV can adapt it to channel condition producing optimized directives and parametric values to the opportune reconfigurable adaptive blocks. For this purpose, a simplified analysis on satellite channel under Additive White Gaussian Noise (AWGN) has been led out in order to obtain Markov chain model useful to test the SDR platform. In order to model the error characteristic of satellite channel (both uplink and downlink), we employed the "Gilbert-Elliot model" based on two states Discrete Time Markov Chain (DTMC). Finally, a c++ simulation tool has been realized to validate the efficiency of proposed system.