SOURCEFORGE » RALF » 2016 Channel emulation for satellite communications

h1. Introduction II

The purpose is to reproduce the satellite channel emulation at RF level in the Satcom lab. The transmission link will be influenced as in a real environment. In the case of the channel emulator developed in the geo satellite system, the channels totally include the links from a terrestrial station, via a transparent satellite and finally to another terrestrial station. Therefore, it is important to consider all these aspects in the channel.

In general, hardware-based satellite channel emulators are around 100k euros on the market thus it is too expensive for the common customers. Compared to a realistic environment, the advantage to reproduce the channel through emulation is much less costly. In fact, it is possible that the total price of the instruments is around 5k euros with controllable features of emulations in the lab. Another motivation to carry out the emulation is related to the bandwidth, given that, the bandwidth for the common satellite emulations on the market is up to 600MHz while it is accessible to reproduce it with only 5MHz.

As far as satellite emulation is concerned, it is increasingly significant to use the FPGA (Field Programmable Gate array) as a resource of software-define radio system (SDR). This implementation technology provides important advantages with higher performances, such as higher design flexibility and lower cost per channel. On the one hand, another advantage of using SDR is the lower cost, which is an around 8k euro.  On the other hand, it contains highly extensible features for signal processing which can be programed in the lab computer, and corresponds to the lab environment.

The next chapter introduces the architectures and devices of the project, including the NI hardware and LabVIEW software.