Penn State used Simulink® to design, develop, and simulate SDR prototypes for the satellite ground station. Simulink, together with a Lyrtech SignalMaster system to digitize and process signals, provided them with a comprehensive development environment for the LionSat project. Because of the computational requirements of the algorithms, the prototype included a combination of TI DSPs and Xilinx FPGAs.
Using MATLAB® and Simulink with related toolboxes and blocksets, Bilén and his team explored different algorithm options, optimized system parameters, and evaluated design trade-offs.
“MathWorks tools helped us to move from floating point to fixed point to get an accurate representation of the hardware,” says Jerker Taudien, a student involved in the SDR projects.
They used Simulink Coder™ to generate code for the embedded DSP, a TI C6000™. Using Xilinx System Generator, they generated VHDL code from their Simulink models without any manual coding.
Taudien used Embedded Coder® to verify and debug their code on the DSP. He also used Communications Toolbox™ to generate simulated modulated signals to debug and verify the systems.
MATLAB enabled Taudien to determine filter coefficients. He explains, “It was very easy to change filter responses with MATLAB. It also helped me plot data and visualize frequency variations.”
“In the next few months, we will validate our designs using real data,” says Bilén. “I’m confident that everything will work as planned.”
Penn State is currently planning an end-to-end communications test. If issues arise, the development environment will enable the team to quickly update the system.
Bilén is also planning to teach a special topics course on SDR, in which students will use Simulink to learn and apply SDR techniques on different SDR platforms.
“SDR opens opportunities for aspiring communications engineers,” Bilén says. “By using a high-level environment such as Simulink, I can focus the course on SDR architecture and applications, rather than the nitty-gritty of VHDL. This will also enable students who come with an electromagnetics and RF background, as I do, to get as much out of the course as those with a signal processing background.”