Researchers at Technical University of Berlin (TU Berlin) needed a flexible SDR system for use in research projects, university teaching and demonstrations, and for experimental evaluation. SDR is a communication system that includes an antenna, front-end Radio Frequency (RF) hardware, and an Analog to Digital Converter (ADC) or Digital to Analog Converter (DAC) — a general-purpose processor where baseband processing takes place.
Typically, general-purpose processors are limited by I/O bandwidth and thus throttle the processing capabilities necessary for implementing an SDR. Gidel developed a multi-platform FPGA system including a highly modular setup of RF components designed by TU Berlin that allowed easy reconfiguration and testing with different module designs.
The system boasted a multi-antenna 2×2 Multiple-Input Multiple-Output (MIMO), high throughput to the host PC interface via PCIe over cable, and a custom dual-channel DAC and ADC interface card to handle multi-GHz sampling rates and GHz-range bandwidth. Most importantly, the system provided adequate memory structure for FPGAs to process the algorithms implemented.
Gidel’s ProcStar II, ProcStar III, and Proc10A FPGA boards provided the SDR system with very large RF bandwidth (250 MHz) due to the large amount of available high speed I/O connections between the FPGA devices and the high-density daughter board connectors. The PROCStar II FPGA board served as carrier board, and was equipped with four Altera Stratix II-180 FPGAs for baseband signal processing. The PROCStar III board powered real-time digital signal processing via a large signal converter daughter board that carried hot-plug-capable RF modules.
State-of-the-art high performance FPGA devices enabled the implementation and experimental evaluation of advanced real time signal processing algorithms for high data rate wireless digital transceivers. “At the time when we developed the concept for this project,” said Dr. Andreas Kortke of TU Berlin, “no other FPGA platform was available that met our requirements to a greater extent than Gidel’s.”
TU Berlin started the project without an existing IP core library or a tool chain for an existing programmable hardware platform, so the university was completely free to select the technology, products, and development tools that promised the best results with respect to system performance at a reasonable level of workload for the programmable hardware.
Gidel’s hardware provided sufficient I/O signals to connect the FPGAs to multiple high-speed ADC and DAC signal converter devices at their software-defined radio daughter board. Gidel’s ProcWizard software design tool enabled hardware and software engineers to work together simultaneously in development, integration, and testing, which delivered a running SDR system with all necessary basic functions in a very short time.
Getting the initial system up and running with on-board memory controllers and the host PC interface relatively quickly allowed TU Berlin to start implementing their custom signal processing early on in the process. The university is now able to improve the SDR system over time based on progressive hardware components and software tool versions from Gidel.