Tag Archives: FPGA

Wireless@CU – Prototypes

GENI Cognitive Radio Platform

The GENI Cognitive Radio Platform is an active development project that involves ground-up design and deployment of a highly programmable, frequency agile, multi-FPGA, wideband cognitive radio which will be connected to the GENI testbed framework. The basic idea behind this initiative is to make the platform accessible to other researchers using internet to run cognitive radio experiments in a realistic network. CU has teamed up with Rutgers University and Radio Technology Systems in this initiative to build this next generation testbed of cognitive radios.

Following is a demonstration of the latest version of the radio, which can be tuned from 100MHz to 7.5GHz.

GENI Cognitive Radio Prototype- version 1

The earlier version of the radio had the following features:

  • Virtex5-LX50 FPGA – Acts as the motherboard for the baseband OFDM design and ADC/DAC and RF daughter cards.
  • 100Mbps Ethernet to send control and data packet to and from the radio board.
  • Tunable to 2.4GHz and 5GHz ISM band.
  • Complete design and implementation of the OFDM pipeline is done using a combination Xilinx System Generator and ISE tools.
  • Design capabilities include – Non-contiguous OFDM with fine grain control over modulation and bandwidth.
  • Full transmit receive path implemented for OFDM based 802.11a/g packets.
  • Backward compatible with standard off the shelf Wi-FI cards.

We will continue to work on improving the prototype and add new features to achieve the ultimate goal of being a part of a global network testbed.

Nallatech XtremeDSP/Fidelity Comtech SDR

SDR prototype using Nallatech/Fidelity Comtech front-end

Prior to the GENI initiative, wirelesss@CU had been involved in development of basic software defined radio capable of demonstrating frequency agile techniques. The basic SDR was built as a hybrid design with partitioning of DSP algorithms into software and hardware components providing high flexibility as required in SDRs and cognitive radio. The development was carried out using a Nallatech XtremeDSP-IV kit with high speed ADC/DAC chip allowing wideband designs along with a RF front-end box that operates in the 2.4GHz.

Since its deployment in 2007-08, the prototype has been used in various experiments and resulted in a number of publications in the field of  wireless networking, cognitive radio and radio architectures.  Please refer to the publication list under various projects within the wireless@CU research group for more details on the design and development of the SDR prototype.


Wireless Networking Research

Non-Contiguous OFDM

Spectrogram using Non-Contiguous OFDM

Wireless networks provide data networking for more people than any other network technology. At Colorado, we’re focused on technologies that allow software defined cognitive radios to enhance spectrum use. Our research focuses on prototypes, technical mechanisms and analysis. We’ve developed a series of prototype systems based on FPGA’s for signal processing. We have developed a sophisticated software stack that lets us easily manipulate an OFDM waveform for real-time, high-bandwidth application.Earlier systems used devies from Nallatech and Fidelity Comtech. We’ve also done substantial work towards investigating the efficacy of directional and phased-array antenna technology in optimizing wireless networks and adhoc unmanned aerial networks, have developed more robust and realistic simulation techniques, and have done some work towards investigating coverage mapping strategies for large area wireless networks.

Active Projects

Hardware & Systems

  • NallaTech/Fidelity Comtech Software Defined Radio
  • GENI Cognitive Radio
  • Directional Antenna Radio

Recent Publications

  • Eric Anderson, Caleb Phillips, Douglas Sicker, and Dirk Grunwald. Signal Quality Pricing: Decomposition for Spectrum Scheduling and System Configuration. IEEE Dynamic Spectrum Access Networks 2011 (DySPAN2011). Aachen, Germany. May 3-6, 2011.
  • Aveek Dutta, Dola Saha, Dirk Grunwald, Douglas Sicker, SMACK – A SMart ACKnowledgment Scheme for Broadcast Messages in Wireless Networks,  ACM SIGCOMM, Barcelona, Spain, August 2009
  • Eric Anderson, Caleb Phillips, Douglas Sicker, and Dirk Grunwald. Modeling Environmental Effects on Directionality. Mathematical and Computer Modeling Journal. Special Issue on Modeling and Simulation of Wireless Networks. June, 2010. Elsevier.
  • Caleb Phillips, Douglas Sicker, and Dirk Grunwald. Bounding the Practical Error of Path Loss Models in Urban Environments. IEEE Dynamic Spectrum Access Networks 2011 (DySPAN 2011). Aachen, Germany. May 3-6, 2011.