Sponsored by: USNA
Project Duration: Ongoing
Cognitive radios are an emerging technology that promises greater efficiency in utilizing the available wireless spectrum. In particular, spectrum-sensing cognitive radios provide the ability to search for and utilize an unoccupied portion of the wireless spectrum during periods of time when the incumbent user is inactive. A key requirement to operating cognitive radios, therefore, is accurately and reliably identifying unutilized frequency bands, even when those bands may contain extremely weak signals.
In this project, we are investigating and characterizing spectrum occupancy between 700 MHz and 6 GHz, with an emphasis on recording signals with an RSSI of -120 to -130 dBm, a range which is 10 - 30 dB below values that have been previously reported. Analysis of the measurement results indicate that spectrum utilization increases exponentially as the receiver's noise floor decreases and that spectrum utilization does not show any obvious characteristics which might be associated with the choice of location. Analysis of the average available bandwidth in a given frequency range demonstrates that as the noise floor of the receiver decreases, the bandwidth available to the cognitive radio is severely diminished.
Sponsored by: DoD
Project Duration: August 2007-August 2008
The objective of this project is to design a cooperative/collaborative communication scheme to relay information from ground-level sensors to personnel traveling in the area as well as or to command & control centers. The communication scheme must be capable of operating in the presence of jamming and interference, and must be able to relay data in a timely manner. Achieving low latency, high reliability, and robust operation of the communication link are highly desired features.
Sponsored by: National Science Foundation
Project Duration: September 2007-June 2008
The objective of this workshop is to bring together hardware, software, and communications theory engineers from academia, industry, and government to advance multi-disciplinary collaborative research and development across all aspects (physical layer, software, framework, algorithm, and education) of software defined radios (SDR). Our efforts will be focused on creating an open-source architecture for SDR that can be reviewed, edited, and improved by all members of the SDR community. This workshop will also serve as a forum to bring together researchers from around the world in order to facilitate international collaboration on SDR research and development.
Sponsored by: National Science Foundation
Project Duration: May 2007-Present
Over the past decade, research and development in wireless sensor networks has investigated novel and exciting applications for a number of different scenarios. Impulse ultra wideband (UWB) communications promises a number of benefits for use in wireless sensor networks–particularly in forest environments where it can provide robust operation along with the ability to combine communications with precision position location. This research effort involves performing UWB propagation measurements and deriving empirical models for four different forest environments: light brush, light, medium, and dense forest. Initial results indicate that UWB signals experience Rician fading, with K-factors in the range of 8-24 dB. Ongoing efforts involve characterizing a larger number of forest locations, as well as investigating the fading of individual multipath components.
Sponsored by: Office of Naval Research
Project Duration: January 2005-June 2006
This project developed an advanced Software Defined Radio (SDR) which can take advantage of the unique properties of Ultra Wideband communication—such as precision position location, ranging, and low probability of intercept—for Navy applications. The UWB SDR receiver utilizes a Time Interleaved Sampling approach using an array of ADC converters along with a Xilinx VirtexII Pro FPGA. The receiver supports a wide variety of UWB modulation and multiple access techniques, and can also be reconfigured to operate using more traditional broadband communication schemes. Additionally, several design features, such as a data capture mode, have been incorporated into the receiver design to support research efforts into UWB MIMO communications and precision ranging and position location.