Area Communication Systems

Communication Systemsand Signal Processing: 

Communication Systems and Signal Processing

Direct Sensor-to-Satellite Linkfor Sensor-Detected Activities : 

Direct Sensor-to-Satellite Link for Sensor-Detected Activities Faculty: A. Zaghloul Theses are in preparation by: Erica Lau and Mohammad Al-Saleh Description: Information on terrorist/enemy activities related to seismic, nuclear, chemical or thermal data are picked up through randomly located and camouflaged micro-sensors. Information is coded and relayed to satellites with miniature, continuously scanning phased arrays. Objectives are to prove the concept by analysis and parametric studies and develop the model for the sensor package that includes miniature phased array that uses MEMS or MMIC components, CDMA modulator, upconverter, power and control subsystems. System Concept Sensor Package

Robust Suppression of Impulsive Noise in Cellular Communications: 

Robust Suppression of Impulsive Noise in Cellular Communications Faculty: Lamine Mili Funding: Lockheed Martin Description: Developing robust methods to detect and suppress impulsive noise (“clicks”) using LPC synthesis and robust Kalman filtering in wireless communications (cellular). Read more: M. Gandhi et al., “Robust Methods for Impulsive Noise Suppression in Speech”, IEEE Symposium on Signal Processing and Information Technology, Dec. 2005

Ultra-Wideband Communication Systems: Spectrum Overlay Issues: 

Ultra-Wideband Communication Systems: Spectrum Overlay Issues Faculty: Claudio da Silva Description: Analysis of the effects of narrowband interference for ultra-wideband systems, including signal acquisition, channel estimation, and multipath combining. Development of interference mitigation techniques for UWB transceivers. Read more: C. R. C. M. da Silva and L. B. Milstein, “The Effects of Narrowband Interference on UWB Communication Systems With Imperfect Channel Estimation,” IEEE JSAC, April 2006.

Faster Mitigation of NB Interference: 

Faster Mitigation of NB Interference Faculty: A. A. (Louis) Beex Collaborating with: J. R. Zeidler at UCSD Description: We are analyzing the beneficial effects of alternative structures for adaptive algorithms; one such benefit can be faster convergence (by several orders of magnitude). Read more: A. Batra, J.R. Zeidler & A.A. Beex, “Mitigation of Unknown Narrowband Interference Using Adaptive Equalizers,” EUSIPCO, Florence, Italy, 4-8 September 2006.

Game Theory and Interference Avoidance: 

Game Theory and Interference Avoidance Faculty: A. B. MacKenzie, R. M. Buehrer, and J. H. Reed Student: R. Menon Description: We have developed game theoretic models of spread-spectrum interference avoidance (IA). These models enable new IA techniques which are uniquely applicable to ad hoc networks. Read more: R. Menon, et. al. “A Game-Theoretic Framework for Interference Avoidance in Ad Hoc Networks,” to appear IEEE Globecom, 2006.

Transmit Pre-coding for Ultra-Wideband Communication Systems: 

Transmit Pre-coding for Ultra-Wideband Communication Systems Faculty: R.M. Buehrer Sponsor: ONR Description: UWB channels are very rich in multipath. With link feedback this rich multipath can be exploited to provide large performance gains (akin to transmit beam-forming) even with noisy channel estimates Read more: J. Ibrahim, R. Menon, and R.M. Buehrer, “UWB Signal Detection Based on Sequence Optimization for Dense Multipath Channels,” IEEE Communications Letters, vol. 10, no. 4, pp. 228-230, April 2006.

Ultra Wide Band Ranging for Unloading Ship Cargo: 

Ultra Wide Band Ranging for Unloading Ship Cargo Faculty: R.M. Buehrer, A. Nayfeh, with support from W.A. Davis Funding: ONR Description: Develop an UWB based system that will allow fast and smooth loading/unloading of cargo crates from ship to ship or ship to dock. Status: A proposed system was developed and demonstrated using a 1/24 scale crate and crane.

Location Positioning of Non-Active Objects Using Ultra-Wideband Radios: 

Location Positioning of Non-Active Objects Using Ultra-Wideband Radios Faculty: Claudio da Silva and R. Michael Buehrer Description: we are developing indoor location positioning method for non-active objects (that is, objects that do not transmit radio waves) using off-the-shelf ultra-wideband radios. Read more: W. C. Headley, C. R. C. M. da Silva, and R. M. Buehrer, “Indoor Location Positioning of Non-Active Objects Using Ultra-Wideband Radios,” IEEE RWS 2007.

UWB Position-Location Networks: 

UWB Position-Location Networks Faculty: R. Michael Buehrer Funding: NSF, ONR Description: We are developing ultra-wideband position-location networks, capable of fusing low-data rate communications with accurate localization in dense multipath environments, especially indoors. Applications of such networks include tracking of fire-fighters, military personnel and robots in remote or hazardous locations. Read more: S. Venkatesh et al., “Multiple-Access Design for UWB Position-Location Networks,” IEEE Wireless Communications and Networking Conference, March 2005.

Wireless Vital Signs Monitoring : 

Wireless Vital Signs Monitoring Faculty: R. Michael Buehrer Funding: IR&D Description: We are developing UWB-based radar system which is capable of monitoring breathing and heart rate for multiple individuals. System tracks small repetitive changes in the multipath profile in specific frequency bands to estimate heart and chest cavity motion. Applications include home health monitoring, disaster relief, in-transit vital signs monitoring, etc. Read more: S.Venkatesh, C.R. Anderson, N.V.Rivera and R.M. Buehrer, “Implementation and Analysis of Respiration-Rate Estimation using Impulse-based Ultra-Wideband,” IEEE Military Communications Conference MILCOM2005, Atlantic City, NJ, October 2005.

Nonlinear Effects in Adaptive Filtering: 

Nonlinear Effects in Adaptive Filtering Faculty: A. A. (Louis) Beex Collaborating with: J. R. Zeidler at UCSD Description: We are analyzing the beneficial nonlinear behavior of adaptive filtering algorithms in a wide range of applications and looking for practical scenarios with performance benefit. Read more: A.A. Beex & J.R. Zeidler, “Steady-state dynamic weight behavior in (N)LMS adaptive filters,” Least-Mean-Square Adaptive Filters, eds. S. Haykin & B. Widrow, Hoboken: John Wiley, 2002. Adaptive Equalization Example

Signal Processing on FPGA: 

Signal Processing on FPGA Faculty: A. A. (Louis) Beex Description: Maximizing DSP capability and flexibility for adaptive processing by maximizing the signal processing tasks executed on the Field Programmable Gate Array (FPGA). This kind of optimization is critical for applications with limited (legacy, space, etc) computational resources.

Graphical Inferencing Techniques for Joint Separation, Equalization, Synchronization, and Decoding : 

Graphical Inferencing Techniques for Joint Separation, Equalization, Synchronization, and Decoding Description: We are developing graphical modeling and inferencing algorithms to efficiently solve the unified receiver design problem. Faculty: L. Mili, A. Zaghloul Student: R. Taylor, Sponsor: MITRE Simple example: Forney-style factor graph of an asynchronous two-user multiple access channel with 3-tap impulse responses and (7,4,3) Hamming-coded sources. http://filebox.vt.edu/~rmtaylor/Graphical_Modeling/graphical_modeling_references.html