My general areas of research lie in the areas of signal processing, DSP, digital communications and information theory. In particular these include (but not limited to) the topical areas of adaptive filtering, time-frequency analysis and representations for non stationary signals specifically AM–FM type signals, co-channel signal separation, MAI suppression in multi-user communications, aerial image enhancement in optical lithography. Some of the specific projects that I have been or am currently involved with and the associated students are listed below [PDF]:

• Resolution Enhancement for Optical Nanolithography
  Imaging Interferometric Lithography (IIL), optimum frequency parsing strategies for IIL, error metrics for optimization in IIL, optimal combining of multiple exposures in IIL, pupil filtering, multi-channel image restoration for imaging interferometric microscopy (IIM). This research was associated with CHTM and the MURI project.
  Graduate students: (a) Eric Wu, (b) Mark Tridhavee.
   
• Energy Operators and Energy Demodulation
  Energy separation and demodulation, energy demodulation for large deviations, energy demodulation in noise, multi-component AM–FM signal separation and demodulation, co-channel and adjacent channel signal separation, co-channel-voice speaker separation, algebraic separation of mixtures of periodic signals, estimation of
  multiple periodicities in noise, periodic algebraic separation and energy based demodulation (PASED), energy demodulation of CPM signals, component enumeration for multi-component AM–FM signals using generalized energy operators. Graduate Students : Malay Gupta (department).
   
• Discrete Fractional Fourier Transform
  Fractional Fourier Transform (FRFT), discrete rotational Fourier Transform (DRFT), discrete Fractional Fourier Transform (DFRFT), time-frequency analysis of multi-component chirp signals via the DFRFT, subspace methods for multi-component chirp rate estimation, discrete Wigner distribution, modified spectrogram
  based on the DFRFT, a unified framework for time-frequency analysis of non stationary signals, time-frequency multiplexing, multi-component signal separation, other applications of the DFRFT. Graduate Students: Juan Vargas Rubio (department).
   
• Design of Cost Effective DRFM Systems
  Multi-rate frequency transformations, bandwidth compression and noise shaping, reduced sampling rate requirement for digital radio frequency memory devices, A/D & D/A design for very high sampling rates. Graduate Students : David Boutte (AFRL).
   
• Adaptive IF Tracking and CPM Demodulation
  Adaptive linear predictive frequency tracking, instantaneous frequency and envelope estimation, CPM demodulation, adaptive forgetting factor and variable step-size RLS and LMS algorithms. Graduate students: Malay Gupta
   
• MAI Reduction in DSSS-CDMA
  Adaptive IIR normalized lattice filtering for reduction of MAI in DS–CDMA systems, subspace-MOE based MAI suppression, ICA-based MAI reduction, prior ICA-based MAI suppression, joint MAC and physical layer design for WLAN and structure-less networks, virtual infrastructure (VI) for covering networks with the minimum redundancy and overhead, graduate students: (a) Ryan Shoup, (b) Saeid Taheri, (c) Malay Gupta.
   
• Modulation Classification
  Robust recognition and classification of analog and digital modulation via support vector machines and other machine learning algorithms. Multiuser detection using machine learning approaches, Graduate Students: David Boutte (AFRL).

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