Steve Hranilovic


	Dr. Steve Hranilovic
	Research Interests

My primary research focus is on the design of modems for high-speed signalling over wireless optical intensity channels. These optical channels transmit information by modulating and detecting the optical intensity of a laser diode or light-emitting diode. Wireless optical communications provide a high-data rate, low cost, secure link which is free of spectral licensing issues.

My research addresses the modem design problem through theoretical and experimental studies. I develop of communication algorithms, signal processing strategies and information theory to allow for the design of efficient signalling strategies for the wireless optical channel. Additionally, I develop prototype wireless optical links on which practical signalling strategies can be verified and tested under realistic conditions. Several projects that I am currently working on are :

Coding and Modulation for Optical Intensity Channels

Conventional information and communication theories cannot be applied directly to optical intensity channels due to the amplitude constraints of the channel. Some areas in which my research presents new results are:

Signal-Space Models for Optical Intensity Channels
Shaping and Coding Gain for Optical Intensity Lattice Codes
Coded Modulation for Wireless Optical Intensity Channels
Channel Capacity of Wireless Optical Channels
Optical Intensity Multiple-Subcarrier Modulation

Diffuse and Point-to-Point Free-Space Optical Channels

My research also concerns the investigation into the design of signalling strategies for practical wireless optical systems. I am currently investigating the design of wireless optical systems for a variety of applications:

Channel Topologies exploiting Spatial Diversity
Point-to-Point Wireless Optical Links for Chip-to-Chip and Board-to-Board Interconnect
Non-linear Modulation for Multipath-Limited Diffuse Optical Channels

Diffuse and
Point-to-Point Free-Space Optical Channels

Pixelated Wireless Optical Communications

My recent work proposes and develops the pixelated wireless optical channel which transmits information by projecting data-bearing images produced by arrays of millions of optical elements at receiver arrays with millions of pixels. We develop signal processing, communications algorithms and experimental prototypes for this large scale multiple-input/multiple-output (MIMO) channel to exploit the spatial diversity to improve data rate and reliability. Several on-going topics of research in this area are :

Design of Spatial Modulation, Spatial Synchronization Techniques and Spatio-Temporal Codes
Capacity of Multi-Element links
Non-linear Spatial Modulation
Experimental point-to-point pixelated optical channels
Experimental diffuse pixelated channels with high-speed Micro-Electro-Mechanical transmitters and CMOS imagers

Please consult by publications page for more details regarding my research program.