Technology that arises out of the laboratory’s research is available for industrial applications. Some of the laboratories technologies available from the laboratory are highlighted below; for additional examples, contact the laboratory. All such technologies can be freely used for noncommercial purposes. If you are interested in licensing any for commercial purposes, please contact either:
Professor Gregory W. Wornell
Professor of Electrical Engineering
and Computer Science
Research Laboratory of Electronics
… or …
MIT Technology Licensing Office (TLO)
Quantization Index Modulation (QIM)| Download QIM reference code: << DOWNLOAD >>
In recent years, there have been a growing realm of applications that require one to embed digital information into some host signal, which may be inherently analog or digital and which is generally not known at the decoder. There is a fundamental tradeoff between the number of bits embedded, the distortion incurred by the embedding process on the host signal, and the robustness with which the bits are embedded. Good information embedding systems make these tradeoffs efficiently. Spread-spectrum systems are examples of information embedding systems that are not efficient, except when the host signal is known at the decoder. Quantization Index Modulation (QIM) systems, by contrast, do achieve the fundamental performance limits in many practical scenarios of interest, particularly when combined with a technique referred to as distortion-compensation (DC-QIM) and error control coding (coded DC-QIM). Moreover, QIM systems can be implemented in a computationally very efficient manner.
At one end of a spectrum, applications of QIM and its variants include digital watermarking, data hiding and covert communication. At the other end of the spectrum, there provide important solutions to problems of backwards-compatible upgrading of existing analog and digital communications infrastructure, and efficient multiplexing of transmissions to different users in multiple-antenna wireless systems.
More information on QIM and its applications can be found in several of the papers and patents listed in the publications section of the web site. Those interested in experimenting with QIM in some application of interest can click on the link below to download the public QIM reference code we are making available below, which can serve as a useful starting point for more sophisticated implementations.