Source and channel coding for low-bandwidth speech communication between optoelectronic devices

Abstract

Optical communication is one solution to the communication problem that many military forces face in today's urban environments. The recent advances in optoelectronic fibers by the Photonic Bandgap Fibers and Devices Group allow optoelectronic fibers to be woven into standard military equipment. This thesis aims to design an optical communication system that would be capable of using these fibers. Since this project was undertaken with several collaborators this thesis focuses on the source and coding techniques used for an optical communication system. A freeware linear predictive vocoder developed by Speex was eventually adopted to compress speech to the bandwidth of the optoelectronic fibers. Several channel coding techniques were examined for an optical channel. This thesis describes the pulse modulation technique eventually used. Finally, this thesis explores how the optical communication system can be integrated into standard military equipment.