Bandwidth and Power-Efficient Modulations for Multimedia Transmission Over Wireless Links

Project summary:

This project is in the general area of wireless communications, and is motivated by the demand for greater spectral and power efficiency in systems that transmit multimedia information (voice, images, and video) over wireless links. The main objective of the research is to design and evaluate the performance of hierarchical constellation systems, which have the advantage of offering different degrees of error protection and/or different rates for various bit streams. The main research achievements include: 1) development and performance analysis of a variable-rate non-coherent M-FSK modulation scheme for power-limited systems; and, 2) the derivation of the exact bit error rate expressions for a variety of hierarchical PSK and QAM constellations and the investigation of the effect of fading as well as timing and phase synchronization errors. This project also pursues several applications of hierarchical constellations, in particular: 1) for simultaneous voice and data transmission over fading channels; 2) for multi-resolution data transmission; and, 3) for multi-user opportunistic scheduling. The researchers are currently in the process of testing by simulation the multi-resolution transmission of an image over a simulated wireless fading channel.