Dr. Marcelo S. Alencar
Federal University of Campina Grande, Brazil
Title: Modulation Diversity to Control the Effects of Fading in Wireless Channels
Biography
Biography: Dr. Marcelo S. Alencar
Abstract
The wireless channel suffers from attenuation and multipath fading, which result from multipath transmission, and also from propagation effects, that include reflection, diffraction and scattering. Multipath fading is a major cause of performance degradation in mobile communications systems. Modulation diversity is a bandwidth-efficient diversity technique that consists of the rotation of a digital signal constellation, associated with the interleaving between the in-phase and quadrature components. It is intended to reduce the effects of fading in wireless communications. In this presentation a scenario is considered in which multiple paths are simulated, with associated random multiplicative noise and delay. The evaluation of the multipath fading effect in this scenario is done by comparing BER values for 4-PSK and 8-PSK transmissions, to obtain the gain provided by the modulation diversity. An analysis of the optimum rotation angle is provided, which consider several multipath scenarios, and include cases with a more severe fading effect.