Time-selective signaling and reception for multipath fading channels

Diversity techniques provide a powerful approach to combat fading. Due to the presence of multipath and Doppler shifts, the mobile wireless channel inherently provides diversity that can be exploited using appropriate signaling and reception. While existing CDMA systems exploit only multipath diversity using spread-spectrum signaling, we develop signaling and reception schemes that exploit joint multipath-Doppler diversity. Significant performance gain can be obtained even for the small Doppler spreads encountered in practice. Additionally, the time-selective signaling scheme allows for substantially higher level of diversity and thereby brings the fading channel closer to an additive white Gaussian noise channel. This facilitates the use of error control codes developed for the Gaussian channel.