Orthogonal signaling over fast fading channels

This paper analyzes the performance of a system consisting of a central base transmitter transmitting to a group of mobiles with on-off orthogonal modulation over a fast fading channel. Because the channel is changing across the symbol interval, inter-code interference appears at the output of each user´s matched filter. The cumulative distribution function at one user´s matched filter output is derived. From this distribution, a metric is introduced to evaluate which pairs of codes lead to the most severe inter-code interference for a particular fading spectrum.