Bandwidth-efficient exploitation of the degrees of freedom in a multipath fading channel

Multipath propagation effects encountered in mobile wireless channels provide additional degrees of freedom that can be exploited via appropriate signaling and reception. In this paper, we propose a framework for spread-spectrum signaling and reception that allows manipulating these inherent degrees of freedom for maximum bandwidth efficiency. We present a simple approach for transforming a multipath channel with a single transmit and single receive antenna into a virtual multiple-input multiple-output system where space-time codes can be directly applied. Performance analysis suggests that simple signaling schemes based on our framework can yield significant capacity gains over existing spread spectrum systems