Space-Time Convolutional Spreading CDMA Systems over MISO Multipath Rayleigh Fading Channels

Abstract

We propose a transmit diversity CDMA scheme which is a combination of convolutional spreading (CS) and space-time block coding over multiple input single output (MISO) multipath Rayleigh fading channels. Using orthogonal space-time block coded CS, we can reduce the communication problem over the multiple-input and multiuser channel to relatively simple communication problem over a single-antenna and single-user system. Similar to the scheme in [5], full transmit diversity gain is achieved, and path diversity gain is achieved as well. For quasiorthogonal space-time block coded CS, we also show that signal-constellation rotation is adopted [16] to achieved the full transmit diversity and path diversity gain.