A New Transmit Diversity Technique for FSK Exploiting its Orthogonality

We propose a new transmit diversity technique for frequency shift keying (FSK). The main idea behind our proposed scheme is to exploit the orthogonality between FSK carriers in order to render signals transmitted from different antennas orthogonal at the receiver, which results in full diversity. Since the proposed scheme achieves antenna orthogonality within one time unit while the well-known Alamouti space-time block code (STBC) needs two time units, it succeeds to be more robust against time-selectivity of the channels than the STBC without deteriorating peak-to-average power ratio (PAPR) of the signal. Simulation demonstrates that the proposed scheme has an error floor that is ten times lower than the STBC over time-selective channels.