Space-time-frequency coded multiband UWB communication systems
In this paper, we propose a general framework to analyze the performance of multiband UWB-MIMO systems regardless of specific coding schemes. A combination of space-time-frequency (STF) coding and hopping multiband OFDM modulation is also proposed to fully exploit all of the available spatial and frequency diversities, richly inherent in UWB environments. We quantify the performance merits of multiband UWB-MIMO systems in case of Nakagami-m frequency-selective fading channels. We show that the maximum achievable diversity of the proposed system is the product of the number of transmit and receive antennas, the number of multipath components, and the number of jointly encoded OFDM blocks. Interestingly, theoretical result shows that the diversity gain does not severely depend on the fading parameter m.. Finally, simulation results are presented to support the theoretical analysis.