Pulsed multi-band MIMO for UWB systems

This paper provides a solid mathematical framework for pulsed multiband MIMO UWB systems. In this regard a novel multiple-input multiple-output (MIMO) technique for pulse based UWB systems is proposed that exploits multi-band UWB signals for improved performance. Each transmit antenna utilizes a different band for the transmission of the signals. A RAKE receiver is employed that captures energy from sequences transmitted from L transmit antennas at M receive antennas for each of K resolved multipath components. Higher gains in diversity per resolved multipath are achieved with the proposed system than in previously considered zero forced MIMO systems [1] resulting in significant performance enhancement. Diversity gain per path is found to be M for the proposed system as opposed to M-L+1 for the zero forcing alternative. Less antennas and/or less combined RAKE paths are therefore required for a certain level of performance. The advantage of utilizing such multiband signaling in a MIMO system are evident from simulated and theoretical results of the system in a simple practical lognormal fading channel developed for the theoretical analysis. Analytical error expressions are also found for the systems presented in this channel model.