Channel Sounding Waveforms Design for Asynchronous Multiuser MIMO Systems

In this paper we provide three contributions to the field of channel sounding waveform design in asynchronous Multi-user (MU) MIMO systems. The first contribution is a derivation of the asynchronous MU-MIMO model and the conditions that the sounding waveform must meet to independently resolve all of the spatial channel responses. Next we propose a chirp waveform that meets the constraints and we show that the MSE of our system meets the Cramer-Rao Bound (CRB) when the time offset is an integer multiple of the sampling interval. Finally we demonstrate that the channel capacity region of the asynchronous system and synchronous system is equivalent under certain conditions. Simulation results are provided to illustrate the findings. Index Terms Multi-user, MIMO, Asynchronous, Channel sounding, chirp waveform