Experimental evaluation of non-coherent MIMO grassmannian signaling schemes

Abstract

In this paper, we present an over-the-air (OTA) performance analysis of Grassmannian signaling strategies in an orthogonal frequency-division multiplexing (OFDM) single-user multiple-input multiple-output (SU-MIMO) scenario. Specifically, we compare the Grassmannian signaling technique to the differential Alamouti scheme and a novel space-time non-coherent scheme recently proposed in the context of 5G. As a performance benchmark we include in the comparison the coherent Alamouti scheme. We study the practical impairments associated to frequency synchronization mismatches (frequency offsets), as well as the effects of time-varying channels for different spectral efficiencies. The experimental results show that non-coherent techniques are more robust to the aforementioned impairments than the coherent Alamouti approach, while Grassmannian methods are close to the differential Alamouti scheme with 2 transmit antennas.