Spatial Modulation and Differential Spatial Modulation for Ambient Backscatter Communication Over Linearized Channel

Multiple-input-multiple-output (MIMO) ambient backscatter communication (ABC) is emerging as one of the promising techniques to combat the deeper fading effects offered by the backscatter link. Based on earlier studies, multiple-antenna backscatter setup has been exploited to ensure lower bit error rate (BER) performance and higher spectral efficiency (SE) with the utilization of spatial modulation (SM) in ABC systems, but its investigations in the literature have assumed that the perfect channel state information (CSI) is available at the Reader, which is practically unreasonable. In an attempt to retain the key feature of SM and eliminate the need for a channel estimation block, this paper takes the first step in establishing a preliminary study of the Differential Spatial Modulation (DSM) scheme in MIMO ABC systems, which interestingly enough exploits a newly set of linearized MIMO ABC channel for its implementation. Simulation results verify that the computational complexity of the proposed DSM backscatter scheme achieves 53% lower in comparison to the SM backscatter scheme over the linearized channel model for a 2 x
$R$
MIMO ABC system, where
$R$
indicates the number of receive antennas at the Reader.