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Semi-coherent detector of ambient backscatter communication for the Internet of Things

We study the semi-coherent detection of a novel communication mechanism, ambient backscatter, where detection-required parameters can be obtained from unknown data symbols and a few pilot symbols. To release dependence on prior knowledge of ambient signals, we propose a type of robust design, called energy detector, with the ambient signal being either complex Gaussian (CG) or phase shift keying (PSK). Detection thresholds, analytical BERs, and outage probability are obtained in closed-form. Interestingly, the CG source would cause an error floor while the PSK source does not, which brings nontrivial indication of constellation design as opposed to the popular Gaussian-embedded literatures. Simulations are provided to corroborate the theoretical studies.