Adaptive Detection for Multiantenna Ambient Backscatter Communications System With MFSK Modulation

Ambient backscatter communications (AmBCs), which utilizes ambient radio frequency (RF) signal for communications, is a promising technology for Internet of Things (IoT) with stringent power-and-cost constraints. To address the issue of jammer attacking a multiantenna AmBC system with
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-ary frequency shift keying (MFSK) modulation, we propose two detectors: 1) maximum a posterior probability (MAP) detector and 2) energy-threshold determination (ETD) detector, which are considered for the frequency spectrum of the jammer overlaps the passband of filters or not. Simulation results demonstrate that implementing multiple antennas and higher-order modulation can enhance the system performance. Moreover, when the frequency spectrum of the low-power jammer does not overlap with the passband of the filters at the receiver, the MAP detector performs better, conversely, the ETD detector outperforms the MAP detector.