Adaptive Detection for Multi-Antenna Ambient Backscatter Communications System With MFSK Modulation

Ambient backscatter communications (AmBC), 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 multi-antenna AmBC system with M-ary frequency shift keying (MFSK) modulation, we propose two detectors: Maximum A Posterior probability (MAP) detector and 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.