Spectrum-Sharing Ambient Backscatter Communications With Multiple Tags: Signal Detector Analysis, Design, and Implementation

This work focuses on joint signal detection problem in spectrum-sharing multi-tag ambient backscatter communication (AmBC). Bit error rate (BER) bounds for the optimal maximum-likelihood (ML) detector are derived via pairwise error probability (PEP) analysis and validated through simulations. To reduce complexity while preserving performance, a residual-guided iterative error correction mechanism is incorporated into linear detectors. Simulations show that the proposed approach closely matches ML performance with significantly lower complexity. Experimental results from a hardware testbed demonstrate reliable three-tag concurrent transmission over 13 meters, confirming the practical effectiveness of the method.