Chirp-Based Multi-Device Ambient Backscatter Communication and Sensing Enabled by OFDM–AFDM Symbiotic Radio

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Abtouche K., Uledi F. S., Boudjelal A. A., Janjua M. B., Behdad Z., Cavdar C., ...Daha Fazla

IEEE Transactions on Green Communications and Networking, cilt.10, ss.4117-4131, 2026 (SCI-Expanded, Scopus)

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This paper presents a novel symbiotic radio system for integrated sensing and backscatter communication (ISABC) technique that enables signal-domain interference-free coexistence of the primary communication signal and the backscatter communication (BC) signal within the same spectrum. The proposed system design allows simultaneous backscatter devices (BDs) sensing and data transmission without mutual interference by exploiting waveform-domain orthogonality between orthogonal frequency division multiplexing (OFDM) and affine frequency domain multiplexing (AFDM) signals. Specifically, a chirp-based AFDM waveform is adopted due to its inherent processing gain, which enhances the detectability and reliability of the weak backscatter signal while simultaneously supporting high-resolution sensing. Unlike conventional methods that attempt to suppress only direct-link interference (DLI), this approach embeds the backscatter transmission within the affine frequency domain while maintaining reliable OFDM-based primary communication. Furthermore, by assigning distinct affine-domain shifts to each backscatter device, the proposed framework inherently suppresses inter-backscatter device interference (IBDI). Comprehensive simulation results demonstrate that the proposed coexistence scheme effectively mitigates interference without degrading the primary OFDM bit error rate (BER). The proposed framework achieves an average missed-detection probability (PMD) close to 10-4 at SNR=25 dB for α =1, supports a multi-BD sum-rate of approximately 160 Mbps for 6 BDs with N=512, and provides sub-meter range estimation accuracy under moderate SNR conditions, making it a promising candidate for future low-power and interference-resilient ISABC systems.