Interference-Free Backscatter Communications for OFDM-Based Symbiotic Radio
Abstract
This study proposes an orthogonal frequency division multiplexing (OFDM) based scheme to achieve interference-free backscatter communications (BC) in a symbiotic radio system. In specific, we propose three frequency shift keying (FSK) based backscatter modulation schemes to shift the primary signal, i.e., the OFDM symbols transmitted from a base station (BS), in the frequency domain to transmit its information. Symbiotically, the BS empties specific subcarriers within the band so that the received frequency-shifted signals from the backscatter device and the primary signal are always orthogonal. The first scheme relies on the combination of on-off keying (OOK) within the FSK modulation while the second and the third schemes are based on the conventional FSK modulation with different in-band null-subcarrier allocation. These schemes allow the use of non-coherent detection at the receiver which addresses the channel estimation challenge for the signals arriving from a backscatter device. We derive the bit-error rate performance of the detector theoretically. The comprehensive simulations show that the proposed approach achieves a lower bit-error rate up to 10-4 at 30 dB with BC by eliminating direct link interference.
Keywords
Cite
@article{arxiv.2408.09192,
title = {Interference-Free Backscatter Communications for OFDM-Based Symbiotic Radio},
author = {Muhammad Bilal Janjua and Alphan Şahin and Hüseyin Arslan},
journal= {arXiv preprint arXiv:2408.09192},
year = {2025}
}