Poster: Polarization-based QAM for Visible Light Backscatter Communication

Visible Light Backscatter Communication presents an emerging IoT connectivity technology that offers low power and flexible angular alignment benefits. State-of-art approaches with unmodified LCD(s) as optical modulator cause flickering with a sub-kbps low data rate, which would be overcome by modulating polarization, but naive implementation requires careful Tx-Rx placement to avoid signal cancellation. To overcome such challenges, we propose a new modulation scheme called polarization-based quadrature amplitude modulation (PQAM). PQAM constructs the orthogonal basis in the polarization domain and provides 2x throughput gain with arbitrary relative orientation.