Sensor-Aware Dual-Edge Polarity–Position Modulation for Event-Based Optical Camera Communication

Event-based optical camera communication (EB-OCC) uses microsecond event timestamps and asynchronous sensing to reduce the rate and processing limits of conventional optical camera communication. However, most EB-OCC schemes either reuse on–off keying (OOK) or pulse-position modulation (PPM) waveforms, or encode information along a single event-domain dimension. Short-symbol EB-OCC therefore requires a compact waveform that preserves symbol separability under background activity, trailing-event overlap, polarity asymmetry, and short-term sensor memory. This paper proposes dual-edge polarity–position modulation (DE-PPM), which jointly encodes edge position and polarity order using a self-resetting pair of opposite-polarity transitions, together with a sensor-aware receiver trained on data-like symbol observations. A 200cm indoor LED–event-camera link evaluates three four-symbol DE-PPM alphabets using approximately 105 payload bits per configuration and compares them with canonical 4-PPM at equal slot widths. The best alphabet increases the BAR=99% bit-rate threshold from 16,832 to 17,616 bps, the SAR=90% threshold from 19,217 to 25,426 bps, and the maximum empirical mutual-information rate from 16,023 to 19,782 bps. Additional tests under distance, illumination, and optical-axis variations further support the feasibility of DE-PPM.