Time-coordinated SPAD-based receiver for high-speed optical wireless communication

In an optical wireless communication system (OWC), the single photon avalanche diode (SPAD) can effectively improve the sensitivity of the receiver. However, the inter-slot interference (ISI) distortion and counting losses are inevitable because of the deadtime of the SPAD device. This effect is especially serious when the symbol time is similar than the deadtime. In this work, we propose a time-coordinated SPAD-based receiver scheme that enables multiple time-gated SPADs to reduce ISI distortion and counting losses in the high-speed transmission. The photon counting models and bit error rate (BER) model are established under the effect of ISI to the time-coordinated scheme. The results show that the proposed time-coordinated scheme not only can effectively reduce the ISI distortion and counting losses, but also can significantly improve the signal to noise ratio (SNR) of the receiver. In addition, compared with the free-running SPADs receiver under the same size, the background light tolerance and BER performance of the proposed time-coordinated receiver are better at the high signal power.