Time-Gated Photon Counting Receivers for Optical Wireless Communication

TL;DR

This paper introduces a time-gated SPAD receiver design that reduces intersymbol interference in optical wireless communication, enhancing bit error rate performance especially at high photon rates.

Contribution

The paper proposes a novel time-gated SPAD receiver that mitigates dead time induced ISI and optimizes gate timing for improved communication reliability.

Findings

Time-gated SPAD reduces intersymbol interference.

Optimized gate-ON time improves BER performance.

Superiority over traditional free-running SPAD in background light tolerance.

Abstract

Photon counting detectors such as single-photon avalanche diode (SPAD) arrays are commonly considered for reliable optical wireless communication at power limited regimes. However, SPAD-based receivers suffer from significant dead time induced intersymbol interference (ISI) especially when the incident photon rate is relatively high and the dead time is comparable or even larger than the symbol duration, i.e., sub-dead-time regime. In this work, we propose a novel time-gated SPAD receiver to mitigate such ISI effects and improve the communication performance. When operated in the gated mode, the SPAD can be activated and deactivated in well-defined time intervals. We investigate the statistics of the detected photon count for the proposed time-gated SPAD receiver. It is demonstrated that the gate-ON time interval can be optimized to achieve the best bit error rate (BER) performance. Our extensive performance analysis illustrates the superiority of the time-gated SPAD receiver over the traditional free-running receiver in terms of the BER performance and the tolerance to background light.