Communications for IoT sensor networks in Smart City applications are demanding new technologies to avoid the radio frequency spectrum saturation and support the massive nodes situation required in this kind of network. Visible Light Communications are gaining interest as an alternative scheme for solving this problem. In particular, Optical Camera Communication (OCC) takes advantage of the presence of cameras in a wide range of devices (smartphones, surveillance systems). Several transmission and modulation schemes, specifically developed for OCC, have been proposed but they present different problems as the communication range, the flickering effects in the transmitted signal, or the system complexity. In this work, an Optical Camera Communication modulation scheme that addresses the considerable variability of the transmitter–receiver distance is proposed. As will be shown, the modulation scheme works properly independently of this separation for a wide range of distances. Additionally, it performs a flickering free transmission to avoid undesired blinking effects for humans and uses a simplified transmission and reception scheme, reducing the system complexity and cost. Results of the modulation’s performance for short (<20 m), medium (20–60 m), and long (>60 m) ranges are presented in the paper, showing a 16 bps transmission rate with Bit Error Rate below the Forward Error Correction (FEC) limit (3.8 · 10⁻³).

中文翻译：

---

OCC的无闪烁无关距离调制方案

智能城市应用中的IoT传感器网络通信要求采用新技术，以避免射频频谱饱和并支持此类网络所需的大量节点情况。可见光通信作为解决此问题的替代方案而引起了人们的兴趣。尤其是，光学摄像机通信（OCC）利用了各种设备（智能电话，监视系统）中摄像机的存在。已经提出了几种专门为OCC开发的传输和调制方案，但是它们提出了不同的问题，例如通信范围，传输信号中的闪烁效应或系统复杂性。在这项工作中，提出了一种光学相机通信调制方案，该方案解决了发射机与接收机距离的巨大差异。如将显示的，调制方案在很宽的距离范围内都独立于这种分离而正常工作。另外，它执行无闪烁的传输，以避免对人类产生不希望的闪烁效果，并使用简化的传输和接收方案，从而降低了系统的复杂性和成本。本文介绍了短（<20 m），中（20-60 m）和长（> 60 m）范围的调制性能结果，显示了16 bps的传输速率，且误码率低于前向纠错（FEC）限制（3.8·10 它执行无闪烁的传输，以避免对人类产生不希望的闪烁效果，并使用简化的传输和接收方案，从而降低了系统的复杂性和成本。本文介绍了短（<20 m），中（20-60 m）和长（> 60 m）范围的调制性能结果，显示了16 bps的传输速率，且误码率低于前向纠错（FEC）限制（3.8·10 它执行无闪烁的传输，以避免对人类产生不希望的闪烁效果，并使用简化的传输和接收方案，从而降低了系统的复杂性和成本。本文介绍了短（<20 m），中（20-60 m）和长（> 60 m）范围的调制性能结果，显示了16 bps的传输速率，且误码率低于前向纠错（FEC）限制（3.8·10^-3）。