## 1 Introduction  
Internet connection among everyday objects is expected to become ubiquitous in the next decade [1]. As the technologies evolve, more devices are expected to be deployed, which will pose several requirements for Internet of Things (IoT) devices. As opposed to radio frequency devices, Visible Light Communication (VLC) technologies have not been targeting the IoT requirements of low-cost, low-power, low-complexity, and small-sized devices. Since VLC systems often use a Field-Programmable Gate Array (FPGA) or a Digital Signal Processor (DSP) in their implementations, they are able to perform a fully digital signal processing. However, the cost, power consumption, and size of such implementations can be a significant impairment for their massive deployment. In this paper, we propose the usage of IoT devices with analog frontends, which aim for receiver simplicity in order to cope with the stringent IoT requirements. Most of the IoT concept relies on widespread simple sensors and actuators, usually resorting to wireless communications. This is commonly known as Wireless Sensors Networks (WSNs), and it has become a growing research topic, having a wide range of applications, which are gradually being adopted in IoT systems [2, 3, 4, 5, 6, 7, 8]. WSNs are characterized as a local network with two main types of devices: nodes and gateways. Networknodes perform a specific task, such as a sensor node (temperature, humidity, RFID tag [5], and body sensors [6]) or an actuator node (irrigation systems [9] and lighting system control). Such devices usually have low power consumption, low cost, and small-size requirements [10], making it impractical to have direct Internet access. Therefore, typical WSNs have a common gateway, which serves as the interface between the nodes and the Internet. Common network architectures include: (i) start networks (all the nodes are connected directly to one gateway); (ii) mesh networks (some nodes may act as data relays between devices and gateways); (iii) tree networks (intermediary data concentrators are used between nodes and gateways) [11]. Most of the current communication technologies in the IoT (WiFi, BLE, ZigBee, LoRaWAN, SigFox(r), and NB-IoT) are able to operate in the star network architecture. Despite the lack of link redundancy, the most commonly deployed architecture is the star network due to the simplicity of the routing algorithms, which also reduces the device's complexity [12]. In the context of VLC, such systems often use existing lighting infrastructure. Therefore, the star network topology can be easily implemented in VLC scenarios, where the IoT node devices communicate with the ceiling light fixtures, which act as gateways. Although Radio Frequency (RF) is widely adopted for WSNs, its performance may degrade in some IoT scenarios due to the high device spatial density, resulting in an increased number of communication packet collisions [12]. Alternative communication technologies are thus welcome to address the lack of connectivity in some places and/or relieve the RF spectrum. During the last decade, visible light communication has been proposed as an alternative and/or complementary communication technology. Derived from Optical Wireless Communication (OWC), VLC exploits the visible part of the electromagnetic spectrum to communicate, resorting to a light source with modulation capabilities. Common VLC systems use Light Emitting Diodes (LEDs) since they allow having common infrastructures for illumination and communication. When compared to RF technology, VLC has several advantages, namely [13; 14; 15]: (i) a free/unregulated spectrum; (ii) the possibility of spectrum re-usage in indoor scenarios, since every room has all the spectrum available; (iii) a high data rate due to the large available bandwidth; (iv) the absence of electromagnetic interference; (v) improved security; and (vi) improved energy efficiency by combining communication and lighting systems.