# Optical Camera Communication as an Enabling Technology for Microalgae Cultivation +
## 1 Introduction
Second, it replaces a generic communications coordinator with an intelligent camera that performs additional routines apart from establishing a communication link. On the one hand, it carries out continuous surveillance of the reactors and the personnel who access the room and can act as an early warning system. On the other hand, it simplifies the estimation of some culture parameters that are difficult to measure or involve intrusive procedures, such as the concentration of biomass or the strain's growth state. For example, for evaluating the biomass concentration, high-cost equipment must be used to automate the extraction of representative samples. In the worst case, this procedure must be carried out periodically by the staff. Furthermore, concerning communications security, an extra layer of protection is added thanks to the light confinement within the room. Finally, cameras' inherent spatial multiplexing capabilities significantly simplify link protocols, making communications more robust and less prone to errors. This work presents part of the ATICCuA Project results, a multidisciplinary research project carried out by the Spanish Bank of Algae (BEA by its Spanish acronym ) and the Photonics and Communications Division of the Institute for Technology Development and Innovation in Communications (IDeTIC). This project addresses the development of prototypes based on the visible light communication (VLC) and, more specifically, those used in underwater wireless optical communications (UWOC) for application in microalgae culture systems. Precisely, its main objective consists of the design of an LED-based dual-use system, which provides configurable lighting for the culture and production of microalgae and cyanobacteria and optical wireless communication capabilities for optical underwater channel characterisation. This work introduces and discusses the microalgae cultivation restrictions that affect the communications' performance and the overall system's design. In addition, a comprehensive analysis based on geometrical constraints is carried out, providing results such as optimal camera positioning concerning a custom-defined metric that relates the aggregate data rate and effective space exploitation. From this analysis, a preliminary study of the plant distribution of a case study is carried out. Furthermore, several experiments that evaluate the system's communications performance are conducted in an indoor and outdoor scenario. The remainder of the paper is structured as follows. Section 2 introduces the proposed OCC-based architecture in a bottom-up manner. Section 3 groups together the discussion of the channel model, the analysis of the data rate achievable for each container and its optimal distribution in the plant for the efficient deployment of this technology. Section 4 describes the methods, materials and procedures involved, on the one hand, in the study of the plant distribution for a real application case and, on the other hand, in the two experiments conducted for the evaluation of the prototype based on the quality of the optical signal received by the camera. Section 5 presents the results obtained, their interpretation and a discussion. The conclusions of this work are summarised in Section 6.