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This paper discusses the opportunities for visible light communications (VLC) in the future 6G. VLC is a highly attractive optical communication approach for short-range communications, which complements radio. The use of reconfigurable optical-radio networks creates a high performance, highly flexible communication system that can be used in the most stringent environments of 6G. The paper presents and discusses other novel VLC concepts, such as interactive VLC, light-based IoT, living surfaces and optical communications through bio-tissues. These very promising concepts can be used in the identified 6G verticals, opening new areas of research for 6G.

In this conceptual paper, we discuss the concept of hospital of the future (HoF) and the requirements for its wireless connectivity. The HoF will be mostly wireless, connecting patients, healthcare professionals, sensors, computers and medical devices. Spaces of the HoF are first characterized in terms of communicational performance requirements. In order to fulfil the stringent requirements of future healthcare scenarios, such as enhanced performance, security, safety, privacy, and spectrum usage, we propose a flexible hybrid optical-radio wireless network to provide efficient, high-performance wireless connectivity for the HoF. We introduce the concept of connected HoF exploiting reconfigurable hybrid optical-radio networks. Such a network can be dynamically reconfigured to transmit and receive optical, radio or both signals, depending on the requirements of the application. We envisage that HoF will consist of numerous communication devices and hybrid optical-radio access points to transmit data using radio waves and visible light. Light-based communications exploit the idea of visible light communications (VLC), where solid-state luminaries, white light-emitting diodes (LEDs) provide both room illumination as well as optical wireless communications (OWC). The hybrid radio-optical communication system can be used in principle in every scenario of the HoF. In addition to the hybrid access, we also propose a reconfigurable opticalradio communications wireless body area network (WBAN), extending the conventional WBAN to more generic and highly flexible solution. As the radio spectrum is becoming more and more congested, hybrid wireless network approach is an attractive solution to use the spectrum more efficiently. The concept of HoF aims at enhancing healthcare while using hospital resources efficiently. The enormous surge in novel communication technologies such as internet of things (IoT) sensors and wireless medical communications devices could be undermined by spectral congestion, security, safety and privacy issues of radio networks. The considered solution, combining optical and radio transmission network could increase spectral efficiency, enhancing privacy while reducing patient exposure to radio frequency (RF). Parallel radio-optical communications can enhance reliability and security. We also discuss possible operation scenarios and applications that can be introduced in HoF as well as outline potential challenges. Keywords Hospital of the future • Reconfigurable networks • Visible light communications • Hybrid wireless networks • Optical wireless communications • Wireless body area networks

In this paper, we propose a reconfigurable optical‐radio wireless network characterized by high flexibility and performance. The hybrid network can be dynamically configured, adapting itself to the changing requirements of users or operating environments, dynamics of the transmission medium, and availability of resources. First, the basic concept, system architecture, and key operating modes are introduced. Possible operating scenarios and their relationship to the operating modes are discussed. Then, a practical implementation of the hybrid network is introduced, describing the network components, architecture, modulation scheme, and implementation technologies. Implementation was carried out using mostly off‐the‐shelf components and universal software radio peripheral blocks. Particular attention has been put in implementing a fast handover mechanism between modes, an essential requirement for seamless network reconfiguration. Network performance is evaluated and different switching approaches are compared. The paper demonstrates practically the proposed concept based on dynamic system reconfiguration. For the implementation, a mode switching algorithm was developed making decisions based on the quality of the wireless channels. The system was tested with live video packets transmitted through the network. System performance was assessed through data throughput and packet loss measured for different modulation parameters. The proposed concept, essentially a software‐defined hybrid network, is flexible and makes efficient use of radio resources. Moreover, the network has the potential to achieve high performance. All these characteristics make reconfigurable optical‐radio networks an attractive candidate for fifth generation and beyond.

In this paper we consider a hybrid optical-radio wireless network as a flexible, secure and high-performance communication network for the hospital of the future. The network consists of access points as well as devices capable to communicate using optical and radio technologies. Wireless body area networks (WBAN) are one of the key elements needed to achieve the desired goals. Within the proposed hybrid network, we extend the conventional WBAN concept to a more generic and highly flexible, reconfigurable optical-radio wireless body area network (RORWBAN). Ultimately, the concept of hospital of the future aims at enhancing healthcare while using thoughtfully and efficiently hospital resources. Wireless networks are one of the key enables of tomorrow's hospitals. However, spectral usage, security, safety and privacy issues of current radio-based wireless networks could undermine the attractiveness of these networks for future healthcare scenarios. The proposed solution, combining optical and radio transmission results in a network that can adapt itself in short-and long-terms to the changing communications requirements of hospitals. In principle, a hybrid network can tackle interference, exposure, privacy and other key problems of conventional networks. The proposed system could intelligently reduce the exposure to radiation and generation of radio interference, while parallel opticalradio transmission could ensure secure, reliable and high capacity communications, using efficiently the available spectrum. In this paper, the overall concept will be presented, and the possible operation scenarios and applications will be introduced too. Finally, we discuss the challenges of hybrid optical-radio WBAN for future hospitals.