This paper surveys recent literature on vehicular social networks that are a particular class of vehicular ad hoc networks, characterized by social aspects and features. Starting from this pillar, we investigate perspectives on next-generation vehicles under the assumption of social networking for vehicular applications (i.e., safety and entertainment applications). This paper plays a role as a starting point about socially inspired vehicles and mainly related applications, as well as communication techniques. Vehicular communications can be considered the “first social network for automobiles” since each driver can share data with other neighbors. For instance, heavy traffic is a common occurrence in some areas on the roads (e.g., at intersections, taxi loading/unloading areas, and so on); as a consequence, roads become a popular social place for vehicles to connect to each other. Human factors are then involved in vehicular ad hoc networks, not only due to the safety-related applications but also for entertainment purposes. Social characteristics and human behavior largely impact on vehicular ad hoc networks, and this arises to the vehicular social networks, which are formed when vehicles (individuals) “socialize” and share common interests. In this paper, we provide a survey on main features of vehicular social networks, from novel emerging technologies to social aspects used for mobile applications, as well as main issues and challenges. Vehicular social networks are described as decentralized opportunistic communication networks formed among vehicles. They exploit mobility aspects, and basics of traditional social networks, in order to create novel approaches of message exchange through the detection of dynamic social structures. An overview of the main state-of-the-art on safety and entertainment applications relying on social networking solutions is also provided.

Wireless network data consumption is experiencing drastic increases due to growing demands of mobile services and applications. Deployed networks using Radio Frequency (RF) communications are characterized by a shared medium, limited available spectrum and limited ability to scale with increasing demand. Directional communications, including Visible Light Communications (VLC), can limit contention in controlled environments and provide scalability through spatial reuse of the medium. This solution can provide massive aggregate data capacity in indoor scenarios if properly distributed. In this paper we propose an indoor hybrid system that integrates WiFi and VLC luminaries. Our system utilizes (i) broadcast VLC channels to supplement RF communications and (ii) a handover mechanism between WiFi and VLC to dynamically distribute resources and optimize system throughput. This approach offers the bandwidth density benefits of VLC, provides a non-intrusive RF back-channel, maintains compatibility with conventional RF devices, and demonstrates excellent scalability. Analytical and simulation results show improvements in aggregate performance (i.e., throughput and delay) of the hybrid, when compared to either system acting alone.

Sixth generation (6G) wireless communication networks are envisioned to be empowered with novel enabling technologies to guarantee ubiquitous coverage requirements, heterogeneous communication scenarios, and improved network intelligence, spectral rates, and security. The 6G vision is not only limited to terrestrial networks, but also extends to non-terrestrial networks encompassing satellites and aerial networks, thus exploring a full spectrum of heterogeneous communication links. In 6G scenarios, the role of unmanned aerial vehicles is of paramount importance, as flying devices are expected to densely populate aerial space, providing an intermediate network layer between ground networks and space ones. As a vision of fully integrated 6G heterogeneous networks, ground, aerial, and satellite networks will coexist, thus realizing the space-air-ground integrated communication network for 6G scenarios. This work highlights several novel 6G enabling technologies, and presents the detailed study and evaluation of communication technology candidates from the perspective of aerial communication networks, key design considerations, and technical challenges.

The Internet of Vehicles (IoV) has emerged as a new spin-off research theme from traditional vehicular ad hoc networks. It employs vehicular nodes connected to other smart objects equipped with a powerful multisensor platform, communication technologies, and IP-based connectivity to the Internet, thereby creating a possible social network called Social IoV (SIoV). Ensuring the required trustiness among communicating entities is an important task in such heterogeneous networks, especially for safety-related applications. Thus, in addition to securing intervehicle communication, the driver/passengers honesty factor must also be considered, since they could tamper the system in order to provoke unwanted situations. To bridge the gaps between these two paradigms, we envision to connect SIoV and online social networks (OSNs) for the purpose of estimating the drivers and passengers honesty based on their OSN profiles. Furthermore, we compare the current location of the vehicles with their estimated path based on their historical mobility profile. We combine SIoV, path-based and OSN-based trusts to compute the overall trust for different vehicles and their current users. As a result, we propose a trust-aware communication architecture for social IoV (TACASHI). TACASHI offers a trust-aware social in-vehicle and intervehicle communication architecture for SIoV considering also the drivers honesty factor based on OSN. Extensive simulation results evidence the efficiency of our proposal, ensuring high detection ratios >87% and high accuracy with reduced error ratios, clearly outperforming previous proposals, known as RTM and AD-IoV.

The need allowing indoor access to the Internet services requires to reduce the electromagnetic pollution. Recently, the scientific community is looking for alternatives to the use of radio frequency communication, leading to propose and study the new paradigm of visible light communications. In order to present a system implementing transmission and access procedures, we propose a logical stream starting from user localization, so as to decide which LEDs can provide access, thus basically performing a space-division multiple access by scheduling data on the basis of the bits to be transmitted. For this aim, a two-bands access scheme is proposed, and implemented through the use of a separated channel where signaling specifies where, in the wavelength domain, the reception must be operated by the different users. A multiple-input multiple-output scheme is considered for data transmission, in order to increase rate with a reliable error rate performance. Performance is evaluated for what concerns localization and access tasks, so as to show the effectiveness of the proposed scheme. Performance comparison with the recent literature has been also reported.

Visible Light Communications (VLC) is emerging as viable means to overcome the crowded radio spectrum for highly-localized communications systems. With such an approach, luminaires can be adopted for supporting data communication in addition to illumination in what we call Cellular Lighting. However, in these systems, the directionality of light as the communication medium introduces new challenges in sustaining network connectivity especially under mobility scenarios. In this paper we investigate mobility in VLC devices and propose an approach to managing handover adopted from wireless cellular systems, but with very small cells and directional characteristic. Moreover, this technique provides the coordination and cooperation among VLC devices to achieve seamless connectivity in two different indoor scenarios consisting of overlapping (uniform lighting) and non-overlapping (spotlighting) cases. Results indicate how different design decisions in supporting luminaire placement achieve full coverage at varying data rates.