As a hyperconnected society, there are occasions when communication networks fail and data access is impossible through conventional means, highlighting the strategic importance of alternative electronic communication methods. Natural disasters cause the collapse of communication towers and Internet services ^[1][2][1,2]; very crowded areas, such as concerts or sports events, affect users’ communications; and areas with few inhabitants need expensive investment for regular communication. It has become clear that social networks have become useful to cover disasters and emergencies ^[3][4][3,4] and connect people. However, in many circumstances, it is very possible that we will be left without access to these networks, the Internet and even, possibly, mobile telephone communications, limiting their utility.

2. Opportunistic Networks or OppNets

Opportunistic networks or OppNets, and specifically local mesh networks, have been seen to be very useful in emergency situations [5]. The term OppNets was coined by Leszek Lilien in 2005, thinking of mobile seed networks that can expand locally and be deployed, for example, for communications after an earthquake ^[6][7][6,7]. An opportunistic mesh network allows for direct communication between mobile devices that are within reach, which can be called nodes, even if there is no cellular or Wi-Fi coverage. The OppNet mesh network uses intermediate nodes to send messages from their sender (or source) to their receiver in an opportunistic way [8]. To do this, low-energy connections can be used to establish personal wireless networks that connect mobiles and their data screens to portable mesh radio devices, for example, using Bluetooth protocols. These networks were originally conceived and designed for emergency situations where no alternative stable telephone communication is available. However, the concept transcends its use for emergencies, and facilitates the use of a free public radio spectra for social, interpersonal, and community communications outside of data networks, Wi-Fi networks or other means to access the Internet [9]. The mesh network can grow and be strengthened by adding new nodes, represented by mobile users and their OppNet devices, and is likely one day to become integrated into the mobile device itself. Obviously, no manufacturer or operator is currently interested in offering inexpensive equipment that bypasses data tariffs and the control of large portals, permitting private communications independent of the data giants and with no need to pay an operator fee. In a typical mesh OppNet scenario, the individual uses their mobile device (without network connection) as a screen, linked to an OppNet radio device that sends the desired information and that simultaneously acts as a node to receive information from others (see Figure 1). Thus, mesh OppNets are networks in which the nodes may be individual users, vehicles, fixed devices, etc. [10]. The more users in the mesh OppNet, the more nodes, and the more nodes, the greater the scope for communication and coverage. This means that the coverage provided by mesh OppNets varies in time and space depending on the density and mobility of the users with devices. As a society, we now assume that mobile media can be characterized not by its technological convergence but rather, by its network organization [11]. However, this network articulation tends to refer to the content and its distribution. By contrast, mesh OppNet communication between people and small communities can also occur according to this model of network organization. Accordingly, mobile media, communication studies, and electronic commerce must consider these emerging technologies, in parallel to the extension of smartphones, which will have important consequences for community and social communications, and in territorial management [12].

3. The Coverage and Scope of the Mesh OppNets

As mentioned above, the coverage of these networks depends on the nodes that exist. Each device not only serves as a sender and receiver of its own communication but is also a node for the transmission of external communications. Considering that the range of these devices is usually a radius of around 4000 m, knowing how many users are around will give us information about the potential coverage we can obtain from our network. Thus, mesh OppNets represent a mode of communication with a scope that is dictated by the number and location of the other users (or nodes). For example, when the distribution of perhaps the most widely implanted device is studied, the goTenna Mesh™ device, a disparity in implantation can be observed over the geographic area of interest with consequent differences in potential coverage. In areas such as California, Florida or New York, the coverage of this device is extensive due to its high density, whereas in areas such as northern and southern Europe, the absence of nodes (or repeating goTenna devices) makes widespread territorial coverage impossible. In the coming years, we are likely to witness an emergence of these small devices, as they are currently being developed by numerous start-ups. At present, there are a few similar commercial devices registered, such as Garmin inReach, SPOT X Satellite Messenger, Beartooth (the most similar to goTenna Mesh), Fogo or Sonnet, but they still do not have the diffusion of goTenna Mesh. Sonnet is a little delayed in its development and was not commercialized in 2023, despite being announced for 2019. All these mesh OppNet devices are priced between $45 and $300, depending on their GPS characteristics, whether they have a screen or use of the mobile phone’s screen, and their autonomy or coverage [13]. It should be remembered that at least two devices are required to establish a mesh network and indeed, they are commonly sold in pairs. In these cases, the mesh network is meaningless if there are no devices to create it.

4. Privacy and Security in Mesh OppNets

The privacy and security of personal messages are among the most important things that interest users, companies, and public administrations today. We know that, through automated processes that use more or less biased algorithms, our connected society accumulates digital dossiers of people online [14]. The problem with this is not simply the loss of control over personal information, the existence of “proto big brother” controllers, or omniscient corporations or portals but rather, the problem is the bureaucratic processing of uncontrolled data that affects our lives [15], constituting an authentic digital tattoo ^[16][17][18][16,17,18]. In this sense, mesh OppNets involve interactions among multiple decentralized nodes [19], not in terms of a social network but rather, through mesh networks that establish opportunistic connections that can occupy the urban space. These communication networks do not require formal leadership, or a command post or control center, nor do they require a vertical organization responsible for distributing information or instructions. Rather, these systems advocate networking as a way of life [19]. In this context, this type of network offers new options in terms of the privacy and security regulations of personal communications. Although there does not currently seem to be an appropriate approach to these situations, it is understood that regulating mesh OppNets should take place within the framework of the unstoppable phenomenon of convergence between the information and communications technologies [20]. Such approaches must align with the new discipline of computer law, which assumes the right to computer freedom as a personal modality recognized by citizens, legally protecting the “computer identity” of each individual [21]. Alternatively, mesh network proposals are emerging, such as payment gateways for Bitcoins using Blockchain or other cryptocurrency transactions, employing protocols with decentralized networks [22]. Without a need for the Internet, these mesh OppNets protocols mask the physical situation of the sender or receiver, and they avoid telephone identification as they do not use a SIM card or IP address ^[23][24][23,24].

5. OppNets and Broadcasters

To date, too little attention has been paid to ad hoc electronic communications and opportunistic networks (or OppNets) in professional settings, outside of security services [25]. Broadcast work in crowded environments, saturated with terminals, a lot of noise, at large events or in places with a complicated orography, places important demands on efficient electronic communications. During the coverage of large events, such as demonstrations, events in stadiums, circuits, outdoor sports, concerts, fairs, etc., coordinating intercommunications is decisive. Recently, this problem has been aggravated by live mobile journalism (MoJo) broadcasts through dedicated Wi-Fi and data networks, especially when connected multi-camera or mobile streaming techniques are employed [26]. For audiovisual retransmissions of such events, it is best to free up the network as much as possible and not to use the entire data bandwidth, directing or sending data to servers for team communications or coordination. In addition, these are often very noisy environments that reach saturation due to the high density of people connected or the difficulties in obtaining a connection that allows for broadcast-quality streaming. Indeed, it is possible that communication is impeded by the inhibition of telephone frequencies due to passive security issues, and/or the presence of authorities [27]. Hence, an electronic communication system through mesh OppNets is presented here as a commercial and professional communications alternative in the field of broadcasting, in particular for mass events such as those described above.