Victor Monzon Baeza, Laura Concha Salor
©SHUTTERSTOCK.COM/GORODENKOFF
Tactical communications are military communications in which information, especially orders and military intelligence, is transmitted from one command, person, or place on the battlefield to another, particularly during combat. It includes any type of information delivery, whether verbal, written, visual, or auditory, and can be sent in various forms.
Many advances in wireless technologies have their origin in military communications. This is the case of frequency hopping in 2G mobile communication or the direct sequence spread spectrum in 3G. Instead, wireless communications have continued to evolve independently of military communications since 4G without considering their needs. Today, 5G introduces new technologies and paradigms that were not present before, such as the virtualization of network elements, a 5G-enabled technology considered fundamental and most attractive to improve tactical communication.
Virtualization can help network security. For this reason, the commercial and tactical security guidelines provided by 5G are analyzed for communications in public environments to validate if the security level of a public 5G network can be extrapolated to military scenarios. Because 5G will dominate next-generation telecommunications networks and enable new applications, playing a pivotal role in future societies, it is time to reunify the advances in civil and military communications.
This brings several challenges and security concerns to the broader community and new opportunities in many military areas, such as capability interoperability, development, resilience, and secure communications, empowering tactical communication networks with enhanced security and protection for all assets that are part of a tactical scenario. All defense systems (land, sea, air, and space) can be seen as enhanced by the new technologies that 5G brings, mainly from a safety point of view. In this context, the North Atlantic Treaty Organization (NATO) and NATO Communications and Information Agency (NCIA) conducted a preliminary assessment of 5G technologies and their potential for military applications, identifying four areas where 5G could have a place:
However, the assessment does not associate which candidate emerging technologies could be related to these areas for different operative use cases (UCs). Recently, other independent works have been carried out to include the opportunities of 5G in the military field. Network slicing (NS), a key 5G technology, was first proposed for military use. Software-defined networking (SDN) comes hand in hand with 5G to guarantee greater network scalability. A mechanism based on SDN to adaptively ensure quality of service (QoS) for user data flow has been proposed by leveraging SDN in heterogeneous tactical networks. Sensor networks are essential on the battlefield, and, thanks to the Internet of Things (IoT), these networks can offer more advantages in the tactical world, as analyzed. The function of interoperability between systems is vital in defense, mainly between command-and-control systems.
Beyond 5G, the study performed by the NCIA is also a key topic for the NATO 2030 agenda, where artificial intelligence (AI), data autonomy, quantum-enabled technologies, hypersonic technologies, and biotechnology should be strategically considered as a technology road map in the evolution of military communications. All of these technologies pave the path of development from 5G to 6G), where AI is the key technology. Preliminary proposals are presented using reinforcement learning as an AI technique used by agents in tactical networks to learn autonomously, improving situational awareness (SA).
Against this background, in this article, we have selected emerging technologies promoted by 5G and 6G that can benefit tactical communications. First, a high-level system description of these technologies has been carried out to identify opportunities for military applications. In addition, it can provide the reader with a context for understanding their application in the proposed tactical scenarios or UCs.
This work is an analysis of emerging technologies and their application to the military field, with a special emphasis on tactical scenarios and on improving such scenarios; therefore, it serves as a starting point for new scientists to open up new lines of research. It is not merely a compilation but an analytical basis for future work.
The rest of this article is organized as follows: The “Tactical Communication Panorama” section presents a brief background of two main elements in tactical communications to be renewed. The “5G/6G Technologies as Potential Candidates” section proposes a group of emerging technologies as potential candidates in tactical communications. In the following section, the UCs are presented. Finally, the conclusions are summarized in the final section.
We begin the analysis by giving an overview of the two main components of tactical communications that are the object of evolution using 5G/6G-enabled emerging technologies: the tactical radios and the waveforms to transmit information on the battlefield. The waveform is the shape of a signal in the time domain that provides information about the signal beyond the spectrum.
Tactical radios are a fundamental necessity for soldiers during military operations, as they allow soldiers to communicate and share a common vision of the entire operating environment. Some examples of military radios currently used are collected here:
The legacy frequency bands for military applications mentioned by these radios are primarily three bands: HF comprises the range of 3–300 MHz; VHF refers to the range between 30 and 300 MHz; and, finally, the UHF band refers to the range of 300 MHz to 3 GHz. Satellite communications for military purposes are used in frequency bands L (1–2 GHz) and X (8–12 GHz) for accessing remote sites in military missions. The great inconvenience these frequency bands present to accommodating new technologies driven by 5G/6G is the limitation in bandwidth (the amount of data that will be able to be transmitted).
With the increasing battlespace and sophisticated adversaries, the availability of effective military communications platforms is more crucial than ever. Tactical waveforms are critical elements for their ability to reliably and securely transmit to and from a combatant on the battlefield. The most used waveforms in tactical environments are summarized in Fig. 1.
Fig 1 The waveforms used in tactical communications.
New military missions with more complex tactical scenarios have requirements that the conventional tactical radios and waveforms used so far cannot cope with. The lines of action for the renewal of tactical communications are reflected in Fig. 2. Fundamental assets, such as radios and waveforms, first need to be upgraded. The mentioned classical waveforms are used with multiplexing and multiple-access schemes (MASs) based on traditional resources, such as frequency-division multiple access, time-division multiple access, or code-division multiple access, which are limited for the high number of active elements in the current tactical scenarios. Therefore, novel nonorthogonal multiple access is a promising technique that outperforms traditional MASs and presents challenges for tactical networks. In addition, these radios and waveforms are provided for low communication bandwidths, which is entirely incompatible with the new technologies driven by 5G.
Fig 2 Renewal in tactical communication.
On the other hand, new scenarios, such as electronic warfare, call for new features in this type of security-focused radio. Everything points to the innate characteristics of 5G and its evolution. The refurbishment criteria are based on achieving higher bandwidths, as modern tactical scenarios exchange more data. New missions include new elements in the scenario that require interoperability between them, which requires the ability to offer scalable networks. More data bring with them the requirement for higher levels of security. Finally, in the face of new elements in modern scenarios, response times between all actors must be shortened to ensure security. The main one to be increased is the limited bandwidth problem, solved in civil communications using new spectrum bands, such as terahertz and millimeter waves. This also becomes a challenge for military equipment. New satellite communications also have emerging bands, such as Q/V and W, which require upgrading tactical radios.
New wireless networks (5G/6G) bring a series of emerging technologies we can use to meet the needs identified under the criteria network in Fig. 2. We have selected, in this work, a group of these technologies, as shown in Fig. 3, to improve tactical communications, mainly based on providing higher bandwidth and more robust levels of security and encryption. In the following, a brief description of each is provided to contextualize their use in military environments. We emphasize that this is not an exhaustive list but only based on the criteria network established in Fig. 2. Any technical detail can be found more in depth in works with the direct object of said technologies in the literature. Other technologies may be included in future works.
Fig 3 The 5G and 6G emerging technologies. AINAI: AI-native air interface.
In addition to the emerging technologies mentioned, it should also be noted that advances in massive multiple-input, multiple-output are making possible the incorporation of noncoherent communications. This type of communication is based on the ability to demodulate signals without the need for channel estimation. Noncoherent communications are not emerging as new technologies but have regained interest and prominence thanks to advances in new technologies. It can be very interesting for the tactical field since the ability to detect without channel information avoids interception problems or signal attacks.
A proposal of these key technologies applied to renew tactical radios is shown in Table 1. The challenge for all tactical radios is the integration into the IoT network and the use of AINAI. Regarding waveforms, SDR, JSC, and NP are the candidates for new proposals.
Table 1. The association of tactical radio with emerging technologies.
A subset of operations and military scenarios that can be carried out on the battlefield has been selected in this work to exemplify the application of some emerging technologies in tactical communications (Table 2).
Table 2. A summary of UCs for tactical scenarios employing emerging technologies.
This scenario refers to the military rescue air operation conducted during war conditions within or near combat zones. The main operational task of the rescue is to locate, communicate with, and recover aircrews shot down during combat and possible survivors. Medicalized helicopters are equipped with tactical radios with limited capacity only for voice communication, low bandwidth, and GPS systems. Any military tactical scenario needs reliable, secure, and fast communications to speed up response times to locate casualties. Larger bandwidths allow more information to be sent to rescue teams, and 5G technology reduces latency and allows reliable connectivity and high efficiency. The IoT on the Battlefield (IoBT) allows significant technological development in military operations. The IoBT uses sensors, wearables, and edge computing technology to reduce communication latency between IoT devices and manage network bandwidth.
This scenario is based on a system of transporting wounded combatants from one location to a specialized hospital. Some of the 5G technologies that can be applied to this scenario are the IoT or wearables. For example, smart clothing has sensors that can measure, for instance, heart rate or blood pressure. It is possible to monitor the health of soldiers in real time with great precision and transmit these data directly to specialized doctors, who can carry out a personalized follow-up so that soldiers can be diagnosed early and evacuated as soon as possible.
Some services used by military troops are essential communication services (voice, data, messaging, and video). However, other value-added services require NS mechanisms to provide ultrareliable communications. Some of these are the following: push to talk, fixed–mobile convergence, QoS, on-demand coverage, and satellite backhaul. Segments are isolated and limited, meaning that, in the face of an enemy attack, not all of the segments of the network are involved, so this provides much more protection, is much more secure, and offers less latency.
This scenario refers to using and exploiting an enemy’s electromagnetic spectrum by blocking or interfering with the communications or the spectrum. Through this scenario, electronic warfare can also intercept, interrupt, and decode communications to obtain information from the enemy. Currently, more and more threats are received by enemies, leading to the need to cover the highest 5G frequencies (24–44 GHz) due to the large capacities and faster speeds available. BC technology should be highlighted in this UC as the main one since access and identity management are essential to avoiding a possible communication intrusion. In addition, trusted and edge computing help overcome any electronic attack. From the point of view of the application layer, the transmission of information can be enhanced by SC that detect intruders and by RIS to prevent interference. The SDR technology has acquired a fundamental role in communication in any combat operation thanks to its performance and flexibility, which help electronic warfare with multifunctional capabilities, such as multiple waveforms that accept SDR, advanced cryptology, and increased processing power, that produce better real-time communication and decision making with just one radio.
Through augmented reality, the virtual world is intermingled with the real world. In the case of the military environment, for example, it is of great help to improve the ability of soldiers to detect the enemy or even obtain information from the battlefield in real time. Significantly, the use of augmented reality for military training is essential. With the help of virtual reality glasses, it is possible to simulate a computer-recreated scenario entirely similar to the real one so that soldiers can train in an environment with real equipment they would use in their missions. Trusted and edge computing as well as tactile and tactical Internet are the technologies that contribute to virtual and augmented reality technology. The tactile Internet focuses mainly on the interactions between person and machine as well as machine and machine. Still, it incorporates tactile and haptic sensations to interact with the environment in real time. It offers high availability, security, and very fast reaction time using virtual reality glasses. In addition, 6G may create a native interface based on AI to empower the bandwidth.
SA refers to having a general view of the entire environment in which a combatant or military platform is. Due to the rapidity with which battle scenarios are changing, real-time SA is necessary. JSC can help collect more information more effectively by using the same signal with radar and communication functions. This information is processed by NPs much faster than would be possible with conventional processors, allowing a greater amount of useful information to be obtained for SA. AI may also help to reduce computing complexity.
This UC is fundamental in army operations since it ensures the correct supply of a units’ resources for their military operations. One of the technologies that has a significant impact on logistics is the IoT. IoT devices provide higher security in monitoring logistic processes; improve visibility in the supply chain; and, above all, obtain information in real time on the status of products and services. The tactical Internet is another technology that can be of remark. These networks are used to provide communication services that connect strategic decision makers with the commanders, which allows real-time information (provided by NP) on the status of the service.
Fire control refers to the set of activities that use the organized use of resources by commanders during the execution of a combat task. For better combat control, fire control is an essential and fundamental element. This UC belongs to the massive machine-type communications scenario. The sensors transmit massive and real-time data at high speeds through IoT technology in complex environments, such as a combat environment.
These are one of the fundamental pillars for the success of military operations. They are responsible for collecting and analyzing information about other countries’ forces, plans, and military operations to discover the possible intentions of rivals and criminal organizations, thereby exploiting their enemies’ weaknesses and helping the commanders with orientation and decision making. One of the technologies could be trusted computing. Since there is so much data exchange worldwide, information security must be critical; one advantage of trusted computing is to avoid exposing information to the adversary. Within this technology, SDN and BC are related. Thanks to the virtualization of the networks, it is possible to increase the network’s security by being more robust thanks to the automation of the processes. SC and AINAI contribute to identifying data within this type of operation.
Command-and-control posts are facilities where military personnel plan, direct, coordinate, and control forces and operations to accomplish the mission. It is a point where large amounts of information are located. NP provides the ability to process all of this amount of information, while trusted computing guarantees the reliability of the data. The post can also be introduced within IoT networks or in one of the NS slices.
The technology associated with 5G and future 6G networks is challenging for military communications in tactical scenarios. This work has selected and analyzed a group of leading technologies that allow tactical networks to evolve. The virtualization of networks with 5G helps to guarantee greater security. These developments are vital in improving the feasibility of truly network-centric operations for military applications. SDNs, the IoT, BC, AI, SC, or NPs help increase communications performance. These technologies have improved 10 classic UCs in the military field. This work is an analysis to serve as a starting point for new scientists to open up new lines of research. It is not merely a compilation but an analytical basis for future work.
• M. Agiwal, A. Roy, and N. Saxena, “Next generation 5G wireless networks: A comprehensive survey,” IEEE Commun. Surveys Tuts., vol. 18, no. 3, pp. 1617–1655, third quarter 2016, doi: 10.1109/COMST.2016.2532458.
• J. Suomalainen, J. Julku, M. Vehkaperä, and H. Posti, “Securing public safety communications on commercial and tactical 5G networks: A survey and future research directions,” IEEE Open J. Commun. Soc., vol. 2, pp. 1590–1615, Jul. 2021, doi: 10.1109/OJCOMS.2021.3093529.
• “NATO tech agency explores the potential of 5G for the alliance,” NCIA, Brussels, Belgium, 2022. Accessed: Dec. 2022. [Online] . Available: https://www.ncia.nato.int/about-us/newsroom/nato-tech-agency-explores-the-potential-of-5g-for-the-alliance.html
• S. M. Eswarappa, P. H. L. Rettore, J. Loevenich, P. Sevenich, and R. R. F. Lopes, “Towards adaptive QoS in SDN-enabled heterogeneous tactical networks,” in Proc. Int. Conf. Mil. Commun. Inf. Syst. (ICMCIS), 2021, pp. 1–8, doi: 10.1109/ICMCIS52405.2021.9486391.
• B. Pannetier, J. Dezert, J. Moras, and R. Levy, “Wireless sensor network for tactical situation assessment,” IEEE Sensors J., vol. 22, no. 1, pp. 1051–1062, Jan. 2022, doi: 10.1109/JSEN.2021.3129181.
• M. Pradhan, M. Manso, and J. R. Michaelis, “Concepts and directions for future IoT and c2 interoperability,” in Proc. IEEE Mil. Commun. Conf. (MILCOM), 2021, pp. 231–236, doi: 10.1109/MILCOM52596.2021.9653093.
• E.-K. Hong et al., “6G R&D vision: Requirements and candidate technologies,” J. Commun. Netw., vol. 24, no. 2, pp. 232–245, Apr. 2022, doi: 10.23919/JCN.2022.000015.
• T. Möhlenhof, N. Jansen, and W. Rachid, “Reinforcement learning environment for tactical networks,” in Proc. Int. Conf. Mil. Commun. Inf. Syst. (ICMCIS), 2021, pp. 1–8, doi: 10.1109/ICMCIS52405.2021.9486411.
• V. M. Baeza and A. G. Armada, “Orthogonal versus non-orthogonal multiplexing in non-coherent massive MIMO systems based on DPSK,” in Proc. Joint Eur. Conf. Netw. Commun. 6G Summit (EuCNC/6G Summit), Porto, Portugal, 2021, pp. 101–105, doi: 10.1109/EuCNC/6GSummit51104.2021.9482419.
• V. M. Baeza and A. G. Armada, “User grouping for non-coherent DPSK massive SIMO with heterogeneous propagation conditions,” in Proc. Global Congr. Elect. Eng. (GC-ElecEng), Valencia, Spain, 2021, pp. 26–30, doi: 10.1109/GC-ElecEng52322.2021.9788350.
• Land mobile radio (LMR) 101,” CISA, Washington, DC, USA, Feb. 2016. Accessed: Sep. 2022. [Online] . Available: https://www.cisa.gov/sites/default/files/publications/LMR%20101_508FINAL_0_0.pdf
• “PR4G Fastnet product family.” Thales. Accessed: Dec. 2022. [Online] . Available: https://ejercito.defensa.gob.es/materiales/transmisiones/Radiotelefono.html
Victor Monzon Baeza (victor.monzon@uni.lu) is with the Signal Processing and Communications Group in the Interdisciplinary Centre for Security, Reliability and Trust, University of Luxembourg, 1855 Kirchberg, Luxembourg.
Laura Concha Salor (laura.concha_salor.ext@nokia.com) is a radio network engineer with Nokia, 28050 Madrid, Spain.
Digital Object Identifier 10.1109/MPOT.2023.3297326