5G on the front lines: Navigating the future of defense communications

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October 11, 2023

Fifth-generation (5G) mobile network technology for the military is intended to improve intelligence, surveillance, and reconnaissance (ISR) systems and processing; enhance networking and security protocols; and streamline logistics operations among U.S. and allied forces. The use of 5G may herald incredible advancements like augmented reality for troops, expansive and immediate battlefield sensor networks, and drones autonomously scouring land, sea, and air.

As the commercial 5G blueprint gets adapted into the complex web of defense needs, such elements as open architecture, technical challenges, adapting commercial technology to military use, and size, weight, and power (SWaP) requirements remain front and center for the industry.

It’s clear, however, why the defense industry has placed such a premium on finding ways to implement 5G. The technology is a highly adaptable solution capable of providing the military a major boost in terms of data collection, says Leon Gross, corporate vice president of Microchip Technology’s discrete products business unit (Chandler, Arizona). “A new generation of … 5G communications solutions [is] ­substantially increasing how much information can be shared in support of real-time decision-making and other military applications,” he says. (Figure 1.)

While earlier 5G systems operating in sub-6 GHz bands were susceptible to high-power jamming signals, the advent of 5G mmWave [millimeter wave) systems – operating at 24 GHz and above frequencies – are poised to revolutionize battlefield communications, providing enhanced resilience against jamming, Gross says.

[Figure 1 | This graph shows Microchip’s GaN on SiC [gallium nitride on silicon carbide] MMIC [monolithic microwave integrated circuit] power amplifiers’ ICP2840 linear gain across frequency and output power levels.]

These systems enable functions like “battlefield sensor networks for command-­and-control data gathering, and augmented-reality displays that enhance situational awareness for pilots and infantry soldiers,” Gross adds, noting that the broadening horizon of 5G extends its applications to “virtual-reality solutions for remote vehicle operation in air (uncrewed aerial systems or UASs), land, and sea missions.”

When it comes to the most promising military applications, Erin Kocourek, vice president for advanced technology and strategy at CAES (Arlington, Virginia), points to the strategic leveraging of the expanded frequency bands provided by 5G and even emerging (but yet-to-be-defined) 6G technology.

“The opened frequency bands ... is creating a larger ecosystem of devices and technologies that can be repurposed to create solutions to military objectives,” she says.

The primary aim, according to Kocourek, is to integrate this technology in a manner that surpasses the traditionally slow pace of the U.S. Department of Defense (DoD) acquisition and deployment process. The Internet of Things (IoT) empowered by 4G and 5G has immense potential when applied to military objectives, she says.

“Leveraging this to port data into the systems at the warfighters’ fingertips and into AI [artificial intelligence]-driven systems has seemingly unlimited potential,” she asserts.

Bill McKenney, marketing director at Analog Devices (Wilmington, Massachusetts), says that 5G for military use is being evaluated across all areas of DoD operations, adding that frequently commercial 5G technology is being used for military purposes. The advantage of using commercial 5G tech is its easy availability and the scope it offers, he says.

“Currently, the DoD has 5G testbeds in 14 locations, evaluating 20-plus use cases,” McKenney says. “These include 5G augmented reality for medical training and telemedicine, ship-wide pier-to-pier connectivity, smart warehouses and logistics, and robust distributed command and control.”

Specific operational needs

While commercial 5G offers a blueprint, the military sector, with its specific operational needs, seeks a fusion of commercial and specialized capabilities.

McKenney says the military is looking at three primary requirements that can be termed as “beyond commercial”: a secure trusted supply chain; preapproved secure bills of material; and operationally useful, value-added applications and enhancements.

Kevin Moyher, product manager for Times Microwave (Wallingford, Connecticut), says the physical properties of the technology must be considered as well. As applications undergo so-called densification, the size of the cable assembly is paramount. Given the military’s stringent demands, ruggedized cables with IP67 ratings [indicating that they’re “waterproof”] become a must, she says. (Figure 2.)

[Figure 2 | For higher-frequency applications of up to 30 GHz, Times Microwave offers MaxGain cables for high-power amplifiers.]

Randy Cordova, CAES business development manager, says that the military’s newer operational demands bring unique sets of issues.

“Battles used to be fought on land and sea,” he says. “Now, we are fighting battles on land, sea, air, space, and cyber.”

This multidomain battlefront requires a seamless flow of colossal amounts of data. The military wants to harness 5G for ISR and autonomous vehicles for ­purposes including mapping and situational awareness.

To meet these demands, Cordova says customers are now calling for designs that support Joint All Domain Command and Control (JADC2), host AI capabilities, and handle data with minimal latency, making 5G-enabled networks the military’s top choice.

Baljit Chandhoke, product manager for RF products at Microchip Technologies, says the move to 5G creates specific technical challenges that his company is working to solve. For example, “RF power amplifiers (PAs) need to deliver linear efficient high-output power,” he says.

As a solution to these multifaceted requirements, “GaN on SiC power amplifiers can operate at high frequencies in the Ka and Ku band from 12 GHz to 40 GHz for satellite communication and 5G, and have broad bandwidths and high gain with better thermal properties,” he adds.

When is 4G good enough?

The introduction of 5G for military use prompts a critical question: Where does 4G still fit in?

Cordova says there certainly is still room for 4G, especially in areas where 5G just isn’t necessary. The decision on when to upgrade is tied closely to the value provided to end users, he says.

“Putting a 5G sensor in an ordnance that does not require the capability would not bring value to the warfighter,” he says. “Everything will likely move to 5G, but not at the same time.”

There will be instances where the legacy of a system – like the B-52, which has been operational since the 1950s – will dictate the pace of its upgrade.

“Decisions will also be made based on the life cycle of a component or system,” Cordova says, indicating that systems nearing their end might not witness an upgrade.

Cost will be a big factor in that upgrade-or-not decision, Moyher says: “Areas where 5G won’t likely be adapted are where it isn’t cost-beneficial to make that change,” she says.

An added layer of complexity emerges when considering potential bandwidth-frequency conflicts with commercial 5G. Moyher suggests that the military must then make strategic decisions about “choosing bands that won’t conflict.”

All that being said, eventually the military is likely to fully lean into 5G, McKenney says. “The incremental flexibility of 5G offers expanded opportunities for targeted applications that can deliver important enhancements in a way that 4G can’t support,” he says.

Open architecture’s place

As 5G rapidly transforms defense technology, how does the omnipresent question of open architecture fit in? McKenney says that the DoD will be keenly interested in keeping systems open as 5G is adopted. (Figure 3.)

“5G Open RAN (open interfaces, not necessarily open source) is endorsed by DoD,” he says. “[Open architecture] provides flexibility to innovate more broadly, so a range of companies can deliver applications … which enable innovative solutions for military applications.”

[Figure 3 | Analog Devices’ 8T8R RU design platform serves as a solution from the optical fronthaul to RF, which enables hardware and software customization for macro and small cell radio units.]

The modular open systems approach (MOSA) framework has become critical to the point of “possible elimination of an award if there isn’t compliance,” Cordova notes.

“MOSA acquisition strategy is driving requests for white papers, requests for information, and consequently requests for proposals,” he says. “An open system architecture for 5G drives standardization and increases opportunities for broader adoption. The open source philosophy also drives faster installation and integration, and future upgrades using a MOSA-driven approach would allow plug-and-play upgrades and maintenance.”

Reduced SWaP and 5G

The U.S. military these days is constantly focused on reducing SWaP requirements for systems, a move that has implications for the future of 5G.

“In the aerospace and defense sector, some of the biggest growth opportunities are in satellite communications, as well as emerging 5G communications solutions for both on-battlefield and off-battlefield applications,” Microchip’s Gross says.

He highlights NASA’s pivotal role in fostering private-sector endeavors, crediting them with enabling the launch of thousands of low-Earth-orbit (LEO) satellites which are advancing a spectrum of services.

“These RF applications consistently seek SWaP-C, or size, weight, power, and cost benefits," he adds.

Dean White, senior director of defense and aerospace at Qorvo (Greensboro, North Carolina), says because the size and form factor for an RF device can impact its linearity and robustness, a larger device may be needed if linearity is a critical requirement. (Figure 4.)

“If the device is exposed to harsh, rugged environments, there should be consideration for durable, reliable components and packaging,” he says.

[Figure 4 | Qorvo’s QPF4001 is a multifunction gallium nitride (GaN) MMIC front-end module targeted at 28 GHz phased-array 5G base stations and terminals.]

In some areas, the interaction between the DoD requirements and the 5G components hasn’t materialized yet. Kocourek says that CAES is “not seeing DoD requirements affecting the components for 5G – it is actually the other way around.”

In fact, innovations from the commercial domain – specifically 5G – are fueling the DoD’s interest in SWaP-C reductions, she says.

Right now, the industry is trying to strike a balance between maintaining higher frequencies and meeting SWaP con-straints, Moyher says.

“Maintaining the higher frequencies as SWaP requirements continue to get stricter for these smaller antennas is a delicate balance,” she says, adding that coaxial cables and assemblies become indispensable to “maintain reliable interconnects, especially in tight spaces and under harsh operating conditions.”

Those same requirements are driving commercial 5G solutions as well, McKenney says. Analog Devices has used “innovative techniques” to cut power requirements; he says that by incorporating many programmable functions into their latest transceivers, they’ve managed to reduce energy hotspots that require larger heat sinks, a move that ultimately reduces size and weight.