By assuring 5G product and system performance throughout the design cycle, system designers can reach their goals while advancing military and government capabilities.

Communications for military and government applications has evolved from analog to video, high-resolution imagery and the rapid adoption of new users. Today’s critical communications networks serve military, government and public safety personnel with ad hoc communications to boost networks in emergencies and fill coverage holes. 5G cellular further extends the capabilities of critical communications, such as 5G networks on bases, deployed to respond to emergencies, or on the battlefield.

Beyond tactical communications, 5G will enable new applications for military and government, such as autonomous vehicles and robotic surgery, and 5G non-terrestrial networks (NTNs) will help make these a reality. To assure performance, however, these different applications require unique approaches for design and test. By taking a multi-step approach, designers can ensure that products seamlessly integrate into the final design, and the design supports all the promises of 5G for military and government users.

5G IN SPACE

Figure 1 One of the enabling technologies for NTN is the global navigation satellite system (GNSS).

Using spaceborne or airborne assets, for example, 5G can enable service in areas of the globe that don’t have coverage (see Figure 1). Tactical military users can use this capability to establish communications over new terrain, in the air or at sea. First responders responding to emergencies in forests, mountains or other areas where communication is not available can also leverage these capabilities.

Researchers and developers who want to tap into NTNs face several challenges. The 5G NTN standard has not yet been developed, so commercial equipment isn’t available—not even prototype commercial equipment—so other ways to research, prototype or develop these systems are required. No matter the final application, however, the architecture will start with the user equipment (UE) or device block. The UE normally communicates with the base station, called the gNodeB in 5G networks. The 5G core network is known as the next-generation core. Unfortunately, commercial off-the-shelf (COTS) UEs and gNodeBs will not work for NTNs because of the amounts of Doppler and delay in spaceborne communications links. The process to develop NTN requires a “crawl, walk, run” approach starting with basic software modeling, with the software modeling tool including the following: downlink and uplink transmit and receive chains of the UE, the gNodeB, the signal propagation to and from the satellite, the motion of the satellite, the antennas and the delay and Doppler through the system.

Using global navigation satellite systems, the UE can establish its own position, frequency and time reference and compute the time and frequency difference from the satellite signal and apply timing advance and frequency adjustments. Each UE will pre-frequency shift its transmission to counter the Doppler shift from the motion of the satellite. The gNodeB must also do this, but in a way common to all the served UEs, no matter their locations. When a UE attaches to the network and looks for a base station, it must assume a greater range of frequency offsets than with a terrestrial link.

Figure 2 The 5G NTN testbed combines this channel emulator with a network and UE emulator to enable research, prototyping and development before commercial equipment is available.

Prototypes with COTS devices are not yet available, but NTN links can be simulated in software and prototyped with emulators. Hardware emulators are more easily customizable for mimicking NTN links (see Figure 2). Initial prototyping can be done in a lab or a chamber on a small scale. Once satisfied and when NTN equipment is developed and available, prototyping with actual equipment in the lab or in a chamber is wise, again on a small scale and followed by full-scale implementation with the actual equipment on the target platform. After development, periodic maintenance testing should also be performed.

VEHICLES: 5G ON THE MOVE

Soon, we will see 5G links in the air for unmanned aerial vehicles, other aircraft, ships, Humvees and other vehicles. Outfitted with 5G for long-haul communications, these vehicles will use 5G to enable communications, high data rate video conferencing and IoT sensors. Eventually, these capabilities will evolve into integrated systems for self-driving or autonomous vehicles, aiming to eliminate soldiers from some missions. Initially, a hybrid approach will require that soldiers remain in the loop to oversee vehicle performance.

Use cases range from vehicles used on base, which will improve energy efficiency, to field and/or combat vehicles. The development projects spurring this progress focus on advancing methods for vehicles to identify and understand their surroundings. Examples are radar, lidar and other sensors. Artificial intelligence (AI) and machine learning must sort through, process and act on this information. Connecting all the information is critical to system success, setting expectations for 5G performance in a crowded and complex signal environment.

Ships, planes and ground vehicles have different types of transmitters and receivers: telemetry, communications, radar, satellite links and surveillance. All must operate simultaneously without compromising the performance of the other systems or, worse, damaging them. If not designed with adequate margins, for example, radar signals can damage sensitive satellite receivers. Adding 5G to planes, ships and other vehicles makes the RF environment more complicated, with potential electromagnetic compatibility issues. Careful planning must take place so that all the systems can operate simultaneously and safely. By first modeling the communications link and other signals in software, potential issues can be identified and addressed early in the development. The software tool should model the downlink and uplink transmit and receive chains of the UE, the gNodeB, as well as the signal propagation of the other communications systems on the vehicle.

Figure 3 Model-based design across baseband and RF can simulate 5G base stations and UEs, radar, communications and DVB signals.

During the planning phase, simulating signals in software can assess electromagnetic compatibility using a 3D model of the deployment platform (see Figure 3). The finite-difference time-domain (FDTD) method is based on volumetric sampling of the electric and magnetic fields throughout the complete space. This method updates the field values while stepping through time, following the electromagnetic waves propagating through the structure. A single FDTD simulation can provide data over an ultra-wide frequency range.

Following modeling, confidence is increased by prototyping the signals in the lab, on a small scale, to gauge the performance in the field. Hardware emulators, which can be easily customized and adapted, can be used in place of COTS equipment, with other emulation equipment or signal generators used to simulate the signals seen in the real world environment. Measurements of the prototype can assess electromagnetic compatibility. Once satisfied with the performance of the prototype, full-scale implementation follows, deploying with actual equipment on the target platform. After the system is deployed, periodic maintenance testing follows to assure the continued performance of the system.

ROBOTIC SURGERY

In addition to autonomous vehicles, the military landscape will evolve with greater integration of robotics and exoskeletons, all employing AI. Advances in AI will ease soldiers’ workloads and physical burdens while improving situational awareness. Using 5G will enable development of robotic surgery, an application that will transform medical care for military personnel.

In a conflict, medical response time determines survival. With extensive injuries and blood loss, the time to perform life-saving procedures is very short. With robotic surgery, military doctors can quickly perform operations from a distance, using robotic arms and cameras. Housing this equipment on medical vehicles eliminates the need to transport patients to another location before receiving treatment.

For remote surgery to succeed, however, these highly intelligent systems must work under a variety of environmental conditions with no downtime. Eventually, the goal is for these systems to be so intelligent they perform some procedures with minimal or no oversight. The adoption of 5G offers the possibility for connecting soldiers with remote medical personnel by supporting high data rates and latencies approaching real time.

The 3GPP, which oversees 5G standards development, has defined ultra-reliable low latency communications (URLLC) for critical networks. The standard defines the typical latency of an end-to-end connection between the client and server of just 2 to 3 ms and as low as 1 ms. The standard assures the network is configured to provide an ultra-reliable and low latency connection between the device and the cloud. By adapting URLLC to work from space, 5G NTN can provide high reliability on a widespread basis.

URLLC’s potential, however, comes at a cost. Harnessing the components required to make URLLC work presents significant challenges across the wireless communications spectrum. Chipset and device suppliers face design and test constraints, and network equipment manufacturers and mobile network operators must address network latency and reliability demands. URLLC requires all the elements of the network—chipsets, devices, networking equipment and controlling software—to deliver to achieve the promise of applications like robotic surgery.

THE FUTURE

These new applications enabled by 5G promise to transform the capabilities of military and government. To support the development of these use cases requires successful development and innovation projects. Successful development can be achieved with the following approach:

• Simulate or prototype the 5G advancement or feature with software
• Perform development and integration testing, where the prototype equipment has the capability to control, observe and repeat testing the functionality
• Characterize the performance of the complete system with the real hardware and software
• Test and assess the security of the finished solution.

Despite their promise, new capabilities will be diminished if they cannot deliver adequate reliability. Service cannot go down in life or death scenarios. As cybersecurity risks increase, data reliability becomes critical. If the data being transmitted is compromised, devices, patients and whole operations are at risk. By assuring product or system performance throughout the design cycle and then monitoring it throughout the system life cycle, advancing military and government capabilities can be achieved. As 5G technology evolves, so do the risks—especially when it comes to reliability and security. The latest developments and processes must be implemented to guarantee the performance users need and assure their safety.