5G Network Digital Twins to Manage Urban Airspace

July 28, 2021 by Leslie Provenzano

Growth of Autonomous Aircraft Usage

In the age of autonomous systems, urban air vehicles are a growing trend. With 5G environments set to support a new era of city skies, how can the network infrastructure promise safety and performance?

Autonomous air traffic is on the rise. Drone technology has already proved useful for film and photography and is now emerging in agriculture, construction, emergency response, insurance, oil and gas, manufacturing, mining, and urban planning. Not only that, but the development of much larger pilotless air vehicles is progressing quickly, as evidenced by companies like XWing and Volocopter. The use of such Unmanned Aerial Vehicles (UAVs) – from personal use, ride sharing, and air taxis to deliveries and inspections – is expected to revolutionize travel and transportation.

Unmanned Aircraft and 5G

While traditional cellular networks are widely deployed and secure, they simply will not be able to support the seamless connectivity and long range that autonomous UAVs demand without significant upgrades. For one, antennas and channels designed for two-dimensional terrestrial use cannot provide coverage for UAVs moving in three-dimensional space. For another, a UAV operating at higher altitudes needs downlinks to multiple base stations at once, which current cellular protocols do not support.

5G networks deliver the performance required for aircraft operating in urban air environments and provide a solution to larger questions around coverage for UAVs traveling at higher altitudes and out of the line of sight.

  • They overcome the limitations of antennas and channels in 3D and multiple downlinks inherent in traditional cellular networks.
  • They can provide stable and fast transmission speeds, up to 10Gbp/s. High speeds and low latency are paramount for trusting an autonomous system’s capacity for real-time responses. Recent drone tests demonstrated a 40% improvement in latency by employing a standalone 5G network.
  • They provide strong and far-reaching connectivity, using which whole UAV fleets can use network slicing to create clear, dedicated signals even in dense environments, eliminating concerns over downlink signals becoming jammed or overwhelmed.

Challenges to Wide-spread Deployment of UAVs

For high volume operation of UAVs in dense urban airspace, technical challenges and safety concerns are both plentiful and critical. Several factors need to be addressed before UAVs can safely operate in urban areas.

Technical Challenges

The communication network used to control the UAVs should have sufficient capacity to adequately serve the large number and high density of aircraft expected to operate in urban environments. Flight patterns need to be optimized to ensure maximum network coverage while avoiding forbidden areas. Beyond no-fly zones, UAV operators and authorities also need to be aware of areas with diminished, temporarily unavailable, or non-existent connectivity.

Aspects such as radio signal strengths, bandwidth, latency, passive radar, MIMO, and beamforming must be taken into consideration when developing and deploying an effective 5G air management network. The infrastructure also needs to allow for new types of aerial vehicle sensors, avionics, and payloads.

Safety Considerations

As in current air traffic control, UAV operators need to track and avoid other moving objects which may share the airspace.

One of the most critical safety considerations is cyber threats that may significantly degrade, disrupt, or cause failures in the communication network. Cyber attacks can also corrupt or spoof the aircraft identities used by Identification Friend or Foe (IFF) and GPS locations used for tracking, thus compromising the safe operation of Unmanned Aircraft Systems (UAS) Traffic Management (UTM). The network must be resilient to cyber attacks at least to the extent that safe operation of UAVs is not jeopardized.

Regulatory Considerations

All manned and unmanned aircraft must conform with military and civilian regulations, such as avoiding no-fly zones and implementing tracking and identification requirements.

Entities like the FAA and NASA are currently working on air traffic management networks and procedures for a world where aircraft with and without pilots share the same airspace. However, to have confidence that the traffic management network can deliver the required performance, addresses the safety considerations, and complies with regulations, its design must be thoroughly tested before deployment. Additionally, even after deployment, the network needs to be continually evaluated as it evolves to address changing technologies, traffic requirements, and policies, procedures, and regulations.

Figure 1. Manned and Unmanned Aircraft in a Dense Urban Environment

Network Digital Twins as A Solution

Network digital twins are emerging as an invaluable tool for the aeronautics industry to address the above challenges. A network digital twin of a UTM system is a virtual representation of manned and unmanned aircraft and their flight paths, the control center which operates the UAVs, the communication network to support UAV operations, and terrain and weather characteristics that affect wireless communications. Representations of no-fly zones can also be included. Cyber attacks and their impact on communications can also be modeled. Network digital twins offer multiple benefits throughout the lifecycle of UTM systems, including:

  • A cost-effective and convenient platform to test UTM systems “at-scale”. They provide a safe environment to test the network supporting UAV operations. The impact of the 5G network’s topology, operational parameters, and the resulting connectivity, coverage, and latency on UAV operations can be easily assessed without using physical assets. Testing the system with real aircraft would be prohibitively expensive and time consuming.
  • Realistic operational scenarios that can be faithfully represented in network digital twins, which provide a highly cost-effective platform for training. Thousands of hours of experience and training can be achieved at a fraction of the cost of a system with physical components.
  • Designing the optimal 5G network which provides the services required for UAV operations by helping determine the most efficient network layout and operational parameters.
  • Providing a zero-risk environment for evaluating the cyber resilience of the UTM system: cyber attacks can be launched on the network digital twin and their effect on the system’s operations can be studied without endangering physical assets.
  • Comprehensive testing including physical factors such as weather and battery depletion.
  • The impact of advances in network technologies and alternatives can be evaluated before implementing them in a deployed system.

Figure 2. Network Digital Twin of 5G UTM

Network digital twins stand to increase the development speed of the support systems required for autonomous aircraft while also reducing costs. Replicating different environments in a lab and running multiple what if scenarios, offers a safe, efficient, cost-effective way to assess the system’s performance and safety under different conditions, which may include cyber threats. Thus, network digital twins can be used both before initial deployment to design the optimal communication network and after deployment to assess how changes in operational factors (traffic, weather, etc.) and evolving communication technologies impact the operations. Figure 2 shows a simple urban scenario with planned 5G tower placements that can be used to assess coverage and application throughput and latency for multiple what if scenarios.

Learn more about how SCALABLE’s EXata platform can be used to plan, analyze, test, and optimize any flight network using cutting edge network digital twin technology.