This is how 5G NR for public safety could save lives

Imagine firefighters entering a smoky and burning building on a search and rescue mission, protected by safety monitoring data sent from their personal protective equipment (PPE) to the control center. Medical service personnel are saving lives on the field with remote support from medical experts at a hospital, or drones transporting critical medical equipment to a hazardous infectious area. First responders, such as fire-fighters, policemen and emergency medical service personnel, require fast, reliable and secure communications in various mission critical (MC) situations such as these, where availability of communication can be a question of life or death.

Traditionally, the public safety community has used specialized land mobile radio (LMR) systems for push-to-talk (PTT) as its primary mobile communication system. TETRA and P25 are the predominant in use PTT systems. These narrowband communication systems can only provide voice-centric services with limited data capabilities. As different public safety institutions typically use different networks (frequencies and technologies), inter-agency communication can be difficult to coordinate.

Legacy public safety networks require modernization to improve the safety, situational awareness and operational effectiveness for first responders. It is now a global trend that the LMR systems are being replaced by 3GPP LTE/NR broadband networks in order to support more advanced  use cases and MC services, like MC real-time video, augmented reality AR, and heads-up display. Fast and reliable voice communications should be guaranteed between public safety agencies and beyond national borders. Life monitoring data from safety sensors must be shared instantly to command centers to enable better decisions that can save lives. Robots and drones empowered with augmented reality and haptic technology can be remotely controlled by the network for real-time video streaming and even for conducting complex rescue operations.

In this research blog post, we discuss how different 5G NR features can be utilized to support advanced public safety use cases. The following sections introduce standardized 5G NR solutions, as well as future enhancements, in the areas of coverage extension, group communication, user priority handling, situational awareness and network resilience.

The role of 5G in public safety: connectivity everywhere

Typically, operators lay out a well-studied and optimized network deployment plan, based on the density of the population within a territory. However, in disaster and emergency situations, the cellular coverage and capacity provided by the network at this particular geographical location may not be sufficient. In such a situation, additional means are required to support reliable, mission-critical communication.

To guarantee coverage and capacity for first responders beyond areas typically available for commercial user equipment (UE), several network coverage extension solutions already put in place in current release of 5G NR (Rel-16) can be applied for MC services. These solutions for coverage and capacity will continue to evolve to include enhancements and new features in future NR releases (Rel-17 and beyond).

Different 5G NR technology components for coverage extension are illustrated in Figure 1. In areas with limited coverage, public safety network operators can apply advanced antenna systems, together with beamforming techniques supported in NR to increase signal strength in a particular direction to better serve MC communication needs in an area. Integrated access and backhaul (IAB), a multi-hop wireless backhaul relaying feature introduced in NR Rel-16, is also a very good candidate for flexible network coverage extension for public safety. In the future, public safety network operators will be able to set up flexible temporary networks by mounting portable IAB nodes on emergency land vehicles, referred to as cell-on-wheels IAB, and even on unmanned aerial vehicles (UAV), i.e., cell-on-wings IAB, such as drones to provide coverage to isolated areas.

Figure 1. 5G NR coverage solutions for public safety

When out of network coverage, sidelink (SL) communication, specified in NR Rel-16, is a key feature for public safety users to facilitate direct device-to-device communication. SL communication can also be used to extend the coverage by using the UEs for relaying. In NR Rel-17, two SL relaying features will be studied, including UE-to-network relay for network coverage extension and UE-to-UE relay for SL coverage extension.

To allow communication in situations where the connection between a base station and the core network is not available or in the event of connection loss, a solution called isolated E-UTRAN operation for public safety (IOPS) has been standardized for LTE. This solution provides isolated communications within a base station, or a set of base stations, using fully self-contained local core functionality. Similar solutions are expected to be introduced in a later NR release.

Building efficient communication for first responder groups

First responders typically work in groups and communication within their groups is essential for efficient coordination during an emergency. Services such as MCPTT, MCVideo, group messaging and broadcast of emergency messages allow these personnel to communicate within their groups. A common characteristic of these services is that a common set of data needs to be transmitted to all the users within a group, as shown in Figure 2. It is therefore beneficial to transmit this data to a group using a minimum set of resources to reduce the spectrum and time needed as much as possible. The resources can instead be used to serve more first responder groups and other users.

Figure 2. Group communications for public safety services

With these services and benefits in mind, an enhanced Multimedia Broadcast Multicast Services (eMBMS) framework for enabling efficient group communications has been established in LTE networks, and a multicast and broadcast framework to enable similar functionality is being developed in 5G NR Rel-17. The 5G NR broadcast mechanism will build on the already feature-rich unicast design, with the goal of minimizing the feature implementation cost at the user equipment, thereby reducing the time to market.

Furthermore, to improve the reliability of group communications, acknowledgment feedback for multicast transmissions is being developed for NR broadcast feature, which can be combined with Hybrid Automatic Repeat Request (HARQ) retransmissions to improve system spectral efficiency. Moreover, the NR multicast and broadcast feature promises the ability to dynamically switch between unicast and multicast transmission, which enables the existing unicast features of NR to serve smaller groups more efficiently.

Ensuring priority and quality

When a major emergency occurs in a small area, there can be a high demand of mission critical traffic for supporting first responders’ rescue operations on site. At the same time, the data traffic generated by general public users can increase significantly, for example, making emergency calls, sharing information to friends or relatives. If first responders and general public users share the same network, higher priority must be given to the first responders to ensure a fast connection to the network and to secure MC traffic during incidents of network congestion. In some cases, different priorities between different first responders and different MC services are also required. These requirements can be met by utilizing different NR features and functionalities to restrict regular users from accessing the network (as illustrated in Figure 3), together with different traffic management solutions for users that are already connected to the network.

NR has introduced a unified access control (UAC) framework, which is enforced at the UE side for access restriction. Before the UE sends a connection request to a network, the UE will determine if it is allowed to send the request or not. This is done by checking the broadcast system information received from the network, and the user or service priority information stored in the UE. In a high traffic load situation, the network can configure the broadcasted system information so that the connection requests from first responders are allowed, but the requests from regular users are barred.

Figure 3. Different levels of network accessibility based on user or service priorities.

If the connection request from a user is permitted, then the user can perform a random-access procedure to establish a connection to the network. During this procedure, the network can identify the service type or the UE access identity that triggers the connection request. Utilizing such information, the network can control the access request from each user individually and reject the requests from regular users when necessary.

Once a user is connected to a 5G NR network, the network can acquire QoS, Priority and Pre-emption (QPP) related parameters of the requested service, like the network slice ID, the 5G QoS Indicator (5QI), and the allocation and retention priority (ARP), and so on. Based on these priority identifiers, the RAN scheduler can perform differentiated traffic management and apply load balancing mechanisms to prioritize important MC traffic flows and pre-empt non-MC traffic during resource limitations.

Situational awareness and operational efficiency

Acquiring situational awareness is key for first responders arriving at a rescue site. This information is used to help first responders better assess and plan an ongoing operation, making sure they can do their jobs in a safe and efficient way.

One important component of the situational awareness is the ability to locate first responders and/or the equipment being used throughout a rescue operation. The current NR specification includes both device-centric positioning solutions and network aided positioning solutions. A first responder can share their position, signal measurements, and/or relevant information from sensors with the network or with other first responders. Additionally, the 5G network can provide direct positioning support, by transmitting down link positioning reference signals (PRS) for example, or measuring on uplink sounding reference signals (SRS).

Through some of its key features and technical components, 5G NR can enhance the positioning capabilities of the network. By exploiting the large bandwidths available in the high frequency bands, together with directive transmission of positioning signals using beamforming, more accurate positioning can be achieved. Additionally, the use of IAB enables the possibility to flexibly deploy additional temporary base stations in the vicinity of a rescue area. By adding supplementary communication links to a first responder, these additional base stations can contribute to further increasing the accuracy of positioning services provided by the network, enhancing the situational awareness, as shown in Figure 4.

Figure 4. 5G NR IAB based accurate positioning for first responders.

Drone communications, a feature standardized in LTE that will be introduced in NR Rel-17, is another feature that can be utilized for improving situational awareness and operational efficiency for first responders. As demonstrated in a public safety drone trial in Canada, cellular network connectivity can enable reliable and beyond line of sight remote control of public safety drones. In this trial, a drone delivered automated external defibrillators (AEDs) to a remote site, showcasing the possibility to reduce time-to-treatment for remote cardiac arrest victims. A public safety drone can also be used in search and rescue operations for delivering sensory information and real-time video to the incident commander and the control center.

Ensuring high network availability and reliability

Cellular networks offer features and mechanisms to make the network resilient to failures and to provide ultra-reliable communications.

The cellular network typically relies on a core network to host services and manage a network of base stations that enable communication between users. In the case of a natural disaster, the connectivity between the base stations and the core network can be lost, making these base stations incapable of serving the users. To make the network resilient to such events, the functionalities supported by the core network can be enabled at each base station or at a subset of the base stations. The IOPS solution – a feature standardized in LTE and to be introduced in NR – allows a single base station or a group of base stations to serve the first responders independently of the core network when needed.

‘Self-healing’ networks, where the network adapts its parameters to cope with a network failure event, can be established to continue to serve the first responders in mission critical situations. When one or a few base stations of the network are damaged due to a disaster or urban fires, the base stations located close to the rescue area can adjust their cell shapes to focus on serving first responders, by narrowing the beam or directing the beam towards that rescue area.

The ultra-reliable low-latency communication (URLLC) feature of 5G NR provides MC services with very strict reliability and latency requirements, like those needed for remote controlled robots, or drones in a hazardous situation. Furthermore, redundancy in terms of available resources and the number of base stations needed to provide the necessary coverage can be used to improve the resiliency of the network in case of unforeseen events.

5G NR for public safety: ensuring connectivity that helps save lives

As we have presented in this blog post, 5G NR offers several powerful and flexible features that can secure reliable communication for the public safety community. The 5G NR networks can not only provide basic voice and data services, they also open up new, flexible deployment solutions and innovative services. This will improve coverage, accessibility and resilience of the networks, and provide improved communication capabilities and situational awareness for first responders.
Furthermore, the NR standard will continue to evolve in coming releases to address public safety communication needs, enabling 5G NR to help make sure the public safety community saves lives.

Learn more

Read more about Mission Critical networks.

Read our paper, 5G evolution: 3GPP releases 16 & 17 overview.

Explore advanced antenna systems for 5G networks.

Learn more about Cellular IoT

Unleash the drones! Learn how drone use cases can save lives.

Read more about the EU Primo-5G project

Read more about Core network