5G Critical Communications: Ready for Duty?

5G Critical Communications: Ready for Duty?
 

No one should be surprised that talk of 5G technology has arrived in the critical communications sector. Agencies responsible for public safety communications supporting law enforcement, fire operations, and emergency medical services must pay attention to emerging technology trends. But at a time when mission-critical LTE technology is starting to enter the operational world of public safety agencies, the accelerated arrival of 5G naturally raises important questions for critical communications agency leadership. With 5G now on the horizon, should agencies defer mission-critical LTE deployments? What happens to mission-critical LTE technology when 5G enters the picture? Why does 5G matter to public safety critical communications practices?

These questions are legitimate points of concern for agency officials. Mission-critical communication technology investment taps scarce taxpayer funds and requires careful integration into end-user operational practice. At the same time, legacy professional mobile radio systems – those TETRA, Project 25, or analog radio networks providing voice communications – may need to be refreshed or replaced. Interest in modernization aside, the arrival of a new generation of mobile broadband radio technology means officials must contend with yet another puzzle piece to an already complex challenge. In this insight report, we will consider these questions and offer recommendations to the agencies, suppliers, and network operators supporting public safety critical communications systems.

 

What is 5G ... and why is LTE not enough?

 

Historically, mobile radio technology lurches ahead with radical new functionality every ten years. These generations, starting with analog 1G systems of the 1980s, bring a harmonious set of new radio access network infrastructure and device capabilities into existence with painstaking attention towards interoperability between system elements. After its introduction, of course, a mobile generation will continue to evolve with backward compatible enhancements. Eventually, however, new desired features call for modifications that cannot co-exist with system or device elements present in the field. These advances become the basis for the next generation.

The cadence of generational change is arbitrary but based on the practical need to collect a critical mass of innovation that can warrant expensive and disruptive programs of a technology refresh. These innovations emerge thanks to advances in fundamental research in academic circles and industry labs. Innovations also materialize as vendors and network operators gain real-world experience with deployed technology. Lessons are learned, leading to enhancements that are introduced to reduce cost and improve performances. When enhancements break interoperability with existing equipment and devices in the field, the new capabilities become candidates for the next wave of generational change.

With 5G, mobile broadband radio technology gains several substantial new capabilities that 4G LTE does not support:

Flexible use of time and space over the radio link to open up sizable contiguous spectrum blocks: LTE introduced OFDM techniques into the cellular radio transmission. The resulting rigid grid mapped space – spectrum width – and time using proven transmission techniques for combining overlapping radio signal components. But this fixed time and space numerology created challenges when accommodating massive bandwidth becoming available in higher spectrum bands. 5G New Radio (NR) moves to flexibly numerology that enables grid dimensions to be set optimally for a given spectrum band. Large swaths of untapped millimeter spectrum can offer throughput that approaches 10 Gbps, a sharp contrast to lower band LTE performance that hits limits 1 Gbps.

Future-proof radio air interface: The radio air interface supports a wide variety of digital streams. The LTE air interface lacks a means for old devices to ignore new types of incompatible digital traffic. With 5G NR, legacy devices have a method to ignore portions of the space and time grid that support new functionality the legacy device cannot handle.

Ultra-high reliability and low latency (URLLC): LTE enables a robust mobile broadband experience. But the acknowledgment mechanisms employed by LTE to recover from lost data resulted in round-trip delay that limited time-sensitive applications. With changes to the acknowledgment process, 5G NR drives down the latency of transmission across the air interface. Future changes in edge computing will further drive down delay by removing transmit time across the core network. Along with improvements in latency, the 5G NR provides mechanisms supporting ultra-reliable transmissions that go beyond LTE-levels of reliability.

Energy efficiency: The 5G NR air interface is designed to enable reduced power in portions of the grid where transmissions are not in progress. These efficiencies reduce the cost to operate and help 5G devices save battery life.

The radio air interface that 5G brings is an important step forward, but more radical change is coming in the system architecture that governs how the 5G air interface is used. The first release of 5G moved to market quickly, however, and this 3GPP Release 15 version brings a system architecture that implements features aimed at enhanced mobile broadband. Features required for massive IoT, ultra-high reliability, and ultra-low latency will be defined in future 3GPP releases. For public safety operations, this means that the primary advantage of 5G will be limited to very high bandwidth that becomes available when frequency bands above 6 GHz are tapped.

Beyond the first 5G deployments that remain limited to simple mobile baseband services, the future system architecture enables the network of interconnected gateways, servers, subscriber identity databases, and mobility management mechanisms to support simultaneous operation of radically different use cases over a single 5G radio air interface. One important concept that is promised with later releases of 5G is network slicing, a logical partitioning of traffic into flows with deterministic transmission characteristics. With network slicing, a single radio air interface can support both general mobile customer traffic along with private traffic streams for enterprise traffic. Each of these streams operates as a separate pipe with the traffic in one stream hidden from the others as the data flows from the device and across the network. While it is too early to tell what the impact of network slicing on public safety critical communications will be, the technologies potential is significant because it enables deterministic access shared radio resources using a model that should offer compelling economics.

 

Should agencies skip mission-critical LTE?

 

As the expansive and tantalizing 5G vision takes shape, the natural question arises for public safety critical communications network managers: should agencies skip mission-critical LTE and await 5G? Given the lengthy government procurement process, such a question is reasonable. The answer, however, is a definite "no."

There are many reasons why mission-critical LTE must be the choice for public safety officials for the coming years:

Mission-critical LTE provides a stable and robust communications platform today: The current suite of mission-critical features in LTE arrived over multiple 3GPP standards releases. Guided by the requirements of the ambitious US FirstNet and UK Emergency Services Network programs, the 3GPP standards development organization incorporated fundamental capabilities needed for mission-critical traffic handling. These new LTE features provide a foundation for LTE-based mission-critical push-to-talk voice communications. With LTE networks in several major nations now supporting these capabilities in live operation, the functionality is getting a real-world test under demanding circumstances. IHS Market believes advanced 5G networks supporting mission-critical functionality will not enter the market until 2022. The long process of building public safety operational trust in the new 5G technology will require several years following introduction.

LTE continues to evolve: The initials LTE stand for long-term evolution, and LTE continues to gain new functionality even as 5G appears in the market. While the rigid LTE air interface structure may not change, enhancements in multiple-in/multiple-out antenna technology, advanced radio modulation codings (e.g., moving from QAM16 to QAM256), and a growing range of radio carrier aggregation combinations have brought potent enhancements in data throughput capacity. Likewise, refinements to the LTE interface is bringing one-way radio link latency down to under one millisecond. With this evolution, public safety agency investment in LTE today will deliver benefits for years to come.

The first 5G phase has limited functionality: The mobile industry accelerated 5G progress by splitting the features across two 3GPP releases. The first phase, in 3GPP Release 15, delivers on the promise of faster mobile broadband by opening up higher spectrum bands. While much of the groundwork is established for advanced features needed for public safety critical communications, the first 5G networks do not support the full range of 5G features. Worse, multimedia broadcast capability, an important feature required for the large-scale operation of mission-critical push-to-talk, is not even slated for 3GPP Release 16. With broad Release 16 network deployments unlikely before 2022, commercial 5G support for multimedia broadcast may not be available until the 2024 timeframe. Public safety operations will continue to require LTE until that gap is addressed.

Subsequent 5G phases introduce a radical change in network operation: Along with 5G NR, the new radio air interface, a dramatic redesign of the core network that links the 5G base stations is in progress. Initially, however, new 5G base stations remain connected to a core network based on traditional LTE technology. This operation is called a non-standalone (NSA) because of the dependence on LTE core network support. Pure 5G networks, called standalone (SA) networks require a deployment of a dramatically different core network architecture that includes a microservice-based architecture along with network slicing mechanisms. This continued reliance on LTE core networks means that many of the most advanced 5G features must wait until 5G network operators are ready to invest in costly upgrades to legacy core networks. For public safety operations, it will take several years after the SA networks are operational to gain trust in its reliability and robustness.

5G is architected to co-exist with - and complement - LTE: In a departure from past generations that assume older generations of technology are eclipsed by the new, 5G is designed to give devices simultaneous connectivity over LTE and 5G air interfaces. Even within an air interface, techniques for spectrum sharing allow LTE and 5G to co-exist with minimal efficiency loss. These features ensure there will be no flash cut from LTE to 5G. As long as LTE is required to solve customer problems, the technology will remain available. And because the two technologies are designed to co-exist in harmony, network operators will face lower barriers to introducing 5G. This compatibility means public safety agencies will have opportunities to supplement LTE with 5G mobile broadband to support high capacity applications such as video.

Without question, the complete 5G vision is compelling. The introduction of ultra-reliable and ultra-low latency air interfaces, network slicing, and edge computing should translate into remarkable new applications that are difficult to imagine today. But while 5G will deliver significant benefits over time, public safety critical communications agencies are unlikely to depend on these capabilities for operational success. The basic critical communications requirements are amply met by mission-critical LTE supporting 3GPP Release 13 and above.

 

How 5G can make a difference for emergency services operations

 

As emergency services agencies expand the use of LTE mobile broadband technology to supplement professional mobile radio systems, the arrival of 5G capacity and speed brings the promise of improved operational effectiveness. As an architecture, 5G can operate on low-frequency bands below 3 GHz. But delivering on the promise of very high capacity and speed requires access to the new larger high-frequency bands 5G NR enables above 6 GHz.

Unfortunately, the challenging propagation characteristics of these higher bands require advanced massive multiple-in/multiple-out antennas with limited range. The high cost of delivering this coverage means that public safety agencies seeking 5G support for very high data rates will find these services limited to islands of coverage surrounded by lower speed LTE or 5G coverage operating in smaller frequency bands. In short, 5G may be attractive and available for use in emergency services operations, but it will not be a ubiquitous layer of coverage that agencies expect with voice communications.

Given these limitations, how does 5G technology deliver value to emergency services agencies? Where high-capacity 5G radio access is supported, agencies can leverage the ample bandwidth for video transmission. Lower capacity LTE networks are challenged by the demands of video, but large radio channels enabled by 5G NR handle these demands with ease. This capacity advantage can solve challenges with video surveillance, and drone video downlink feeds. Because 5G is based on a deterministic scheduled air interface – in sharp contrast to unlicensed air interfaces such as Wi-Fi – the transmissions are protected from interference.
 

Reccomendations

Emergency Services Agencies

 

As 5G gains momentum, do not lose track of the benefits that LTE offers. Remember that LTE continues to gain enhancements in coming 3GPP standards releases. Some of the upgrades will bring LTE closer to 5G capabilities.

Anticipate leveraging 5G as part of a long-term technology vision. Pressure your mobile broadband supplier for roadmap vision and sufficient details to enable informed decision processes.

When drafting RFPs, be sure to incorporate flexible language that allows the freedom to utilize 5G if, and when, the technology becomes part of a network operator's offering.

Evaluate early enhanced mobile broadband 5G service offers for use with video applications and mobile gateways. These applications do not require more advanced 5G features but will benefit from faster mobile broadband service that should be readily supported soon after 5G arrives in your region.

Keep in mind the fact that higher throughput with 5G comes as a result of operating in very high-frequency bands. The economic basis for network operators to support these bands in lower-density population areas is weak. As a result, your agency will not have universal access to high capacity 5G, and your operational plans should not assume the capability is available. Know your operator's coverage.

Network Operators

 

Avoid over promising 5G functionality to specialized verticals such as law enforcement, fire/rescue, and emergency medical service operations. Be realistic when communicating the benefits and limitations of planned technology offerings.

Ensure a broad coverage umbrella of advanced LTE across your service area. Offering higher order MIMO antennas, advanced modulations, and ample carrier aggregation can go a long way to smoothing the performance as users move from small 5G coverage islands to the broader LTE footprint.

Take advantage of 5G spectrum sharing features offered by the LTE and 5G equipment suppliers. One radio carrier can simultaneously support 5G and LTE to provide a smooth transition of technologies.

Equipment Suppliers

 

Suppliers offering mobile routers for emergency services vehicles should incorporate 5G NR modules that are now coming into the market. Because these routers have easily swappable interfaces, mobile routers should be one of the devices that bring 5G into agency operations. For specialized vehicles such as mobile command centers, 5G can bring substantial operational benefits. But ensure useful LTE fallback capabilities remain available on the mobile gateway.

Suppliers offering hybrid handset devices that combine TETRA/P25 voice with mobile broadband should be cautious about incorporating 5G. The limited 5G coverage areas above 6 GHz sharply constrains the value to field personnel. On the other hand, do consider integrating support for 5G operating at 3.5 GHz. The wider transmission channel can provide a significant boost to video transmission or reception.

Suppliers offering drone solutions should consider using LTE for support of beyond visual line of sight (BVLOS) flight along with 5G for video downlink transmission where 5G is available. Because the value proposition of drone operations supporting public safety programs is centered around situational awareness, the incorporation of 5G in addition to LTE helps cement the drone's value. That said, 5G offers very little beyond LTE when it comes to BVLOS communication. The URLLC mechanisms promised by 5G are not required for BVLOS flight.