June 13, 2017 —
Fifth-generation (5G) wireless communications may offer public safety agencies capabilities to improve their responses to emergencies. Emil Olbrich, president of PrimeLime, speaking at a conference in March, said the primary reason for public safety agencies to adopt 5G technology is for mission-critical, push-to-talk voice communications. He reported that most public safety communications is voice-centric, based on a callout from a public safety answering point (PSAP), which typically is an emergency communications center that answers telephone calls placed to the 911 universal emergency number.
The 3rd Generation Partnership Project (3GPP) included functionalities desired in future public safety communications systems in its standards-setting process for 5G. Olbrich said that in late 2015, 3GPP set up the System Architecture 6 (SA6) working group. The working group’s primary role is to evaluate public safety communications and justify 3GPP plans to develop standards to support requirements that must be achieved to support 5G communications for public safety agencies.
Olbrich listed 5G capabilities many public safety agencies desire:
· Ability to operate in harsh environments
· Two-factor authentication
· Loudspeaker phone
· Body camera
· Instant data access
· Haptic feedback (sense-of-touch interface)
· Mission-critical push-to-talk communications
Meanwhile, a European Union initiative that Olbrich reported on asked 3GPP to consider 74 descriptions, sometimes called use cases, of how 5G technology would be used. The EU named the initiative Smarter, which stands for new services and markets technology enablers for next-generation mobile telecommunications. A preliminary list of functional descriptions related to public safety for 5G standards yet to come from 3GPP is expected to be seen in the standards body’s Release 14 for 5G use of Long Term Evolution (LTE) high-speed wireless data technology.
3GPP’s Release 14 was frozen in June. Once a release is frozen, only essential corrections are allowed. At that point, 3GPP forbids adding and modifying functions. Olbrich said trials of the Release 14 requirements probably will begin in about a year’s time.
Olbrich said he conducted research in 2007 on behalf of the U.S. Department of Commerce evaluating multiple broadband technologies and concluded that LTE is the best one for public safety communications. The national public safety broadband network that AT&T will build under contract with the First Responder Network Authority (FirstNet) will use LTE.
LTE for public safety in the 3GPP standard is expected to provide for mission-critical video and data, enhancements to user location reporting and some of the EU’s Smarter requirements. Among the requirements Olbrich mentioned are ultra-reliable communications, Multimedia Broadcast Multicast Service (MBMS) public warnings, lifeline communications for natural disasters, remote control and connectivity for unmanned aerial vehicles (drones) and emergency services over a wide-area local-access network.
Additional public-safety related communications involve vehicles communicating with infrastructure, also known as vehicle-to-everything (V2X) communications. These include road safety services and vehicle-to-vehicle (V2V) emergency stop, for collision avoidance.
Key Corner Cases for 5G
Olbrich said three International Telecommunications Union key corner cases lie at the foundation of 5G. The main key corner case is enhanced mobile broadband (eMBB), which, he explained, refers to video downloads, principally supporting augmented reality, virtual reality and 4K video, with a few 8K video examples helping to support eMBB. Olbrich said AT&T reported that in the past five years since it deployed LTE in its network, it has seen a 250,000 percent increase in video traffic. The increase requires AT&T to add more radio-frequency spectrum to its network and to find better ways to use the spectrum. Olbrich said this is why 5G is so important.
A second key corner case Olbrich mentioned is massive machine-type communications (MMTC), used to communicate with many devices. He reported that a downtown London business district in a kilometer-square area populated by 52,000 people was defined for MMTC with 52,000 sensors served by one cell. He said it became a reason to justify MMTC.
For a key corner case germane to public safety, Olbrich identified ultra-reliable, low-latency communications (LLTC) — the ability to have fast communications that can puncture packets in the wireless data communications stream to insert emergency messages. He gave an example of interrupting a video stream in mid-frame for 407 microseconds, which is two symbol periods, less than a millisecond.
Olbrich said ultra-reliable LLTC is extremely important for V2V communications — remember the V2V emergency stop, for collision avoidance. 4G LTE has about 10 milliseconds of one-way latency; Olbrich said the goal for 5G is to reduce latency to 1 millisecond. He explained that a good 4G LTE network has about 50 milliseconds of latency from end to end, including the core network equipment and transmission line losses, the air interface and the packet core network (see Figure 1).
“In 5G, they re-architect the network,” Olbrich said. “They move more functionality to the network edge, and they want reduce end-to-end latency to 5 milliseconds. You might think, ‘What are all these numbers? What do they mean? I don’t understand.’
“Vehicles already communicate emergency stop information with people at extremely low latencies, faster than 5 milliseconds,” Olbrich said. “You just don’t know it. It’s called the brake light. Legacy brake lights were incandescent. Newer vehicles have LED lights. That’s the next generation of communication, communicating from a vehicle to a human being, to let you know it’s time to stop.”
Figure 2 shows an example of what Olbrich means. The curved line represents the time it takes for an incandescent light to reach full brightness after it is switched on. A vehicle brake light takes about 300 milliseconds to reach full brightness. “So, when I push my brake pedal, 300 milliseconds later the brake light is at full brightness,” Olbrich said. “That’s about 300 million nanoseconds. An LED light turns on in 100 nanoseconds. That’s 0.0001 milliseconds. That’s a huge difference. At 65 miles an hour, 200 milliseconds is about 19 feet. So, when people ask about a 5G use case, I say it’s about 20 feet.”
5G wireless technology will bring many advantages to public safety communications, thanks to the use of LTE high-speed wireless data and the standards-setting process at 3GPP that responds to public safety agencies’ input on what they need for emergency communications.
Emil Olbrich spoke on March 27 at the International Wireless Communication Expo’s Network Infrastructure Forum. In addition to serving as president of PrimeLime, he serves in an analyst role as vice president of network technology for Signals Research Group. He is one of the trainers at 5G-Courses.com.
Emil Olbrich, president of PrimeLime, speaking at the IWCE Network Infrastructure Forum.
Figure 1. 4G air interface latency is about 10 milliseconds. 5G could reduce that to 1 millisecond. For end-to-end network communications, 5G could reduce latency to 5 milliseconds, compared with 50 milliseconds with 4G.
Figure 2. A typical incandescent brake light switches on to full brightness in 300 milliseconds. An LED light switches on in 100 nanoseconds. At 65 miles per hour, a vehicle travels 19.1 feet in 200 milliseconds.