Updated: FirstNet supports eMBMS one-to-many capability, set for FirstNet PTT on iOS devices this month

[Editor’s note: This article was updated on April 15 to include clarification about current and future network-integration plans for FirstNet Rapid Response. It also addresses AT&T’s long-term plans for interoperability between FirstNet PTT and FirstNet Rapid Response—functionality that does not exist today.]

FirstNet soon will offer 3GPP-standard mission-critical-push-to-talk (MCPTT) service on Apple iOS devices, and the public-safety LTE network can deliver efficient one-to-many broadcast communications via evolved multimedia broadcast and multicast services (eMBMS) LTE technology, according to an AT&T official.

Scott Agnew, assistant vice president of FirstNet solutions for AT&T—the nationwide contractor building the nationwide public-safety broadband network (NPSBN)—said these capabilities are part of a series of enhancements to the FirstNet MCX portfolio being announced last month and this month.

Given the popularity of Apple devices in the public-safety sector, having an iOS-capable version of FirstNet PTT—the Samsung-powered MCPTT offering—available is important, Agnew said.

“We wanted to have it at the same time as the launch [in March of the latest version of] FirstNet PTT, but we’ll have it this month,” Agnew said yesterday during an interview with IWCE’s Urgent Communications.

During the IWCE 2022 event conducted a few weeks ago, multiple entities outlined plans to adopt MCPTT over FirstNet for primary mission-critical voice communications while abandoning aging, limited LMR systems. But such announcements have been rare, in part because of two technical limitations for FirstNet PTT: an inability to deliver one-to-many communications and direct-mode communications.

FirstNet has taken a big step in addressing the one-to-many issue by making the NPSBN capable of supporting eMBMS, the 3GPP standard that is designed to let one-to-many communications—voice, data and video—be broadcast efficiently to a group of users, instead of being delivered on an individual basis.

“For the end customer, you get to broadcast one-to-many—the talk groups, video—that’s what you value,” Agnew said, noting that eMBMS-enabled talk groups can be much larger than those lacking the broadcast capability. “To us [as the network operator], it’s just a more efficient use of capacity, too.

“eMBMS has multiple values—for the customer, for the network—and we’ve got to protect public safety’s network.”

Although this eMBMS capability has been enabled on the FirstNet system, AT&T did not make a “loud” announcement last month, because the eMBMS functionality initially is limited only to users of the Samsung Galaxy XCover Field Pro device, Agnew said.

“You need the network, and then you need the devices—the network’s rolling out capability, and now it’s the devices that need to catch up,” Agnew said. “That’s the same thing that always happens.

“Just like we did with [encouraging device makers to include support for operations on 700 MHz] Band 14, we’re seeding the market and making sure that OEMs are integrating eMBMS. It’s small now, but clearly it’s starting the discussion about, ‘Hey, we need eMBMS in these devices,’ and how it’s going to benefit public safety.”

Many in public safety have focused on the ability for eMBMS to deliver one-to-many push-to-talk voice calls—mirroring a key feature of LMR systems—but Agnew acknowledged that the eMBMS broadcast capability is even more important to deliver high-bandwidth MCVideo in an efficient manner.

While the eMBMS progress represents a significant step in FirstNet addressing the one-to-many communications, delivering a solution that allows MCPTT users to communicate with each other when outside coverage footprint of the terrestrial LTE or 5G network remains a challenge, Agnew said.

3GPP create a proximity services (ProSe) capability within the LTE standard to support direct-mode communications between devices—conceptually similar to simplex mode in LMR systems—but it has not gained traction. At the heart of the problem is the fact that low-powered LTE devices with internal antennas can only support direct-mode communications for about a half-mile distance, while high-powered LMR devices with external antennas let simplex users talk to each other from miles away in similar conditions.

Agnew—who delivered a keynote address at IWCE 2022 (see picture above)—said that AT&T has “nothing to report right now” about direct-mode functionality. However, the carrier remains committed to finding a solution that will work effectively for FirstNet users that may need to communicate in locations where terrestrial network coverage is unavailable, he said.

“We’re still looking at direct mode—it’s very important for public safety,” Agnew said. “We’re still looking at various options and solutions. We are definitely committed to figuring out how to do that, but right now, we know ProSe didn’t have the distance necessary [to meet public safety’s signal range for off-network communications], so we’re looking at the standard to see what’s there.”

In addition to FirstNet PTT developed by Samsung, another push-to-talk option is FirstNet Rapid Response, which is based on the Kodiak technology owned by Motorola Solutions.

“It [FirstNet Rapid Response] is definitely a premium solution,” Agnew said. “It supports more devices, has more features, is more mature, and carries a premium in the marketplace.

“So, you have a low-cost, very efficient [solution in FirstNet PTT] versus a premium solution that has a lot more features [FirstNet Rapid Response]—and, of course, interoperability with Motorola’s Critical Connect, which we know is very important.”

FirstNet Rapid Response currently is provided as a hosted solution—“it’s network-interfaced, just to be clear,” Agnew said—and is available at a list price between $2 per month for the standard service to $15 per month the advanced service for the first year. After the first 12 months, the rates for FirstNet Rapid Response increase to $12 per month for the standard service and $27.50 per month for the advanced service, according to information posted on the www.firstnet.com website.

Currently a network-interfaced solution, FirstNet Rapid Response from Motorola Solutions is able to provide quality-of-service characteristics that some over-the-top MCPTT offerings cannot achieve, but it is not integrated with the FirstNet system as the FirstNet PTT offering from Samsung, Agnew said. Future iterations of FirstNet Rapid Response are expected to include greater network integration as the offering evolves, he said.

In contrast, FirstNet PTT powered by Samsung is fully network-integrated and “is specifically designed … for public safety—the interface is very clean and very easy to use,” Agnew said. FirstNet PTT is being positioned as “a lot less expensive” than FirstNet Rapid Response, he said.

Through June, FirstNet PTT is being offered at no monthly cost for a year “just to get users adopted and familiar with it,” Agnew said. The normal cost for FirstNet PTT is $10 per month, he said.

AT&T’s interoperability goal is to allow FirstNet PTT users to talk with FirstNet Rapid Response users with no additional infrastructure, but that is not possible today, Agnew said. In fact, there currently is no way for FirstNet PTT users to talk with FirstNet Rapid Response users, even via one of the many gateway solutions that are commercially available today, he said.