Verizon selects MCPTT vendor, expects to launch MCPTT service this year

Verizon has chosen a vendor to deliver mission-critical-push-to-talk (MCPTT) service based on the 3GPP standard and expects to launch the offering by the end of this year, according to a Verizon official.

“We have selected a mission-critical-push-to-talk vendor,” Nick Nilan, Verizon’s director of public-sector product development, said yesterday during an interview with IWCE’s Urgent Communications. “We anticipate being able to announce that this year, but I’m not ready to tip my hat as to who that is or exactly a date.

“We’re working to make sure that the product is exactly what it says it is—mission critical. We want to make sure that, when it launches, it’s fully ready for our public-safety customers. It will be coming out later this year.”

Following the interview, a Verizon spokesperson confirmed that the carrier giant plans to announce both its MCPTT vendor and launch an MCPTT service by the end of the year.

A Verizon MCPTT launch would follow the announced offerings of push-to-talk-over-cellular offerings based on the 3GPP standard announced by FirstNet—the nationwide public-safety broadband network being built and maintained by AT&T—and Southern Linc, the southeast U.S. regional carrier that also provides communications for Southern Company utility.

MCPTT is a push-to-talk standard established by 3GPP that is designed to meet the key performance metrics of LMR push-to-talk technologies like P25 and TETRA, including low latency to enable quick call-setup times. The platform used to deliver MCPTT also is designed to support mission-critical video (MCVideo) and mission-critical data (MCData) services—capabilities often referenced collectively as MCX services.

There are multiple vendors that have developed MCPTT components—from servers to client interfaces—that have exhibited the ability to interoperate during ETSI plugtests during the past several years. However, several industry sources have asserted that the 3GPP standard’s challenging performance metrics only can be achieved in real-world scenarios if the MCPTT vendor is tightly integrated throughout a carrier’s network.

Southern Linc appears to be pursuing such an end-to-end approach by deploying Ericsson’s MCPTT solution, which also is expected to include eMBMS functionality that is designed to enable more efficient delivery of one-to-many group calls.

AT&T announced the availability of FirstNet PTT on March 31, the due date for the carrier to provide a MCPTT-compliant service under its contract with the FirstNet Authority. To date, AT&T officially has not announced the vendor for the service, but Samsung provided the only FirstNet PTT-capable device.

Officials for AT&T have long vowed that FirstNet subscribers would be able to choose from multiple MCPTT vendors. Multiple industry sources have indicated that AT&T has completed the procurement process to select a second MCPTT vendor, but AT&T has declined to respond to inquiries from IWCE’s Urgent Communications on the matter.

FirstNet PTT performance was applauded by users in a New Jersey police department that tested the service early this year, but there have been no announcements of FirstNet PTT being adopted to date.

Meanwhile, both AT&T and Verizon continue to offer carrier-integrated push-to-talk-over-cellular (PoC) services that utilize Kodiak technology owned by Motorola Solutions. Despite the fact that both carriers use the Kodiak platform, PoC subscribers on one carrier are not able to talk to PoC subscribers on the other carriers without investing in additional gateway solutions.

With this in mind, over-the-top PoC solutions such as ESChat and BeOn from L3Harris recently have gained new levels of traction as enterprises have sought flexible, cost-effective, push-to-talk solutions that can be deployed quickly in response to challenges associated with the COVID-19 pandemic.

Such over-the-top PoC offerings do not meet the high-performance metrics of MCPTT, but they often enable much greater interoperability between users of disparate LMR and LTE systems. In addition, proponents note that public safety’s to prioritized and preemptive access to the FirstNet and Verizon LTE networks has removed the greatest argument against over-the-top PoC services—the availability of reliable connectivity.

For years, industry experts have said that PoC and MCPTT-compliant services could provide better on-network audio quality than LMR, because higher-level codecs can be used, thanks to the closer proximity of LTE devices to cell sites and the fact that LTE makes much more bandwidth available than a narrowband LMR system.

However, there are significant questions whether LTE-based push-to-talk solutions will ever match the performance that LMR technologies can deliver when network connectivity is not available.

To date, Samsung is the only manufacturer that publicly claims it has devices that are capable of supporting ProSe, the LTE standard for delivering direct-mode communications when no LTE network is available. Samsung officials have said ProSe has been used in South Korea, but the company has declined to comment on the performance of the direct-mode functionality.

Even if ProSe works, skeptics question whether the technology would be considered useful to public safety, based on the physics challenges.

Public safety is accustomed to direct-mode communications through LMR devices that feature external antennas and transmit signals using 3 to 5 watts of power, supporting miles of communications coverage without the help of a network.

In contrast, LTE devices typically have internal antennas and transmit signals using just 200 milliwatts of power, which would greatly limit their coverage range. However, proponents of PoC solutions note that ubiquity of LTE and Wi-Fi networks, along with the rapid development of deployable LTE solutions—cells on wheels, cells on drones, as well as backpack and Pelican-case packages—could dramatically reduce the need for direct-mode communications in most public-safety scenarios.

With this in mind, Southern Linc previously indicated that it has been working with Sonim Technologies on the development of an direct-mode accessory that attaches to the top of rugged Sonim devices and uses LoRaWAN—a low-power, wide-area networking protocol—that operates on unlicensed 900 MHz spectrum.

Neither AT&T nor Verizon have unveiled any details about how they plan to provide direct-mode MCPTT.