With this in mind, the ESN’s initial direct-mode-voice likely will be a “remote-speaker-mic arrangement” with a TETRA radio to leverage existing technology and the propagation characteristics of the 380-400 MHz spectrum that currently supports the Airwave system, Shipley said.

By leveraging TETRA for direct-mode operations, “I know I can get at least what they get today, and I also know that I’ve got that spectrum,” Shipley said. 

“So, my solution to proximity services—as originally conceived for the emergency services—is to continue to use TETRA direct-mode technology until I see where [proximity services for LTE] is going to finish up.”

Shipley said Motorola Solutions’ WAVE 7000 push-to-talk-over-cellular solution will provide the PTT voice platform for ESN users. However, Shipley expressed a level of frustration that the UK system does not yet have the most fully featured version of WAVE 7000, which also is slated for use on FirstNet.

“I’m not anticipating that it won’t work, because we have seen quite a lot of features,” Shipley said. “But I haven’t seen it working … in a live environment.

“There are a couple of Middle Eastern customers—that they [Motorola Solutions officials] are quite sensitive about—who they say they have done this for, but I have not been allowed to go visit them yet.”

After the PSCR meeting, Shipley said he would visit Motorola Solutions’ headquarters in Chicago to get greater clarification about the WAVE 7000 matter. When asked about the visit with Motorola Solutions, Shipley told IWCE’s Urgent Communications via e-mail that the meeting was “constructive” but referred an MCPTT-related question to Motorola Solutions.

Yesterday, Motorola Solutions provided the following statement on the matter to IWCE’s Urgent Communications:

“The Home Office contracted a pre-standards Push-To-Talk (PTT) capability provided by Motorola Solutions,” according to the statement. “The current contract was agreed prior to the publication of 3GPP Release 13 standards that are defining this technology.

“Motorola Solutions is progressing with the implementation of PTT on ESN via WAVE 7000, and Motorola Solutions, EE and the Home Office will agree on a plan to deploy a Release 13-compatible version later in the current contract.

“With respect to WAVE 7000, we will have several other customer systems running live on the product before ESN goes live.”