T-Mobile US moved on previously announced plans to launch a narrowband Internet of Things (NB-IoT) network, unveiling a field trial in Las Vegas.

The carrier said the test was conducted over a live commercial network using equipment from Qualcomm and Ericsson. The equipment was deployed across multiple sites, with the IoT technology using a small sliver of wireless spectrum.

At this year’s Mobile World Congress event, T-Mobile CTO Neville Ray said the operator would deploy an IoT-specific network, but did not give a timeline for that deployment.

As part of the Las Vegas deployment, T-Mobile announced a deal to deploy IoT technology across the city, including NB-IoT. The deal includes several project trials, beginning with the city’s “Innovation District” dedicated to developing emerging technologies.

Specific projects include flood and storm drainage sensors to provide early warning and fault detection; T-Mobile powering the city’s smart lighting initiative; and environment monitors placed on existing smart light poles to track temperature, humidity and environmental gases.

Unlike the various Category M-based technologies deployed by its domestic rivals, the NB-IoT technology used by T-Mobile does not operate inside of its LTE network. Instead it operates as a separate network outside of the direct control of the LTE platform. However, all of these technologies, which include Cat-1 and LTE-M, are part of the 3GPP standards process and use licensed spectrum.

Dima Tokar, co-founder and CTO at MachNation, noted the NB-IoT technology has advantages in that it does not require an LTE network to be deployed or siphon off capacity from an LTE network. However, this can result in higher upfront deployment costs, and NB-IoT network speeds are about one-third that of Cat-M.

“At the end of the day, I don't believe that the performance differences will be important to buyers of LPWAN solutions,” Tokar said.

Verizon in late March said it had launched LTE Cat-M support across more than 2.4 million square miles of its network. AT&T in May said it had completed the nationwide deployment of its LTE-M network, with plans to cover Mexico by the end of the year. Sprint has said it plans to deploy a comparable technology in support of IoT services by the end of this month.

T-Mobile touted the scalability of its standards-based NB-IoT technology compared with other options developed outside of industry standards bodies or that use unlicensed spectrum.

“With its ability to scale and support a direct pathway to 5G, narrowband IoT is already seeing rapid adoption across the globe, even ahead of other technologies,” the company said in response to questions on the network launch. “LTE-based connectivity also ensures the privacy, security, and performance of its own dedicated spectrum – something existing technologies like Zigbee and Wi-Fi will never have.”

ABI Research said operators are moving on their standards-based IoT network plans in response to “continued pressure by the proprietary [low-power, wide-area] technology suppliers, whose low-cost network and module costs also create a compelling business case for tracking and asset monitoring markets.” These unlicensed alternatives include Sigfox and Ingenu.

“LPWAN technologies operating under unlicensed spectrum have the early market advantage and provide the quickest time to deployment, and the lowest infrastructure and operating costs for many IoT applications,” said Samuel McLaughlin, research analyst at ABI Research. “However, emerging 3GPP LPWAN technologies like [LTE-M] and NB-IoT are promising similar performance and have many more advantages. These include strong support from the telecommunications ecosystem, the ability to operate ubiquitously across the cellular infrastructure already in place, and most importantly, the scalability for service providers to easily and quickly add new services to their portfolios using the same infrastructure.”

Others echoed the sentiment, noting the initial cost advantage of non-cellular networks is likely to dissipate as cellular operators move on their deployments.

“Size and speed matter in the burgeoning LPWAN market,” said Steve Hilton, analyst at MachNation. “The more devices ordered for a technology like Cat 1, the lower the per unit price per device. And most assuredly the success of this market is going to depend on extremely inexpensive devices. In addition, the sooner that LPWAN solutions are available on licensed spectrum from carriers like Sprint, AT&T, and Verizon, the less market opportunity there is for non-dedicated spectrum solutions like Sigfox and Ingenu.”