T-Mobile USA is asking the FCC for permission to conduct tests in the 3550-3700 MHz band, also known as the 3.5 GHz band, to evaluate the technical performance of precommercial Nokia equipment.

It’s the latest sign of operators’ interest in using the 3.5 GHz band. Last month, Verizon confirmed its interest in deploying small cells—both low power and high power—using the 3.5 GHz/Citizens Broadband Radio Services (CBRS) band, saying it would use 3.5 GHz spectrum “as soon as practically possible.”

Currently, members of the CBRS Alliance are working hard to establish the framework to make the 3.5 GHz band suitable for sharing under the FCC’s directive (PDF). The FCC finalized rules for the band nearly a year ago, making 150 MHz available for mobile broadband and other commercial uses.

Sponsored by Blue Planet, a division of Ciena Embrace everything as a service. Appledore Analyst Report reveals what it takes to shift to NaaS, its many benefits and demands, and who's getting it right. CSPs need to evolve from legacy OSS and hardware networks to cloud-native, software-enabled networks. See who's leading. Read the article

RELATED: Verizon aims to deploy small cells in 3.5 GHz when practical

Clearly, T-Mobile hopes the FCC will revisit the rules for 3.5 GHz. “The 3.5 GHz band has the potential to provide additional spectrum for LTE but we also think it is ideal for 5G, in alignment with the rest of the world,” the company said in a statement to FierceWirelessTech. “Additionally, the current rules for licensing the CBRS band should be revisited to create more certainty and align with 5G requirements.”

Indeed, when the FCC voted on the 3.5 GHz rules last year, current FCC Chairman Ajit Pai and fellow Republican Commissioner Michael O’Rielly cited concerns about certain aspects of the 3.5 GHz framework. Pai at the time called the 3.5 GHz proceeding an experiment and said he wasn’t sure if the FCC struck the right balance for a variety of providers and technologies to compete in the band.

As recently as March 16, 2017, Michael Calabrese, director of the Wireless Future Program at New America’s Open Technology Institute (OTI), met with O’Rielly’s legal advisor, Erin McGrath, and suggested that the commission not reopen the 3.5 GHz rules concerning the geographic size, renewability or duration of Priority Access Licenses (PAL). He urged the commission to stay the course and test whether “this more dynamic and small cell approach to spectrum band sharing spurs deployment and innovation, as expected,” according to an ex parte filing (PDF).

In its application for an experimental license pending at the FCC, T-Mobile said (PDF) it would like to start operating in the 3550-3700 MHz band to understand the propagation characteristics and gain a better understanding of new innovative services the band can offer. The trials would be conducted in Bellevue, Washington, where T-Mobile is headquartered, and in nearby Bothell, Washington.

RELATED: Ericsson seeks permission to conduct 3.5 GHz experiments in Plano, Texas

T-Mobile is asking that the experimental license be granted starting April 15 and run through Sept. 30, 2018.

All four nationwide U.S. wireless operators—Verizon, AT&T, T-Mobile and Sprint—are members of the CBRS Alliance, which has grown considerably since its formal launch last year. Some of its members have been busy demonstrating the types of private LTE networks that can be deployed using the CBRS band.

Nokia, Qualcomm and GE Digital recently demonstrated a private LTE network at 3.5 GHz aimed at the industrial IoT market. The trio is targeting industrial companies that operate businesses in remote locations or temporary sites where connectivity can be difficult to access.