T-Mobile is using 2.5 GHz mid-band spectrum as the backbone layer for its 5G network. Indeed, mid-band spectrum provides power, heft, and performance for T-Mobile’s 5G network. The company’s 2.5 GHz mid-band spectrum provides significant depth of 150 MHz, which was acquired through its merger with Sprint.

T-Mobile is targeting a strong consumer experience, on its mid-band layer, with no buffering and no noticeable latency. Furthermore, mid-band 5G spectrum is much more economic for T-Mobile to deploy on its towers.

Indeed, the alternative would be to deploy hundreds of thousands of small cells for high-band (millimeter wave) purposes. For example, Verizon is taking this more difficult and expensive approach to achieve contiguous 5G coverage and experience.

Deployment of 2.5 GHz Mid-Band Spectrum

T-Mobile is rolling-out its 2.5 GHz mid-band spectrum for 5G across its significant tower portfolio. Specifically, T-Mobile is overlaying and rolling-out the 2.5 GHz radios on its existing sites. For its 2.5 GHz equipment deployments, T-Mobile is not building new tower sites but rather adding radios and antennas to its existing tower sites. On average, it only takes 5 to 10 working days for T-Mobile and Ericsson, its vendor partner, to install the 2.5 GHz mid-band equipment on each tower site.

In the months of May and June 2020, T-Mobile completed 2.5 GHz overlays at a rate of 1k per month. Currently, T-Mobile’s pace of build-out has accelerated to achieve 2.5 GHz overlays at a rate of 2k per month. Indeed, T-Mobile ended Q3 2020 with 30 million points of presence (PoPs) covered with 2.5 GHz. Furthermore, at the end of 2020, the carrier reached 100 million PoPs covered with 2.5 GHz.

By the end of 2021 T-Mobile expects to have 200 million PoPs, equating to 2/3rds of the U.S., covered with 2.5 GHz. This coverage with 2.5 GHz, represents double the number of PoPs achieved at the end of 2020.

Major U.S. Cities Receiving 2.5 GHz Mid-Band Spectrum

T-Mobile has lit up a significant number of the major cities in the U.S. with 2.5 GHz spectrum during 2020. Indeed, this strategy ensures both breadth and depth across T-Mobile’s 5G network. In 2021, T-Mobile expects to continue its build-out of 2.5 GHz spectrum, in what will be a formative year for mid-band spectrum.

T-Mobile’s size and scale allows it to invest $40bn, over the next three years, to build its 5G network. As T-Mobile progresses its integration of Sprint, it will migrate the former Sprint customers. In turn, this will allow T-Mobile to commit more spectrum towards 5G.

Deployment of 2.5 GHz in Philadelphia, New York City, Los Angeles, Chicago, and Houston

T-Mobile began its 2.5 GHz spectrum build-out in Philadelphia and New York City. Indeed, the carrier was able to turn that spectrum up in April 2020. Additionally, during summer 2020, T-Mobile began deploying its 2.5 GHz spectrum in Atlanta, Chicago, Dallas, Houston, Los Angeles, and Washington, D.C.

Philadelphia and New York City, on 2.5 GHz spectrum, with only 40 MHz to 60 MHz of depth being allocated, produced peak speeds of 600 to 700 megabits per second and average speeds of 300 to 400 megabits per second.

Over time, T-Mobile will increase its dedicated 5G spectrum depth to 100 MHz and then eventually to 150 MHz on its 2.5 GHz frequency. Indeed, this will substantially enhance the available speeds and performance of its 5G network. In comparison, peak 4G/LTE speeds in these markets are currently 100 megabits per second. Moreover, the average 4G/LTE speeds are only 30 to 40 megabits per second.

Deployment Mechanics of 2.5 GHz Spectrum for Maximum Performance and Propagation

Historically, 2.5 GHz spectrum has had propagation constraints, mainly because of its uplink capabilities. Similar to any other wireless spectrum, uplink is the weaker link from the mobile handset, back to the base station.

T-Mobile is using primarily a 4G/LTE uplink in mid-band, through its PCS (1.9 GHz) and AWS (1.7/2.1 GHz) bands, while 2.5 GHz is used for downlink. The net result is that geographic coverage from a 2.5 GHz overlay on one of T-Mobile’s sites, is 25% greater than previously existed. Before, 2.5 GHz was used for both uplink and downlink, which is what Sprint was doing pre-merger.

Structurally, this formation gives T-Mobile a much larger cell radius from each tower. In turn, this larger cell radius allows T-Mobile to cover more geography on its mid-band grid with 2.5 GHz frequencies.

Mid-Band Dilemma in the United States

The United States faces a mid-band “dilemma”, which was only solved by the combination of T-Mobile and Sprint and its 2.5 GHz mid-band spectrum. Mid-band is the backbone layer for 5G and provides the performance needed for 5G networks nationwide. Therefore, it is important to have it up-and-running in the United States.

AT&T and Verizon do not currently have a short-term solution for how to move to the next level of performance with 5G. Specifically, because they need further mid-band spectrum. Public auctions either do not provide a comprehensive solution (i.e., CBRS) or have an extended timeframe (i.e., C-band).

C-band Auction 107 (3.7 GHz to 3.98 GHz)

T-Mobile’s 2.5 GHz mid-band spectrum with 150 MHz of depth, is something that is difficult to replicate in the United States. In order to try and close the mid-band spectrum gap with T-Mobile, Verizon and AT&T are expected to spend heavily buying C-band spectrum. Indeed, the C-band auction, which began on December 8th, is offering 280 MHz of spectrum in the 3.7 GHz to 3.98 GHz range.

Specifically, Verizon will likely spend $25bn in the C-band auction to secure 125 MHz of spectrum depth. Additionally, AT&T will likely spend $10bn in the C-band auction to secure 60 MHz of spectrum depth. Indeed, both of these moves by Verizon and AT&T will help to close the gap on T-Mobile’s mid-band spectrum holdings.

However, T-Mobile is also likely to further strengthen its mid-band spectrum holdings through the C-band auction. Specifically, T-Mobile will likely spend $5bn in the C-band auction to secure 35 MHz of spectrum depth. Indeed, T-Mobile’s acquisition of C-band spectrum will help minimize the relative improvements from its competitors Verizon and AT&T.

Adam Simmons is the Founder & CEO of Dgtl Infra. He started his career with an S&P 500-listed big box retailer, in an operations management role. Adam's entrepreneurial "itch" led him to start a 5G-driven company, focused on innovative retail solutions using augmented reality and shoppable videos, which was eventually sold to an advertising and consulting group. After, realizing the potential of 5G, Adam shifted his efforts towards investing in the "building blocks" of 5G - known as digital infrastructure, completing a number of strategic investments, buying cellular towers, data centers and fiber networks.


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