By Phil Goldstein

Much of the coverage of LTE revolves around how many people the networks cover or how fast the speeds are. Yet how much spectrum the carriers have to support their LTE services, and where exactly they have it across the country, is a more arcane but perhaps an even more important metric.

Indeed, how much spectrum carriers control determines how much network capacity they have in specific markets and often how fast their network speeds are.

With this in mind, FierceWireless has partnered with AllNet Labs, a wireless consulting firm, to map out exactly how much spectrum each of the four Tier 1 carriers currently has that they could deploy for LTE service, broken down on a county-by-county basis. According to AllNet President Brian Goemmer, a wireless industry veteran with nearly 20 years of experience, AllNet has developed what it calls "Download Spectrum Depth Maps" to represent the available LTE spectrum for each of the Tier 1 carriers based upon their current LTE deployment configurations. AllNet's "Spectrum Analysis Tool" was used to determine the largest LTE channel size in each carrier's spectrum bands.

Goemmer noted that since the current 3GPP release for LTE only supports inter-band contiguous carrier aggregation through the end of 2014, only the largest contiguous channels controlled by a carrier are considered.

AllNet's Spectrum Analysis Tool evaluations are based on a June 2014 FCC dataset. Goemmer noted that leased spectrum is included. Goemmer added that since Sprint's 2.5 GHz deployment utilizes Time Division Duplex (TDD-LTE) technology, spectrum values in this band are reduced by 25 percent, reflecting the time slots that are dedicated to uplink traffic.

Essentially, these maps show how much spectrum each of the nation's Tier 1 carriers currently has for LTE based on their stated LTE deployment plans. It doesn't show actual LTE deployments, only the spectrum that likely is used or will be used for LTE deployments.

Scroll down for maps for Verizon, AT&T, Sprint and T-Mobile.

Verizon Wireless (XLTE)

Verizon is using up to 10 MHz of its 700 MHz spectrum and up to 20 MHz of its AWS spectrum for LTE.



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Verizon Wireless' (NYSE: VZ) 700 MHz LTE network covers around 306 million POPs. The carrier has also been busy deploying its LTE service on its 1700/2100 MHz AWS spectrum to bolster its network capacity; Verizon purchased roughly 20 MHz of nationwide AWS spectrum from a group of cable companies for $3.9 billion in a deal the FCC approved in 2012.

Verizon has dubbed the combination of LTE on its 700 MHz and AWS spectrum as "XLTE." Verizon recently announced that more than 300 markets now have XLTE service (up from around 250 in mid-May). Verizon's 700 MHz LTE network is available in more than 500 markets. In these markets Verizon is in some cases deploying a full 30 MHz of spectrum, building on top of the 10x10 MHz or 20 MHz total it used for its 700 MHz deployment.

AT&T Mobility

AT&T is using up to 10 MHz of its 700 MHz spectrum and its AWS spectrum for LTE.



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AT&T Mobility's (NYSE: T) LTE network covers 290 million POPs on its 700 MHz spectrum, which is a 10x10 MHz deployment in most markets, though in some it is a 5x5 MHz deployment. The company plans to deploy LTE on its AWS spectrum as well, which in some cases will be a 5x5 MHz deployment and in others 10x10 MHz. AT&T has also started to refarm its 1900 MHz PCS spectrum for LTE in multiple markets, including, Baltimore, Dallas, New York City, Philadelphia, San Francisco and Washington, D.C. AllNet's maps focus on AT&T's 700 MHz and AWS holdings.

Sprint (Spark)

Sprint is using 5 MHz of its SMR spectrum, 5 MHz of its G block PCS spectrum, and up to 40 MHz of its 2.5 GHz spectrum for LTE.



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Sprint (NYSE: S) owns a vast amount of spectrum for LTE thanks to the 2.5 GHz spectrum holdings it acquired from Clearwire. Sprint controls around 120 MHz of 2.5 GHz spectrum in 90 percent of the top 100 U.S. markets, and plans to deploy two-carrier 2.5 GHz spectrum, or 40 MHz in the band, by year-end. However, the 2.5 GHz spectrum has weaker propagation characteristics than low-band spectrum, requiring more towers for Sprint to build it out. The spectrum builds on top of the 5x5 MHz 1900 MHz G Block Sprint uses for LTE as well as the 5x5 MHz 800 MHz SMR band. Sprint says its LTE footprint covers 471 markets and 225 million POPs. The company has said it expects to reach 250 million POPs with LTE by mid-year. Sprint calls its tri-band LTE service "Spark" and expects to have 100 million POPs covered with Spark by year-end.

T-Mobile US

T-Mobile is using up to 5 MHz of its 700 MHz spectrum combined with up to 20 MHz of its AWS spectrum for LTE.



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T-Mobile US (NYSE:TMUS) uses AWS spectrum in 10x10 MHz deployments for most of its LTE network, which currently covers 230 million POPs. The company is now offering what it calls "Wideband LTE," with 15x15 MHz service, in 16 U.S. markets. The Wideband LTE moniker is the operator's marketing term for spectrum deployments of at least 15x15 MHz.

At the time of its first-quarter 2014 earnings announcement, T-Mobile said it had deployed 15x15 MHz LTE in nine metro areas and would have 19 covered by year-end. It had also deployed 20x20 MHz LTE in North Dallas and Detroit and pledged to have seven such deployments by the end of 2014.

T-Mobile also plans to deploy 5x5 MHz 700 MHz A Block spectrum by year-end, which it acquired from Verizon for $2.4 billion.