Sprint to bring carrier aggregation to all of its LTE bands in bid to boost performance

Sprint (NYSE: S) will use carrier aggregation technology to combine TD-LTE and FDD-LTE transmission across all of its spectrum bands. Sprint disclosed its carrier aggregation plans and its overall network progress as part of its fourth-quarter earnings report.

Sprint CEO Marcelo Claure said implementing carrier aggregation across all Sprint spectrum bands means Sprint eventually will be able to deploy 1900 MHz FDD-LTE for uplink and 2.5 GHz TD-LTE for downlink, and ultimately improve the coverage of 2.5 GHz LTE to levels that its 1900 MHz spectrum currently achieves. Carrier aggregation, which is the most well-known and widely used technique of the LTE Advanced standard, bonds together disparate bands of spectrum to create wider channels and produce more capacity and faster speeds.

Sprint CTO Stephen Bye said that the carrier does not yet have a timeframe for deploying the TD/FDD carrier aggregation. He said Sprint is talking with its handset and network vendors about the effort and expects the deployment to be a "near term" goal.

In an interview with FierceWireless, Sprint CFO Joe Euteneuer said that the carrier will provide more details on its carrier aggregation progress when it reports first quarter earnings.

Euteneuer noted that in the fourth quarter Sprint actually did wind up deploying on its network 2x20 MHz carrier aggregation in just the 2.5 GHz band. He said that the company has started seeding its device base with phones that can take advantage of that 2x20 MHz carrier aggregation, but that the process is still in the early stages.

Sprint said its overall LTE network now covers 270 million POPs, up from 260 million POPs at the end of the third quarter. Additionally, Sprint said it now covers 125 million POPs with TD-LTE service on its 2.5 GHz spectrum, up from 100 million POPs in mid-December.

Both Verizon Wireless (NYSE: VZ) and AT&T Mobility (NYSE: T) cover more than 300 million POPs with their LTE networks, while T-Mobile US (NYSE:TMUS) currently covers 265 million POPs with its LTE network. T-Mobile has pledged to expand that to 285 million by mid-year and 300 million by the end of 2015.

Claure said during a conference call with investors that a "great network" was one of the key pillars of Sprint's turnaround, along with a compelling value proposition and aggressive distribution. Sprint has been deploying its tri-band "Spark" LTE service using its 800 MHz and 1900 MHz spectrum for FDD-LTE and 2.5 GHz airwaves for TD-LTE service.

Further, Sprint said it has completed its deployment of 800 MHz voice service nationwide. Claure said on the company's earnings conference that this will bring immediate benefits to the 75 percent of Sprint's postpaid phone subscriber base who have phones with 800 MHz voice capabilities. Claure said Sprint notched a 50 percent year-over-year improvement to its dropped call rate based on independent, third-party data provided by Nielsen. He said the company is now seeing its lowest dropped call rates ever, though he didn't say what those exact rates were.

Source: Sprint

Claure said Sprint has now deployed 800 MHz LTE on 60 percent of its LTE footprint and the company is focused on completing the other 40 percent by year-end, which he said will improve Sprint's LTE coverage and capacity. Claure said Sprint will focus on densifying its network through macro and small cells.

Sprint did not disclose its coverage goals for 2015, or its specific 2.5 GHz LTE coverage target. Euteneuer said that Sprint will provide more details on its next quarterly earnings call, especially in regard to how Sprint will use its 2.5 GHz spectrum.

Claure said one of the challenges Sprint faces is that it takes time for consumers to realize and appreciate improvements to the company's network. "All we can do is continue to build, every day, a better network," he said.

Claure said Sprint might soon start touting its network improvements in its advertising.

Claure also said Sprint remains "full speed ahead" with its 2.5 GHz deployment. He added that Sprint expects to transition an IP-based network platform and launch Voice over LTE services, though he did not say when Sprint would deploy VoLTE.

In January at an investor conference, Claure indicated Sprint might look to sell some of its excess 2.5 GHz spectrum. The company controls an average of 120 MHz of those airwaves in 90 of the top 100 U.S. markets. However, Claure said the company is not actively looking at a sale of the spectrum.

"It is our responsibility to continue looking at the value of our assets," he said. Claure said that he was "very surprised" that the AWS-3 spectrum auction netted as much money as it did ($41.3 billion in net winning bids).

Claure again noted that with TD/FDD carrier aggregation technology, Sprint's 2.5 GHz spectrum could become "very valuable" and that Sprint is assessing that value and looking at various analyses. However, he said that "doesn't mean we are out there marketing the sale of spectrum."

For more:
- see this release
- see this Sprint presentation (PDF)

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Correction, Feb. 6., 2015: In one instance, this article incorrectly spelled the last name of Sprint CFO Joe Euteneuer.