Sprint's tri-mode LTE smartphones don't support simultaneous voice and data

Sprint (NYSE:S) has been touting its "Sprint Spark" tri-mode LTE service as major advancement in its network capabilities, but the first tri-mode LTE smartphones the carrier has rolled out do not support simultaneous voice and data over LTE.

Sprint has rolled out a handful of tri-mode LTE smartphones so far, including the HTC One max, LG G2, Samsung Galaxy Mega and Samsung Galaxy S4 mini. Sprint has said all of the smartphones it sells in 2014 will be tri-mode LTE devices. The devices' capabilities were questioned in a post on Geek.com, which noted that unlike earlier Sprint LTE phones, the new tri-mode devices can only handle one transmission path at a time--CDMA for voice or LTE for data.

"It is true that when on a phone call or sending a text, customers cannot simultaneously use LTE," Sprint spokeswoman Kelly Schlageter told FierceWireless about the tri-mode phones. "However, the reverse is not true. If a customer has an active LTE session, they will still receive calls and texts."

She noted that Enhanced Circuit Switched Fallback (eSCFB) is "the technology that allows that to happen." The Geek.com report intimated that there are large sections of Sprint's network where eCSFB is not deployed. "If you own a tri-band LTE phone in a market where these technologies have not been deployed, you'll find that your LTE is practically nonexistent," the report said.

However, Schlageter disputed the scope of the problem. "There are still a small percentage of sites in a few markets (about 3%) in our LTE footprint where eCSFB needs to be deployed," she said. "The majority of those sites will be complete by the end of the year. In the interim, customers served off of those cell sites will be unable to connect to LTE."

Schlageter said the tri-mode LTE smartphones will be able to handle simultaneous voice and LTE data when Sprint deploys Voice over LTE. She noted Sprint has not yet set a timetable for when that will happen.

Sprint has said its Spark service, which combines 800 MHz, 1.9 GHz and 2.5 GHz LTE transmissions, will come to the top 100 U.S. markets during the next three years, with speeds capable of reaching 50-60 Mbps and perhaps faster. The first markets with limited availability of Sprint Spark are Chicago, Los Angeles, New York, Miami and Tampa.

Sprint expects to cover 200 million POPs with LTE on its 1.9 GHz spectrum by the end of 2013, and will expand that to 250 million POPs by mid-2014. The company has also started deploying LTE in its 800 MHz spectrum, which was freed up from the closure of its Nextel iDEN network. That deployment will continue into 2014.

As for its 2.5 GHz spectrum, Sprint plans to have 5,000 2.5 GHz TD-LTE sites on air by year end, and expects to cover 100 million POPs with 2.5 GHz LTE by the end of 2014. Sprint controls 120 MHz of 2.5 GHz spectrum in 90 of the top 100 U.S. markets.

For more:
- see this Geek.com post

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