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May 27, 2014

Sprint's Big Mistake: Upgrading Its 3G Network to HD Voice

Over the years, Sprint seems to have had a talent for backing the wrong wireless technologies. Supporting HD voice on its legacy 3G network is the latest in a series of bad decisions and one that will likely cost it both operational dollars and customers better spent on accelerating a Voice over LTE (VoLTE) deployment.

Back in 2005, Sprint bought Nextel and its iDEN cellular network for a whopping $35 billion. The iDEN technology merged the concept of push-to-talk, walkie-talkie style communication with the use of a phone. It took seven years before Sprint finally pulled the plug on Nextel's 2G network for good, leaving it with little more than an estimated 45,000 tons of "network junk" according to GigaOm, along with a $1.6 billion loss in 2013.

WiMAX once held great promise for Sprint when launched in 2008, but a bizarre corporate structure with partner/subsidiary Clearwire, along with failed marketing and deployments by Clearwire, ultimately left Sprint stuck clearly owning Clearwire and its assets in July 2013. The WiMAX network, billed as the first "4G" network in the U.S., will be shut down in 2015 -- seven years after launch.

In its latest folly, Sprint started deploying upgraded CDMA 1X Advanced technology to support HD voice last year as a part of its Network Vision network modernization plan. Network Vision would include support for 3G HD voice, LTE and an enhanced high-speed LTE service called Sprint Spark. Network Vision was started in 2012 and was expected to be completed by the end of 2013 or early 2014. Today, the network upgrades are steadily rolling along, but aren't quite finished yet.

Sprint executives say the network will have nationwide 3G HD voice coverage by the middle of this year.  When complete, Sprint will be the only U.S. carrier running the EVRC-NW HD voice codec, just like it was the only carrier to embrace WiMAX. Should we start the clock for a shutdown of Sprint's 3G network at 2012 with a shutdown date of 2019?

Nobody knows exactly how much money Sprint spent on the Qualcomm 1X Advanced upgrade, but it will be the gift that keeps on spending when the company finally gets around to deploying Voice over LTE (VoLTE). Network managers will presumably have to transcode (translate) between the EVRC-NW codec and the de facto standard AMR-WB codec used in GSM, HSPA+ and LTE networks for HD voice. Transcoding adds some delay and complexity since you have to translate on the fly, or lose HD voice "goodness."

AT&T and Verizon's solution to the HD voice 3G/4G dilemma was simple: The legacy network is for legacy narrowband calls. LTE and VoLTE will be our HD voice network, due in part because both carriers would like to accelerate the migration of customers from 3G to 4G as soon as possible so they can shut down the 3G network to shed all the legacy gear and its operating expenses. Once the 3G network is shut down, radio spectrum can be reallocated to better/faster/cooler 4G LTE bandwidth.

T-Mobile chose the most elegant solution for deploying HD voice. The company deployed it on its HSPA+ network in January 2013 and is starting to turn up VoLTE on its network. It will be able to more or less seamlessly support HD voice between its existing HSPA+ and LTE networks without breaking a sweat.

Sprint has indicated no urgency in deploying VoLTE. I think that's a big mistake, because its three major competitors will be hammering the superiority of VoLTE in their marketing campaigns. Sprint will be left trying to explain and defend 3G CDMA HD voice while it is working to deploy VoLTE, so you're going to see marketing spending more time in defense. It's not going to be pretty.


Edited by Rory J. Thompson


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