Rumor mill: Sprint laying groundwork for mid-2015 VoLTE launch

Sprint (NYSE: S) has stressed time and again that it is not rushing to launch voice over LTE (VoLTE), but that does not mean the operator is snubbing the technology. Far from it, in fact, given that a "high-level" Sprint executive has shared details regarding the "programming phase" the operator is reportedly in as it prepares to launch a VoLTE network designed for interoperability with domestic and international carriers.

According to an anonymous Sprint executive cited by the S4GRU blog, Sprint's current VoLTE programming initiative addresses design criteria and functionality intended for its VoLTE system. The operator is engaging device and network vendors regarding its plans and necessary hardware support. Sprint is focusing its initial VoLTE efforts on FDD frequencies rather than its 2.5 GHz TD-LTE network.

Once the programming phase wraps up this summer, Sprint will reportedly shift to field implementation testing (FIT) to identify any issues that should be addressed. S4GRU said the testing is planned for Kansas, the Chicago area and Virginia, and it will involve key roaming partners to ensure interoperability.

Sprint reportedly has not set a firm date internally for commercial VoLTE introduction, though the blog entry said service could launch in mid-2015 or even earlier. Asked by FierceWirelessTech to comment on the report, Sprint spokeswoman Kelly Schlageter replied that Sprint has not announced "any timelines for VoLTE."

Shifting voice traffic where possible from CDMA to VoLTE would enable Sprint to engage in more spectrum refarming and launch LTE on frequencies currently encumbered by CDMA. However, some CDMA capacity would be maintained to start, and the planned system would enable handoffs of VoLTE calls to the legacy CDMA network through the EVRC-NW codec.

Sprint executives have said repeatedly that the operator is in no rush to launch VoLTE, preferring to rely on its CDMA network and EVRC-NW-powered HD Voice technology for voice calling services during the foreseeable future. That stance could reflect the operator's desire to take a measured approach to VoLTE minus the pressures of trying to stick with a publicly stated schedule. Sprint's ambitious Network Vision project has often fallen behind schedule due to a variety of factors, casting an unflattering light on the company. By not announcing its specific VoLTE plans, Sprint would be able to quietly address any VoLTE stumbling blocks.

Ron Marquardt, vice president of technology for Sprint technology innovation and architecture, told RCR Wireless earlier this month that VoLTE "is not as near term of an issue," for the operator. "We will be more measured with our plans, working on it more behind the scenes," he added.

Sprint is apparently engaging a number of roaming partners to ensure interoperability, potentially complicating its VoLTE rollout efforts. S4GRU said Sprint's VoLTE service "will allow HD Voice to be interoperable with several other providers by using the 3GPP EVS (Enhanced Voice Service) codec and integrating other networks together." However, the EVS codec may not be standardized before Sprint starts deploying VoLTE, which could restrict initial HD Voice interoperability.

Sprint has been working diligently to line up rural LTE roaming partners. VTel Wireless, one of the 12 smaller wireless carriers Sprint announced LTE roaming deals with in June, recently launched LTE service in parts of Vermont and has said it intends to introduce VoLTE phones in late 2014 or early 2015.

A Sprint spokeswoman told FierceWireless the operator will help VTel in those efforts even though Sprint has not officially committed to deploying VoLTE in the near future.

T-Mobile US (NYSE:TMUS) has officially launched VoLTE only in the Seattle area though T-Mobile customers reported making VoLTE calls in Philadelphia, Chattanooga, Tenn., and Alexandria, Va. AT&T Mobility (NYSE: T) in late May launched VoLTE in select areas in Illinois, Indiana, Minnesota and Wisconsin. Verizon Wireless (NYSE: VZ) has not yet launched VoLTE but says it will sometime this year.

For more:
- see this S4GRU blog entry

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