Will voice-over-LTE become a casualty of the T-Mobile-MetroPCS merger?


Those of you who got really excited about a combined T-Mobile-MetroPCS(s pcs) accelerating the take-up of voice-over-LTE (VoLTE) in the US, may wind up being disappointed. Light Reading has noted that in a slide presentation the companies distributed last week outlining the combined T-Metro’s unified network, any mention of VoLTE is curiously absent.

As Light Reading points out, the VoLTE box in in Metro’s current network doesn’t point to a corresponding VoLTE box in the unified network – just to plain old LTE. What to make of that is hard to say. The lack of any mention of VoLTE post-migration is ominous. But if T-Mobile really wanted to emphasize plans for shuttering Metro’s nascent 4G VoIP service, it would have drawn a line straight from VoLTE to HSPA+, where its circuit-switched voice services currently resides.

That said, shutting down VoLTE wouldn’t be a big of surprise. The reason why MetroPCS is so aggressive on mobile VoIP – it was the first US operator, if not the first global operator, to offer it – is because of its own capacity constraints. Leaving voice on its CDMA networks would mean Metro would be forced to maintain sizable 2G networks for years to come. Given that in some cities Metro has LTE networks using only a measly 3 MHz of capacity, it could really use that 2G spectrum for 4G. Consequently, MetroPCS has plans to roll out VoLTE across its entire footprint in the next 4-6  months.

A combined T-Mobile-MetroPCS, however, wouldn’t face such constraints. Along with its GSM systems, T-Mobile’s HSPA+ data networks support circuit-switched voice. The way its network plans would play out, T-Metro would devote almost all of the 1700 MHz/2100 MHz to LTE, while reserving the 1900 MHz PCS band for HSPA+ and GSM. It will have plenty of capacity for the long haul, and won’t feel the same pressures to shut down its legacy voice infrastructure.

But T-Mobile might have plenty to gain if it took Metro’s VoLTE technology and ran with it. It would be one more integration headache to solve and require adopting VoLTE technology and handsets far sooner than T-Mo had planned. But the faster it moves voice traffic off of its 2G and 3G networks, the sooner it could refarm that spectrum for LTE and other future technologies. It’s important to note T-Mobile only gets a spectrum boost from MetroPCS in a handful of major markets. In other regions of the country, T-Metro will still be on the hunt for more LTE capacity.

If T-Mobile does shutter Metro’s VoLTE service post-merger, then we won’t have to wait to long to see another mobile VoIP service emerge. At CTIA MobileCon Tuesday, Verizon Wireless(s vz)(s vod) CTO Nicola Palmer said Big Red will have a consumer VoLTE trial live in late 2013. AT&T(s t) and Sprint(s s) have both targeted their VoLTE launches for 2013 as well.


Marcelo Puig

Maybe the reason is because the MNO’s does not want to kill the regular and profitable voice service…

guest 1

Metro already launched Volte in the dallas market and will proceed to launch volte in other markets by the end of the year.



Doesn’t T-Mobile technically ALREADY have this technology on hand with their current WiFi Calling system in place? Originally UMA however at the end of last year T-Mobile switched their WiFi Calling technology to be IMS-based with all phones released since the HTC Amaze and Samsung Galaxy S II. A lot of people speculated the reason for the switch to IMS WiFi Calling was so calls between WiFi and LTE could be handed off in the future.

If you look at the technology carriers are going to use for VoLTE it looks like it’ll be IMS for a lot of them. Can’t seem to find anything anywhere on WHY T-Mobile switched to IMS WiFi Calling but preparing for a voLTE solution seems like it would make sense.

Also how different would WiFi Calling and VoLTE be? I would imagine since both are voice/text over strictly data they could work interchangeably with little effort. Also I’m wondering if T-Mobile recent announcement they made their whole network IPv6 capable helps out with any technical aspects?


What you don’t understand is that VoLTE needs to come with support for legacy in terms of service being able to hand over a call to CS when LTE hands over to HSPA. Because of that a VoLTE deployment is very complex and vendors of equipment are not ready yet to support SRVCC. T-Mobile can’t launch VoLTE without SRVCC. You can also check that CS fallback is in plan for all including ATT exactly because the technology is not ready. Sure VoLTE is desired and T-Mobile is ready for it – check the WIFI calling solution they have that is using the same back-end IMS.

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