The lack of support for legacy voice and SMS services within LTE could threaten the deployment progress, claims T-Mobile International. Given that LTE is an all-IP network and does not support existing circuit-switched services, T-Mobile is calling for the operator community to back the new Voice over LTE via Generic Access (or VoLGA) initiative.
However, Orange has been reluctant to openly support the VoLGA project, and instead sees LTE--in the short-term--as being a data-only platform. Both Verizon Wireless and Orange favour the circuit-switched fallback option for voice and SMS, which would mean using the existing 2G/3G networks for these services.
According to a report carried by Unstrung, T-Mobile believes that without support for voice services from day one, the promised cost-per-bit efficiency of LTE would not be fully realised. Also, T-Mobile's assumption, according to Franz Seiser, head of core network architecture at T-Mobile, is that the majority of classic 2G/3G services would also be expected of LTE. "It's difficult to position LTE as a data-only network. We need a good solution for voice and SMS as soon as possible."
While the VoLGA Forum has the support of nearly all the major mobile infrastructure vendors, except for Nokia Siemens Networks, T-Mobile stands alone in its backing for the idea. To build more momentum for the concept, the operator community believes VoLGA will need more active involvement by service providers to get its specifications accepted by the 3GPP standards body.
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