Summary
With the announced support of IMS-based voice and messaging over 4G/LTE by major mobile operators, T-Mobile International (now Deutsche Telekom) and other technology backers of VoLGA (a GSM-signaling over IP approach) are left with a key decision as whether to follow or remain isolated. Companies supporting VoLGA will be highly exposed, unless change course quickly.
Analysis
Major mobile and converged operators such as AT&T, Verizon, France and Telecom/Orange along with powerful wireless equipment vendors such as Ericsson and Nokia-Siemens yesterday announced their plan to followed the IMS-based approach for delivery of voice and messaging services over Long Term Evolution (LTE) broadband mobile radio access. The industry has been anxiously waiting for an outcome and this announcement may have solidified the approach since these carriers and equipment vendors have a strong position in the industry.
The alternative model for voice and messaging is what T-Mobile International is pursuing which is based on Unlicensed Mobile Access (UMA) which is GSM signaling over IP, connected to an existing legacy 2G/3G circuit code and mobile switching center (MSC). There are several important reasons that TMO is pursuing which are all relevant. The existing mobile core is extremely feature rich and there are a large number of services along with existing customer care, service management, and network operational support systems that are in place that have to be replicated for IMS and that could delay the roll out of voice and messaging services over LTE.
In parallel, LTE is not going to be a ubiquitous service any time soon and they will be coverage holes for many years. In that case, the subscribers have to receive service from the legacy core while roaming on 2G/3G networks.
IMS-based systems are still in infancy and a long way to go to achieve that parity. However, there are interim gateway solutions that can solve the problems. They are proposed by Nokia-Siemens Networks (NSN) and Mavenir Systems in collaboration with Acme Packet. In one scenario, the existing MSC will have SIP/IMS interfaces in the front end that make the MSC to appear as an IMS application server (called Fast Track) as proposed by NSN and the other is a SIP-based BSC where any MSC can appear to be the IMS application server. The second model does not assume that NSN MSCs are there or required.
In summary, it seems that the industry is finally converging on a working model and VoLGA is going to disappear. The backers of VoLGA, companies such as Kineto Wireless, have to resharpen their tools and decide what they would have to do next.
