What's Behind One Voice?

On Nov. 4, a slew of telecom vendors and operators announced the “One Voice” initiative. It defined “the preferred way to ensure the smooth introduction and delivery of voice and SMS services on LTE” and surprise, surprise, IMS was the preferred way.

 

The slew of heavy-hitters are: AT&T, Orange, Telefonica, TeliaSonera, Verizon, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung Electronics Co. Ltd. and Sony Ericsson. They concluded that IMS was “the most applicable approach to meeting the consumers’ expectations for service quality, reliability and availability when moving from existing circuit switched telephony services to IP-based LTE services.” 

 

I doubt if the average consumer has any LTE expectations right now, but my conclusion, for what it’s worth, is that One Voice was a reaction to the negative media coverage about voice and SMS over this air interface. And if that was the case, then these organizations should have made a better business case. There is one, so please read on.

 

I had written about this issue before. See “Where Are We Going With Wireless?”, so I went back to a couple of contacts, one at Alcatel-Lucent with Ed Elkin, director of IMS marketing, carrier product group, and one at Nokia Siemens Networks with Bareld Meijering, marketing and communication manager. The remainder of this article is a summary of what I learned with a few of my own thoughts thrown in.

 

LTE was primarily designed for high-speed data, not voice or SMS, and the first LTE devices will be for notebooks, i.e. PC cards and USB dongles. The service is needed to match the huge increase in mobile data traffic, which comes from the appeal of smartphones, wireless-enabled laptops, netbooks and flat rate pricing. This is leading to a 3G data crunch, therefore some operators may deploy LTE as a data-overlay, with either no-voice, or voice reverting to 2G/3G via CSFB. This term indicates that when a voice call is received the LTE data connection is abruptly terminated and the connection “falls back” to 2/3G instead.

 

Cell phones will come later – much later. Therefore if the industry doesn’t get its act together the interface will be used for over-the-top VoIP services such as Google Talk and Skype. The wireless operators will have opened the window to the competition and they might lose out. They don’t want to have a similar experience to that of the wireline operators. And when LTE does come to cell phones there’s another issue. Without support, an over-the-top user on an LTE data connection would be unreachable in areas where there was no LTE coverage. Subscribers need global roaming in LTE, as they have today with 2G/3G.

 

Address books and PBX-type functionality are another consumer issue. Without IMS there would be one address book for the over-the-top notebook service and another on the cell phone. With IMS they could be synchronized. In addition these services don’t have PBX features such as call forwarding and mobile business professionals need them. Another limitation is the fact that Skype doesn’t talk to Google and vice versa and these are just two of the many consumer VoIP services. Therefore operators will want to have IMS in place when commercial LTE services are launched. Only time will tell if it happens.

 

The good news about IMS is the fact that it has a lot of functionality, but that’s also the bad news. It’s big and it’s complex so it’s taken a long time from conception, which started around ten years ago, to the implementation of commercial services. And even now they are thin on the ground and are only operational for fixed-line services, such as AT&T’s U-Verse Voice. It would therefore seem that the One Voice initiative acknowledges that IMS has become too complex and that operators need to be able to pick and mix the functional components they need to deliver a particular service; in this case Voice and SMS over LTE. In another it was the 3G-based service RCS, which is a near-term deliverable. Operators are in final trials and services are expected to start in early 2010. 

 

An operator that employs the requisite functional components for RCS can migrate the enhanced address book and the rich call experience to LTE. They can blend the merged service with voicemail and social networking sites, add high definition voice and so on. It’s doable, but we’ll have to wait and see what actually gets done. This is an industry that has a distressing habit of being long on promises and short on delivery.

 

Nokia Siemens Networks is up front about the complexity and cost of implementing IMS in mobile networks. Obviously the new system has to work in the existing infrastructure – it has to work with all the back-office systems such as billing, both pre- and postpaid. And that, as they used to say, is no walk in the park. However, a key issue is the equally obvious need to enable VoIP over LTE roaming, which means that interoperability between the IMS systems of different vendors has to be nailed down. Subscribers won’t accept anything less. In addition, there needs to be connectivity between the different air interfaces in the same network.

 

IMS is a contentious subject and at times it’s hard to filter out hard facts from marketing hype, but when it comes to interoperability there is an organization, the MultiService Forum, whose only agenda is to run test events. Next year the MSF LTE/EPC interoperability event will focus on: basic interoperability, roaming, non-LTE access and handover. The latter will include the all-important handover between LTE and legacy 3G.  Therefore it would seem that NSN’s cautionary approach is correct and even though IMS will be deployed for RCS in various networks, those interop issues remain.

 

The approach that this vendor is proposing is a solution called Fast Track Voice over LTE, which is compliant with One Voice. NSN says that the company’s mobile softswitch has a SIP signaling capability and the Fast Track software update will allow the switch to handle VoIP traffic in LTE networks. This is an intrinsic design feature of the company’s soft switches; it also means that in future the mobile and fixed domain can be handled by the same voice systems.

 

When IMS is deployed Fast Track will continue to work in the same way, i.e. as part of IMS, moreover there won’t be a back-office integration hassle. It’s a personal opinion, but updating software in legacy hardware would seem to be a better option than installing new hardware.