WiMAX, LTE and Femtocells Some Insights from AIRCOM International

WiMAX, LTE and Femtocells Some Insights from AIRCOM International
TMC Net - Norwalk,CT,USA

..."Although people didn't originally think of LTE for voice, you actually have two solid propositions for voice call network," says Goetz. "First, there's the IMS [IP Multimedia Subsystem] approach or the Unlimited Mobile Access [UMA]-derived approach called VoLGA [Voice over LTE via Generic Access] which enables mobile operators to deliver mobile voice and messaging services over LTE access networks based on the existing 3GPP Generic Access Network [GAN] standard. Again, you're getting a system that's designed from the handset to the point of interconnect with other networks to provide voice calls. But what you get with WiMAX is a ASN and a CSN, as I said previously. On top of that the operator must provide its own voice solution. I worked a vendor up until about two years ago involving a major WiMAX deployment in Pakistan. They needed a core network for VoIP. At the time we provided the world's largest IMS deployment for commercial VoIP. But if you were then to take those WiMAX devices and attempt to use them in another network, that core network isn't there, and so the roaming capability would not be there either, which means that you wouldn't have a seamless, wireless voice solution for customers. So 3GPP and VoLGA on one side offers a specified solutions end-to-end, while WiMAX is effectively an access network, and you have to worry about the call running on top."

 

Goetz adds, "What you have to take into account with LTE is the migration from the existing 3GPP network where you have effectively a C7-based core switching network even with the split architecture Mobile Switching Center [MSC] servers and media gateway, and you've got evolve that into either an IMS or VoLGA environment. Hopefully operators will standardize on one of those, and predominantly a Session Initiation Protocol (News - Alert) [SIP]-based technology, and still have legacy interconnect to other networks still utilizing the older technologies. LTE has a good foundation; there are still a few issues to solve, but it's better placed from an end-to-end standard with which to deal with these issues." ...