In the Transition to 4G, Voice will Stay on 3G

Most cellular operators are beginning the transition from 3G technologies to 4G LTE. That will mainly be for high-speed data and not voice, support for which will come years later. Communications engineer Jim Murphy describes some of the networking issues that make voice impractical on LTE on day one.  To his comments I’d add that the preferred LTE voice solution is VoIP on the IP Multimedia System (IMS) framework, which has had slow adoption in the mobile community.

Jim’s example is from the 3GPP family of technologies, of which LTE is part. Most 3GPP2 operators, such as Verizon Wireless, are also planning a migration to LTE. They migrate from a different family of technologies, those specified in 3GPP2 and which include cdma2000 developed largely by Qualcomm. In Verizon’s transition, high-speed data on cdma2000 networks, now provided by EV-DO, will migrate to LTE. Voice will stay on cdma2000 1x for several years. That’s not a problem, because that technology keeps improving. The latest version, called cdma2000 1x Advanced, has achieved a 50x increase in voice capacity over the predecessor IS-95 system launched in 1993.

Both 3GPP and 3GPP2 3G voice feature a soft-handover (make-before-break) scheme that allows for, essentially, a circuit-switched connection. Yes, you’ll be able to run Skype and other VoIP services on 4G LTE data networks, if you want. In terms of the total user experience, however, most will prefer the seamlessness of standards-based integrated voice capability.

VoIP is the future. For 4G voice, though, it’s just great in theory at this time.