Voice Over LTE

Posted by Sam Churchill on

Verizon’s soon to be available LTE smartphone, the LG Revolution, was used to complete the first VoLTE call over its LTE network this week. Verizon has said they will make all voice calls on their 3G network, with a commercial launch of the VoLTE system planned for late 2012.

LTE and WiMAX are the current “4G” networks in the United States. But they are data networks. There’s no voice. 4G phones like Verizon Thunderbolt (LTE) or Sprint EVO 4G (WiMAX) need two networks; a 3G network (for voice) and 4G network (for data).

Integrating voice and data on one network makes sense. Voice is just data, after all. Infrastructure could be used more efficiently with a single, integrated network.

Wireless voice and data can be integrated using a variety of approaches:

  • Unlicensed Mobile Access (UMA). This approach uses voice over WiFi. T-Mobile has used it for home or office based hubs. Phone calls can be automatically switched from cellular service to a Wi-Fi access point if UMA software is used the WiFi hotspot and phone. The WiFi access point connects to the Internet. Kineto Wireless supports this approach. Kineto says its smart Wi-Fi application has been deployed on more than one million Android handsets worldwide. It lets you use a dual mode (WiFi/cellular) cell phone inside a home or office without racking up a lot of minutes.
  • Voice over LTE via GAN (VoLGA). GAN (Generic Access Network) is just a synonym for a UMA-like WiFi connection). Volga is different from UMA in that it replaces the Wi-Fi layer of UMA with LTE. Kinto also offers a VoLGA solution for Android phones. It is a pragmatic approach for voice over LTE and provides a smooth migration to IMS telephony.
  • VoLTE (Voice over LTE). Voice is sent over licensed LTE bands (not Wi-Fi). LTE services are data only. No voice. LTE phones currently require a 2nd (3G) network for voice conversations. Any Voice over LTE implementation must be standardized over the entire LTE industry, however. That takes time.
  • IP Multimedia Subsystem (IMS). An architectural framework for delivering Internet Protocol (IP) multimedia services (voice, video and data). “Integrated services” can be more easily switched and managed.

Terrestrial “4G” networks that integrate voice and data may make sense, but the approach must be standardized. Otherwise it won’t work.

Perhaps that explains some of the excitement behind proposals for reusing Mobile Satellite Service by Lightsquared (at 1.6 GHz) and TerreStar (at 2 GHz).

One (LTE) network might rule them all.

Posted by Sam Churchill on Wednesday, February 9th, 2011 at 10:58 am .

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