EVDO Rev-A Voice/Data Channel

WhatAboutEVDO · EVDO Newbie Joined: 09 Mar 2006 Posts: 1

Does anyone know if Rev-A will support simultaneous voice and data sessions? I heard it would, but have not been able to get confirmation.

Scott · Posted: Sat Mar 11, 2006 7:35 pm Post subject:

Yes and no... Revision A supports Quality of Service (QoS) and thus Voice over IP (VoIP), which would allow simultaneous voice and data... BUT that is handling voice and data differently than how it is currently handled on older CDMA networks. Even without QoS (and some other things) the current EVDO Rev. 0 can sort of support VoIP, mainly because of the data-rate EVDO allows for. But it doesn't work very well (and your provider's ToS most likely has language forbidding VoIP).

Part of the problem is backward capability with older devices and standards. Unless the entire network is Rev. A and all devices are doing VoIP, "roaming" wouldn't work since a handoff from a Rev. A tower to an older CDMA/1xRTT-only tower would require the older technology to handle the VoIP and data (and the higher data-rates), something it can't do.

You may have read or heard about WCDMA or UMTS getting rolled out by current GSM providers, and how UMTS has the capability to handle simultaneous voice and data. Sounds pretty good. Well... even while UMTS has the capability to do this, older GSM towers STILL will not. So if you're talking on your new UMTS/HSDPA device and streaming media, and then are handed-off onto a tower this is still only GSM GPRS/EDGE, that streaming media is going to STOP. ;]

Its about the coverage.

When all the networks are either EVDO Rev. A or UMTS/HSDPA, then we will experience some really cool simultaneous voice/data "roaming". Until that point you had better hope that the updated tower(s) near where you work and live cover you well enough so that you don't jump onto an older tower... "Umm... Houston, we have a problem."

I haven't even touched on frequency usage and world roaming... THAT is another whole "can of worms".

This is why I like my EVDO data card soooo much. Talk and connect right NOW!

Resources: EVDOinfo.com pages here and here offer a good jumping off point for Rev. A info. A good glossary covering many mobile technologies (and their multiple strange acronyms) is here.