Dual CDMA phones to allow voice/data at same time?

xenophon · EVDO Addict Joined: 30 Aug 2005 Posts: 2004

One advantage Cingular's HSDPA handsets will have next year is that you will be able talk and do data at the same time. This is likely because HSDPA is CDMA-based and voice is GSM, requiring two different radios.

This article loosely mentions dual chip CDMA phones coming next year, which in principle would allow EVDO and voice at the same time for Sprint/Verizon phones. If true, this could be an interim solution until VoIP over EVDO becomes available, which would allow simultaneous voice/data over one data connection.

But I wonder how much battery drain will be caused by two chipsets active?

http://www.newsfactor.com/story.xhtml?story_id=03200000RCHS

Zorog · EVDO Heavy User Joined: 08 Jul 2005 Posts: 135

xenophon · EVDO Addict Joined: 30 Aug 2005 Posts: 2004

^Correct. But you can't actively use data while on a voice call. With dual chipsets, you could be on your phone, say speakerphone or earpiece, and browse the web a the same time. Or as salesperson could be tethering phone to laptop, talking on the phone while looking up account information for a client.

Dual chipsets will be the interim solution until VoIP becomes standard over Rev A/B.

IamtheWalrus · EVDO Newbie Joined: 19 Dec 2005 Posts: 8

xenophon · EVDO Addict Joined: 30 Aug 2005 Posts: 2004

Thanks for clarifying. I simply used the term because it uses the same principals as CDMA, different than GSM. The point was only made to show that two different radios are required in HSDPA phones because HSDPA is not based on GSM, but rather a CDMA type technology, specifically called W-CDMA.

Since Cingular could potentially have an edge with simultaneous voice/data via two independent radios on one phone, it looks like dual CDMA phones will also come out to compete, until VoIP over once channel.

At least that is what the article implies.

IamtheWalrus · EVDO Newbie Joined: 19 Dec 2005 Posts: 8

xenophon · EVDO Addict Joined: 30 Aug 2005 Posts: 2004

^Um, OK. But anywho.. GSM/HSDPA is ultimately using two (or dual-mode) chipsets because of differing technologies. Dual CDMA will allow similar simultaneous voice/data functionality.

I've been reading about difficulties of stepping between Edge/HDSPA and that it has more issues than switching from EVDO/1xRTT states. Makes sense because Edge is GSM/TDMA, HSDPA is WCDMA. EVDO/1xRTT is all CDMA so likely can switch more easily.

IamtheWalrus · EVDO Newbie Joined: 19 Dec 2005 Posts: 8

Iceman · Posted: Wed Dec 21, 2005 12:22 pm Post subject:

I don't think the Sprint and Verizon EV-DO networks are behind anyone in the world, except maybe Japan. And since wCDMA is not backwards compatible with GSM, I'm not sure what your point is about international standards.
The future belongs to phones that can seamlessly switch between available frequencies to get the fastest and/or cheapest connection for the customer. In particular, I want a phone that works on the forthcoming citywide WiFi/WiMAX network in Minneapolis, and switches to EV-DO when no WiFi connection is available. With current technology, this setup requires two radios.

SL10 · Posted: Wed Dec 21, 2005 12:33 pm Post subject:

SL10 · Posted: Wed Dec 21, 2005 12:51 pm Post subject:

I do believe with Sprint's EVDO phone can do voice and data together. Meaning that voice and 1xrtt is one channel and EVDO is a separate channel? Anyone wish to confirm this that has a Sprint EVDO phone?
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xenophon · EVDO Addict Joined: 30 Aug 2005 Posts: 2004

^EVDO phones can't do voice/data simultaneously until there are dual CDMA chipsets. The behavior of incoming calls is slightly different for an EVDO phone vs. a 1xRTT phone.

If you are streaming active data on a 1xRTT phone and a voice call comes in, the phone will not ring and it will roll over to voice mail and you don't know a call came in until the voice message icon appears. (The key word is is active data. If browsing and the page finishes loading, the phone will ring - but will roll over to voicemail if still downloading the page.)

If you are streaming data on an EVDO phone, the phone will ring during active transmission. If you answer, EVDO streaming will stop and resume after you hang up from the call.

With dual CDMA chipsets, you'll be able to answer the call and keep on browsing or whatever during the call. You could of course place a call as well.

Michael · Posted: Wed Dec 21, 2005 2:33 pm Post subject:

As an interesting side (somewhat related) note...

If your phone/pda has WiFi built-in, you may be able to keep your data connection going while on voice. Which makes sense, since you not using data & voice via the same built-in radio.

I have tested the PPC-6700 (See PPR-6700 Review) and if I have WiFi on, I can be on the phone and do data at the same time.
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