uhjon
@comcast.net | Between 1 in 2?
i hate statistics.
3G (WCDMA) is not GSM? that's CDMA, the technology that Verizon Wireless uses, right? |
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en102
Canadian, eh?
join:2001-01-26
Valencia, CA
 ·RoadRunner Cable
 ·DSL EXTREME
·DSL EXTREME
| not quite..
GSM is a corporate 'name' given to GSM / UMTS (3G) which uses WCDMA
Similarly, CDMA2000 is used for CDMA 1x/EVDO/EVDV.
WCDMA and CDMA have a similarity in air spectrum interface in that they are CDMA based (i.e. Code Division Multiple Access), but that's where the similarities end. Just as GSM (TDMA) and TDMA (ANSI) or iDEN are TDMA based, they are not the same, and neither is WCDMA to CDMA 1x/EVDO/EVDV.
There's 2 parts...
Air interface:
WCDMA uses paired 5MHz channels for spectrum (painfully large), while CDMA (1x/EVDO/EVDV) use paired 1.25MHz channels for air interfaces.
Back end:
GSM/UMTS (WCDMA) uses the 'map' (Mobile Application Part) core, which is common between GSM and UMTS/3G.
CDMA (1x/EVDO/EVDV) uses the 'ANSI' - AMPS (analog - now dead), TDMA (IS-136) and CDMA IS-95/1x/EVDO
The 2 back ends are not exactly compatible, as GSM based devices (and iDEN as well) use SIM/IMEI as identifiers, while ANSI uses ESN. There are other differences as well.
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Canada = Hollywood North |
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opus74
Deep Thought
Premium
join:2002-03-04
Coello, IL
clubs:  | Well said.
We are seeing more & more new CDMA handsets with IMEI identifiers instead of ESNs. |
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TechieZero
Tools Are Using Me
Premium
join:2002-01-25
Wesley Chapel, FL |  reply to en102
Which Tech is Better?
Which tech is considered better? |
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en102
Canadian, eh?
join:2001-01-26
Valencia, CA
·RoadRunner Cable
·DSL EXTREME
·DSL EXTREME
| Both are 'CDMA' based, and one isn't really better than the other.. just have somewhat different features and issues.
eg. WCDMA/UMTS devices do voice and data at the same time (i.e. you can surf on your Palm while on a call using handsfree or speaker phone). On the downside, WCDMA requires LARGE slices of spectrum to operate (5MHz x 2) vs. 1.25MHz x 2 for CDMA1x/EVDO.
Verizon/Sprint use CDMA 1x/EVDO
AT&T and soon T-Mobile use UMTS/WCDMA.
The 'tech' that is considered better is the one that works where you need it.
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Canada = Hollywood North |
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