I'm kinda confused about something. When you make a call on an ATT 3G phone is it GSM and the data is W-CDMA? I read somewhere that HSDPA/UMTS is CDMA based? Any clarification is appreciated. Thanks! Mike
When you make a call on a 3G network, its actually going through said network using the UMTS standard, not GSM. They're 2 completely different beasts, your either on one or the other, not both, which is why you hear about calls dropping between the two networks.You were right about WCDMA being the data portion of the network. Its the equivilant of GPRS or EDGE on the GSM network. WCDMA is based of off CDMA, just as GSM was based off the older standard of TDMA, CDMA is just more efficent.
Well, if the network engineers configure the network properly for IRAT then GSM <> UMTS handovers shouldn't be a problem
No. It's WCDMA, which is similar to CDMA, but is not compatible. ie: you need different phones for WCDMA (ATT) and CDMA (Verizon, Sprint)
its a WCDMA air interface, which uses Code Division Multiple Access methodologies, but was developed by NTT DoMoCo in japan.
okay cool thanks. so I have sprint and they have 3G, but it's just not WCDMA? Are their any plans of sprint upgrading? I'm sure they can't use the same technology as AT&T?
Right Sprint's 3G is called EvDO. They won't be upgrading to UMTS (WCDMA) since they are betting on a different type of technology called WiMax for their 4G network..
Sounds cool. When they update technologies do they have to go to the towers and change them out or just upgrade the software? When an iphone is on 'E' of the Edge network, are voice and date running thru the GSM network? Thanks Mike
] It depends on the upgrade. When Sprint went from EvDO Rev 0 to Rev A, engineers swapped cards out in the cell tower base stations. The same would apply when AT&T wants to go to faster speeds on their 3G network, (going from HSDPA 1.8Mbps to 3.6Mbps, etc.). When Sprint started building out their WiMax network, it required all new equipment.and new panels on towers. Of course its not as easy as flipping a switch, and a lot of planning goes into upgrades. Yes, your voice/data are going through the GSM network if your iPhone says "E".
