Originally posted by: pm
I actually spent a while reading on CDMA and TDMA (like 2G GSM), and I have to agree with Secret's assertion. CDMA is probably better in most respects than TDMA. This came as a bit of a surprise to me.
Still, 3G GSM is UMTS which is based on W-CDMA.
http://en.wikipedia.org/wiki/U...ecommunications_System
yup, the 3GSM stuff is actually a sort of CDMA. while the regular '2G' gsm vs. cdma was techincally in favor of cdma (requiring less spectrum space to get the same amount of stuff done is pretty important), the fact that europe and most other countries allowed only gsm pretty much determined that gsm would stick around.
the reason that 'CDMA' carriers such as sprint and, in particular, verizon, seem to work better is that their spectrum penetrates structures better than t-mobile's, rather than the technical specifications of the air interface.
also, verizon and sprint have rolled out 3G to a very large part of their respective networks (and are already rolling out an upgraded version of that) while at&t is still working on its 3G network (and is still releasing slower '2.75G' devices like the iphone), while t-mobile hasn't even started rolling out 3G (iirc).
the main benefit of GSM, of course, is the fact that your device has the potential to work overseas if it uses the right bands (typically quad band, but also triband; dual band users are SOL). how useful that is to the average american who does little overseas travel is up for debate. the 'CDMA' carriers typically offer a business class 'world phone' with both types of air interface marketed to the types of people who are more likely to use it (whereas tourists will typically pick up a prepaid SIM and a cheap handset, as international roaming is $$$). the other benefit of GSM is that you can buy phones that aren't offered by the carriers, pop in a SIM, and go.
sprint at this point is going it alone with wimax (which isn't from the qualcom cdma family), though europe is supposed to decide to open up airspace to air interfaces other than those promulgated by the 3GPP (GSM) standards body any day now. some european carriers have expressed interest in wimax, though whether as a mobile or fixed service i don't know.
edit: oops, forgot that korea is doing wimax as 'wibro'