Originally Posted by jb510
I love the retina display on my iPhone 4, but I actually don't care much about the screen on the iPad HD... It'd be a nice bonus, niether do i care about strwaming video, but I do care about:
#1 Does 4G LTE allow for international roaming? (ie like GSM)
#2 Does 4G LTE allow for simultaneous voice and data? (for phone since I'm not into having an AT&T iPhone and a Verizon tablet).
LTE can be considered more of a "unified standard" that only China has opted out of. They want higher density, but the same chips that do LTE will do TDLTE too, eventually. So depending on what stabilizes after initial LTE rollout.
Verizon's network is complicated to explain. They have a 2G Voice network with a 2G Data (1X) and 2.5G(EV-DO(Data Optimized (max 3Mbps))) and a 4G (LTE.) There was supposed to be another technology in between called EV-DV (Data and Voice) for the 3G network that never panned out, so they skipped straight to 3.9G LTE.
Sprint's network is a quagmire of bad planning. They have the same 2G and 2.5G voice and data technologies Verizon has, but then throw WiMax(Clearwire) in as their 4G network. They are now forced to roll out LTE or lose more customers to AT&T or Verizon.
Both Verizon and Sprint can "fall back" to AMPS, but phones released after 2005 tend not to have AMPS support anyway.
Meanwhile AT&T went from 1G AMPS to 2G TDMA to 2G GSM to to 3G UMTS to 3.9G LTE for the voice path and 2G TDMA to 2.5G EDGE(GPRS) to 3G UMTS, to 3.5G HSDPA to 3.9G LTE. After the conversion to GSM, then AT&T Wireless and Cingular merged to have one larger GSM family network. AT&T no longer operates it's 1G AMPS or 2G TDMA networks.
T-Mobile, under it's previous incarnation started out as a 2G GSM network and offered GPRS around 1999. It likewise made all the same moves as AT&T did, except it's nearly fatal mistake was rolling out UMTS on 1700Mhz
Likewise in Canada, Rogers followed AT&T on 850/1900, where as the new carriers followed T-Mobile on 1700Mhz. Bell and Telus didn't follow Verizon, and actually went from EV-DO to operating a HSDPA network first in time for the Olympics to cash in on the expected roaming revenue. They're now also running LTE as well.
So all the issues regarding LTE roaming are centered on which UMTS bands are supported. If you are roaming in North America, you get the best coverage from AT&T/Rogers because they operate all the same frequencies and technology. If you Roam while being a customer on Verizon, you will have degraded data if you go to Canada while being forced to use the EV-DO and 2G voice network. But if you can fallback to HSDPA you're good. If you use T-Mobile, you roam on the Wind network in Canada if you have a AWS UMTS device (eg not the iPhone/iPad) but you can probably force your device to roam on Rogers /Fido or Bell/Telus HSDPA networks.
If you go to Europe, LTE networks are being rolled out on 800Mhz, 1800Mhz, 2000Mhz,2500Mhz and 2600Mhz. None of these are supported by American devices except 800/900/1800/1900 as 2.5G.
But it's important to point out that LTE is not a "GSM family" technology, if the operators decided to shut down their 2G/2.5G/3G/3.5G networks overnight, the LTE networks do not listen to GSM calls at all. The carriers do spectrum migration as their older networks become underutilized. This is what T-Mobile needs to do to continue to support the iPhone, migrate some more of their 1900Mhz spectrum to LTE.
Likewise Regional Carriers in the US make up portions of the the coverage map for AT&T and T-Mobile. When you have a plan that lets you use your phone nationwide, you utilize these networks seamlessly. Don't underestimate the greediness or mismanagement at AT&T, they are totally looking for ways to nickel and dime the customer. Local/Regional plans that AT&T used to offer were designed for people who never leave their zip code and you used to be charged roaming charges, for roaming on the home network but outside the home area. Most of this nonsense has gone away and is now focused on squeezing customers for Data. There is absolutely no logical reason for any ISP to have a data cap, as it's not a consumable resource. Rather the bandwidth is consumable and it would make more sense to upgrade everyone to the most efficient technology (that is currently LTE) in order to get more customers to use data instead of the current scam of trying to trick customers into accidently using data and charging them an arm and a leg.
And whoops was that ever a soapbox.