Related
Hey,
The T9193 version of the HD2 has the radio bands 850/2100 in it for HSDPA 3G speeds, but just the 850 band is needed to support AT&T's 3G service in the US.
Would it be possible to create a new radio ROM that disables/turns-off the 2100 band for U.S. users, since this band is useless anyway, and it may help extend the battery life of our HD2 by not having to power the 2100 section of the radio, especially if it makes any transmit attempts by the phone on the 2100 band (transmitting uses a lot more power then receiving).
Any chance of this?
JohnCody said:
Hey,
The T9193 version of the HD2 has the radio bands 850/2100 in it for HSDPA 3G speeds, but just the 850 band is needed to support AT&T's 3G service in the US.
Would it be possible to create a new radio ROM that disables/turns-off the 2100 band for U.S. users, since this band is useless anyway, and it may help extend the battery life of our HD2 by not having to power the 2100 section of the radio, especially if it makes any transmit attempts by the phone on the 2100 band (transmitting uses a lot more power then receiving).
Any chance of this?
Click to expand...
Click to collapse
T-mobile is also using HSPDA/3G @ 850 also and nowhere else? I hope so because pretty much half or better of the users of these forums are T-Mobile and *not* AT&T subscribers. Jus sayin.
JohnCody said:
Hey,
The T9193 version of the HD2 has the radio bands 850/2100 in it for HSDPA 3G speeds, but just the 850 band is needed to support AT&T's 3G service in the US.
Would it be possible to create a new radio ROM that disables/turns-off the 2100 band for U.S. users, since this band is useless anyway, and it may help extend the battery life of our HD2 by not having to power the 2100 section of the radio, especially if it makes any transmit attempts by the phone on the 2100 band (transmitting uses a lot more power then receiving).
Any chance of this?
Click to expand...
Click to collapse
ROM cooks do not have such fine grain control over radio bands.... Sorry.
I don't believe the T9193's radio has the 2100 Mhz band, otherwize I'd be able to use it in my area to get 3G coverage. (We only have Edge on the 850 Mhz band here)
Hopefully someone who knows for sure can answer this.
JohnCody said:
Hey,
The T9193 version of the HD2 has the radio bands 850/2100 in it for HSDPA 3G speeds, but just the 850 band is needed to support AT&T's 3G service in the US.
Would it be possible to create a new radio ROM that disables/turns-off the 2100 band for U.S. users, since this band is useless anyway, and it may help extend the battery life of our HD2 by not having to power the 2100 section of the radio, especially if it makes any transmit attempts by the phone on the 2100 band (transmitting uses a lot more power then receiving).
Any chance of this?
Click to expand...
Click to collapse
Hi mate,
you already tried this?
In Dialer > Menu (right soft-buttom) > Baseband > Band Frequency
or
Start > Settings > Personal Settings > Phone
But 850 Mhz is just for GSM not WCDMA... it's right?
2udCrRAZdK said:
I don't believe the T9193's radio has the 2100 Mhz band, otherwize I'd be able to use it in my area to get 3G coverage. (We only have Edge on the 850 Mhz band here)
Hopefully someone who knows for sure can answer this.
Click to expand...
Click to collapse
I'm pretty sure the T9193 has the 2100 band, but 2100 is useless in the US because AT&T uses 850/1900 for 3G. The T9193 is an Australian phone made for Telstar (their cell phone company). The 3G bands used over there are 850/2100. So, because AT&T also uses the 850 band, thats why we are able to use this phone with AT&T's 3G here over in the US.
However, the 2100 band of the phone is useless in the US because is was intended to be used for 3G in australia.
The good news is that AT&T is phasing out the 1900 band for 3G and switching everything over to 850, so the HD2 will just get more and more 3G coverage as time goes on and then even the 1900 band won't be used anymore so it would be irrelevant if the HD2 has a 1900 band or a 2100 band because both would be useless.
NRGZ28 said:
ROM cooks do not have such fine grain control over radio bands.... Sorry.
Click to expand...
Click to collapse
Gotcha - thanks for the info.
2udCrRAZdK said:
I don't believe the T9193's radio has the 2100 Mhz band, otherwize I'd be able to use it in my area to get 3G coverage. (We only have Edge on the 850 Mhz band here)
Hopefully someone who knows for sure can answer this.
Click to expand...
Click to collapse
Well, you neglected to say where "here" is
The best available combination for world-wide 3G access is 850/2100 Mhz. This is because:
1) 850Mhz is used in Canada, US, S Americas, Aus, S Africa for 3G broadcasting in regional areas (and in some city areas)
2) 2100Mhz is used in Asia, EU, Aus cities for 3G broadcasting
This is due to the actual physics of velocity = frequency x wavelength
Some telcos use 1900Mhz in the cities, but also broadcast in 850Mhz
Other telcos use 900Mhz in the regional areas, but also broadcast in 2100Mhz in the cities
ATT in the US uses 850mhz in the regionals and 1900Mhz in the cities. This ensures that "their" PDA's cannot use other SIM's - I have no idea why the dumbed-down US market meekly accepts that
The perfect combo is tri-frequency hardware, such as PDA manufacturers used to provide but do not any more (no excuses, it's just straight cost-cutting and sleight-of-hand marketing BS to suit the greedy telcos)
The HD2 released in Aus through Telstra is hardware-filtered for 2100/850 Mhz, the best available combo for world-wide use (not perfect, of course)
The HD2 released in EU/Asia is 2100/900 Mhz. This will access 3G in most cities world-wide (note that China uses 2100/850) but has limited coverage in regional areas - yes, I know there many 900 Mhz deployments but these are very limited geographically
The HD2 released in the US is 1900/850 Mhz. This is very limited for world-wide cities and excludes 3G coverage for those countries that use 2100/900 Mhz
None of this has any relation to GSM coverage, so please do not confuse them
Is the hardware actually different?
I live in NZ and unfortunately bought a T-Mobile unit which is set up for 1700/2100mHz which means that when in the cities I get full broadband, but in the regions I only get dial up speeds through GSM.
My question is does anyone know if the hardware could actually use the 900mhz broadband - or is it a pipe dream on my part that hopefully someone will release a ROM to access some previously hidden hardware?
I do recall with my Touch that there was a GPS built into the hardware that no-one was aware of for a year or two!
mikey555 said:
I live in NZ and unfortunately bought a T-Mobile unit which is set up for 1700/2100mHz which means that when in the cities I get full broadband, but in the regions I only get dial up speeds through GSM.
My question is does anyone know if the hardware could actually use the 900mhz broadband - or is it a pipe dream on my part that hopefully someone will release a ROM to access some previously hidden hardware?
I do recall with my Touch that there was a GPS built into the hardware that no-one was aware of for a year or two!
Click to expand...
Click to collapse
The hardware is definitely different...
JohnCody said:
The T9193 is an Australian phone made for Telstar (their cell phone company).
Click to expand...
Click to collapse
The Phone company in Australia is Telstra (just in case you are goggling it and wonder why you cant find it)
t9193 vodafone
i can use 900/2100 bands on t9193
i use Vodafone australia on Telstra hd2 with quick 3g data everywhere
what are the hardware differences?????
am i alone?
is there anyone else in this community that has
T9193 + Vodafone AUS + Custom ROM/Radio
Everyone keeps pasting crap about incompatibility but it seems to be fine
I have a brand new unlocked Streak with an AT&T sim card in it, from my old lg vu. All I have is just the calling plan. I want to get a no contract unlimited plan to get online, etc., since I now have this beautiful new phone. Which carriers can I use and which are the cheapest? AT&T's data plan seems too pricy. Thanx, in advance, for the help...
Your only alternative to AT&T is T-Mobile, and if your phone was bought direct from Dell, it will be a very painful alternative in terms of speed. Streaks purchased direct from Dell cannot see all of T-Mobile's frequencies, and thus data will be limited to EDGE (2G) speeds.
Bite the bullet and get an AT&T smartphone plan. Even though T-Mobile has an unlimited everything plan, the penalty you pay in speed offsets any savings you might gain from changing carriers.
Carrier, Network
I bought my Streak off of Ebay from someone in Canada. It was brand new from Rogers. I unlocked it through Dell. Does this make a difference? I have seen unlimited plans from Boost Mobile and Straight Talk and was curious if my Streak would work on their networks. I read on another site that the unlocked Streak would work on any network. Just looking for other info... Thanx.
Unlocked GSM type phones will generally work on any GSM type network.
Boost mobile is a CDMA type network and straight talk is by tracfone? Straight talk might work depending on the donor phone (or if you can get a bare sim card)
Rogers is basically the At&t of the north in the way they handle the streak, and more importantly in compability between phones.
They're both 3g 850/1900
Tmobile is 1700.
The US streak is 850/1900/2100 (which is the one offered by the dell website/rogers/at&t)
straight talk uses verizon/at&t/tmobile as it's base network(?)
You'll get call/2g off either tmo's or at&t's networks and straight talk if it uses their network for coverage.
You wont get 3g except on the at&t 3g available portions of the network.
You cant use boost mobile at all if it's only CDMA, only if they offer GSM service on top of CDMA
TheManii... Thanx for the reply and the help. At least now I have a starting point. I am really new to all this and any help and advice is really welcomed and appreciated. Keep the info coming... Thanx again.
Unlocked Tmobile phone, ST sim
Hello, noob here... This is the closest thread I've found to my problem after extensive searching, and not being "senior" enough to post on more experienced threads. My issue: I have an unlocked Tmobile branded Moto Defy. Put the sim from my Straight Talk E71 in there, and, as many have said before, I only get edge speeds. I've read other forums of people claiming to pick up the HSPDA 850 band, but would have to travel hundreds of miles from SC to actually prove that. My real question here is, why can't my truly quad band Defy pick up the same exact HSPDA 850 / 1900 bands that my Straight talk Nokia E71 was picking up? Do I have to root it? Can you explain why exactly it doesn't pick up the AT&T 1900 band? Themanii, you seem knowledgeable here. Any info is much appreciated. Thanx.
Here's the info for the two phones:
Defy: 2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 900 / 2100 HSDPA 1700 / 2100 or HSDPA 850 / 1900
E71: 2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 900 / 2100 HSDPA 850 / 1900 - American version
info derived from gsmarena.com
Firstly dont bump old threads, to granted this one isnt THAT old.
Which carrier are you on exactly?
If you're on Tmo USA your e71 doesnt support AWS(1700)
If you're using At&t with your AWS defy it doesnt support 1900
Defy = 900/1700/2100 OR 850/1900
E71 = 900/2100 OR 850/1900
Looking for any insight to using the SGS2 on TMo and getting anything better than EDGE speeds.
As I understand it (via wikipedia) TMo has these bands:
[TMobile USA] owns licenses to operate a 1900 MHz GSM (Global System for Mobile Communications) PCS (Personal Communications Service) digital cellular network and a 1700 MHz/2100 MHz UMTS AWS (Advanced Wireless Services) digital cellular network that cover areas of the continental U.S., Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. It provides coverage in areas in which it does not own radio frequency spectrum licenses via roaming agreements with other operators of compatible networks.
And then from Samsung's website:
Network
HSPA+ 21Mbps/ HSUPA 5.76Mbps
EDGE/ GPRS Class 12
Quad band GSM 850/900/1800/1900
Quad band UMTS 850/900/1900/2100
So, what gives? Seems like the 2100 UMTS service should match up between the two. Is this an issue because TMo is somehow blocking the use of the unbranded phone on their system? If so, and on a much more advanced level, I'd think there'd be a way to make TMo think I'm using the PoS smartphone they gave me to use on their system... or am I smokin' that crackberry?
Needs both 1700 and 2100 if I remember correctly.
gmstrollo said:
Looking for any insight to using the SGS2 on TMo and getting anything better than EDGE speeds.
As I understand it (via wikipedia) TMo has these bands:
[TMobile USA] owns licenses to operate a 1900 MHz GSM (Global System for Mobile Communications) PCS (Personal Communications Service) digital cellular network and a 1700 MHz/2100 MHz UMTS AWS (Advanced Wireless Services) digital cellular network that cover areas of the continental U.S., Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. It provides coverage in areas in which it does not own radio frequency spectrum licenses via roaming agreements with other operators of compatible networks.
And then from Samsung's website:
Network
HSPA+ 21Mbps/ HSUPA 5.76Mbps
EDGE/ GPRS Class 12
Quad band GSM 850/900/1800/1900
Quad band UMTS 850/900/1900/2100
So, what gives? Seems like the 2100 UMTS service should match up between the two. Is this an issue because TMo is somehow blocking the use of the unbranded phone on their system? If so, and on a much more advanced level, I'd think there'd be a way to make TMo think I'm using the PoS smartphone they gave me to use on their system... or am I smokin' that crackberry?
Click to expand...
Click to collapse
One is up and the other is down so you need both 1700 and 2100 to use T-Mobile's data network. No version of the SGS2 any where in the world supports T-Mobile's AWS bands. T-Mobile's getting a dual-core version of the Infuse in September that supports their bands.
BarryH_GEG said:
One is up and the other is down so you need both 1700 and 2100 to use T-Mobile's data network. No version of the SGS2 any where in the world supports T-Mobile's AWS bands. T-Mobile's getting a dual-core version of the Infuse in September that supports their bands.
Click to expand...
Click to collapse
HERCULES..
pachi72 said:
HERCULES..
Click to expand...
Click to collapse
What's the chance of one of those "Hercules"...SGS2 by another name apparently...having an antenna board that will drop into another SGS2?
I see a lot of brilliant software hacks and tweaks around here. Don't see a lot in the hardware realm, tho (like a new antenna board, for instance.) Is this not the place for that or is that at a completely unrealistic level of development?
gmstrollo said:
What's the chance of one of those "Hercules"...SGS2 by another name apparently...having an antenna board that will drop into another SGS2?
I see a lot of brilliant software hacks and tweaks around here. Don't see a lot in the hardware realm, tho (like a new antenna board, for instance.) Is this not the place for that or is that at a completely unrealistic level of development?
Click to expand...
Click to collapse
You'll need an antenna engineer with a test chamber to tune the antenna. A lot of factors play into more than just fitting into it. You might have to play with different patterns depending on how much different the overall phone mechanics and materials are from Hercules to the SGS2.
Ok guys I have an atrix 4g running on t-mobile. My question is why cant I get 4g/3g on this phone ? T-mobile runs on the 2100 band and the phone does support that band so why no 4g or 3g? common sense would tell me that if t-mo runs 4g on 2100 and the phone is capable of running on 2100 that it would work. have searched for a total of about 4 hours or so over the past couple days and cant find a straight answer only thing i can find is that att doesnt run on 2100 band yet the phone does. thanks in advance to anybody that can answer and taking the time to read.
are you getting H+ or H? (This is "3.5g") The Atrix 4g is not a true 4g phone.
Because the 2100 spectrum that you're using the phone on now is part of the quad-band gsm which is edge/2g. The difference lies in the bands used for 3g/4g, in which case AT&T only uses 850/1900 and tmobile only uses 1700/2100.
There is also a bunch of things that include HSPA, AWS, WCDMA, and so on and so on but I don't know enough about that to comment.
EDIT: Also, the only phones I know that can be used on both AT&T and Tmobile 3g/4g are "penta-band" phones like some European Nokia phones and the unlocked Galaxy Nexus that needs to be imported as well.
shattar01 said:
Ok guys I have an atrix 4g running on t-mobile. My question is why cant I get 4g/3g on this phone ? T-mobile runs on the 2100 band and the phone does support that band so why no 4g or 3g? common sense would tell me that if t-mo runs 4g on 2100 and the phone is capable of running on 2100 that it would work. have searched for a total of about 4 hours or so over the past couple days and cant find a straight answer only thing i can find is that att doesnt run on 2100 band yet the phone does. thanks in advance to anybody that can answer and taking the time to read.
Click to expand...
Click to collapse
Wcdma=utms=3g
Yes, WCDMA and AWS(1700), as far as I know, are both from UMTS and the differences in regards to 3G between AT&T and Tmobile lie in the spectrum use (850&1900 vs 1700&2100). And both AT&T and Tmobile use HSPA(+) based off their respected UMTS frequencies.
I just don't understand the "leap" in GSM technology that breaks the quad-band compatibility, that's all.
matthew5025 said:
Wcdma=utms=3g
Click to expand...
Click to collapse
Also I've read 850 is att's main spectrum for large areas and 900 for T-Mobile. All higher spectrums are for smaller, rural areas.
If your looking for 3g maybe find a town or, buy a dual band amplifier? That's IF they have 2100 MHz band working where you are located.
Lower bands ie 850/900 are the download streams. 1700/1900/2100 are upload streams. If I'm not mistaken
Also a T-Mobile vibrant supports att, it also has our main band, 850mhz. Again which is the main large areas, like T-Mobile 900mhz. 1700-2100mhz for att/T-Mobile range is only as good as the towns that still has that band currently operating for hspa/3g data. I've seen alot of T-Mobile phones that have 850/1900/2100, and work on att. If they were 1600/1900/2100 did not for me.
You need that lower frequencies to ensure it to work. Then....
Also for regional based frequencies...
http://en.m.wikipedia.org/wiki/Universal_Mobile_Telecommunications_System
That link will let you know what that all really means.
I think you are mixing up gsm and umts.
GSM = 2G/Edge
UMTS (HSPA, HSPA+, HSDPA/HSUPA, WCDMA, AWS) = 3G
Have a look here. You will see they label "3G" as "UMTS" which is HSPA/WCDMA. A little more down you can see they label their data as "HSDPA", which is download, and "HSUPA" which is upload. Further delineating the speeds they label either one as UMTS for down and Edge as up, which to me tells me they use gsm for the upload and only use UMTS for download. Either way, there is not a T-mobile phone available that can be unlocked and used on AT&T's 3G, just 2G and vice versa. As I have previously mentioned, you will need a penta-band phone for that.
Ciloteille said:
Also I've read 850 is att's main spectrum for large areas and 900 for T-Mobile. All higher spectrums are for smaller, rural areas.
If your looking for 3g maybe find a town or, buy a dual band amplifier? That's IF they have 2100 MHz band working where you are located.
Lower bands ie 850/900 are the download streams. 1700/1900/2100 are upload streams. If I'm not mistaken
Also a T-Mobile vibrant supports att, it also has our main band, 850mhz. Again which is the main large areas, like T-Mobile 900mhz. 1700-2100mhz for att/T-Mobile range is only as good as the towns that still has that band currently operating for hspa/3g data. I've seen alot of T-Mobile phones that have 850/1900/2100, and work on att. If they were 1600/1900/2100 did not for me.
You need that lower frequencies to ensure it to work. Then....
Also for regional based frequencies...
http://en.m.wikipedia.org/wiki/Universal_Mobile_Telecommunications_System
That link will let you know what that all really means.
Click to expand...
Click to collapse
And don't get me wrong, I'm not trying to give anyone a hard time but it's misinformation to tell anyone that a T-mobile phone can work on AT&T 3G.
And I'll say it again, I'm not an expert so if anyone can better explain then I'm all ears (eyes).
live4nyy said:
I think you are mixing up gsm and umts.
GSM = 2G/Edge
UMTS (HSPA, HSPA+, HSDPA/HSUPA, WCDMA, AWS) = 3G
Have a look here. You will see they label "3G" as "UMTS" which is HSPA/WCDMA. A little more down you can see they label their data as "HSDPA", which is download, and "HSUPA" which is upload. Further delineating the speeds they label either one as UMTS for down and Edge as up, which to me tells me they use gsm for the upload and only use UMTS for download. Either way, there is not a T-mobile phone available that can be unlocked and used on AT&T's 3G, just 2G and vice versa. As I have previously mentioned, you will need a penta-band phone for that.
And don't get me wrong, I'm not trying to give anyone a hard time but it's misinformation to tell anyone that a T-mobile phone can work on AT&T 3G.
And I'll say it again, I'm not an expert so if anyone can better explain then I'm all ears (eyes).
Click to expand...
Click to collapse
I am just merely stating that I have a motorola defy on ATT, and it worked great for a long time with great speeds before I got a motorola atrix and infuse.
Im not saying that every tmobile phone will have working talk/text, or data for that matter. I have just posted an idea, or atleast what to look for when you are cruising for phones not labeled for your carrier.
I was getting my motorola defy with the att "grand fathered internet" for 10 dollars a month and it was about 160-420KB/s down, and 80-190KB/s up. but some phones are capable of this, others arent. I have a general idea, and have played with several different carrier cellphones and used them with att and att's 3g data.
Rogers HTC Dream (x2 of them)
Telus Milestone
Tmobile Defy
Rogers Atrix
ATT Atrix (x2 of them)
ATT Infuse
Rogers and Telus actually use the same 3G bands as AT&T so as long as those are unlocked they will work. And I'm not saying an unlocked T-mobile can't work on AT&T, because they can (they both use quad-band gsm) but you can not use an unlocked T-mobile phone an AT&T 3G. That's all I'm saying.
Now, they did make an European version of the Defy that uses the 850 3G band but not the T-mobile "branded" one.
I'm going to stick to my guns on this one because I don't want to give anyone the wrong idea about interchanging AT&T and T-mobile phones and expecting 3G service. I'm fairly certain about this and unless someone can prove otherwise that's how I will think.
Ciloteille said:
I am just merely stating that I have a motorola defy on ATT, and it worked great for a long time with great speeds before I got a motorola atrix and infuse.
Im not saying that every tmobile phone will have working talk/text, or data for that matter. I have just posted an idea, or atleast what to look for when you are cruising for phones not labeled for your carrier.
I was getting my motorola defy with the att "grand fathered internet" for 10 dollars a month and it was about 160-420KB/s down, and 80-190KB/s up. but some phones are capable of this, others arent. I have a general idea, and have played with several different carrier cellphones and used them with att and att's 3g data.
Rogers HTC Dream (x2 of them)
Telus Milestone
Tmobile Defy
Rogers Atrix
ATT Atrix (x2 of them)
ATT Infuse
Click to expand...
Click to collapse
---------- Post added at 08:47 AM ---------- Previous post was at 08:36 AM ----------
Upon further research, I have found this article, where under certain circumstances, you can use an unlocked AT&T iPhone with T-mobile 3G:
http://www.gsmarena.com/tmobile_usa_running_1900mhz_3g_in_some_areas_iphones_invited-news-3537.php
Now, this shows that an AT&T phone can maybe use T-mobile 3G but not the other way around. Again, I'm always up for learning something new but I need references/proof.
Well I do get att 3g on the defy and vibrant. I am currently getting about 300ish KB/s on them and 600+KB/s on my attic, I'm just going with the facts. Those facts are that certain T-Mobile phones will work with Att, provided they have 850mhz band. That allows you in most towns (near me) to get 3g
False.
300KB/s is Edge speed, which is only 2G.
http://en.wikipedia.org/wiki/2G
http://www.phonescoop.com/glossary/term.php?gid=107
That's why you get faster speeds on the Atrix because it actually uses 3G.
Again, both AT&T and T-mobile use quad-band GSM. Which is why you can unlock a T-mobile phone and use it on AT&T, and vice versa, but it is only 2G/Edge and NOT 3G.
http://www.phonescoop.com/glossary/term.php?gid=139
http://www.phonescoop.com/glossary/term.php?gid=3
Furthermore, here are the wiki pages for AT&T and T-mobile which both inlcude frequency charts outlining the technology (2G or 3G) each one uses:
http://en.wikipedia.org/wiki/AT&T_Wireless
http://en.wikipedia.org/wiki/T-Mobile_USA
Here are the charts:
AT&T:
Frequency Protocol Class
Frequencies used on the AT&T Network
850 MHz GSM/GPRS/EDGE 2G
1900 MHz GSM/GPRS/EDGE 2G
850 MHz UMTS/HSPA 3G
1900 MHz UMTS/HSPA 3G
700 MHz LTE 4G
T-mobile:
Frequency Band Protocol
850 MHz GSM/GPRS/EDGE 2G
1900 MHz GSM/GPRS/EDGE 2G
1700 MHz UMTS (W-CDMA)/HSPA/HSPA+ 4G (formerly 3G[34])
1900 MHz UMTS (W-CDMA)/HSPA/HSPA+ 4G
I check for facts and references, I'm only saying what I find in research.
Again, when unlocked, a T-mobile phone can use AT&T 2G/Edge, not 3G
Ciloteille said:
Well I do get att 3g on the defy and vibrant. I am currently getting about 300ish KB/s on them and 600+KB/s on my attic, I'm just going with the facts. Those facts are that certain T-Mobile phones will work with Att, provided they have 850mhz band. That allows you in most towns (near me) to get 3g
Click to expand...
Click to collapse
Hello everyone,
"The LTE standard can be used with many different frequency bands. In North America, 700 and 1700 MHz are planned to be used; 800, 1800, 2600 MHz in Europe; 1800 and 2600 MHz in Asia; and 1800 MHz in Australia. As a result, phones from one country may not work in other countries. Users will need a multi-band capable phone for roaming internationally." (en.wikipedia.org)
So far, I have not heard of any LTE cell phone able to adapt to this multi-frequency international situation.
Even within the USA, it does not seem possible for an unlocked LTE cell phone which has been bought through one carrier to be used with another one.
Well, it should be possible !
After all, LTE is an international standard supporting all frequency bands, flexible bandwidth and both FDD and TDD duplexes ...
So it might not be that difficult to make these phones be able to use different LTE frequencies.
All radio systems can easily scan the whole spectrum in order to settle on the next available or desired channel. Another example, on Android Gingerbread phones :
"Settings-->Wireless & Networks-->Mobile Networks-->Network Operators--> Search Network" shows you all the mobile carriers available in your area, offering you the possibility to manually register on a specific network.
All this means that it should be technically possible to buy an unlocked LTE cell phone in the US for example, buy a sim card in another country where the LTE frequency is different, and everything should work fine, maybe with some software tweak.
Has anybody tried this already ?