Results 1 to 15 of 15

Thread: T-Mobile: Please share data so that LTE Discovery apps can accurately report LTE band

  1. #1
    Join Date
    Nov 2013
    Posts
    14
    Feedback Score
    0

    T-Mobile: Please share data so that LTE Discovery apps can accurately report LTE band

    There's been some discussion recently about the LTE Discovery Android app reporting some of the bands wrong. So, I've written an open message to T-Mobile on Reddit, but I also wanted to post it here because I know that there are more technical users here. In order to improve the app, we are looking for the proper T-Mobile engineers that can help.

    --

    Hi T-Mobile,

    I'm one of the two developers for the LTE Discovery Android app, that has over 160k downloads. One of the most highly requested features is the ability for people to determine what LTE band their devices are connected to. This band topic is also raised up in just about every mobile-related forum, including this T-Mobile forum.

    Typically, people must figure out what band they are connected to by using various pre-loaded LTE engineering apps provided by the OEM or carrier. Some are difficult to access, some are easy to get to, and some devices don't provide any opportunity for people to figure out what LTE band they are connected to.

    That's where LTE Discovery comes in.

    One of our goals is to allow everybody to easily find out what band their device is connected to (among other signal-related info). At this time we have support for 15+ different carriers around the world, thanks to the many users who have contributed the information that we need to add LTE band support, including Verizon, AT&T, and Sprint!

    Most carriers have a pattern they use to help quickly classify what band they are connected to based on the LTE GCI / eNodeB ID. The most common pattern is using the last two digits of the GCI to map to the band. For example, on Sprint, if the GCI ends with 00, 01, 02, or 03, then we know that to be Band 25. If we should see 09, 0A, 0B, 19, 1A, or 1B, then we know that is Band 26.

    With recent updates to their network, T-Mobile does not follow this common relational pattern. And, coverage maps aren't always useful or accurate. So, T-Mobile subscribers are unfortunately stuck with the more manual process of trying to individually map each base station (tower) to its proper band. The number of towers classified grows a little everyday.

    CALL TO ACTION: We would like T-Mobile to release just a little bit of (un-proprietary) data for how they organize their LTE towers/bands so that interested T-Mobile subscribers can have the benefit of knowing what band they are connected to.

    Thank you,
    - Danial Goodwin -
    Co-Developer for LTE Discovery

    Anybody can also always contact us at feedback [at] simplyadvanced.net, or reach out to me personally at dan [at] simplyadvanced.net.

    ps - I've been a T-Mobile subscriber for about six years now.

  2. #2
    Join Date
    Jun 2004
    Location
    Baja California / Baja California Sur / Sinaloa / D.F.
    Posts
    22,257
    Device(s)
    Apple iPhone 8 Plus / BlackBerry KEYone BBB100-3 / Samsung Galaxy S8 / Netgear AC815S
    Carrier(s)
    Pacific Bell Wireless / Verizon Wireless / Movistar MX / Telcel MX
    Feedback Score
    0
    I thought about the ZTE MAXX, but backed off since the device didn't come with anyway to determine if Band 12 is being used or not. Granted there's LTE Discovery. however I soon learned that this app uses the CGI to determine if Band 12 is being used or not. I believed that this was a serious flaw in the app since it relied on accurate information regarding CGI and not on the ability to find this information directly off the SoC/RF chipset.

    While Samsungs, BBs and iPhones aren't the darlings for everybody, the stock OS can directly read the SoC/RF chipset to provide this information to end users without relying on an external app which requires values to be programmed in. Even better is that it provides the exact EARFCN and bandwidth channel.
    Last edited by i0wnj00; 02-17-2015 at 01:23 PM.

  3. #3
    Join Date
    Nov 2013
    Posts
    14
    Feedback Score
    0
    Yep, that is great about some devices. And, it's an unfortunate limitation of LTE Discovery and all signal apps because those other field test apps typically don't build explicit ways for app developers to also access that information.

    But, so far we've been able to reverse engineer the HTC Field Test APK. So a few HTC models will say "Verified" in LTE Discovery because the band and frequency information comes directly from the system -- NOT using the GCI.

    Mainly, we were able to do that because we were lucky to have a HTC device that we can physically use and examine. It's proving to be much harder to reverse engineer Samsung ServiceMode APK when we don't have the device to test code on lol.

  4. #4
    Join Date
    Jun 2004
    Location
    Baja California / Baja California Sur / Sinaloa / D.F.
    Posts
    22,257
    Device(s)
    Apple iPhone 8 Plus / BlackBerry KEYone BBB100-3 / Samsung Galaxy S8 / Netgear AC815S
    Carrier(s)
    Pacific Bell Wireless / Verizon Wireless / Movistar MX / Telcel MX
    Feedback Score
    0
    Is there any way to extract the information or program the app to read directly off the SoC/RF chipset? It seems like you guys have to examine an a file which already access to the hardware, is it possible to write the app to eliminate the need to reverse engineer the app and go directly to the hardware?

  5. #5
    Join Date
    Jan 2005
    Location
    USA
    Posts
    851
    Device(s)
    Tmobile Note 4
    Carrier(s)
    T-Mobile
    Feedback Score
    0
    Here you go, below are three different locations I found Band 12 on my Note 4. The first picture is a screenshot will be of the service menu, next will be signal check app, followed by lte discovery.

    Hope this helps.

    Location 1).






    Location 2).






    Location 3).





  6. #6
    Join Date
    Nov 2013
    Posts
    14
    Feedback Score
    0
    Quote Originally Posted by i0wnj00 View Post
    Is there any way to extract the information or program the app to read directly off the SoC/RF chipset? It seems like you guys have to examine an a file which already access to the hardware, is it possible to write the app to eliminate the need to reverse engineer the app and go directly to the hardware?
    I'll admit that I'm not that good at the lowest level hardware stuff.. yet. I'm slowly working my way down from the higher abstraction levels. So far, I've looked into that just a little bit. From what I have gathered about the RIL (Radio Interface Layer) for Android is that commands to the modem(s) use the Hayes AT command set, which is possible to access with root. There are StackOverflow posts showing usages of that also, for example: http://stackoverflow.com/questions/1...ia-adb-android. And, this old thread goes into a bit more details about that: https://groups.google.com/forum/#!to...rm/tVyNMnXtcEI.

    Ideally, yes, I wouldn't want to rely on any specific framework/OEM/carrier/app. I want to just be able to connect to the different Qualcomm LTE modems and see when the signal information is getting passed. There is so much to read and learn about this.

    At one of the highest levels for Android app developers to potentially talk with the RIL is a method called `TelephonyManager.invokeOemRilRequestRaw(byte[] oemRequest, byte[] oemResponse)`. This method is not security protected by the `@SystemApi` annotation that stops many other telephony operations (especially in Lollipop). And, as you can tell by the name, it is likely for OEMs so that they don't have to create their own communication channels from RIL to front-end. I've started to ask people who have the different engineering apks to send me a copy of them so that I can look through them and hopefully find the encoding that they are using for the byte arrays.

  7. #7
    Join Date
    Nov 2013
    Posts
    14
    Feedback Score
    0
    @mardukeme, thank you very much for those screenshots! One of the T-Mobile "patterns" that we are tentatively using is GCI ending of "04, "05", and "06". I say tentatively, because so far we've also gotten a band 4 report with GCI ending in "04". So, those "patterns" might eventually be changed to something else. Since you have provided me the screenshots. I'll be updating the tower/band list with these for next release. (Sidenote: Whenever I receive a email via [email protected], I tend to provide an updated APK right away. )

  8. #8
    Join Date
    Aug 2015
    Posts
    96
    Feedback Score
    0
    Hi did you all get any further with this? I haven't been able to detect band 2 with Tmobile using this app.

  9. #9
    Join Date
    Nov 2013
    Posts
    14
    Feedback Score
    0
    Unfortunately, we haven't been able to get anything from T-Mobile directly. So, we're still asking people to submit screenshots of engineering screens with a debug email from the LTE Discovery app. We will still be adding further T-Mobile band support manually

  10. #10
    Join Date
    Aug 2012
    Location
    Almont, Michigan
    Posts
    3,472
    Device(s)
    Galaxy S8, S8+, and S9+
    Carrier(s)
    "The Big 3"
    Feedback Score
    0
    LTE Discovery reports LTE Band 12 fine on my Samsung Tab S (tablet). However, it doesn't report B4 at all. Just says LTE band unknown.

  11. #11
    Join Date
    Feb 2004
    Location
    Los Angeles/Canada
    Posts
    10,779
    Device(s)
    iPhone 6+, Google Nexus 6
    Carrier(s)
    T-Mobile
    Feedback Score
    0
    Seems to work OK on Nexus 6
    Attached Images Attached Images  
    AT&T... your world, throttled.

  12. #12
    Join Date
    Aug 2010
    Posts
    1,453
    Feedback Score
    0
    Nice thread.

    What do you think atomic50?

  13. #13
    Join Date
    Aug 2010
    Posts
    1,453
    Feedback Score
    0
    Quote Originally Posted by formercanuck View Post
    Seems to work OK on Nexus 6
    That doesn't mean it's accurate.

    Even the developer of the very app is telling you [and everyone else] the same thing.

  14. #14
    Join Date
    Feb 2008
    Location
    Socal
    Posts
    2,643
    Carrier(s)
    T-Mobile
    Feedback Score
    0

    T-Mobile: Please share data so that LTE Discovery apps can accurately report ...

    Quote Originally Posted by Fabian Cortez View Post
    Nice thread.

    What do you think atomic50?
    great reference source.

  15. #15
    Join Date
    Oct 2015
    Posts
    1
    Feedback Score
    0
    Which HTC phones are able to read the Band Info directly?
    ("Verified" label in LTE Discovery app)

    I tried on an HTC One M9 but it was not able to read the info in LTE Discovery
    ( the CellID is not in the database where I am so I am looking for an HTC phone compatible with the LTE Discovery application)

Similar Threads

  1. Walmart Family Mobile Ups Shared Data
    By Conan Edogawa in forum General Prepaid discussion
    Replies: 2
    Last Post: 01-31-2013, 05:55 AM
  2. Replies: 1
    Last Post: 01-21-2013, 11:41 PM
  3. Replies: 3
    Last Post: 03-01-2012, 05:46 PM
  4. Replies: 22
    Last Post: 07-15-2009, 11:41 PM

Tags for this Thread

Bookmarks