Breaking Band: Tri-band LTE / eCSFB issues thread

[GrappleFu]

*Should* be. There could be issues still (especially in Ericson markets).

 

Thanks. For months, if I use CDMA/LTE mode, its a 50/50 chance my phone will ring or get texts on time. Even if I'm not connected to an LTE tower it still has this problem.

[EvanA]

Thanks. For months, if I use CDMA/LTE mode, its a 50/50 chance my phone will ring or get texts on time. Even if I'm not connected to an LTE tower it still has this problem.

Have you called Sprint?

[GrappleFu]

Have you called Sprint?

 

They're no help since LTE isn't "officially" launched here

[SturgeonGeneral]

No, you need to back up that assertion with evidence. Your word is not sufficient. Plenty of other posters, who are likely more knowledgeable on the matter than you are, have technical and empirical experience to the contrary. e/CSFB is using LTE as the bearer for SMS.

 

AJ

 

I just dropped my GS4T into LTE only mode and ran a little test.

The first text was sent while connected to my home network.

 

The second two were with wifi disabled and only connected to a B26 connection.

 

Once I took it back out of LTE only mode to LTE+CDMA+EVDO mode and restarted, the backlogged texts came through.

 

He's right. I've run into this whenever I have been out in the boonies in LTE only mode looking for new 4G towers.

 

It may be peculiar to certain phones, but I know for a (demonstrated) fact that mine is one of them.

 

 

 

 

 

While it may be listed in the standard, like volte, it isn't necessarily implemented -yet.

[SturgeonGeneral]

After reading more, I decided to continue my tests and wandered around the house to connect to all the towers around me.  Depending on where I am in the house, I can normally mask signals and connect to three 4G towers reliably, and intermittently to three more.

 

The second tower looped back the test text flawlessly and instantly, and by the time I returned to the first, it was working perfectly also.

 

Can anyone explain that?  Is there some theoretical "wake-up" or boot-up of idle software?

 

OM03XC020  B26

OM23XC452  B41

OM70XC487  B25

 

I'm at a loss to explain the first result, but it does demonstrate that it DOES happen, even on an apparently capable tower.

 

The only major change was the necessary reboot of the phone to take it back into LTE+CDMA+EVDO mode.  I do not reboot when going into LTE only modes.  They've never proven necessary.

 

After reboot, I allowed the phone to reconnect to vowifi, I took the phone into LTE only again and tested text loopback on VOWIFI again as I wandered to my 2nd tower access location in the house.

 

Once there, I disabled wifi, and that tower (B25) worked.  I walked to the third tower (B41), and that worked, and I returned to my starting point in the basment and the first tower was now working fine for a text loopback on LTE only.

 

FM (and I don't mean Frequency Modulation)

[maxsilver]

I just dropped my GS4T into LTE only mode and ran a little test.

 

*snip*

 

He's right. I've run into this whenever I have been out in the boonies in LTE only mode looking for new 4G towers.

 

It may be peculiar to certain phones, but I know for a (demonstrated) fact that mine is one of them.

 

While it may be listed in the standard, like volte, it isn't necessarily implemented -yet.

 

Your observations are accurate, but your tests don't imply what you seem to think they do.

 

Just because LTE only mode doesn't always allow you to receive text messages, doesn't mean you can assume text messages aren't sent over LTE -- they still are.

 

As was already stated above numerous times and in greater, more precise detail: "LTE Only" mode can ignore/turn off other services (such as call notifications and text messages). In regular LTE mode, these are required to happen (still as data over LTE).

 

If IMS/eCSFB data over LTE can't be established in regular LTE mode, you'll be forced back to 1x/EVDO to make sure you don't miss calls/texts -- even if a otherwise-strong LTE signal exists. In "LTE Only" mode, IMS/eCSFB can be ignored -- it's your way of telling your phone that you don't care about missing calls and texts (which is why it's normally hidden behind a MSL).

 

All your test actually proves is that when you ask your phone to not care about calls and texts, your phone really stops caring about calls and texts. It's not new knowledge in any way -- what you've seen is 100% expected, normal behavior.

[Dkoellerwx]

I just dropped my GS4T into LTE only mode and ran a little test.

The first text was sent while connected to my home network.

 

The second two were with wifi disabled and only connected to a B26 connection.

 

Once I took it back out of LTE only mode to LTE+CDMA+EVDO mode and restarted, the backlogged texts came through.

 

He's right. I've run into this whenever I have been out in the boonies in LTE only mode looking for new 4G towers.

 

It may be peculiar to certain phones, but I know for a (demonstrated) fact that mine is one of them.

 

While it may be listed in the standard, like volte, it isn't necessarily implemented -yet.

 

Test are sent and received over LTE, however, you must have an eCSFB connection for that to happen. That is how the network registers your device to know where you are for calls and texts. In LTE Only, eCSFB is turned off.

[SturgeonGeneral]

Test are sent and received over LTE, however, you must have an eCSFB connection for that to happen. That is how the network registers your device to know where you are for calls and texts. In LTE Only, eCSFB is turned off.

 

 

That doesn't follow experience.  After the initial "proving" test, I took out out of LTE only, reset the phone to get it back to full functionality, then decided to experiment more midway through the boot process.  Look at my subsequent post.  By the time I walked around the house to my second tower, it worked.  Flawlessly.

 

It worked on that new tower, another one, and then even on the original.

 

So, is it randomly throwing these other "background switches" also?

 

I'd prefer to have a more hard and fast rule -and reliable explanation.

 

I'm just going to have to do some more experimentation.

[mikejeep]

That doesn't follow experience.  After the initial "proving" test, I took out out of LTE only, reset the phone to get it back to full functionality, then decided to experiment more midway through the boot process.  Look at my subsequent post.  By the time I walked around the house to my second tower, it worked.  Flawlessly.

 

I can't explain why you might be seeing what you are seeing, but I know on my Nexus 5 (as stock/pure Android as it gets), when in LTE Only mode, I cannot send or receive any calls or SMS. As soon as I switch to another mode that includes CDMA, calls and SMS instantly begin working. I accidentally left my N5 in LTE Only mode for a couple of days while traveling all over the place.. when I switched it back, I was instantly flooded with text messages asking why I wasn't answering the phone.. hah!

 

-Mike

[Dkoellerwx]

That doesn't follow experience.  After the initial "proving" test, I took out out of LTE only, reset the phone to get it back to full functionality, then decided to experiment more midway through the boot process.  Look at my subsequent post.  By the time I walked around the house to my second tower, it worked.  Flawlessly.

 

It worked on that new tower, another one, and then even on the original.

 

So, is it randomly throwing these other "background switches" also?

 

I'd prefer to have a more hard and fast rule -and reliable explanation.

 

I'm just going to have to do some more experimentation.

 

What doesn't follow user experience? As far as I can tell from what you have posted, it does follow.

[SturgeonGeneral]

What doesn't follow user experience? As far as I can tell from what you have posted, it does follow.

 

 

This:   (Which may be a mistaken observation as I cannot reproduce it today despite a long testing session playing with every possible order of action I could think of)

 

 

After reading more, I decided to continue my tests and wandered around the house to connect to all the towers around me.  Depending on where I am in the house, I can normally mask signals and connect to three 4G towers reliably, and intermittently to three more.

 

The second tower looped back the test text flawlessly and instantly, and by the time I returned to the first, it was working perfectly also.

 

Can anyone explain that?  Is there some theoretical "wake-up" or boot-up of idle software?

 

OM03XC020  B26

OM23XC452  B41

OM70XC487  B25

 

I'm at a loss to explain the first result, but it does demonstrate that it DOES happen, even on an apparently capable tower.

 

The only major change was the necessary reboot of the phone to take it back into LTE+CDMA+EVDO mode.  I do not reboot when going into LTE only modes.  They've never proven necessary.

 

After reboot, I allowed the phone to reconnect to vowifi, I took the phone into LTE only again and tested text loopback on VOWIFI again as I wandered to my 2nd tower access location in the house.

 

Once there, I disabled wifi, and that tower (B25) worked.  I walked to the third tower (B41), and that worked, and I returned to my starting point in the basment and the first tower was now working fine for a text loopback on LTE only.

 

FM (and I don't mean Frequency Modulation)

 

 

The biggest problem in the back and forth is a lack of desire to be patient and try to understand the context of what everyone is talking about and what their knowledge levels are.  People are getting frustrated and aren't taking measures to mitigate that.

 

"LTE-only", taken at face value doesn't suggest "LTE-only (plus some other switches thrown in that aren't specifically listed, but that may be important to what you're trying to accomplish.)"

 

In turn, "texts can be sent purely via LTE" doesn't match up to the experience of those of us that use LTE-only as a tool to help find new towers and filter out interference from 3G towers.

 

Keep in mind that while some of you may be hardcore on the subject or employed in the field, a lot of those trying to help search, simply want more information on where to expect the best service when they are out and about.  We play with some tools that help with that, but are also trying to learn bits and pieces as we go.  We get things wrong because there is a lot of bad information out there and you don't always know who is right or wrong.  When things don't add up, you use common sense to try to fill in the gaps.

 

If the high-end self-proclaimed tech masters can't figure out how to understand the misunderstanding and clarify it in such a way that in can be explained to noobs, how do you expect a noob to be able to articulate what is going on?   The educated have a much better grasp of the overall picture and they should bear the heavy lifting if they're going to take exception with the things that are said.

 

 

they all have empirical evidence, my knowledge or word on this subject comes from my day to day lively hood.

 

 

This post suggested to me that this guy is using LTE-only mode, and like me, didn't know that it was more than that.

 

 

Uh, no. Your post is incorrect. Posts above already correctly cite that e/CSFB devices can idle solely on LTE and send/receive SMS tunneled through LTE.

 

AJ

 

 

Which is nice and all, except for:

 

 

I cannot fully explain it, but on multiple handsets set to "LTE only" mode, I can attest to them still dropping back to CDMA1X briefly to send SMS.  SMS cannot be received, though, except for Google Voice SMS.

 

AJ

 

 

Which is what I saw today when I ran my tests.  The problem is that, in my limited experience and studies, I have read this article,

 

http://s4gru.com/index.php?/blog/1/entry-357-nexus-5-and-lg-g2-experience-temporary-sprint-lte-connectivity-issues-due-to-circuit-switched-fallback-technology/

 

 

Which talks about:

 

"Here is how it works in the simplest way I can describe. When your Triband LTE device has an LTE signal, it cannot receive or make calls on its own. It is just using LTE data happily. However, what if someone calls you? How does it get through the CDMA network to your device? Via CSFB.

 

When the Sprint network tries to forward a call to your device but cannot see it via CDMA, it then checks for an LTE connection to your device. If it sees one, it tells your device to disconnect from LTE for a moment and reconnect to CDMA. Your device then jumps over to take the call on Sprint CDMA and the LTE session is interrupted. This happens very fast and seamlessly. Except for the loss of data availability. If you receive a text, the Sprint network is able to route it to your device via LTE."

 

 

Use some imagination and you can see how someone might be confused into thinking that this is what they are seeing for texts in LTE-only as well.  It looks like it is trying to do an eCSFB fallback.  Once they see the parallels, then it's a short jump of logic to mistakenly equate the two.

 

If someone is trying to learn, help them learn, don't just stomp on them.  Sending them back through the thread isn't always a good idea either.  Going back and reading the thread is painful, and you don't always know who is right or wrong.  Re-emphasize what is correct and explain why something they claim is wrong.  Ideally with external and reliable references and little tests that can help prove a point.

 

At one point someone said that it was so because it was in the SPEC.  In that same spec VOLTE (voip) is possible too.  I laughed.  Is VOLTE implemented yet?  See how it looks to an outsider?  The one that pointed at the spec looked the fool.  He was right, but he was wrong at the same time.  The spec alone is no guarantee since there is more to it than that.

 

http://s4gru.com/index.php?/topic/5001-breaking-band-tri-band-lte-ecsfb-issues-thread/page-42&do=findComment&comment=372779

 

=================

 

 

Having said all that, this is my current takeaway:

 

 

If you're using LTE-Only mode on a GS4T (Galaxy S4 Triband / (Spark), do not expect to have a texting conversation with anyone.  One way or another, something necessary (don't care what / doesn't matter what?) to that process is disabled -even though the process can take place over LTE, something else is keeping it from happening.  A text is apparently not just a pure "data" transaction like browsing the internet, or using any other number of internet applications capable of a similar thing.

[Dkoellerwx]

If you're using LTE-Only mode on a GS4T (Galaxy S4 Triband / (Spark), do not expect to have a texting conversation with anyone.  One way or another, something necessary (don't care what / doesn't matter what?) to that process is disabled -even though the process can take place over LTE, something else is keeping it from happening.  A text is apparently not just a pure "data" transaction like browsing the internet, or using any other number of internet applications capable of a similar thing.

Texts can be sent/received via LTE on tri-band devices, but cannot be sent/received in LTE Only mode. That's what has been said the entire time. I'm really not sure what that super lengthy post was all about.

[SturgeonGeneral]

Texts can be sent/received via LTE on tri-band devices, but cannot be sent/received in LTE Only mode. That's what has been said the entire time. I'm really not sure what that super lengthy post was all about.

Going the extra mile for clarity to end the confusion instead of prolonging the agony. It's obviously not being done as well as it could to this point.

 

Sent from my SPH-L720T using Tapatalk