Breaking Band: Tri-band LTE / eCSFB issues thread

[Dkoellerwx]

What I've seen in Olathe is eCSFB, because you would be kicked off LTE again within a few seconds/minutes after an airplane toggle. This isn't the case in the Houston area. Any theories?

 

I'm going to go drive around to Katy and Houston sites tomorrow and watch the 'LTE enginerring' screen. I'll wait for it to scan and see what it does. Even with no background data, they are not moving up to LTE.

 

eCSFB kicks you off in seconds. If there is an eCSFB problem, the connection is rejected immediately.

[S4GRU]

Yeah, it seems like eCSFB is being ascribed here as the bogeyman to any LTE connection issue. If you don't have a CSFB connection on a Triband device, even toggling airplane mode will not get you back to LTE. If you are having CSFB problems on a Triband device, your only relief is LTE Only mode to get to LTE.

 

If you are constantly being pushed down to 3G from LTE where you can regain LTE with an airplane mode toggle, either it's the network deciding to push you off, you have a poor quality LTE signal or your device had an issue. CSFB is not the culprit if you can toggle airplane mode and get back on LTE.

 

I am an AT&T customer. When my LTE gets worse than -108 RSRP on my N5, I constantly get shoved down to WCDMA. I have to cycle airplane mode to get back. That's the network settings deciding that. In fact, I typically have to stream something to keep my LTE signal from shunting me down to WCDMA.

 

In many places, ATT WCDMA is fine as a backup. But at my office, it's not. B4 ATT LTE at -110 RSRP runs at 20Mbps. Whereas the WCDMA I will get handed off to will be 10-200kbps.

 

So I understand your frustration. But in my instance, and in most likely many of yours, the issue is not CSFB.

[dedub]

I think the problem, at least with the nexus 5, is that there are multiple towers in an area, one or more with csfb issues.

 

When the nexus 5 comes into an area, it has multiple choices of towers to connect to.

 

What I think happens, based purely upon my user experience, is that as long as the n5 does not or is not required to jump on to the tower with csfb issues, it will stay connected to LTE.

 

However, if the n5 jumps towers (either at device or network direction) and hits a tower with csfb issues, it will remain in 3g for a long time, typically either until airplane mode, or your long out of range of the csfb issue tower(s) and the device has had time to rescan lte without seeing any other csfb issue tower(s).

[TheForce627]

Yeah, it seems like eCSFB is being ascribed here as the bogeyman to any LTE connection issue. If you don't have a CSFB connection on a Triband device, even toggling airplane mode will not get you back to LTE. If you are having CSFB problems on a Triband device, your only relief is LTE Only mode to get to LTE.

 

If you are constantly being pushed down to 3G from LTE where you can regain LTE with an airplane mode toggle, either it's the network deciding to push you off, you have a poor quality LTE signal or your device had an issue. CSFB is not the culprit if you can toggle airplane mode and get back on LTE.

 

I am an AT&T customer. When my LTE gets worse than -108 RSRP on my N5, I constantly get shoved down to WCDMA. I have to cycle airplane mode to get back. That's the network settings deciding that. In fact, I typically have to stream something to keep my LTE signal from shunting me down to WCDMA.

 

In many places, ATT WCDMA is fine as a backup. But at my office, it's not. B4 ATT LTE at -110 RSRP runs at 20Mbps. Whereas the WCDMA I will get handed off to will be 10-200kbps.

 

So I understand your frustration. But in my instance, and in most likely many of yours, the issue is not CSFB.

What about calls that simply never go to the phone? One of the reasons i moved one of my lines from sprint is that I would get a lot of calls going straight to voicemail. Have you seen issues where the phone won't hand off from LTE to CDMA? Thats the only thing I could think is the issue because my signal was usually good.

[cornelious2]

What about calls that simply never go to the phone? One of the reasons i moved one of my lines from sprint is that I would get a lot of calls going straight to voicemail. Have you seen issues where the phone won't hand off from LTE to CDMA? Thats the only thing I could think is the issue because my signal was usually good.

that happened a bunch while towers were getting worked on, but hasn't been an issue lately.

 

Sent from my Nexus 5 using Tapatalk

[KD8JBF]

What about calls that simply never go to the phone? One of the reasons i moved one of my lines from sprint is that I would get a lot of calls going straight to voicemail. Have you seen issues where the phone won't hand off from LTE to CDMA? Thats the only thing I could think is the issue because my signal was usually good.

Unfortunately this is still an issue for me in my area. No B26, only B25. B25 LTE doesn't propagate as well as 1x 1900 does, so I'm noticing i'm missing calls when my signal is below -112 to -114dBm (Signal isn't as good when the channel is wider ((1.5Mhz to 5Mhz)). Once B26 kicks in it will be better, but for now...I get voicemail notifications all the time. However, I am working with Sprint on the issues and they seem motivated to get it resolved.

 

Kris

[TheForce627]

Unfortunately this is still an issue for me in my area. No B26, only B25. B25 LTE doesn't propagate as well as 1x 1900 does, so I'm noticing i'm missing calls when my signal is below -112 to -114dBm (Signal isn't as good when the channel is wider ((1.5Mhz to 5Mhz)). Once B26 kicks in it will be better, but for now...I get voicemail notifications all the time. However, I am working with Sprint on the issues and they seem motivated to get it resolved.

 

Kris

I'm just lost as to why its happening when I have tuned b26 and 25 available at a good signal (-100dBm-95dBm). It was frustrating and I hope they figure it out.

[mikejeep]

I'm just lost as to why its happening when I have tuned b26 and 25 available at a good signal (-100dBm-95dBm). It was frustrating and I hope they figure it out.

After suffering with this for awhile myself, the problem went away several weeks ago.. but suddenly started occasionally happening again this week. Hopefully it's just a sign of more upgrades and a temporary nuisance. Putting my N5 in 3G mode completely resolves the issue. Sprint just tells me to do a factory reset, so I'll just have to be patient.

 

-Mike

[dedub]

I think every time they upgrade a tower in the vicinity of other towers that were already upgraded and stable, it causes a disturbance in the force.

 

As if millions of voices suddenly cried out in terror and were suddenly silenced.

[EvanA]

I'm just lost as to why its happening when I have tuned b26 and 25 available at a good signal (-100dBm-95dBm). It was frustrating and I hope they figure it out.

After suffering with this for awhile myself, the problem went away several weeks ago.. but suddenly started occasionally happening again this week. Hopefully it's just a sign of more upgrades and a temporary nuisance. Putting my N5 in 3G mode completely resolves the issue. Sprint just tells me to do a factory reset, so I'll just have to be patient.

 

-Mike

This started happening to me today. My Nexus 5 will be sitting on band 26 at -95dBm and then get shunted to 3G. It'll scan back to LTE after a bit, keep it for a bit, then end up on 3G again.

[Sanyo M1]

This started happening to me today. My Nexus 5 will be sitting on band 26 at -95dBm and then get shunted to 3G. It'll scan back to LTE after a bit, keep it for a bit, then end up on 3G again.

Okay, yeah I thought something was up. I'm a mile away from a tower which usually gives me -70 to -85 dBm signal, but it just keeps flipping to eHRPD even with a slight move. It keeps flipping between that and Band 25 and 26.

 

So far, this only has happened in suburb of Chicago, where I'm currently visiting.

[mikejeep]

This started happening to me today. My Nexus 5 will be sitting on band 26 at -95dBm and then get shunted to 3G. It'll scan back to LTE after a bit, keep it for a bit, then end up on 3G again.

 

I was specifically referring to missing calls while connected to LTE despite having a strong signal and in a known solid 3G area.

 

-Mike

[TheForce627]

I was specifically referring to missing calls while connected to LTE despite having a strong signal and in a known solid 3G area.

 

-Mike

were you also affected by late text messages like me? It had been happening in my area for years but I thought NV would fix it yet I would still get messages between 5-15 minutes late at times.

[mikejeep]

were you also affected by late text messages like me? It had been happening in my area for years but I thought NV would fix it yet I would still get messages between 5-15 minutes late at times.

No, not really.. it's just phone calls. Any SMS delays I've noticed usually had a good reason. Although this might be a good time to ask this -- should SMS work when in LTE-only mode? I can't send or receive any messages when I do that.

 

-Mike

[The_Chemist]

No, not really.. it's just phone calls. Any SMS delays I've noticed usually had a good reason. Although this might be a good time to ask this -- should SMS work when in LTE-only mode? I can't send or receive any messages when I do that.

-Mike

Mike, I remember AJ saying a while back that a text message can tunnel through on LTE with eCSFB devices.

[Rasta Cheesehead]

No, not really.. it's just phone calls. Any SMS delays I've noticed usually had a good reason. Although this might be a good time to ask this -- should SMS work when in LTE-only mode? I can't send or receive any messages when I do that.

 

-Mike

 

no sms use the same signal as voice

[EvanA]

no sms use the same signal as voice

Not on tri-band devices. SMS goes over LTE. I think the reason SMS doesn't work in LTE only mode is due to the phone not listening for circuit switched calls, so it doesn't expect to send SMS.

[Dkoellerwx]

No, not really.. it's just phone calls. Any SMS delays I've noticed usually had a good reason. Although this might be a good time to ask this -- should SMS work when in LTE-only mode? I can't send or receive any messages when I do that.

 

-Mike

 

Still need a eCSFB connection. That doesn't happen in LTE Only mode. 

[mikejeep]

Mike, I remember AJ saying a while back that a text message can tunnel through on LTE with eCSFB devices.

Oh in "regular" LTE mode it definitely does, messages are sent/received much faster than without LTE. But I was referring to LTE-only, where I suspected you have no eCSFB because you have no 1X fallback..

 

Still need a eCSFB connection. That doesn't happen in LTE Only mode.

..which confirms my suspicion. Thanks!

 

-Mike

[lilotimz]

Oh in "regular" LTE mode it definitely does, messages are sent/received much faster than without LTE. But I was referring to LTE-only, where I suspected you have no eCSFB because you have no 1X fallback..

 

 

..which confirms my suspicion. Thanks!

 

-Mike

Robert can attest to LTE only mode not working with the numerous *tests* he's recieved from me testing clear and sprint sites...

 

Sent from my Nexus 5 using Tapatalk

[WiWavelength]

Not on tri-band devices. SMS goes over LTE. I think the reason SMS doesn't work in LTE only mode is due to the phone not listening for circuit switched calls, so it doesn't expect to send SMS.

Still need a eCSFB connection. That doesn't happen in LTE Only mode. 

 

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

[S4GRU]

I am able to send SMS in LTE Only mode on my N5 on AT&T. And AT&T uses eCSFB. So if it cannot on the N5 on Sprint, it makes me think it is a network setting or limitation for Sprint.

 

I have to stay in LTE Only mode on AT&T all the time because in my office I have a fringe signal that wants to drop me back to WCDMA every time I touch my phone. And the WCDMA Channel my phone sits on is broken and runs really slow. So in LTE Only mode I can use the data and still be able to text. And if someone calls I will also still get a voice mail notification too.

 

Using Tapatalk on BlackBerry Z30

[mikejeep]

I am able to send SMS in LTE Only mode on my N5 on AT&T. And AT&T uses eCSFB. So if it cannot on the N5 on Sprint, it makes me think it is a network setting or limitation for Sprint.

 

I have to stay in LTE Only mode on AT&T all the time because in my office I have a fringe signal that wants to drop me back to WCDMA every time I touch my phone. And the WCDMA Channel my phone sits on is broken and runs really slow. So in LTE Only mode I can use the data and still be able to text. And if someone calls I will also still get a voice mail notification too.

Interesting. My N5 definitely has never dropped back to send or receive, so it must be a limitation with Sprint or CDMA in general. I like not dropping back to 3G in fringe areas, but it's tricky because I know I'm not receiving any texts. I still get voicemail notifications, but I'm using Google Voice for that.

 

-Mike

[Dkoellerwx]

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

Does that include the N5? I've never been able to send a text while in LTE Only mode. The G3 doesn't have that setting so can't compare.

 

Sent from my Nexus 5

[Rasta Cheesehead]

Not on tri-band devices. SMS goes over LTE. I think the reason SMS doesn't work in LTE only mode is due to the phone not listening for circuit switched calls, so it doesn't expect to send SMS.

 

LTE is for data only. no device uses lte to send sms on the sprint network