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[Q] Data drops from LTE to 3G/HSPA During phone call

When I make a phone call my data connection switches from LTE to 3g/hspa. Is anybody else seeing this?
Sent from my SAMSUNG-SGH-I727

Sheolrock said:
When I make a phone call my data connection switches from LTE to 3g/hspa. Is anybody else seeing this?
Sent from my SAMSUNG-SGH-I727
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Same here on AT&T Downtown Los Angeles, drops to HSPA+. Honestly to me, it doesn't really matter.

thats what its supposed to do.
when on a call, it goes into HSPA/3G, then after the call ends, LTE should kick back in.
thats how AT&T LTE works. there is no VOICE over LTE yet

Pirateghost said:
thats what its supposed to do.
when on a call, it goes into HSPA/3G, then after the call ends, LTE should kick back in.
thats how AT&T LTE works. there is no VOICE over LTE yet
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Well said. I couldnt of said it better lol
Sent from my SAMSUNG-SGH-I727 using xda premium

Oh
Sent from my SAMSUNG-SGH-I727

LTE is a Data only network, No voice calls should go through it.
The LTE standard only supports packet switching with its all-IP network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to re-engineer their voice call network. Three different approaches sprang up. Most major backers of LTE preferred and promoted VoLTE (Voice over LTE, an implementation of IP Multimedia Subsystem or IMS) from the beginning. The lack of software support in initial LTE devices as well as core network devices however led to a number of carriers promoting VoLGA (Voice over LTE Generic Access) as an interim solution.[13] The idea was to use the same principles as GAN (Generic Access Network, also known as UMA or Unlicensed Mobile Access), which defines the protocols through which a mobile handset can perform voice calls over a customer's private Internet connection, usually over wireless LAN. VoLGA however never gained much support, because VoLTE (IMS) promises much more flexible services, albeit at the cost of having to upgrade the entire voice call infrastructure. While the industry has seemingly standardized on VoLTE for the future, the demand for voice calls today has led LTE carriers to introduce CSFB (Circuit Switched Fallback) as a stopgap measure. When placing or receiving a voice call, LTE handsets will fall back to old 2G or 3G networks for the duration of the call.
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Source

T-Mobile, drops from LTE to 3G when making a call

Just wondering if this happens to anyone else. My N5 was originally on Sprint but just recently switched to TMO. I have noticed that when on the TMO network my phone will drop to 3G whenever I make or receive a call. As soon as the call is over it switches back to LTE.
If I put my Sprint SIM back in and use their network it seems to hold LTE while on the call.
This is not scientific and am basing this observation from the network signal indicator on the top status bar. And as far as I can tell it isn't affecting performance. More of a curiosity at this point.
Sent from my Nexus 5 using xda app-developers app

this is how its supposed to work. phone calls cant go through the lte signal(in this case, with tmibile) to the phone, so it drops to 3G(H).

LTE in it's current implementation is a DATA ONLY service so when you make voice calls it drops that connection and connects the call. Since 3G is Voice/Data it shows the 3G/H connection available to you at that time. When you hang up it goes back to LTE.
With Sprint it uses CDMA so theres no simultaneous option with that so LTE is kept alive in order to deliver data at the sametime.
All expected behavior as already mentioned

Thanks for the info. Makes perfect sense how that is explained. I am rooted and cleaned out some apps I don't want. I'm particularly careful to not mess things up and noticed the change in behavior on TMO. Wanted to make sure something I hacked for Sprint didn't FUBAR the connection.
Sent from my Nexus 5 using xda app-developers app

I noticed this too on ATT.
When in calls it drops to H .
Thanks for the explanation
Sent from my Nexus 5 using xda app-developers app

It is called CSFB (circuit switched fallback), which will soon be replaced by VoLTE (Voice over LTE), which will be a plain and simple SIP-controlled VOIP call using LTE as carrier. Not sure if current phones can and/or will be upgraded to be able to do VoLTE, or if todays LTE handsets are stuck falling back forever...

[Q] T-Mobile S3 dropping calls switching from 4G to Edge?

Is there a bug in the SGH-T999 4.3 (UENC2) firmware relating to radio frequency switching while on a call? I am fairly certain from testing that if I am on 4G (HSPDA+. I do NOT have the LTE phone) during a call, and am driving into an area with only a strong 2G tower, that the call gets dropped instead of switching me over. I can see the radio lose all the bars and then change to a full strength 2G signal as soon as the call gets dropped. I can then immediately make a call with the 2G signal.

fdecker said:
Is there a bug in the SGH-T999 4.3 (UENC2) firmware relating to radio frequency switching while on a call? I am fairly certain from testing that if I am on 4G (HSPDA+. I do NOT have the LTE phone) during a call, and am driving into an area with only a strong 2G tower, that the call gets dropped instead of switching me over. I can see the radio lose all the bars and then change to a full strength 2G signal as soon as the call gets dropped. I can then immediately make a call with the 2G signal.
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I believe you want to go to T-Mobile Galaxy S 3 forum. This is for the T-Mobile Galaxy S 4G.
Sent from inside the time vortex

Making and receiving calls issue

My D800 for some reason can not make or receive calls while on lte. For some reason when it switches from lte to 4g during call it gets hung up and just ends call. Text and sms are fine. Now, on the 3g or hspa+ everything is fine. So I been on cloudy 2.2 for the hspa+ but can't get it to stick after reboot. So my questions are, has anyone ever had this issue with making calls? The second question would be how can I make hspa+ stick after reboot it thats the route I must go?

Simultaneous voice and data on verizon Note 5

I searched this but was unable to find any matching scenario. This is typical CDMA carrier's simultaneous voice and data issue. The phone (Galaxy Note 5) was bough from Verizon and gets 4glte fine when on Verizon SIM card... even simultaneously. I wanted to use the phone with a AT&T sim and after changing APN settings it does work fine, but NO simultaneous voice and data. When I make a call the 4glte signal on the top status bar changes to 1x and there is no data. Once the call ends it switches to 4glte. I have activated Advanced calling with Ver sim card on and when the ATT sim is in it does show HD calling enabled. So what's wrong with the device?? Did anyone face same issue ? Any suggestion will be greatly APPRECIATED. btw I am w/o any contract plan with Verizon

FWIW my Note 5 switches from 4G LTE to 1x as soon as I start a call. Unless I enable advance calling then I have 4G while in a call. However if you ask me the call quality is lower when I have HD Voice enabled in the advance calling tab.

MRBULLRED said:
FWIW my Note 5 switches from 4G LTE to 1x as soon as I start a call. Unless I enable advance calling then I have 4G while in a call. However if you ask me the call quality is lower when I have HD Voice enabled in the advance calling tab.
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Same problem here. I do not want to use HD Voice but still want simultaneous voice and data. I had no issue with this on my Galaxy S5.

I just wish it would stop notifying me telling me I don't have data on a call.

This is very annoying. I didn't have to set this on my older note 3. But I also went ahead and got the advanced calling 1.0. I dont know why, its dumb but it is what it is.

The new phones don't have 2x radios like the old phones did, so can't do both simultaneously. That is why you have to use advanced calling to get both.
It is a physical limitation of the phone, nothing you can do about it.
Sent from my SM-N920V using Tapatalk

Why doesn't Verizon switch to GSM? Would it mess up their coverage if they decided to do it? I'm being hypothetical. I know it would cost them way more than they would ever spend to do it.

In a sense they are all moving to the lte spectrum. Att is GSM. Verizon is cdma. Both are using similar lte at 700mhz. When using advance calling it's no longer using cdma 1x or GSM but lte using voip over lte data. Therefore you can use voice and data.

socsoff0404 said:
I searched this but was unable to find any matching scenario. This is typical CDMA carrier's simultaneous voice and data issue. The phone (Galaxy Note 5) was bough from Verizon and gets 4glte fine when on Verizon SIM card... even simultaneously. I wanted to use the phone with a AT&T sim and after changing APN settings it does work fine, but NO simultaneous voice and data. When I make a call the 4glte signal on the top status bar changes to 1x and there is no data. Once the call ends it switches to 4glte. I have activated Advanced calling with Ver sim card on and when the ATT sim is in it does show HD calling enabled. So what's wrong with the device?? Did anyone face same issue ? Any suggestion will be greatly APPRECIATED. btw I am w/o any contract plan with Verizon
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I ended up getting a AT&T Note 5 and sold the Verizon Note 5. Everything works fine (4G data and voice simultaneously) on this one. I believe it's a limitation of Verizon Note 5.

MRBULLRED said:
FWIW my Note 5 switches from 4G LTE to 1x as soon as I start a call. Unless I enable advance calling then I have 4G while in a call. However if you ask me the call quality is lower when I have HD Voice enabled in the advance calling tab.
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Yes. But that is true when you use a Verizon SIM card... with a ATT sim there is no way to get data on the Ver Note 5. So bottom line is on a Verizon Note 5 you must use a Verizon SIM card to have voice and data at the same time, with AC on. On a ATT Note 5 it works by default, no options to turn on and perfect quality.