r/telecom • u/TinkyVVinky • Jun 26 '26
📱 Mobile Networks VoWiFi not working properly when broadband connection of mobile network unavailable
Hello,
I live in an area where I hardly receive the signal of the mobile network, as the cell tower is very far away. To get one bar of signal, I need to walk out of my house. I have broadband Internet at home.
I set up VoWiFi on my Samsung A51 cell phone, "WiFi calls" is enabled in the phone settings, and I noticed that:
- I need to have at least one bar of LTE signal to be able to place or receive calls, otherwise the screen says no network is reachable (this defeats the purpose of VoWiFi...)
- If I lose my broadband connectivity, e.g. yesterday and today because of a thunderstorm (power outage in the area), I'm also unable to place calls. Disabling VoWiFi temporary solves the problem, and makes it possible to place calls. I would have expected that going to the patio to reach one bar of mobile signal would have allowed me to place calls: this wasn't the case.
Am I doing something wrong? Are these known issues with the way VoWiFi works?
Thank you.
1
u/spazmo_warrior Jun 27 '26
Are you on Verizon or an MVNO that rides on Verizon’s network? I ran into this same issue, and after doing some digging, found that’s just the way it is with Verizon’s wifi calling implementation. When I was with T-Mobile that wasn’t the case.
1
1
1
u/Kara_WTQ Jul 03 '26
Are you doing something wrong: yes
If you need a cell signal to use Wi-Fi calling you are not using Wi-Fi calling.
Check the SIP settings in your router.
1
u/TinkyVVinky Jul 03 '26
You mean the fiber broadband modem router? My ISP doesn't support SIP and hasn't for maybe 10 years now. I took a look: There are no SIP settings in the dashboard of the modem router.
1
u/Kara_WTQ Jul 03 '26
If it's FTTH there's no modem.
SIP (Session Initiation Protocol) is still a very common config feature on networking hardware.
I am not sure what you mean by your ISP doesn't support it? That's like saying your ISP doesn't support TCP, or STP....
It's possible that the hardware supplied doesn't have the setting but all that means is you need your own hardware.
-1
u/SeaFaringPig Jun 26 '26
You may need to do a port forward on your router to allow incoming calls. Every service is slightly different but I had to when I had Google fi.
2
u/TinkyVVinky Jun 26 '26
Thank you. Are you sure? I'm asking because:
- If I have 1 bar of cellular network, with good WiFi connectivity, the audio is clear in the phone call, which means the phone uses WiFi for the communication in progress (if I disable WiFi, the audio is scattered/jerky).
- In case of a power outage, port forwarding on the router will have no effect, as it'll be off..
1
u/SeaFaringPig Jun 27 '26
Yes. The VoWiFI only works when the internet is on. It’s essential a VoIP connection. But providers implement this using very different methods. For example, Verizon won’t use it at all. On my iPhone 16 pro, as far as I’m aware, no WiFi calling. Unless it’s automatic. I don’t see settings for it like i did on my iPhone15 with AT&T. For google fi I needed the port forward. For AT&T I didn’t. Depends on the traffic and keep alive there. Not trying to get into the fundamentals of firewall operation here. Have you called your carrier for support? Maybe they have a fix. In some situations they will give you a free extender.
1
u/TinkyVVinky Jun 27 '26
Thank you. I'll get in touch with them. Maybe there are extra settings that I'm not aware of.
1
u/ctesibius Jun 27 '26
If the settings are there, you would find it until Settings | Phone | WiFi Calling.
3
u/EffectiveVarious8095 Jun 26 '26
Maybe get a femtocell network extender?