FP4: The phone call quality is terrible for the partner while good for the FP4 user
- /e/ version: 1.8
- Device model(s): FP4
- Developer mode enabled: no
- Device rooted: no (murena phone with /e/OS pre-installed)
- Trackers blocker enabled: yes
Summary
If I call someone with my FP4 the receiver perceives my voice as terribly disturbed, while I hear everything with good quality.
The problem
As already described in the German Fairphone forum entry https://forum.fairphone.com/t/keiner-kann-mich-vernunftig-verstehen-beim-telefonieren/89097 there is a problem when calling someone with the phone app. The call quality is really bad for the receiver. In that forum issue you can also find the link to an audio recording of such a call: https://seafile.rlp.net/f/275a6ce090f24288bb96/ (from https://forum.fairphone.com/t/keiner-kann-mich-vernunftig-verstehen-beim-telefonieren/89097/79)
with the following (default) settings under settings>network&internet>SIM cards (O2 esim) (German: Einstellungen>Netzwerke&Internet>SIM Karten(O2 esim)) * 4G-calls (4G-Anrufe): off * WiFi telephony (WLAN-Telefonie): off * prefered Network type (bevorzugter Netzwerktyp): NR/LTE/GSM/WCDMAwithin big german city with apparently good local network (with other phones)
What is the current behavior?
bad quality for the call receiver when using the telephone app (not with other apps like signal), while good call quality for the caller (the receivers voice is completely clear and understandable).
What is the expected correct behavior?
crystal clear voice without disturbances for both sides of the call
Technical informations
Applied Testing to narrow down the problem
changing the settings of only network type
:
* NR/LTE/GSM/WCDMA: with the problem
* NR: no mobile phone network
* LTE: the call starts, but get immediately automatically terminated
* only GSM: seems to work
* only WCDMA: no mobile phone network
* GSM/WCDMA/LTE: with the problem
* GSM/WCDMA (automatic): seems to work
Relevant logs (adb logcat
)
Relevant screenshots
Solutions
Workaround
- 4G-calls (4G-Anrufe): off
- WiFi telephony (WLAN-Telefonie): off
- prefered Network type (bevorzugter Netzwerktyp): changed from
NR/LTE/GSM/WCDMA
toGSM/WCDMA (automatic)
After changing the network type to GSM/WCDMA (automatic)
the problem disappeared. Strangely the setting was immediatly changed to WCDMA in the config screen.
I'm wondering if this workaround will still work, after the 2G networks will be discontinued (as in Switzerland this year).
Possible fixes
Looking at the testing (see above) the problem could lay in the LTE implementation or in switcher between the network types. Considering that the problem also occures with the Fairphone Android (see forum entry above) it might be located in some common code (the drivers or even the chipset?).