16-10-2018 08:47 PM
18-10-2018 08:07 AM
29-10-2018 02:52 AM
I have experienced this problem before and very possibly if you experience drop of 4G signal level after a scheduled maintenance upgrade but used to enjoy good 4G line quality before, the cause of the problem is that the telco vendor turned on the weaker LTE Band 7 in your area enabling LTE-A coverage.
This weaker 4G LTE Band 7 signal will override the stronger Band 3 signal in your area causing network signal quality degradation and sometimes it fades so bad, it forces your phone to fallback to 3G-HSPA.
The only solution is that if your phone is rooted(voiding your warranty) and allows pre-selection of bands to connect by force, you need to de-select Band 7 to solve your woes. Most unrooted 4G devices will not have this developer/debugging option, thus there is no way to rectify this issue unless the telco turns off Band 7 totally in your area.