This phone has serious problems with reception. It never really bothered me, I got this phone since launch, (exynos variant, dual sim) but now that I don't have broadband until my new provider sets up their network in the house, I have to rely on my mobile data, and it's amazingly bad. I have 2 sims in the phone, but it doesn't make any difference if I remove one or other. I'm in the UK, it could be Vodafone's fault, however I tried my sim in my previous phone (honor 8) and the signal was better (in dBm ofc) and I also tried my gf's sim in my phone and the signal was worse in my phone. I've spent days searching for solution and it turns out Samsung might went cheap on antennas so there isn't much to do. I've tried some 3rd party apps, tried to force only 4g, also tried 3g, reset network settings, reset access point etc; no luck. I'll transfer my number to an other provider and hope that it will help a little bit but to be fair, I don't think it'll help.