Right off the assembly line
For a month now, I've been facing the same issue. The wifi speed in my mobile phone is too slow; but it works just fine in my laptop. I've tried rebooting, resetting the modem and router. Rebooting and updating my phone android OS, but nothing worked. I don't know what to do. I contacted the guy who installed the wifi connection, but he too wasn't of any help. I don't know much bout it either.