bought the phone only about a month, everything was working perfectly until the past couple of days.
out of the blue wifi started to disconnect itself during my usage, for example I'm reading or playing mobile game, suddenly no connection without a sign.
the worst is when I'm in the car using GPS to navigate direction, even the 3G mobile data and location disconnect, the navigation just paused when I'm in the middle of the traffic!!! this is horrible.i didn't update the phone or did anything at all, not expert about high tech, please help me fix this!

update to the latest Firmware and perform a factory reset in recovery after that.

wipe data/factory reset in recovery (this will delete your data/settings):
- Power off and then press Power and Volume up together for around 10 Seconds
- be sure that the little arrow point on recovery (select with volume up, enter with volume down)
- Then the open android with red triangle+"no command" is shown press Power and Volume up together again
- Select Wipe data/factory reset with volume keys, confirm with power
- After factory reset select reboot system now

Please report if this solved your issue or not.