Wireless network keeps disconnecting problem

I encounter a Wireless network keeps disconnecting problem (often, frequently disconnection). My laptop is a DELL Precision 5510 with Windows 10, and my router is an O2 router (O2 box 6431).

  • Problem: When I use DELL Precision 5510 with Wifi with O2 router (O2 box 6431). Restart the router only solve the problem temporary.
  • My solution: It seems 802.11n of DELL Precision 5510 has a problem with my router. I am not sure the problem is which side (notebook or router). But these two stop communicate after a while. The router can still connect to Mac book and Fairphone, but the DELL notebook cannot connect to the router.
  • Detailed steps