After upgrade to 16.04, wifi signal strength jumps from perfect to zero and back

Question

I upgraded from 14.04 LTS to 16.04 LTS on HP Z230. Internet connection worked perfectly under 14.04 LTS. There were no hardware changes.

The computer connects to the router by a wireless usb device (this was the case under 14.04 LTS as well). After the upgrade, the wifi signal strength keeps jumping (sometimes every few seconds) between perfect and zero. Sometimes the browser says that there is no connection to the internet, although the connection indicator does not report being disconnected.

Not sure if the following symptoms are also related:

• I am connected through a filtering service. Sometimes the service says that I am trying to access a forbidden page. It especially likes to pick on the tab with gmail open, probably because gmail is constantly updating. I am not sure whether this happens exactly when I get disconnected.

• Chrome says that it cannot access the system proxy settings: "either your system is not supported or there was a problem launching your system configuration". I am pretty sure that this was not the case with the older versions of Chrome under 14.04 LTS.

I searched a lot through answers to similar questions, but did not come across a solution... Please let me know which diagnostics I should post.

EDIT

Here is the output of lsusb:

Bus 002 Device 002: ID 8087:8000 Intel Corp. 
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 005: ID 0bc2:ab21 Seagate RSS LLC Backup Plus Slim
Bus 003 Device 004: ID 058f:9410 Alcor Micro Corp. Keyboard
Bus 003 Device 003: ID 192f:0916 Avago Technologies, Pte. 
Bus 003 Device 002: ID 0bda:8179 Realtek Semiconductor Corp. RTL8188EUS 802.11n Wireless Network Adapter
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Answer 1

I did the following and the connection is good so far (with some drops of strength, which I still cannot explain):

1. Plug off and back on the router.

2. See what usb wireless adapter you have by running lsusb in the terminal.

3. Install the driver for the wireless adapter and also make sure that the power management for this device is off. I have Realtek Semiconductor Corp. RTL8188EUS 802.11n Wireless Network Adapter and this post took me through all the steps.