Hi ppl! After browsing weeks thru forums and spending hours I think I finally managed to find out the cause of the problem. I was running on the latest WIFI BROADCOM 7.35.295.0 driver. Its the problem within the latest driver. I tried to go roll back to previous Broadcom Wireless- DW1560 Driver (6.30.223.227). But it was very complicated. Basically few guys have managed to rollback by downloading/extracting manually and then setup.exe doing it manually. But my WIDCOMM bluetooth software was not allowing to install it. I tried to delete it but. without bluetooth button activated the previous broadcom version was not possible to install.
SO HERES WHAT I DID:
I went to dell website. Support>for home>Auto detect product (in my case xps13 9343)> DRIVERS AND DOWNLOADS>Find it Myself>NETWORK>Dell wireless1560 Wifi driver click on OTHER VERSIONS AVAILABLE> and get the previous 7.35.267.0
Download it. In option install or extract. Choose EXTRACT.
Before Installing manually. GO to your device manager. Uninstall your current driver>
Network adapters, dell wireless 1560, left click > uninstall.
And now INSTALL YOUR NEW EXTRACTED driver. Do it manually. setup.exe
RESET and your done.
It fixed my previous problems. After loosing wifi signal if my pc went further away from modem it didn`t reconnect automatically back to previously chosen networks when came close to it again. Same thing after waking up from sleep or hibernating.
P.S. for some whose wifi is still weak try to: Power Options>Chose > High performance than click Change Plan settings>Change advanced power settings>On High performance>Wireless adapter settings> chose MAXIMUM performance