I already asked this question in the Acer Community- if someone answers there, I will share the solution. But hopefully someone here will be even faster.
As mentioned in a different thread, I finally got Ubuntu 15.10 installed on my E5 573G-71L9. At first, the wireless LAN was not working, but I managed to find and install the presumably correct drivers.
What I did was: first ensure that I had the correct r8168 driver for the Realtek card, downloaded from the Realtek site.
As wifi still didn't work, I also figured out that it was the Atheros card that needed a proper driver. I followed this method (I basically just copied-pasted all commands without understanding them completely): Qualcomm Atheros Device [168c:0042] (rev 30) Wi-Fi driver installation
This brought my wireless connection to live, but I got disconnected frequently, about every two minutes. According to the network manager, I am still connected, but I can't even ping the DNS server (I can ping localhost). Sometimes the connection gets restored after some time, other times I need to 'disconnect' and reconnect again.
In addition, I purged the r8168 driver that I downloaded from Acer and installed the r8168 from the Ubuntu Software Center - no difference. I also replaced the Atheros driver with the one that solved the problem for a person with the same system configuration (see other thread). For me, it did not work.
My regdomain is set to Germany (where I live). I tried to disable hardware encryption (nohwcrypt=0) and various other parameters for iwlwifi that were suggested in several forums and on askubuntu, which I don't really remember anymore (nothing worked, so I removed them all from the /etc/modprobe.d/ files, so they should be 'clean' again.
Wired internet works without any problems.
dmesg | grep ath10k [ 12.529816] ath10k_pci 0000:03:00.0: pci irq msi-x interrupts 8 irq_mode 0 reset_mode 0 [ 12.835697] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/cal-pci-0000:03:00.0.bin failed with error -2 [ 13.299474] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/board-2.bin failed with error -2 [ 15.171270] ath10k_pci 0000:03:00.0: qca9377 hw1.0 (0x05020000, 0x003820ff sub 11ad:0806) fw WLAN.TF.1.0-00267-1 fwapi 5 bdapi 1 htt-ver 3.1 wmi-op 4 htt-op 3 cal otp max-sta 32 raw 0 hwcrypto 1 features ignore-otp [ 15.171273] ath10k_pci 0000:03:00.0: debug 0 debugfs 0 tracing 0 dfs 0 testmode 0 [ 15.228201] ath10k_pci 0000:03:00.0 wlp3s0: renamed from wlan0
With the ethernet cable disconnected, I executed the wireless-info script, as provided at Ubuntuforums. As the file is too large to copy here and attachments are not allowed, I put the output in my public Dropbox folder: https://dl.dropboxusercontent.com/u/22984057/Acer/wireless-info.txt
I would be grateful for any pointers in the right direction. Thanks!