Please create the below file with below content and reboot the system to overcome from regular disconnection of secured wifi connection. I have tried in mint 17.3 and it works. Please let me know if it fail with proper log.
echo "options rtl8723be fwlps=N ips=N" | sudo tee /etc/modprobe.d/rtl8723be.conf
echo "options rtl8723be fwlps=N ips=N" | sudo tee /etc/modprobe.d/rtl8723be.conf
