Wifi not working (no replies)

I have had this problem for years and after a lot of reading, I still can't find a solution.

I am current use Linux debian 5.5.1-kirkwood-tld-1 #1.0 PREEMPT Sat Feb 1 22:28:36 PST 2020 armv5tel GNU/Linux. I have both ethernet and usb wifi plugin. Here is my /etc/network/interfaces looks like:

auto lo eth0
iface lo inet loopback
iface eth0 inet static
        address 192.168.100.152
        netmask 255.255.255.0
        network 192.168.100.0
        broadcast 192.168.100.255
        gateway 192.168.100.1

allow-hotplug wlxxxxxxxxxxxxx
auto wlxxxxxxxxxxxxx
iface wlxxxxxxxxxxxxx inet static
	address 192.168.100.153
        netmask 255.255.255.0
        network 192.168.100.0
        broadcast 192.168.100.255
        gateway 192.168.100.1
	wpa-ssid myrouter
	wpa-psk xxxxxxxxx

After booting, both wired and wifi connections are pingable and work. However, if I disconnect ethernet, I will also lose wifi (not pingable all together). Wifi comes back if I re-plug ethernet. I have tried to reboot with just wifi pluged in and ehternet disconnected, but then I never got wifi to work or was able to login to see what is going on. My goal is to be able to use just wifi without ethernet pluged in. Anyone has any solution to this problem? Thanks.