source: https://superuser.com/questions/1331768/why-is-usb-tethering-much-slower-than-wi-fi-tethering
ping -c 5 google.com | grep ttl
sudo iptables -t mangle -A POSTROUTING -j TTL --ttl-set 65
Your operators might limit your speed based on detecting the number of middle hops in your TCP connection. Using the following command, you will be able to check your TTL (Time to leave) value while using USB tethering vs WIFI tethering.