The best replacement for usb modem is ethernet modem.

The best alternatives to usb modem are rated as following:
★★★★★  ethernet modem
★★★★  mifi
★★★★  pdanet
★★★★  data card
★★★  hotspot
★★  jetpack
★★  pc card
★★  wifi modem
★  express card
★  pocket wifi
★  mobile hotspot
★  aircard
  lg vl600 4g usb modem
  serial modem
  tethering

Your alternative for usb modem is not listed? Suggest!
Speaking about usb modem, one probably shouldn't forget about external antenna.

Other search terms related to usb modem and their ratings are:
★★★★★ external antenna
You have in mind a companion for usb modem and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of usb modem in all years. Click on graph for more.
usb modem
ethernet modem
mifi