Enabling usb wifi on Centos is really a difficult job. most of the times it requires drivers compilation and adding /removing modules which may be time consuming.
Its better to upgrade kernel to the latest release
To upgrade the kernel without kernel compilation follow below steps
Step 1: Install elrepo to your CentOS 7 system
# rpm –import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
# rpm -ivh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
# yum –enablerepo=elrepo-kernel list available |grep kernel
# yum –enablerepo=elrepo-kernel install kernel-ml* (select kernel-ml as they are the stable release kernels)
# grub2-set-default “CentOS Linux (4.18.1-1.el7.elrepo.x86_64) 7 (Core)”
reboot your system and configure network to the wireless usb card.
