FreeRadius Authentication Protocol

Hi, I have a FreeRadius EAP-TLS working enviornment. Going forward, I would like to avoid installing client certificates on every new mobile client and maintaining the current installs. I think the solution will be EAP-TTLS. However, I would like to get input from the experts about best available option/s. The goal is to authenticate supplicants via FreeRadius without the use of client certificates (server certificate is ok). Any help is appreciated. Regards, Hamid.