Yes. There are a number of proposals for LTE voice. They include Circuit Switched (CS) Fallback, Single Radio Voice Call Continuity (SRVCC), and the IP Multimedia Subsystem (IMS). The key stage 2 specs that discuss these topics are 23.272 for CS Fallback, 23.207 for SRVCC, and 23.228 for IMS. A video discussing these options can be found at