Systems, methods, and instrumentalities are disclosed for enhancements to NAS Protocol to transmit user data over a signaling plane. A wireless transmit receive unit (WTRU) may send a first NAS message to a network device that may include a request to send user data via a control plane. The network device may establish the control plane for the WTRU. The control plane may be established without establishing a user plane connection. The network device may determine a maximum transmission rate for the WTRU to send user data via the control plane. The network device may send a second NAS message to the WTRU. The second NAS message may indicate that the control plane has been established for the WTRU and the maximum transmission rate.