Abstract: A communication system and method of providing cellular connectivity in a vehicle using the communication system. The method includes the steps of: registering a telematics unit in the vehicle with an internet protocol (IP) multimedia subsystem (IMS) in a cellular network; using the telematics unit, attempting to establish a voice-over long-term evolution (VoLTE) connection via the IMS with an endpoint device; in response to the attempt, receiving an indication of a connectivity issue; and in response to receiving the indication, automatically attempting to de-register with the IMS.

Abstract: A system and method of controlling a wireless device communicating with a cellular communications system includes: establishing a cellular connection between the wireless device and a first cell tower; detecting, at the wireless device, a reference signal received power (RSRP) measurement of a signal broadcast by the first cell tower; increasing an RSRP threshold used by the wireless device by adding an offset value to the RSRP threshold; determining whether the detected RSRP measurement of the signal broadcast by the first cell tower falls below the increased RSRP threshold; and initiating a cellular connection with a second cell tower.