A communication device may transmit messages to an Internet Protocol Multimedia Subsystem (IMS) network through an untrusted non-3GPP radio access network (RAN). A process to be implemented on a communication device may include generating a message having a location identifier (ID) that is indicative of a current location of the communication device, and transmitting the message, through an untrusted non-3GPP RAN, to a node within the IMS network. A process to be implemented on one or more nodes of the IMS network may include receiving, from a communication device and via an untrusted non-3GPP RAN, a message having a location ID, and in response to receiving the message, estimating a current location of the communication device based at least in part on the location ID.