US Patent 10327185 IuGW architecture with RTP localization

A method for localizing a voice call is disclosed, comprising: receiving an originating leg setup message for an originating leg bearer from the first base station for a first user equipment (UE); creating a first call correlation identifier and storing the first call correlation identifier in association with the first UE; extracting a second call correlation identifier from a terminating leg setup message for a terminating leg bearer received from the core network; determining a real time protocol (RTP) localization status for the originating leg bearer and the terminating leg bearer based on matching the second call correlation identifier of the terminating leg against the stored first call correlation identifier of the originating leg; and sending transport layer assignment messages to the first base station to redirect RTP packets from the first UE to the second UE via the terminating leg bearer without the RTP packets transiting the core network.