Patent ID: 9450782
Filing Date: 2016-09-20
CPC Classification: H04L

Claim Text:
1. One or more non-transitory computer readable media having instructions that, when executed, cause a first communication terminal to: process a set up message of a circuit-switched (CS) communication connection that is received from a second communication terminal, the setup message to include a first CSI correlator, which is a random reference number, that is associated with the second communication terminal; determine the first CSI correlator was not previously saved at the first communication terminal; save the first CSI correlator based on the determination that the first CSI correlator was not previously saved at the first communication terminal; generate a second CSI correlator, which is another random reference number, that is associated with the first communication terminal; and transmit a connect message, which includes the second CSI correlator, to the second communication terminal, wherein the first or second CSI correlator is to be used to establish an IP multimedia services (IMS) communication connection that is to be maintained in parallel with the CS communication connection and the instructions, when executed, further cause the first communication terminal to: process an invite message that is to initiate the IMS communication connection between the first and second communication terminals, the invite message to include a third CSI correlator and a label to indicate the third CSI correlator is in use; determine the third CSI correlator equals the first CSI correlator; and transmit an OK message based on determination the third CSI correlator equals the first CSI correlator to facilitate establishment of the IMS communication connection.