Patent ID: 9654954
Date: 2017-05-16
CPC Classifications: H04L,H04M,H04W

Claim:
1. A method of providing an availability of an execution of an Internet Protocol Multimedia Subsystem voice session with a terminal via a packet switched capable radio access network of an Internet Protocol Multimedia Subsystem based communication network, wherein the communication network comprises a packet switched domain associated with the packet switched capable radio access network and comprises a circuit switched domain associated with a circuit switched capable radio access network, wherein the communication network supports an Internet Protocol Multimedia Subsystem voice session via the packet switched capable radio access network, the method being executed by a control node of the packet switched domain, the method comprising: determining that the terminal supports an Internet Protocol Multimedia Subsystem voice session via the packet switched capable radio access network and also supports an Internet Protocol Multimedia Subsystem emergency voice session via the packet switched capable radio access network; determining whether the circuit switched capable radio access network spatially at least covers the packet switched capable radio access network; and sending to the terminal, responsive to said determining that the terminal supports an Internet Protocol Multimedia Subsystem voice session via the packet switched capable radio access network and also supports an Internet Protocol Multimedia Subsystem emergency voice session via the packet switched capable radio access network, and based on the result of said determining whether the circuit switched capable radio access network spatially at least covers the packet switched capable radio access network, instruction information that instructs the terminal that the terminal may execute an Internet Protocol Multimedia Subsystem voice session via the packet switched capable radio access network without regard to whether the communication network has indicated support of an emergency session related data transmission via the packet switched capable radio access network and the packet switched domain, wherein the instruction information further instructs the terminal to exclusively initiate any emergency voice session as a circuit-switched emergency voice session via the circuit switched capable radio access network.