Scheme of Retaining LTE connection during Circuit Switch Fall Back
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsWeigang LI, Indranil TAPADAR, Guoqiang XUE
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Abstract
The present solution enables a packet switched connection to be temporarily released at the wireless terminal for supporting voice calls over a Circuit-Switched (CS) Fallback. The packet switched connection of the LTE core network retained for a pre-defined period of time during the CSFB session allowing the user to quickly switch back to the packet switched connection when the CSFB session is shorter than the predefined period or when the voice call CSFB attempt fails. This is accomplished by the introduction of a timed buffer to control the length of time the LTE core network connection and wireless context information will be retained.
Claims16
In a Long Term Evolution (LTE) core network, a method of retaining a packet switched session during a circuit-switch fallback connection attempt between a wireless terminal and Circuit Switched (CS) core network, comprising:
- a) receiving a circuit-switch connection request at a node serving said wireless terminal;
- b) instructing said serving node to release said packet switched session between said wireless terminal and said serving node but delay the release of said packet switched session between said serving node and said LTE core network;
- c) forwarding said circuit switched connection request to said wireless terminal to establish a CSFB session on said CS core network;
- and
- d) initiating a timer indicative of the time limit said wireless terminal's CSFB session is retained.
A wireless terminal configured, when already having a registration and/or session for a packet switched service with a Long Term Evolution (LTE) core network, to make a registration for a circuit switched fall back (CSFB) session with a circuit switched (CS) core network, the wireless terminal being characterized in that, in conjunction with the registration for the circuit switched (CSFB) session, the wireless terminal is configured to release said packet switched session with a serving node of said LTE core network but delay the release of context information associated with said packet switched session such that when said circuit switched registration is terminated, said wireless terminal can re-establish the original packet switched session with said serving node of said (LTE) core network.
A method of operating a wireless terminal comprising:
- when already having a registration and/or session for a packet switched (PS) service with a Long Term Evolution (LTE) core network, making a registration for a circuit switched fall back (CSFB) session over a CS air interface with a circuit switched (CS) core network;
- the method characterized by:
- releasing said packet switched session with a serving node of said LTE core network but delaying the release of context information associated with said packet switched session such that when said circuit switched registration is terminated, said wireless terminal can re-establish the original packet switched session with said serving node of said (LTE) core network.
Dependencies are inferred from the claim text.