5DETAILED ACTION
This office action is in response to the application filed on November 6, 2024.
Claims 1-20 are pending in this application.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-5, 6-8, 10-15, 16-18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Bollapalli et al (US 2018/0063764 Al) (hereinafter “Bollapalli”) in view of Chung et al (US 2025/0184834 Al) (hereinafter “Chung”), and in further view of 3GPP TS 23.502 V19.1.0 (2024-09) (hereinafter “TS 23.502”).
Regarding claim 1, Bollapalli teaches a method of call handover, performed by a user equipment (UE), comprising:
initiating a mobile originating (MO) call using a Voice over Wi-Fi (VoWiFi) service (Bollapalli, FIG. 1 wherein the UE is connected to a Wi-Fi network and a cellular network; FIG. 3 step 321, wherein the UE initiates a VoWiFi call)
Bollapalli does not explicitly teach but Chung teaches:
detecting a failure of the MO call (Chung, FIG. 1 - Architecture; FIG. 4, wherein there are no SIP responses after the SIP INVITE in step 403 and the Request Timeout timer expires in step 406);
determining whether voice calling is supported by a cellular network in response to detecting the failure (Chung, FIG. 4 step 408 checking for VoNR = Enabled and going to step 410 wherein the UE silently redials over the alternative RAT); and
retrying the MO call using the cellular network (Chung, FIG.4 step 410).
Chung does not explicitly teach VoWiFi service. It would have been obvious to one of ordinary skill in the art at the effective date of the application to combine the normal call handling steps (Bollapalli, FIG. 3, steps 322-325) with the failure detection steps, the check for voice support on cellular network, and the call reattempt on cellular network steps in Chung’s teaching to create a VoWiFi MO call attempt failure and call reattempt on cellular networks flow.
Bollapalli teaches performing a handover of an established VoWiFi call to cellular connection, however Bollapalli does not explicitly indicate a handover (a reattempt) of a failed VoWiFi call to cellular connection. Bollapalli, as improved by Chung, teaches a handover of a failed VoWiFi call to cellular connection but does not explicitly indicate an IMS PDN connection (an IMS PDU session in 5G) handover (UE-WAP-N3IWF-SMF/UPF-P-CSCF to UE-gNB-SMF/UPF-P-CSCF). TS 23.502 Section 4.9.2.1 - Handover of a PDU Session procedure from untrusted non-3GPP to 3GPP access (non-roaming and roaming with local breakout) teaches a handover of an IMS PDU session when the UE moves from untrusted non-3GPP access to 3GPP access.
It would have been obvious to one of ordinary skill in the art at the effective date of the application to combine Bollapalli’s teaching and Chung’s teaching with TS 23.502’s teaching to perform an IMS PDN handover when an MO VoWiFi call fails and voice support is available on a cellular network to preserve session state (TS 23.502 section 4.9.2.1 wherein the UE performs registration and a PDU Session Establishment procedure on 3GPP access using the PDU Session ID of the PDU Session on non-3GPP access, keeping the same UE IP address and minimizing packet loss during the radio access switch) to provide a seamless user experience.
Regarding claim 2, Bollapalli, as improved by Chung and TS 23.502, teaches the method of claim 1, further comprising:
establishing a connection to both the Wi-Fi network and the cellular network (Bollapalli, FIG. 7 step 710 and step 752); and
registering the UE for the VoWiFi service (Bollapalli, FIG. 3, steps 312-315).
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 3, Bollapalli as improved by Chung and TS 23.502, teaches the method of claim 1, further comprising determining whether the UE is registered to the cellular network in response to detecting the failure (Bollapalli, [0043], wherein the UE initiates an optimized registration process; FIG. 4, steps 422-424).
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 4, which teaches the method of claim 3, further comprising scanning for at least one cellular network with voice capability if the UE is not registered with the cellular network (Bollapalli, [0033], wherein the UE is aware of registration states (full registration, refresh registration)).
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 3.
Regarding claim 5, Bollapalli as improved by Chung and TS 23.502, teaches the method of claim 1, wherein the failure of the MO call comprises at least one of:
receiving a Session Initiation Protocol (SIP) error response;
experiencing a SIP response timeout (Chung, FIG.4 step 406); or
experiencing a predefined call timer timeout;
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 6, Bollapalli as improved by Chung and TS 23.502, discloses the method of claim 1, further comprising scanning for at least one cellular network with voice capability if the voice calling is not supported by the cellular network (Chung, [0022] wherein the network is not configured to support an IMS call over 5G NR and the UE fallbacks to a 4G LTE RAT.)
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 7, Bollapalli as improved by Chung and TS 23.502, discloses the method of claim 6, further comprising terminating the MO call if the at least one cellular network with voice capability is not detected (Chung, FIG.6 wherein the UE is in 5G NR and VoNR is disabled and 4G is not available in step 616. As a result, the UE terminates the call as shown by step 614.)
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 6.
Regarding claim 8, Bollapalli as improved by Chung and TS 23.502, discloses the method of claim 1, further comprising registering the UE for a Voice over LTE (VoLTE) service (Bollapalli, FIG. 4 steps 422-424) or a Voice over New Radio (VoNR) service.
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 10, Bollapalli as improved by Chung and TS 23.502, discloses the method of claim 1 wherein the cellular network uses a Radio Access Technology (RAT) defined by 3GPP (Bollapalli, FIG. 4 shows that the UE is in LTE and LTE is defined by 3GPP 36 series).
The teaching of Bollapalli is combined with Chung and TS 23.502 under the same rationale as claim 1.
Regarding claim 11, Bollapalli teaches a user equipment (UE), comprising:
a memory (Bollapalli, FIG. 1 Memory 114); and
a processor (Bollapalli, FIG. 1 Processor(s) 112); coupled to the memory, configured to perform the method in claim 1 (see mapping to claim 1).
Regarding claim 12, which teaches the UE of claim 11, wherein the processor is further configured to perform the operations in claim 2 (see mapping to claim 2).
Regarding claim 13, which teaches the UE of claim 11, wherein the processor is further configured to perform the operations in claim 3 (see mapping to claim 3).
Regarding claim 14, which teaches the UE of claim 13, wherein the processor is further configured to perform the operations in claim 4 (see mapping to claim 4).
Regarding claim 15, which teaches the UE of claim 11, wherein the failure of the MO call comprises at least one of the three options in claim 5 (see mapping to claim 5).
Regarding claim 16, which teaches the UE of claim 11, wherein the processor is further configured to perform the operations in claim 6 (see mapping to claim 6).
Regarding claim 17, which teaches the UE of claim 16, wherein the processor is further configured to perform the operations in claim 7 (see mapping to claim 7).
Regarding claim 18, which teaches the UE of claim 11, wherein the processor is further configured to perform the operations in claim 8 (see mapping to claim 8).
Regarding claim 20, which teaches the UE of claim 11, wherein the cellular network is specified in claim 10 (see mapping to claim 10).
Claims 9 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Bollapalli, in view of Chung, TS 23.502, and in further view of RFC 3261 - SIP: Session Initiation Protocol (June 2002) (hereinafter “RFC 3261”)
Regarding claim 9, Bollapalli as improved by Chung and TS 23.502, discloses the method of claim 1, further comprising:
determining whether the handover of the IMS PDN connection is successful (TS 23.502 - Section 4.9.2.1 refers to Section 4.3.2.2.1 wherein the UE initiates a PDU Session establishment request. If the UE receives a PDU Session Establishment Accept message from the AMF, the handover is successful. If the UE receives a PDU Session Establishment Reject message from the AMF, the handover fails.); and
Bollapalli, Chung, and TS 23.502 do not explicitly teach but RFC 3261 teaches:
terminating the MO call if the handover of the IMS PDN connection is successful (RFC 3261, section 15 -Terminating a Session wherein a non-2xx final response terminates all sessions and all dialogs. As a result, the UE terminates the failed MO call on non-3GPP access; section 17.1.1.2 - Formal Description wherein no 1xx responses are received from the network and timer B expires. As a result, the UE terminates the SIP client transaction and the failed MO call on non-3GPP access).
It would have been obvious to one of ordinary skill in the art at the effective date of the application to combine the teachings of Bollapalli, Chung, and TS 23.502 with RFC 3261’s teaching of SIP timeout abort and SIP non-200 final responses to determine whether an IMS PDN handover is successful and to terminate the failed VoWiFi MO call to release resources used by the failed VoWiFi MO call.
Regarding claim 19, which teaches the UE of claim 11, wherein the processor is further configured to perform the operations in claim 9 (see mapping to claim 9).
Citation of Pertinent Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Chiang, H (2019), Call Setup Logic with Emerg-Request-Non-100 Timer (U.S. Patent No. US 10,462,643 Bl). U.S. Patent and Trademark Office.
Youn, M (2022), Method for Moving IMS Voice Session on Non-3GPP to 3GPP Access (U.S. Pub No. 2022/0345949). U.S. Patent and Trademark Office.
Kuppelur, N, Voice over Internet Protocol Multimedia Subsystem, (U.S. Pub No. US 2023/0049004). U.S. Patent and Trademark Office.
Conclusion
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/STEVEN DUONG NGUYEN/ Examiner, Art Unit 2472
/KEVIN T BATES/Supervisory Patent Examiner, Art Unit 2472
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