DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
The amendment submitted on 05/20/2026 has been received and considered by the Examiner. Claims 19, 21, 26, and 28 were amended. Claims 19-34 remain pending.
Response to Arguments
Applicant’s arguments with respect to claim(s) 19-34 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 19-24, 26-31, and 33-34 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ramachandra et al. (US 2026/0052435 A1, hereinafter “Ramachandra2”) in view of Jung et al. (US 2016/0119959 A1, hereinafter “Jung”).
As to Claim 19:
Ramachandra2 describes a method for recovering from RLF failure when handing over to establish a fallback connection for voice services.
Specifically, Ramachandra2 teaches:
Receiving, from a base station of a first radio access technology (RAT) a message to command a handover from a source cell of the first RAT to a target cell of a second RAT
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “4. NR Cell initiates a handover (HO) towards an LTE cell” (Ramachandra2, 0094).
Here, “NR Cell initiates a handover (HO) towards an LTE cell” maps to “receiving, from a base station of a first radio access technology (RAT) a message to command a handover from a source cell of the first RAT to a target cell of a second RAT”.
Performing the handover to the target cell based on the message
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “5. UE successfully completes a handover to LTE Cell-B” (Ramachandra2, 0095). Ramachandra2 also discusses “scenarios when the network fails to handover the UE to the ‘correct’ neighbor cell” which will cause “Handover Failure (HOF)” (Ramachandra2, 0019).
Here, “UE-1 successfully completes a handover to LTE Cell-B” maps to “performing the handover to the target cell based on the message”.
In case that the handover to the target cell is triggered for emergency service fallback and in case that the handover to the target cell is failed, searching for a suitable cell of the second RAT
Ramachandra describes “autonomous actions” that “the UE may take” “[u]pon HOF and RLF” such as “try[ing] to select a cell and initiate reestablishment procedure” which results in “reestablishing the connection ... with the newly selected cell” (Ramachandra, 0020). For context, Ramachandra2 introduces this teaching by describing “scenarios when the network fails to handover the UE to the ‘correct’ neighbor cell” which will cause “Handover Failure (HOF)” (Ramachandra2, 0019). Also, the hypothetical scenario outlined in paragraphs 0091-0098 of Ramachandra2 further clarifies that the handover may occur “for voice fallback reasons” (Ramachandra2, 0094).
Here, “for voice fallback reasons” maps to “[i]n case that the handover to the target cell is triggered for emergency service fallback”,
“HOF” maps to “in case that the handover to the target cell has failed”, and
“initiat[ing] [a] reestablishment procedure” towards a “newly selected cell” maps to “searching for a suitable cell of the second RAT”.
Information on the failure of handover is set in a radio link failure (RLF) report
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “7. UE generates an RLF report in E-UTRA and indicates that the last source cell of the handover was NR Cell-A” (Ramachandra2, 0097).
Here, “generat[ing] an RLF report” maps to “information on the failure of handover is set in a radio link failure (RLF) report”.
The RLF report includes information indicating a time elapsed from the failure of handover in the second RAT
Table 1 in Ramachandra2 describes the contents of a “UEInformationResponse message” used to send a RLF report which includes an element named “TimeSinceFailure-r11” (Ramachandra2, Table 1).
Here, the “UEInformationResponse message” maps to “the RLF report”, and
“TimeSinceFailure-r11” maps to “information indicating a time elapsed from the failure of handover in the second RAT”.
Ramachandra2 does not explicitly disclose:
In case that the suitable cell of the second RAT is not available, selecting an acceptable cell of the second RAT supporting an emergency call
However, Jung does describe situations where a UE falls back to an acceptable cell if no suitable cell is found for IMS emergency services.
Specifically, Jung teaches:
In case that the suitable cell of the second RAT is not available, selecting an acceptable cell of the second RAT supporting an emergency call
Jung describes a scenario where “a radio link failure (RLF) occurs in the emergency call process”, the UE initiates “connection re-establishment”, and “the selected cell is an acceptable cell” if “a suitable cell or a cell using another radio access technology (RAT) is not selected” (Jung, 0008).
Here, “a suitable cell or a cell using another radio access technology (RAT) is not selected” maps to “in case that the suitable cell of the second RAT is not available”, and
“the selected cell is an acceptable cell” maps to “selecting an acceptable cell of the second RAT supporting an emergency call”.
Furthermore, Jung also teaches more explicitly than Ramachandra2 that:
The handover to the target cell is failed
Jung describes “cases where the normal communication is impossible” such as “a case where the UE determines that the handover is failed” (Jung, 0124-0128).
Here, “the handover is failed” maps to “the handover to the target cell is failed”.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
As to Claims 20 and 27:
Ramachandra2 teaches:
The time is obtained between the failure of handover and an access to the ... cell of the second RAT
Table 1 in Ramachandra2 describes the contents of a “UEInformationResponse message” used to send a RLF report which includes an element named “TimeSinceFailure-r11” (Ramachandra2, Table 1).
Here, “TimSinceFailure-r11” maps to “the time is obtained between the failure of handover and an access to the ... cell of the second RAT”.
Ramachandra2 does not explicitly disclose:
The acceptable cell of the second RAT
However, Jung does teach:
The acceptable cell of the second RAT
Jung describes a scenario where “a radio link failure (RLF) occurs in the emergency call process”, the UE initiates “connection re-establishment”, and “the selected cell is an acceptable cell” if “a suitable cell or a cell using another radio access technology (RAT) is not selected” (Jung, 0008).
Here, “an acceptable cell” in “another radio access technology (RAT)” maps to “the acceptable cell of the second RAT”.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
Claim 27 introduces the same new limitations as Claim 20 in the form of an apparatus claim.
As to Claims 21 and 28:
Ramachandra2 teaches:
The message includes information indicating that the handover is triggered by evolved packet system (EPS) fallback for Internet Protocol (IP) multimedia subsystem (IMS) voice and information on a parameter associated with the target cell of the second RAT
Ramachandra2 describes a UE receiving “a configuration to perform a handover to a second network node belonging to a second radio access technology, the configuration comprising an indication that indicates that the handover is for voice fallback purpose” (Ramachandra2, 0051). Ramachandra2 also clarifies the voice service is “Internet Protocol (IP) Multimedia Subsystem (IMS) voice service” (Ramachandra2, 0003).
Here, “a configuration to perform a handover” maps to “the message includes information indicating that the handover is triggered”,
“Internet Protocol (IP) Multimedia Subsystem (IMS) voice service” maps to “volved packet system (EPS) fallback for Internet Protocol (IP) multimedia subsystem (IMS) voice”, and
“configuration to perform a handover to a second network node associated with a second radio access technology” maps to “information on a parameter associated with the target cell of the second RAT”.
The first RAT is new radio (NR) and the second RAT is evolved-universal mobile telecommunication systems (UMTS) terrestrial radio access (E-UTRA)
Ramachandra describes “voice fallback from New Radio (NR) to Long Term Evolution (LTE)” that “direct[s] or redirect[s] the UE from NG-RAN ... towards Evolved Universal Terrestrial Radio Access (E-UTRA)” (Ramachandra, 0003).
Here, “NG-RAN” maps to “the first RAT is new radio (NR)”, and
“E-UTRA” maps to “the second RAT is evolved-universal mobile telecommunication systems (UMTS) terrestrial radio access (E-UTRA)”.
As to Claims 22 and 29:
Ramachandra2 teaches:
Transmitting, to the base station of the first RAT, the RLF report
Ramachandra2 teaches that a “UE would log relevant information at the moment of an RLF and later report to a target cell to which the UE succeeds to connect [sic]” and that the “eNodeB receiving an RLF report could forward to the eNodeB where the failure has been originated” (Ramachandra2, 0028).
Here, “forward[ing]” the “RLF report” to “the eNodeB where the failure has been originated” maps to “transmitting, to the base station of the first RAT, the RLF report”.
The RLF report further includes a cell identity (ID) for the ... cell
Table 1 in Ramachandra2 details the contents of the “UEInformationResponse” that carries the RLF report, and it includes a “reestablishmentCellID-r10” field (Ramachandra2, Table 1).
Information on a connection failure type
Table 1 in Ramachandra2 details the contents of the “UEInformationResponse” that carries the RLF report, and it includes a “connectionFailureType-r10” field (Ramachandra2, Table 1).
Ramachandra2 does not explicitly disclose:
The acceptable cell
However, Jung does teach:
The acceptable cell
Jung describes a scenario where “a radio link failure (RLF) occurs in the emergency call process”, the UE initiates “connection re-establishment”, and “the selected cell is an acceptable cell” if “a suitable cell or a cell using another radio access technology (RAT) is not selected” (Jung, 0008).
Here, “an acceptable cell” in “another radio access technology (RAT)” maps to “the acceptable cell”.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
Claim 29 introduces the same new limitations as Claim 22 in the form of an apparatus claim.
As to Claims 23 and 30:
Ramachandra2 teaches:
Receiving, from the base station, a user equipment (UE) information request message to request the RLF report
Ramachandra2 describes a UE “receiving an UEInformationRequest message with a flag ‘rlf-ReportReq-r9’”, after which “the UE includes the RLF report ... in an UEInformationResponse message and sends the UEInformationResponse message to the network” (Ramachandra2, 0040).
Here, “UEInformationRequest message with a flag ‘rlf-ReportReq-r9’” maps to “receiving, from the base station, a user equipment (UE) information request message to request the RLF report”.
The RLF report is transmitted via a UE information response message based on the UE information request message
Ramachandra2 describes a UE “receiving an UEInformationRequest message with a flag ‘rlf-ReportReq-r9’”, after which “the UE includes the RLF report ... in an UEInformationResponse message and sends the UEInformationResponse message to the network” (Ramachandra2, 0040).
Here, “the UE includes the RLF report ... in an UEInformationResponse message and sends the UEInformationResponse message to the network” maps to “the RLF report is transmitted via a UE information response message based on the UE information request message”.
Claim 30 introduces the same new limitations as Claim 23 in the form of an apparatus claim.
As to Claims 24 and 31:
Ramachandra2 teaches:
Internet protocol (IP) multimedia subsystem (IMS)
Ramachandra describes “deployment scenarios for obtaining Internet Protocol (IP) Multimedia Subsystem (IMS) voice service” (Ramachandra, 0003).
Transmitting, to the base station, information on a connection cause indicating the IMS voice
Ramachandra2 describes a UE “storing information associated to the radio link failure in a report, the information comprising an indication that the last completed handover for the first network node to the second network node was for voice fallback purpose” so that “the network is enabled to identify whether the last completed handover was a voice fallback handover” (Ramachandra2, 0051).
Here, “storing ... in a report ... information comprising an indication that the last completed handover” maps to “transmitting, to the base station”, and
“an indication that the last completed handover ... was for voice fallback purpose” maps to “information on a connection cause indicating the IMS voice”.
Ramachandra2 does not explicitly disclose:
Determining to initiate Internet protocol (IP) multimedia subsystem (IMS) voice
However, Jung does teach:
Determining to initiate ... voice
Fig. 8 in Jung shows a UE initiating an “emergency call” in step S801.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
Claim 31 introduces the same new limitations as Claim 24 in the form of an apparatus claim.
As to Claim 26:
Ramachandra2 teaches:
A transceiver; and a controller configured
Fig. 11 in Ramachandra “shows a block diagram of an exemplary wireless device or UE” including “Radio Transceiver 1140” and “Processor(s) 1110” (Ramachandra, 0052).
Control the transceiver to receive, from a base station of a first radio access technology (RAT) a message to command a handover from a source cell of the first RAT to a target cell of a second RAT
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “4. NR Cell initiates a handover (HO) towards an LTE cell” (Ramachandra2, 0094).
Here, “NR Cell initiates a handover (HO) towards an LTE cell” maps to “control the transceiver to receive, from a base station of a first radio access technology (RAT) a message to command a handover from a source cell of the first RAT to a target cell of a second RAT”.
Perform the handover to the target cell based on the message
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “5. UE successfully completes a handover to LTE Cell-B” (Ramachandra2, 0095). Ramachandra2 also discusses “scenarios when the network fails to handover the UE to the ‘correct’ neighbor cell” which will cause “Handover Failure (HOF)” (Ramachandra2, 0019).
Here, “UE-1 successfully completes a handover to LTE Cell-B” maps to “perform the handover to the target cell based on the message”.
In case that the handover to the target cell is triggered for emergency service fallback and in case that the handover to the target cell is failed, search for a suitable cell of the second RAT
Ramachandra describes “autonomous actions” that “the UE may take” “[u]pon HOF and RLF” such as “try[ing] to select a cell and initiate reestablishment procedure” which results in “reestablishing the connection ... with the newly selected cell” (Ramachandra, 0020). For context, Ramachandra2 introduces this teaching by describing “scenarios when the network fails to handover the UE to the ‘correct’ neighbor cell” which will cause “Handover Failure (HOF)” (Ramachandra2, 0019). Also, the hypothetical scenario outlined in paragraphs 0091-0098 of Ramachandra2 further clarifies that the handover may occur “for voice fallback reasons” (Ramachandra2, 0094).
Here, “for voice fallback reasons” maps to “[i]n case that the handover to the target cell is triggered for emergency service fallback”,
“HOF” maps to “in case that the handover to the target cell has failed”, and
“initiat[ing] [a] reestablishment procedure” towards a “newly selected cell” maps to “search for a suitable cell of the second RAT”.
Information on the failure of handover is set in a radio link failure (RLF) report
Paragraphs 0091-0097 of Ramachandra2 describe an example handover scenario which includes the following step: “7. UE generates an RLF report in E-UTRA and indicates that the last source cell of the handover was NR Cell-A” (Ramachandra2, 0097).
Here, “generat[ing] an RLF report” maps to “information on the failure of handover is set in a radio link failure (RLF) report”.
The RLF report includes information indicating a time elapsed from the failure of handover in the second RAT
Table 1 in Ramachandra2 describes the contents of a “UEInformationResponse message” used to send a RLF report which includes an element named “TimeSinceFailure-r11” (Ramachandra2, Table 1).
Here, the “UEInformationResponse message” maps to “the RLF report”, and
“TimeSinceFailure-r11” maps to “information indicating a time elapsed from the failure of handover in the second RAT”.
Ramachandra2 does not explicitly disclose:
In case that the suitable cell of the second RAT is not available, select an acceptable cell of the second RAT supporting an emergency call
However, Jung does describe situations where a UE falls back to an acceptable cell if no suitable cell is found for IMS emergency services.
Specifically, Jung teaches:
In case that the suitable cell of the second RAT is not available, select an acceptable cell of the second RAT supporting an emergency call
Jung describes a scenario where “a radio link failure (RLF) occurs in the emergency call process”, the UE initiates “connection re-establishment”, and “the selected cell is an acceptable cell” if “a suitable cell or a cell using another radio access technology (RAT) is not selected” (Jung, 0008).
Here, “a suitable cell or a cell using another radio access technology (RAT) is not selected” maps to “in case that the suitable cell of the second RAT is not available”, and
“the selected cell is an acceptable cell” maps to “select an acceptable cell of the second RAT supporting an emergency call”.
Furthermore, Jung also teaches more explicitly than Ramachandra2 that:
The handover to the target cell is failed
Jung describes “cases where the normal communication is impossible” such as “a case where the UE determines that the handover is failed” (Jung, 0124-0128).
Here, “the handover is failed” maps to “the handover to the target cell is failed”.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
As to Claims 33 and 34:
Ramachandra2 teaches:
An internet protocol (IP) multimedia subsystem (IMS) voice service
Ramachandra2 describes “Internet Protocol (IP) Multimedia Subsystem (IMS) voice service” (Ramchandra2, 0003).
Limited service including the emergency call
Ramachandra2 describes “EPS fallback procedure[s] for IMS voice” which is analogous to “limited service including the emergency call” because the fallback procedure must only support the minimum requirements for an emergency call in a legacy RAT.
Ramachandra2 does not explicitly disclose:
The suitable cell supports a normal service of the second RAT including a ... voice service
The acceptable cell supports a limited service
However, Jung does teach:
The suitable cell supports a normal service of the second RAT including a ... voice service
Jung describes a “suitable cell” as “a suitable E-UTRA cell” and “[a] cell in which the UE may receive the normal service” which can be used for “a voice over Internet protocol (VoIP)” (Jung, 0005, 0069, 0042).
Here, “a cell in which the UE may receive the normal service” maps to “the suitable cell supports a normal service”,
“E-UTRA” maps to “the second RAT”, and
“VoIP” maps to “a ... voice service”.
The acceptable cell supports a limited service
Jung defines an “[a]cceptable cell” as “[a] cell in which the UE may receive the limited service” (Jung, 0068).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Jung’s practice of falling back to an acceptable cell when a suitable cell is not available into Ramachandra2’s method for recovering from a handover failure for emergency voice services. As Jung explains, this means “[a]n emergency call can be prevented from unintentionally stopping even if a user equipment performs the emergency call in an acceptable cell” (Jung, 0010).
Claim 34 introduces the same new limitations as Claim 33 in the form of an apparatus claim.
Claim(s) 25 and 32 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ramachandra (US 2026/0052435 A1) in view of Jung (US 2016/0119959 A1) and further in view of non-patent literature cited in the IDS submitted on 09/25/2023 entitled “Early measurement for EPS Fallback” (hereinafter “Vivo”).
As to Claims 25 and 32:
Ramachandra2 teaches:
Performing a measurement of the at least one carrier frequency of the second RAT
The RLF fields in Table 1 of Ramachandra2 include “measResultListEUTRA-v1250”, which maps to “performing a measurement of the at least one carrier frequency of the second RAT”.
Transmitting, to the base station, a result of the measurement
The RLF fields in Table 1 of Ramachandra2 include “measResultListEUTRA-v1250”, which maps to “transmitting, to the base station, a result of the measurement” because this RLF report is sent uplink.
The combination of Ramachandra2 and Jung does not explicitly disclose:
Receiving, from the base station, information on at least one carrier frequency of the second RAT
The message is received after transmitting the result of the measurement
However, Vivo et al. (non-patent literature included in the IDS submitted on 09/15/2023 entitled “Early measurement for EPS Fallback”) does describe methods for a base station to configure a terminal to take and report measurements on a specific set of carrier frequencies during EPS fallback.
Specifically, Vivo teaches:
Receiving, from the base station, information on at least one carrier frequency of the second RAT
Vivo describes a proposal that includes “[i]ntroducing indications on carrier frequency for idle/inactive measurement for EPS Fallback to indicate whether the carrier can be used for EPS Fallback for R17 UEs” (Vivo, p. 3).
The message is received after transmitting the result of the measurement
Vivo’s “Proposal 1” includes “report of measurement results” for “early measurement for EPS/RAT Fallback based on handover” (Vivo, p. 3).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Vivo’s method of measuring the strength of certain carrier frequencies before handing over into Ramachandra’s method for RLF reporting of inter-RAT handover. Measuring the strength of carrier frequencies helps a UE to determine the best candidate target cell, reducing the risk of failure.
Claim 35 the same new limitations as Claim 25 in the form of an apparatus claim.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Purkayastha et al. (US 2021/0235334 A1) describes a handover command with an explicit indication of EPS fallback (paragraph 0146).
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BENJAMIN PETER WELTE
Examiner
Art Unit 2477
/CHIRAG G SHAH/Supervisory Patent Examiner, Art Unit 2477
