Prosecution Insights
Last updated: April 19, 2026
Application No. 18/088,212

SUPPORT REDUNDANT PDU SESSION AFTER INTER-SYSTEM CHANGE

Non-Final OA §103
Filed
Dec 23, 2022
Examiner
RICHMOND, GARTH DANIEL
Art Unit
2644
Tech Center
2600 — Communications
Assignee
MediaTek Inc.
OA Round
3 (Non-Final)
64%
Grant Probability
Moderate
3-4
OA Rounds
3y 1m
To Grant
99%
With Interview

Examiner Intelligence

Grants 64% of resolved cases
64%
Career Allow Rate
7 granted / 11 resolved
+1.6% vs TC avg
Strong +67% interview lift
Without
With
+67.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
43 currently pending
Career history
54
Total Applications
across all art units

Statute-Specific Performance

§101
3.4%
-36.6% vs TC avg
§103
58.0%
+18.0% vs TC avg
§102
18.4%
-21.6% vs TC avg
§112
17.9%
-22.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 11 resolved cases

Office Action

§103
DETAILED ACTION 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 . Reopening of Prosecution In view of the Appeal Brief filed on 24 Oct. 2025, PROSECUTION IS HEREBY REOPENED. New grounds of rejection are set forth below. To avoid abandonment of the application, appellant must exercise one of the following two options: (1) file a reply under 37 CFR 1.111; or, (2) initiate a new appeal by filing a notice of appeal under 37 CFR 41.31 followed by an appeal brief under 37 CFR 41.37. The previously paid notice of appeal fee and appeal brief fee can be applied to the new appeal. If, however, the appeal fees set forth in 37 CFR 41.20 have been increased since they were previously paid, then appellant must pay the difference between the increased fees and the amount previously paid. A Supervisory Patent Examiner (SPE) has approved of reopening prosecution by signing below: { 4 } 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 the 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. § 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claims 1, 2, 5-7, 10 are rejected under 35 U.S.C. § 103 as being unpatentable over US 2020/0329397 (hereinafter, “HUANG-FU”) in view of US 2021/0250788 (hereinafter, “KIM ‘788”). Regarding claim 1, HUANG-FU discloses: A method, comprising: (Abstract: A method for synchronizing evolved packet system (EPS) bearer context status between a user equipment (UE) and a network) maintaining a protocol data unit (PDU) session (PDU session 210) by a User Equipment (UE) (UE 101/102) in a 5G mobile communication network, (fifth generation system (5GS) 152) (¶¶ 0012, 0049: PDU session 210 being maintained) wherein the PDU session is associated with at least one of a PDU session ID; (¶ 0032: [D]uring PDN connection establishment, the UE 101 allocates a PDU session ID and sends the PDU session ID to the SMF 123) performing a first intersystem change (first session switch process 231) from N1 mode to S1 mode, (¶ 0049: [A]n inter-system change from N1 mode to S1 mode takes place; ¶ 0061: Upon inter-system change of the UE 102 from N1 mode to S1 mode takes place) wherein the PDU session in 5G is mapped to a packet data network (PDN) connection (PDN connection 220) in 4G; (evolved packet system (EPS) 151) (¶ 0041: [M]apping relationship 200 between a PDU session 210 in the 5GS 152 and a PDN connection 220 in the EPS 151 when inter-system changes between N1 mode and S1 mode take place; ¶ 0074: [A] PDU session in the 5GS 152 is transferred to the PDN connection at [S510] as a result of an inter-system change from the 5GS 152 to the EPS 151) associating the at least one of the PDU session ID to a default EPS bearer context of the PDN connection corresponding to the PDU session after the first intersystem change; and (¶ 0035: [T]he corresponding default EPS bearer context . . . has an association with 5G QoS parameters after an inter-system change from N1 mode to S1 mode ([i.e.], has an association with one or more QoS flows defined by the corresponding 5G QoS parameters). The 5G QoS parameters can include a PDU session identity; ¶ 0064: [A]t the end of the first session switch process 231, the UE 101 can associate an identity of the PDU session 210 with the default EPS bearer context 223) performing a second intersystem change (second session switch process 232) from S1 mode to N1 mode, (¶ 0064: Upon inter-system change of the UE 101 from S1 mode to N1 mode takes place; ¶ 0076: At S530, an inter-system change from S1 mode to N1 mode can be initiated) wherein the PDN connection is mapped to the PDU session, and (¶ 0041: [M]apping relationship 200 between a PDU session 210 in the 5GS 152 and a PDN connection 220 in the EPS 151 when inter-system changes between N1 mode and S1 mode take place; ¶ 0064: [S]econd session switch process 232 can be performed to switch the PDN connection 220 in the EPS 151 to the PDU session 210 in the 5GS 152) wherein the UE associates the PDU session ID to the PDU session corresponding to the PDN connection after the second intersystem change. (¶ 0064: [A]t the end of the second session switch process 232, the UE 102 can associate the EBIs [EPS bearer identities], the QoS parameters . . . with the respective QoS flows 221-223 in the PDU session 210. The associations are stored at the UE 102; ¶ 0035: [T]he corresponding default EPS bearer context . . . has an association with [a PDU session identity] after an inter-system change from N1 mode to S1 mode) HUANG-FU does not explicitly disclose: at least one of a PDU session pair ID and a redundancy sequence number (RSN). In the same field of endeavor, however, KIM ‘788 teaches: a PDU session pair ID and a redundancy sequence number (RSN). (Abstract: [A] first redundancy sequence number (RSN) which is allocated by the first SMF node for managing a first PDU session and an identifier of the first PDU session; transmitting, to a second SMF node for managing a second PDU session, a second message including the first RSN and a PDU session pair ID, which is identical to the identifier of the first PDU session; ¶ 0282: [A network function] selects the value of Redundancy Sequence Number (RSN) to indicate to NG-RAN that redundant user plane resources shall be provided for the given PDU sessions by means of dual connectivity. Based on the RSN and RAN configuration, the NG-RAN sets up dual connectivity so that the sessions have end to end redundant paths) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s PDU session ID to provide a PDU Session pair ID and a redundancy sequence number (RSN) as taught by KIM ‘788 to provide an indication that the second PDU session may be a duplication of the first PDU session, so that when two redundant PDU sessions are handled via different network functions, each knows the PDU session ID which is handled by the other. See KIM ‘788, at ¶ 0068. The Examiner finds that one of ordinary skill in the art would have appreciated that KIM ‘788’s RSN or session airing identifier is merely a refinement of HUANG-FU’s generic PDU session identity, serving the same stated purpose of correlating session contexts across network transitions. Applying an explicit identifier to conventional inter-system change procedures would have been an obvious design choice to improve procedures for persisting identifiers across disjoint paths in support of highly reliable communication services. See KIM ‘788, at ¶¶ 0067 and 0280. Regarding claim 2 and claim 7, the combination of HUANG-FU and KIM ‘788 as applied herein renders obvious the method of claim 1 and the UE of claim 6, respectively. HUANG-FU further discloses: wherein the PDU session is established by a UE-initiated PDU session establishment process (¶ 0066: UE-requested PDU session establishment process for establishing a PDU session) HUANG-FU does not explicitly disclose: a PDU session establishment request message. However, KIM ‘788 further teaches: wherein the PDU session is established by a UE-initiated PDU session establishment request message. (¶ 0159: UE initiates the UE Requested PDU Session Establishment procedure by the transmission of a NAS message containing a PDU Session Establishment Request within the N1 SM container. The PDU Session Establishment Request includes a PDU session ID) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s UE-initiated PDU session establishment process to provide a UE Requested PDU Session Establishment procedure as taught by KIM ‘788 to provide a request message, so that when two redundant PDU sessions are handled via different SMFs, each SMF is able to know the PDU session ID which is handled by the other SMF. See KIM ‘788, at ¶ 0068. Regarding claim 5 and claim 10, the combination of HUANG-FU and KIM ‘788 as applied herein renders obvious the method of claim 1 and the UE of claim 6, respectively. HUANG-FU does not explicitly disclose: wherein the UE initiates two redundant PDU sessions, and wherein the PDU session belongs to one of the two redundant PDU sessions. However, KIM ‘788 further teaches: wherein the UE initiates two redundant PDU sessions, and wherein the PDU session belongs to one of the two redundant PDU sessions. (¶ 0070: [A] method for supporting redundant protocol data unit (PDU) sessions) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s UE-initiated PDU session establishment process to provide redundant protocol data unit (PDU) sessions as taught by KIM ‘788 to provide two redundant PDU sessions, so as to support highly reliable URLLC services, such that a UE may set up two redundant PDU Sessions over the 5G network via disjoint user plane paths of the two redundant PDU Sessions. See KIM ‘788, at ¶ 0067. Regarding claim 6, HUANG-FU discloses: A User Equipment (UE), comprising: (UE 101/102) a protocol data unit (PDU) session handling circuit (processing circuitry 610) that maintains a PDU session (PDU session 210) in a 5G mobile communication network, (fifth generation system (5GS) 152) (¶¶ 0012, 0049: PDU session 210 being maintained) wherein the PDU session is associated with at least one of a PDU session ID; (¶ 0032: [D]uring PDN connection establishment, the UE 101 allocates a PDU session ID and sends the PDU session ID to the SMF 123) an intersystem change handling circuit (processing circuitry 610) that performs a first intersystem change (first session switch process 231) from N1 mode to S1 mode, (¶ 0049: [A]n inter-system change from N1 mode to S1 mode takes place; ¶ 0061: Upon inter-system change of the UE 102 from N1 mode to S1 mode takes place) wherein the PDU session in 5G is mapped to a packet data network (PDN) connection (PDN connection 220) in 4G; (evolved packet system (EPS) 151) (¶ 0041: [M]apping relationship 200 between a PDU session 210 in the 5GS 152 and a PDN connection 220 in the EPS 151 when inter-system changes between N1 mode and S1 mode take place; ¶ 0074: [A] PDU session in the 5GS 152 is transferred to the PDN connection at [S510] as a result of an inter-system change from the 5GS 152 to the EPS 151) a control circuit (processing circuitry 610) that associates the at least one of the PDU session pair ID and the RSN to a default EPS bearer context of the PDN connection corresponding to the PDU session after the first intersystem change; and (¶ 0035: [T]he corresponding default EPS bearer context . . . has an association with 5G QoS parameters after an inter-system change from N1 mode to S1 mode ([i.e.], has an association with one or more QoS flows defined by the corresponding 5G QoS parameters). The 5G QoS parameters can include a PDU session identity; ¶ 0064: [A]t the end of the first session switch process 231, the UE 101 can associate an identity of the PDU session 210 with the default EPS bearer context 223) the intersystem change handling circuit that performs a second intersystem change (second session switch process 232) from S1 mode to N1 mode, (¶ 0064: Upon inter-system change of the UE 101 from S1 mode to N1 mode takes place; ¶ 0076: At S530, an inter-system change from S1 mode to N1 mode can be initiated) wherein the PDN connection is mapped to the PDU session, and (¶ 0041: [M]apping relationship 200 between a PDU session 210 in the 5GS 152 and a PDN connection 220 in the EPS 151 when inter-system changes between N1 mode and S1 mode take place; ¶ 0064: [S]econd session switch process 232 can be performed to switch the PDN connection 220 in the EPS 151 to the PDU session 210 in the 5GS 152) wherein the control circuit associates the PDU session ID to the PDU session corresponding to the PDN connection after the second intersystem change. (¶ 0064: [A]t the end of the second session switch process 232, the UE 102 can associate the EBIs [EPS bearer identities], the QoS parameters . . . with the respective QoS flows 221-223 in the PDU session 210. The associations are stored at the UE 102; ¶ 0035: [T]he corresponding default EPS bearer context . . . has an association with [a PDU session identity] after an inter-system change from N1 mode to S1 mode) HUANG-FU does not explicitly disclose: at least one of a PDU session pair ID and a redundancy sequence number (RSN). In the same field of endeavor, however, KIM ‘788 teaches: a PDU session pair ID and a redundancy sequence number (RSN). (Abstract: [A] first redundancy sequence number (RSN) which is allocated by the first SMF node for managing a first PDU session and an identifier of the first PDU session; transmitting, to a second SMF node for managing a second PDU session, a second message including the first RSN and a PDU session pair ID, which is identical to the identifier of the first PDU session; ¶ 0282: [A network function] selects the value of Redundancy Sequence Number (RSN) to indicate to NG-RAN that redundant user plane resources shall be provided for the given PDU sessions by means of dual connectivity. Based on the RSN and RAN configuration, the NG-RAN sets up dual connectivity so that the sessions have end to end redundant paths) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s PDU session ID to provide a PDU Session pair ID and a redundancy sequence number (RSN) as taught by KIM ‘788 to provide an indication that the second PDU session may be a duplication of the first PDU session, so that when two redundant PDU sessions are handled via different network functions, each knows the PDU session ID which is handled by the other. See KIM ‘788, at ¶ 0068. The Examiner finds that one of ordinary skill in the art would have appreciated that KIM ‘788’s RSN or session airing identifier is merely a refinement of HUANG-FU’s generic PDU session identity, serving the same stated purpose of correlating session contexts across network transitions. Applying an explicit identifier to conventional inter-system change procedures would have been an obvious design choice to improve procedures for persisting identifiers across disjoint paths in support of highly reliable communication services. See KIM ‘788, at ¶¶ 0067 and 0280. Claims 3 and 8 are rejected under 35 U.S.C. § 103 as being unpatentable over HUANG-FU in view of KIM ‘788, as applied above to claims 2 and 7, respectively, and further in view of 2022/0053390 (hereinafter, “KIM ‘390”). Regarding claim 3 and claim 8, the combination of HUANG-FU and KIM ‘788 as applied herein renders obvious the method of claim 2 and the UE of claim 7, respectively. HUANG-FU in view of KIM ‘788 does not explicitly disclose: wherein the PDU session establishment request message comprises the at least one of the PDU session pair ID and the RSN. In the same field of endeavor, however, KIM ‘390 teaches: wherein the PDU session establishment request message comprises the at least one of the PDU session pair ID and the RSN. (¶ 0270: PDU Session Establishment Request message may include information related to RSN (e.g., RSN #1) and/or PDU session ID) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s UE-initiated PDU session establishment process to provide for a UE Requested PDU Session Establishment procedure as taught by KIM ‘390 to provide a PDU session pair ID and an RSN, so as to provide a “remapping allowed indication” indicating that the RAN node can change mapping relationship between the RSN and PDU session ID for MCG and SCG bearer. See KIM ‘390, at ¶ 0270. Claims 4 and 9 are rejected under 35 U.S.C. § 103 as being unpatentable over HUANG-FU in view of KIM ‘788 and KIM ‘390, as applied above to claims 3 and 8, respectively, and further in view of MediaTek et al., “Correction to 5GSM/ESM Coordination,” 3GPP TSG-CT WG1 Meeting #111bis; C1-184422 (hereinafter, “MediaTek”) (a copy of which was submitted by Applicant with the IDS dated 6 Sept. 2023). Regarding claim 4, the combination of HUANG-FU, KIM ‘788, and KIM ‘390, renders obvious the method of claim 3. HUANG-FU does not explicitly disclose: wherein the UE associates the at least one of the PDU session pair ID and the RSN provided by the UE in the PDU session establishment request message to the PDU session. In the same field of endeavor, however, MediaTek discloses: wherein the UE associates the at least one of the PDU session pair ID and the RSN provided by the UE in the PDU session establishment request message to the PDU session. (Summary of Change: 1. For the UE in N1 mode, interworking to EPS is supported for a PDU session, if the context includes the mapped EPS bearer(s) or has association(s) between QoS flow and mapped EPS bearer. 2. For the UE in S1 mode, interworking to 5GS is supported for a PDN connection, if the corresponding default EPS bearer context includes parameters for 5GS included in (e)PCO IE, or the default EPS bearer context has association with 5GS parameters) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify HUANG-FU’s UE-initiated PDU session establishment process to provide for a UE Requested PDU Session Establishment procedure as taught by MediaTek to provide associating a PDU session pair ID and an RSN to a PDU session, so as to provide an “[A]ssociation between source and target system is made after previous intersystem change.” See MediaTek, at Reason for Change. Conclusion The prior art made of record and not relied upon is considered pertinent to Applicant's disclosure. In particular, non-patent literature, “Correction on Redundant PDU Session,” 3GPP TSG-SA WG2 Meeting #146; S2-2105572 (hereinafter, “NPL”) (a copy of which was submitted by Applicant with the IDS dated 29 Aug. 2025). For example, NPL discloses that a “UE initiates two redundant PDU Sessions and may provide PDU Session Pair ID (optional) and the RSN (optional).” See p. 4., § 5.33.2.1. NPL further discloses that the “PDU Session Pair ID identifies the two redundant PDU sessions that belong together. The value of the RSN parameter and the PDU Session Pair ID indicates redundant user plane requirements for the PDU Sessions.” Id. NPL further discloses that the RSNs and PDU Session Pair IDs “denote the two traffic are redundant with each other.” See p. 3, § 5.33.2.1. NPL further discloses that the RSNs and PDU Session Pair IDs “ensure appropriate PDU session handling ensures fully redundant user plane path.” See p. 2, § 5.11.1. Thus, the Examiner finds that these sections of NPL are relevant to at least the claimed limitation, “wherein the PDU session is associated with at least one of a PDU session pair ID and a redundancy sequence number (RSN).” Any inquiry concerning this communication or earlier communications from the Examiner should be directed to Garth D Richmond whose telephone number is (703)756-4559. The Examiner can normally be reached M-F 8 a.m. - 5 p.m. ET. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, Applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the Examiner’s supervisor, Kathy Wang-Hurst can be reached at 571-270-5371. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /GARTH D RICHMOND/Examiner, Art Unit 2644 /KATHY W WANG-HURST/Supervisory Patent Examiner, Art Unit 2644
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Prosecution Timeline

Dec 23, 2022
Application Filed
Oct 28, 2024
Non-Final Rejection — §103
Jan 28, 2025
Response Filed
Mar 16, 2025
Final Rejection — §103
Jun 12, 2025
Interview Requested
Jun 18, 2025
Applicant Interview (Telephonic)
Jun 26, 2025
Examiner Interview Summary
Jul 21, 2025
Notice of Allowance
Jul 30, 2025
Response after Non-Final Action
Sep 22, 2025
Response after Non-Final Action
Sep 22, 2025
Response after Non-Final Action
Oct 03, 2025
Response after Non-Final Action
Oct 07, 2025
Response after Non-Final Action
Oct 24, 2025
Response after Non-Final Action
Dec 10, 2025
Response after Non-Final Action
Jan 13, 2026
Non-Final Rejection — §103 (current)

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Expected OA Rounds
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99%
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