Prosecution Insights
Last updated: April 19, 2026
Application No. 18/325,802

DISTRIBUTED UNIT ARCHITECTURE FOR INCREASING VRAN RESILIENCE

Final Rejection §102
Filed
May 30, 2023
Examiner
KIM, CHONG G
Art Unit
2443
Tech Center
2400 — Computer Networks
Assignee
Microsoft Technology Licensing, LLC
OA Round
2 (Final)
83%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
87%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
352 granted / 424 resolved
+25.0% vs TC avg
Minimal +4% lift
Without
With
+4.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
44 currently pending
Career history
468
Total Applications
across all art units

Statute-Specific Performance

§101
12.0%
-28.0% vs TC avg
§103
35.8%
-4.2% vs TC avg
§102
36.3%
-3.7% vs TC avg
§112
12.2%
-27.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 424 resolved cases

Office Action

§102
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 . Response to Amendment The Amendment filed on 1/8/2026 has been entered. Claims 1, 4-12, 19 and 21-29 remain pending in the application. Applicant’s amendments to Claims have overcome the 112(b) rejection previously set forth in the Non-Final Office Action mailed on 1/8/2026. Response to Arguments Applicant’s arguments on pages 9-10 with respect to claims 1 and 19 have been considered but are moot upon a further consideration and a new ground of rejection made under 35 U.S.C. 102(a)(2) as being anticipated by Kwon (US PGPub 2023/0189077). Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claims 1, 4-12, 19 and 21-29 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Kwon (US PGPub 2023/0189077). Regarding claims 1 and 19, Kwon teaches in a telecommunications environment including a plurality of distributed units and a centralized unit on a virtualized radio access network, a method for increasing resilience in the virtualized radio access network (Kwon, see abstract, A method of communication by a radio access network device including a distributed unit (DU) may include obtaining information about resource usage of a first DU executed through a first server by a scaling controller, selecting a second DU based on the information about the resource usage of the first DU by the scaling controller), the method comprising: establishing, by a middlebox entity, a first stream control transmission protocol (SCTP) connection between the centralized unit and a first distributed unit of the plurality of distributed units (Kwon, see figure 3B and paragraphs 0048 and 0050, an F1 splitter 311 [corresponding to a middlebox entity] decoupling the at least one DU 320 a and 320 b and the CU 310. Kwon fails to expressly teach that CU is establishing a SCTP connection with the source DU via the F1 splitter, but Kwon teaches that the F1 splitter 311 provides the decoupling function between the CU 310 and the DU 320 a or 320 b, referring to the 3GPP F1 interface standard. 3GPP TS reveals that F1 interface, connecting the gNB-CU and gNB-DU, utilizes Stream Control Transmission Protocol (SCTP) over IP for reliable signaling transport. Therefore, Kwon embeds that the connection between the CU and the source DU by the F1 Splitter is an SCTP connection), the first SCTP connection being an active connection by which fronthaul traffic is routed to the centralized unit via the first distributed unit (Kwon, see paragraph 0060, in the radio access network device, as an operation of the scaling controller (312 of FIG. 3B0 , information about the resource usage of the first DU (source DU, 320 a of FIG. 3B) executed through the first server may be obtained from the first DU 320 a); establishing, by the middlebox entity, a second SCTP connection between the centralized unit and a second distributed unit of the plurality of distributed units (Kwon, see figure 3B and paragraph 0070, the F1 splitter 311 may create a new stream control transmission protocol (SCTP) communication session with the target DU 320 b), the second SCTP conection being an inactive connection (Kwon, see figure 3C, the uplink/downlink of the data flow is transmitted between the RU, the source DU, F1 Splitter and the CU, so the SCTP connection between the target DU, F1 Splitter and the CU is inactive), wherein the middlebox entity is implemented on a server device positioned between the first distributed unit and the centralized unit and between the second distributed unit and the centralized unit (Kwon, see figure 3B and paragraph 0050, the F1 splitter 311 provides the decoupling function between the CU 310 and the DU 320 a or 320 b. The F1 splitter 311 may be a standalone component or be a component included in the CU 310); detecting, by the middlebox entity, a failure condition of the first distributed unit (Kwon, see paragraphs 0058 and 0060, as an operation of the scaling controller (312 of FIG. 3B0 , information about the resource usage of the first DU (source DU, 320 a of FIG. 3B) executed through the first server may be obtained from the first DU 320 a. in the source DU 320 a, at least one event for scaling out may be detected, and in response to the detected event, the target DU 320 b for scaling out may be generated (or designated). Here, the event may indicate that the ratio of the currently used resource to the overall resource available to the source DU 320 a (or the server for driving the source DU 320 a) is a threshold ratio or more); and in response to detecting the failure condition of the first distributed unit, activating the second SCTP connection and causing fronthaul traffic to be routed to the centralized unit via the second distributed unit (Kwon, see paragraph 0060, The scaling controller 312 may select (403) the second DU (target DU, 320 b of FIG. 3B) based on the information about the resource usage of the first DU 320 a by 312 of FIG. 3B. The second RU (e.g., 330 b and/or 330 c of FIG. 3B) to be migrated to the second DU (e.g., 320 b of FIG. 3B) may be selected (405) from among the first RUs (e.g., 330 a, 330 b, and 330 c of FIG. 3B) which are processing the service of the first DU 320 a by the scaling controller 312). Regarding claims 4 and 21, Kwon teaches wherein the first distributed unit is implemented on a first server device of an edge network (Kwon, see figure 2A and paragraph 0037, the CU 222 (or virtual CU) and at least one DU 221 (or virtual DU) may be configured to be distributed in the central office 220 or cloud environment (e.g., a cloud data center) and be connected via a fronthaul (FH) 223, saving the overall operation cost. At least one DU 221 may correspond to (or be connected to) one CU 222), and wherein the second distributed unit is implemented on a second server device of the edge network (Kwon, see paragraph 0039, For the execution of each dedicated DU, the network device must allocate (or execute) a server (e.g., a VM or a container) for each dedicated DU). Regarding claims 5 and 22, Kwon teaches wherein the first distributed unit is implemented on a first server device of a first edge network in communication with a radio unit (Kwon, see figure 2A and paragraph 0037, the CU 222 (or virtual CU) and at least one DU 221 (or virtual DU) may be configured to be distributed in the central office 220 or cloud environment (e.g., a cloud data center) and be connected via a fronthaul (FH) 223, saving the overall operation cost. At least one DU 221 may correspond to (or be connected to) one CU 222), and wherein the second distributed unit is implemented on a second server device of a second edge network in communication with the radio unit (Kwon, see paragraph 0039, For the execution of each dedicated DU, the network device must allocate (or execute) a server (e.g., a VM or a container) for each dedicated DU). Regarding claims 6 and 29, Kwon teaches wherein each of the first edge network and the second edge network is serviced by the centralized unit (Kwon, see figure 3A and paragraph 0046, the base station may be divided into a three-tier structure, so that the RRC, SDAP, and PDCP may be classified as CUs, RLC, MAC, and high PHY as DUs, and low PHY as an RU. Specifically, midhaul channels may be positioned between the CU 310 and the DU 320, and fronthaul channels may be positioned between the DU 320 and the RU 330). Regarding claims 7 and 23, Kwon teaches wherein detecting the failure condition includes causing an agent of the first distributed unit to periodically communicate a status message to the middlebox entity (Kwon, see paragraphs 0058 and 0060, as an operation of the scaling controller (312 of FIG. 3B0 , information about the resource usage of the first DU (source DU, 320 a of FIG. 3B) executed through the first server may be obtained from the first DU 320 a. in the source DU 320 a, at least one event for scaling out may be detected, and in response to the detected event, the target DU 320 b for scaling out may be generated (or designated). Here, the event may indicate that the ratio of the currently used resource to the overall resource available to the source DU 320 a (or the server for driving the source DU 320 a) is a threshold ratio or more). Regarding claims 8 and 24, Kwon teaches wherein detecting the failure condition includes causing an Ethernet switch positioned between the first distributed unit and a radio unit to communicate to the middlebox entity that a threshold period of time has passed without detecting a communication between the Ethernet switch and the first distributed unit (Kwon, see paragraphs 0058 and 0060, as an operation of the scaling controller (312 of FIG. 3B0 , information about the resource usage of the first DU (source DU, 320 a of FIG. 3B) executed through the first server may be obtained from the first DU 320 a. in the source DU 320 a, at least one event for scaling out may be detected, and in response to the detected event, the target DU 320 b for scaling out may be generated (or designated). Here, the event may indicate that the ratio of the currently used resource to the overall resource available to the source DU 320 a (or the server for driving the source DU 320 a) is a threshold ratio or more). Regarding claims 9 and 25, Kwon teaches further comprising: configuring the second distributed unit to run on a low power mode prior to detecting the failure condition (Kwon, see paragraph 0060, The scaling controller 312 may select (403) the second DU (target DU, 320 b of FIG. 3B) based on the information about the resource usage of the first DU 320 a by 312 of FIG. 3B. The second RU (e.g., 330 b and/or 330 c of FIG. 3B) to be migrated to the second DU (e.g., 320 b of FIG. 3B) may be selected (405) from among the first RUs (e.g., 330 a, 330 b, and 330 c of FIG. 3B) which are processing the service of the first DU 320 a by the scaling controller 312); and in response to detecting the failure condition of the first distributed unit, causing the second distributed unit to run in an operational mode (Kwon, see paragraph 0060, The scaling controller 312 may select (403) the second DU (target DU, 320 b of FIG. 3B) based on the information about the resource usage of the first DU 320 a by 312 of FIG. 3B. The second RU (e.g., 330 b and/or 330 c of FIG. 3B) to be migrated to the second DU (e.g., 320 b of FIG. 3B) may be selected (405) from among the first RUs (e.g., 330 a, 330 b, and 330 c of FIG. 3B) which are processing the service of the first DU 320 a by the scaling controller 312). Regarding claims 10 and 26, Kwon teaches wherein activating the second SCTP connection includes providing one or more configuration parameters to the second distributed unit including instructions executable by the second distributed unit to engage in an operational mode that corresponds to the first distributed unit prior to the failure condition (Kwon, see figure 3B and paragraph 0070, the F1 splitter 311 may create a new stream control transmission protocol (SCTP) communication session with the target DU 320 b). Regarding claims 11 and 27, Kwon teaches wherein the middlebox entity is a network function implemented in the virtualized radio access network of a 5G telecommunications network (Kwon, see figure 3B and paragraphs 0048 and 0050, an F1 splitter 311 [corresponding to a middlebox entity] decoupling the at least one DU 320 a and 320 b and the CU 310). Regarding claim 12 and 28, Kwon teaches further comprising, in response to detecting the failure condition, sending a shutdown signal to the centralized unit to clear a state of the first distributed unit (Kwon, see paragraph 0060, The scaling controller 312 may select (403) the second DU (target DU, 320 b of FIG. 3B) based on the information about the resource usage of the first DU 320 a by 312 of FIG. 3B. The second RU (e.g., 330 b and/or 330 c of FIG. 3B) to be migrated to the second DU (e.g., 320 b of FIG. 3B) may be selected (405) from among the first RUs (e.g., 330 a, 330 b, and 330 c of FIG. 3B) which are processing the service of the first DU 320 a by the scaling controller 312). Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHONG G KIM whose telephone number is (571)270-0619. The examiner can normally be reached Mon-Fri @ 9am - 5pm. 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, Nicholas R. Taylor can be reached at 571-272-3889. 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. /CHONG G KIM/Examiner, Art Unit 2443 /NICHOLAS R TAYLOR/Supervisory Patent Examiner, Art Unit 2443
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Prosecution Timeline

May 30, 2023
Application Filed
Oct 04, 2025
Non-Final Rejection — §102
Dec 17, 2025
Interview Requested
Jan 02, 2026
Examiner Interview Summary
Jan 02, 2026
Applicant Interview (Telephonic)
Jan 08, 2026
Response Filed
Jan 29, 2026
Final Rejection — §102 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
83%
Grant Probability
87%
With Interview (+4.2%)
2y 11m
Median Time to Grant
Moderate
PTA Risk
Based on 424 resolved cases by this examiner. Grant probability derived from career allow rate.

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