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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08/09/2024 was filed after the mailing date. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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, 6, 7, 9, 14, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Kim (US 2024/0129870 A1) in view of Nam (US 2023/0093595 A1).
Regarding claim 1, Kim discloses: A method performed by a base station (BS) in a wireless communication system, the method comprising: performing a beam search using at least one base station beam through a backhaul link between the base station and a reconfigurable intelligent surface (RIS), because Kim teaches selects serving beams through a beam search or beam management procedure (i.e., “performing a beam search using at least one base station beam” as claimed) in a beamforming environment in which beams are reflected on an RIS connected to the base station, where the base station transmits signals to the RIS over a wired or wireless connection between them (i.e., “through a backhaul link between the base station and a reconfigurable intelligent surface (RIS)” as claimed) (Kim, para [0036] “ , ... , SSB N through a beam search or beam management procedure” … para [0037] “The RIS 130 may be connected with the base station 110. For example, the RIS 130 may be wiredly connected with the base station 110. In addition, the RIS 130 may be wirelessly connected with the base station 110.”).
Moreover, Kim discloses: performing the beam search using a plurality of RIS beams for each of the at least one base station beam on the backhaul link when the RIS is set to a multi-beam mode, since Kim teaches controls the RIS reflection pattern to perform RIS beam sweeping (i.e., “performing the beam search using a plurality of RIS beams” as claimed) by transmitting, for a given base station beam, one or more SSBs mapped onto at least one RIS beam corresponding to a sequence of specific reflection patterns (i.e., “a plurality of RIS beams for each of the at least one base station beam” as claimed) the base station knows in advance, so that the RIS sweeps over a plurality of reflection patterns / RIS beams (i.e., “when the RIS is set to a multi-beam mode” as claimed) (Kim, para [0097] “The base station may control the RIS reflection pattern to perform RIS beam sweeping. For example, the base station may already know specific reflection pattern information to apply at each time, and may transmit, to the terminal, one or more SSBs mapped onto at least one RIS beam corresponding to the specific reflection pattern.” … para [0041] “The base station may perform beam sweeping by using at least one RIS pattern in order to efficiently transmit and receive signals by consid ering a beam direction or beamforming.”).
With respect to claim 1, although Kim teaches a base station that selects serving beams through a beam search over an RIS connected to it and controls the RIS reflection pattern to perform RIS beam sweeping over a plurality of reflection patterns mapped to RIS beams for a base station beam: (Kim, para. [0036], [0037], [0041], [0097]), Kim does not explicitly disclose fixing the selected backhaul base-station-to-RIS beam and operating the RIS in a single-beam mode on the access link once the backhaul beam search is finished, for which Nam is relied upon:
Yet, Kim in view of Nam discloses setting the RIS to a single-beam mode on an access link when the beam search of the backhaul link is completed because after the base station has swept the beam directed toward the RIS and selected a single fixed beam directed toward the RIS, that single second SSB is transmitted on the same fixed beam direction toward the RIS and the RIS controller is configured for a single desired reflection state (a single reflection angle) to serve a UE, so the RIS reflects only the one fixed selected backhaul beam (i.e., “a single-beam mode on an access link” as claimed) rather than continuing to sweep, which reads on a single-beam mode attached to the single fixed backhaul beam once the backhaul search is complete (Nam, para [0089], “the base station 110 may transmit the second SSB associated with direct transmission from the base station 110 at the second power on the same beam (e.g., in the same beam direction) as the first SSBs associated with the RIS 605. For example, the base station 110 may transmit the second SSB in the beam direction toward the RIS 605” … para [0077], “The RIS control message may indicate, to the RIS controller 310, a configu ration of the RIS 305 for a desired state (e .g., reflection angle) that enables the data reflected and/or redirected by the RIS 305 to be reliably received by UE 2.”).
Moreover, Nam discloses performing a beam search of the access link by fixing beam information of the backhaul link because once the base-station-to-RIS beam is fixed in a single beam direction toward the RIS, the RIS controller is configured with the fixed reflection state and the base station then conducts SSB beam sweeping toward UEs to select the beams used for communication between the base station and the UE, i.e., it performs the access-link beam search while holding the backhaul beam information fixed (Nam, para [0080], “The base station 110 and the UE 120 may use the one or more indicated SSBs to select one or more beams to be used for communication between the base station and the UE” … para [0077], “the base station 110 may indicate, in an RIS control message, spatial direction(s) and/or signal characteristics for signals reflected by the RIS 305. The RIS controller 310 may configure reconfigurable elements of the RIS 305 in accordance with the RIS control message.”).
Accordingly, it would have been obvious to one of ordinary skill in the art to apply Nam's scheme of fixing the base-station-to-RIS beam direction and configuring the RIS for a single desired reflection state to serve a UE once the backhaul beam has been selected, to Kim's base station that sweeps a plurality of RIS reflection patterns to search the backhaul beam, because both references manage RIS-assisted beams over a base station to RIS link followed by service to a UE, and using the single fixed backhaul beam while sweeping for the access beam predictably reduces signaling and complexity by not re-sweeping the already-resolved backhaul link.
Regarding claim 6, in spite of the fact that Kim in view of Nam teaches the base station performs the RIS backhaul beam search with multi-beam RIS sweeping, then fixes the backhaul beam and sets the RIS to a single-beam mode for the access-link beam search: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]), Kim in view of Nam does not explicitly disclose fixing the backhaul-link beam and setting the RIS to the single-beam mode while the base station performs the access-link beam search, for which Nam is relied upon:
Yet, Kim in view of Nam discloses The method of claim 1, wherein when the base station performs the beam search for the access link, a beam of the backhaul link is fixed and the RIS is set to the single-beam mode because the base station transmits the access SSB on the same fixed beam directed toward the RIS while the RIS controller is configured for a single desired reflection state, so during the access-link search the backhaul beam is held fixed and the RIS reflects only that one selected beam (single-beam mode) (Nam, para [0089], “the base station 110 may transmit the second SSB associated with direct transmission from the base station 110 at the second power on the same beam (e.g., in the same beam direction) as the first SSBs associated with the RIS 605. For example, the base station 110 may transmit the second SSB in the beam direction toward the RIS 605” … para [0077], “The RIS control message may indicate, to the RIS controller 310, a configu ration of the RIS 305 for a desired state (e .g., reflection angle) that enables the data reflected and/or redirected by the RIS 305 to be reliably received by UE 2.”).
Accordingly, it would have been obvious to one of ordinary skill in the art to fix the backhaul beam and place the RIS in a single reflection state during the access-link search as taught by Nam, in Kim's RIS sweeping system, because re-using the already-resolved backhaul beam while searching the access link predictably avoids redundant backhaul sweeping and simplifies the procedure.
Regarding claim 7, even though Kim in view of Nam teaches during the access-link search the base station fixes the backhaul beam and sets the RIS to the single-beam mode as in claim 6: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]), Kim in view of Nam does not explicitly disclose setting the plurality of RIS beams based on the backhaul beam information and searching the access link while changing the ID of each RIS beam, for which Nam is relied upon:
Yet, Kim in view of Nam discloses The method of claim 6, wherein when the beam search for the access link is performed, the plurality of RIS beams are set on the basis of the beam information of the backhaul link, and the beam search of the access link is performed while changing an ID of each of the plurality of RIS beams because with the base-station-to-RIS beam fixed, the RIS performs SSB beam sweeping on behalf of the base station by changing its reflection state for each SSB to redirect the SSBs at different reflection angles, and each such SSB carries a distinct SSB index corresponding to a beam, so the RIS beams are derived from the fixed backhaul beam and the access search advances by changing the per-SSB beam index/ID (Nam, para [0088], “The RIS 605 may receive the first SSBs transmitted by the base station 110, and the RIS 605 may redirect (or reflect) the first SSBs at different reflection angles to perform beam sweeping using the first SSBs. For example, the RIS 605 may change a reflection state of the RIS 605 for each first SSB” … para [0080], “the SSB index may correspond to a beam used to carry the SSB”).
Thus, it would have been obvious to one of ordinary skill in the art to have the RIS derive its sweep beams from the fixed backhaul beam and step through them by per-SSB index as taught by Nam, in Kim's RIS-assisted system, because indexing each redirected SSB lets the UE report the best beam and the base station resolve the access beam predictably and with low signaling overhead.
Regarding claim 9, the claim recites: A base station (BS) in a wireless communication system, the base station comprising: a transceiver; and a controller operably connected to the transceiver, wherein the controller is configured to perform a beam search using at least one base station beam through a backhaul link between the base station and a reconfigurable intelligent surface (RIS), perform the beam search using a plurality of RIS beams for each of the at least one base station beam on the backhaul link when the RIS is set to a multi-beam mode, set the RIS to a single-beam mode on an access link when the beam search of the backhaul link is completed, and perform a beam search of the access link by fixing beam information of the backhaul link. Claim 9 is analogous to claim 1 and is rejected for the same reasons.
Regarding claim 14, the claim recites: The base station of claim 9, wherein when the base station performs the beam search for the access link, a beam of the backhaul link is fixed and the RIS is set to the single-beam mode. Claim 14 is analogous to claim 6 and is rejected for the same reasons.
Regarding claim 15, the claim recites: The base station of claim 14, wherein when the beam search for the access link is performed, the plurality of RIS beams are set on the basis of the beam information of the backhaul link, and the beam search of the access link is performed while changing an ID of each of the plurality of RIS beams. Claim 15 is analogous to claim 7 and is rejected for the same reasons.
Claims 2, 3, 10, and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Kim (US 2024/0129870 A1) in view of Nam (US 2023/0093595 A1) and further in view of Li (US 2020/0366363 A1)
Regarding claim 2, in spite of the fact that Kim in view of Nam teaches the base station performs a backhaul beam search over the RIS with multi-beam RIS sweeping and fixes the backhaul beam to perform an access-link search with the RIS set to a single-beam mode: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]), Kim in view of Nam does not explicitly disclose reusing the control-link beam on the backhaul link when the control link and backhaul link share, or fall within, the same frequency band, for which Li is relied upon:
Yet, Kim in view of Nam and further in view of Li discloses The method of claim 1, wherein when a frequency band used on a control link of the RIS is the same as a frequency band of the backhaul link or is included in the frequency band of the backhaul link, a beam used on the control link is used in the same manner on the backhaul link because the control information and the backhaul data are carried over a control link and an indirect/backhaul link respectively, and when the first resource set (control) and the second resource set (backhaul) are over a same frequency band the repeater relays a signal using the same frequency with which it is received without a frequency shift, so the same beam/resource set used on the control link applies in the same manner on the backhaul link when the bands coincide (Li, para [0095], “the first set of resources and the second set of resources are over a same frequency band. In this case, the repeater 140 may relay a signal using a same frequency with which the signal is received (e .g., without applying a frequency shift or a frequency offset).” … para [0063], “an antenna array 310 may be used to transfer data between the millimeter wave repeater 300 and the base station 110, and the communication component 340 may be used to transfer control information between the millimeter wave repeater 300 and the base station 110”).
Thus, it would have been obvious to one of ordinary skill in the art to incorporate Li's teaching that a control link and a backhaul link sharing a common frequency band can relay using the same frequency without a frequency shift into the Kim-Nam RIS backhaul scheme, because a PHOSITA managing an RIS that has a separate control link and a backhaul link would recognize that when the two occupy the same band the same beam can be reused on both, conserving signaling and simplifying beam configuration.
Regarding claim 3, although Kim in view of Nam teaches the base station performs a backhaul beam search over the RIS with multi-beam RIS sweeping and fixes the backhaul beam to perform an access-link search with the RIS set to a single-beam mode: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]), Kim in view of Nam does not explicitly disclose performing the backhaul beam search in cooperation with a UE when the RIS control-link band differs from, or is not within, the backhaul link band, for which Li is relied upon:
Yet, Kim in view of Nam and further in view of Li discloses The method of claim 1, wherein when a frequency band used on a control link of the RIS is different from a frequency band of the backhaul link or is not included in the backhaul link, the beam search of the backhaul link is performed in cooperation with a user equipment (UE) because the control information is carried on a separate lower-frequency control interface while data on the backhaul link uses a higher-frequency millimeter wave array, so the two links occupy different bands; in that situation the base station identifies the backhaul (first) beam pair by measuring uplink reference signals that the UE transmits and the repeater relays, i.e., the backhaul beam search is carried out with the cooperation of the UE rather than from the control link alone (Li, para [0063], “In some aspects, the communication component 340 may use a lower frequency communication technology, and an antenna array 310 may use a higher frequency commu nication technology (e.g., millimeter wave and/or the like).” … para [0113], “a measurement by the base station 110 in a resource may correspond to a reference signal transmitted by the UE 120 to the repeater 140 via a first beam pair and relayed by the repeater 140 to the base station 110 via a second beam pair. Thus, by identifying a resource corre sponding to the best measurement ( e.g., among multiple measurements performed by the base station 110), the base station”).
Consequently, it would have been obvious to one of ordinary skill in the art to adopt Li's UE-relayed measurement of the backhaul beam pair, used where the control interface operates on a lower frequency than the millimeter-wave backhaul array, in the Kim-Nam RIS system, because when the RIS control link and the backhaul link occupy different bands the control-link beam cannot be reused for the backhaul and a PHOSITA would predictably fall back on UE-assisted reference-signal measurement to resolve the backhaul beam.
Regarding claim 10, the claim recites: The base station of claim 9, wherein when a frequency band used on a control link of the RIS is the same as a frequency band of the backhaul link or is included in the frequency band of the backhaul link, a beam used on the control link is used in the same manner on the backhaul link. Claim 10 is analogous to claim 2 and is rejected for the same reasons.
Regarding claim 11, the claim recites: The base station of claim 9, wherein when a frequency band used on a control link of the RIS is different from a frequency band of the backhaul link or is not included in the backhaul link, the beam search of the backhaul link is performed in cooperation with a user equipment (UE). Claim 11 is analogous to claim 3 and is rejected for the same reasons.
Claims 4, 5, 12, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kim (US 2024/0129870 A1) in view of Nam (US 2023/0093595 A1) and further in view of Li (US 2020/0366363 A1) and further in view of Choi (US 2024/0162968 A1)
Regarding claim 4, in spite of the fact that Kim in view of Nam and further in view of Li teaches the base station, with control-link and backhaul-link beams aligned over a shared frequency band, performs the RIS backhaul and access beam searches as in claim 2: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]; Li, para. [0063], [0095]), Kim in view of Nam and further in view of Li does not explicitly disclose maintaining the existing backhaul beam without beam failure recovery when beam failure is detected at the UE but not at the RIS controller, for which Choi is relied upon:
Yet, Kim in view of Nam and further in view of Li and further in view of Choi discloses The method of claim 2, wherein when beam failure detection (BFD) occurs at a user equipment, but BFD does not occur at an RIS controller included in the RIS, an existing beam is still used on the backhaul link and beam failure recovery (BFR) is not performed because beam failure handling is path-specific: when a communication problem (beam failure) occurs on a particular UE-facing beam pair the controller recovers only by selecting a replacement beam for that path, and where the directly served beams remain above the threshold the reflective/RIS path beams are left undisturbed, so a failure observed at the UE that does not implicate the RIS-side beam leaves the existing RIS path beam in use without triggering recovery on it (Choi, para [0085], “when a communication problem (CP) CPl and CP2 occurs (when a beam has a low measured RSRP value) in a specific beam pair Bla-Blc and B2a-B2c, the BS controller may measure the RSRP of a beam Blb and Blc included in the SSB to which the main beam Bla belongs” … para [0094], “the BS controller may measure the RSRP of each beam, and may preferen tially select a beam included in the direct path when some of measured RSRP values exceed a predetermined threshold R_TH.”).
For these reasons, it would have been obvious to one of ordinary skill in the art to add Choi's path-specific beam failure handling, which recovers only the failed beam path and leaves still-acceptable paths in place, to the Kim-Nam-Li RIS backhaul system, because distinguishing a failure on the UE side from a failure on the RIS side lets the base station avoid needless re-sweeping of a healthy backhaul link, a predictable efficiency benefit.
Regarding claim 5, even though Kim in view of Nam and further in view of Li teaches the base station, with control-link and backhaul-link beams aligned over a shared frequency band, performs the RIS backhaul and access beam searches as in claim 2: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]; Li, para. [0063], [0095]), Kim in view of Nam and further in view of Li does not explicitly disclose performing beam failure recovery on the control link and applying the recovered control-link beam information to the backhaul link when failure is detected at both the UE and the RIS controller, for which Choi is relied upon:
Yet, Kim in view of Nam and further in view of Li and further in view of Choi discloses The method of claim 2, wherein when beam failure detection (BFD) occurs at a user equipment and BFD occurs at an RIS controller included in the RIS, beam failure recovery (BFR) is performed for the control link, and beam information of the control link is applied to the backhaul link because when beam failure occurs the controller performs recovery by selecting, from both the SSB to which the main beam belongs and the SSB to which it does not, a replacement beam including beams on the reflective path through the RIS, and the recovered beam is then used for the link through the RIS, i.e., recovery performed over the RIS-related (control) path is applied to the reflective backhaul path (Choi, para [0084], “When beam failure (BF) occurs in the established communication link, the BS controller may select a beam, based on a measured RSRP values from a synchronization signal block (SSB) to which the main beam belongs and an SSB to which the main beam does not belong” … para [0092], “When beam failure of the main beam 510b occurs and the measured RSRP value of each beam included in the direct path and the reflective path for beam failure recovery exceeds a predetermined threshold R_TH, the controller may select a beam 540c even through the beam 540c is included in the reflective path.”).
Therefore, it would have been obvious to one of ordinary skill in the art to use Choi's recovery that selects replacement beams across both direct and RIS reflective paths in the Kim-Nam-Li system, because when both the UE link and the RIS-controlled path fail a PHOSITA would recover the RIS path and reuse that recovered beam information on the backhaul, predictably restoring the indirect link and preventing radio link failure.
Regarding claim 12, the claim recites: The base station of claim 10, wherein when beam failure detection (BFD) occurs at a user equipment, but BFD does not occur at an RIS controller included in the RIS, an existing beam is still used on the backhaul link and beam failure recovery (BFR) is not performed. Claim 12 is analogous to claim 4 and is rejected for the same reasons.
Regarding claim 13, the claim recites: The base station of claim 10, wherein when beam failure detection (BFD) occurs at a user equipment and BFD occurs at an RIS controller included in the RIS, beam failure recovery (BFR) is performed for the control link, and beam information of the control link is applied to the backhaul link. Claim 13 is analogous to claim 5 and is rejected for the same reasons.
Claims 8 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Kim (US 2024/0129870 A1) in view of Nam (US 2023/0093595 A1) and further in view of Goyal (US 2024/0073938 A1)
Regarding claim 8, although Kim in view of Nam teaches the base station performs the RIS backhaul beam search with multi-beam RIS sweeping and the access-link search by fixing the backhaul beam with the RIS in a single-beam mode, as in claim 1: (Kim, para. [0036], [0097]; Nam, para. [0077], [0089]), Kim in view of Nam does not explicitly disclose reporting, from the RIS to the base station at the RIS's initial access, information on the number of RIS beams needed to sweep the entire RIS area, for which Goyal is relied upon:
Yet, Kim in view of Nam and further in view of Goyal discloses The method of claim 1, further comprising transmitting information on the number of the RIS beams required to perform sweeping on an entire RIS area, to the base station when the RIS makes initial access to the base station because before initiating data transmission, the base station establishes with the RIS the set of weight parameters and RIS configuration modes selected to cover an area of target UEs, and the number of RIS candidate beams M generated by reflecting incident signals defines how many beams sweep the RIS-covered area; in setting up this RIS configuration the count of RIS candidate beams needed to cover the target area is exchanged when the RIS is brought into the system, mapping to reporting the number of RIS beams required to sweep the entire RIS area at the RIS's initial access (Goyal, para [0060], “the BS 303 may set, before initiating the data transmission with the UE 301 via the first MS 405, an MS configuration mode for the first RIS 405 for the selection of weight parameters to cover an area of target UEs and transmitting the set RIS configuration mode to the MS controller 413 of the MS 405.” … para [0071], “where iE{ 1, N}, k=(l, 2, ... , M), wherein N is the number of RIS unit cells, M is the number of RIS candidate beams”).
Consequently, it would have been obvious to one of ordinary skill in the art to incorporate Goyal's exchange of the RIS configuration and the number of RIS candidate beams needed to cover the target-UE area into the Kim-Nam RIS backhaul scheme when the RIS is brought online, because the base station that drives the RIS sweep must know how many RIS beams are required to cover the RIS area in order to schedule the sweep, and providing that count at the RIS's initial access predictably enables correct allocation of sweep resources.
Regarding claim 16, the claim recites: The base station of claim 9, wherein the controller is further configured to transmit information on the number of the RIS beams required to perform sweeping on an entire RIS area, to the base station when the RIS makes initial access to the base station. Claim 16 is analogous to claim 8 and is rejected for the same reasons.
Conclusion
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/CHONGSUH PARK/Examiner, Art Unit 2478
/JOSEPH E AVELLINO/Supervisory Patent Examiner, Art Unit
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