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 06/04/2026 has been received and considered by the Examiner. Claims 1, 5-6, 10, 13, and 17 were amended, claims 7-9 and 18 were cancelled, and claims 2-4, 11-12, 14-16, and 19 were previously cancelled. Claims 1, 5-6, 10, 13, 17, and 20 remain pending.
The IDS document submitted on 04/11/2026 has been received and considered by the Examiner.
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.
Response to Arguments
First, the Applicant offers several arguments against the rejection of Claim 1. On pages 9-10 of their remarks, the Applicant writes that “the ‘periodic position of a frame structure’ in Ren only serves as a detection aid for locating synchronization signals, rather than as a temporal reference defining when synchronization information is valid”, adding, “Ren does not disclose or suggest that any such synchronization information is associated with, or defined as being valid at, a reference corresponding to a network-side timing domain” (Remarks, p. 9-10).
However, the Examiner respectfully disagrees with this argument because the cited passages of Ren explicitly describe using the “periodic position of a frame structure” for “downlink timing synchronization” (Ren, 0039). This clearly meets the broadest reasonable interpretation of “determining ... synchronization information with respect to an implicit time reference”, meaning the rejection based on Ren is properly maintained.
Next, on page 10 of their remarks, the Applicant writes that “the claimed implicit time reference is determined without signaling time information”, adding, “Ren does not teach or suggest eliminating signaling of time information or defining a temporal reference for synchronization information without explicit time indication. Instead, Ren relies on predefined frame structures for signal detection” (Remarks, p. 10).
However, this argument is not persuasive because it is self-contradictory. A “predefined frame structure” is not explicit “signaling of time information”. Rather, the position of this frame structure allows a device to infer the location of a subsequent synchronization signal based on a predetermined offset separating them. Thus, by definition, the “predefined frame structure” used for synchronization in Ren 0038-0039 can only signal timing information implicitly, meaning the rejection based on Ren is properly maintained.
Later, on page 10 of their remarks, the Applicant attempts to distinguish between the claimed invention and Xu, writing that “Xu explicitly relies on the signaling of time information” for synchronization, whereas “the claimed invention expressly recites determining synchronization information with respect to an implicit time reference without signaling time information” (Remarks, p. 10).
However, this argument is not persuasive because Xu was not relied upon to address the limitations requiring “an implicit time reference”. Rather, Ren describes both implicit time synchronization using a frame boundary (Ren 0038-0039) and a System Information Block (SIB1) message that configures random access resources (see, for example, paragraphs 0144 and 146 of Ren, among other passages). Ren only lacks an explicit teaching that the SIB boundary itself can implicitly indicate the position of other information, hence the citation of Xu’s description of inferring the position of a system frame number (SFN) based on the location of a SIB’s end boundary (Xu, 0012). In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Next, the Applicant writes on page 12 of their remarks that “Xu employs time indication for synchronization purposes, whereas the claimed invention employs an implicit time reference as a validity anchor for synchronization information” (Remarks, p. 11). However, again, Ren, not Xu, was cited to teach the “implicit time reference”. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
The Applicant then argues against the propriety of combining Ren’s teachings with Xu’s, writing, “the Examiner has not provided an adequate explanation as to why a person of ordinary skill in the art would have modified Ren to adopt the system information window boundary of Xu as a validity reference for synchronization information” and “even if one were to combine Ren and Xu”, the resulting “combination would not yield the claimed feature in which synchronization information is valid at an implicit time reference associated with system information transmission and determined without signaling time information” (Remarks, p. 12-13).
However, the Examiner respectively disagrees with this interpretation of the prior art. Ren describes (i) implicit synchronization in a non-terrestrial network based on a frame boundary (Ren, 0038-0039) and (ii) a SIB used to communicate random access parameters (Ren, 0144, 0146, etc). Xu complements Ren’s teachings by describing using the frame boundary of a SIB to implicitly communicate the position of a SFN (Xu, 0008). Thus, a skilled artisan would recognize that if a SIB boundary can implicitly indicate the position of a SFN, as taught in Xu, the SIB frame boundary in Ren can serve as the “periodic position of a frame structure” that similarly implies the position of a downlink time synchronization signal (Ren, 0038-0039). Thus, the combination of Ren’s and Xu’s teachings is valid, and the rejection is properly maintained.
Next, the Applicant offers several arguments against the rejection of Claim 10. On pages 13-14 of their remarks, the Applicant writes that “Claim 10 requires (i) a feeder link delay at a reference time, (ii) a feeder link delay drift rate at that reference time, and (iii) deriving a feeder link delay at a given time based on an amount of time elapsed from the reference time”, adding that Ren’s “disclosure relating to Doppler shift or relative motion ... does not teach or suggest modeling a feeder link delay as a time-evolving quantity anchored at a reference time and updated using a drift rate and elapsed time” (Remarks, p. 13).
However, the Examiner respectfully disagrees with this reading of Ren. As noted in the Non-Final Rejection dated 03/19/2026, Ren describes maintaining a downlink connection using “a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035). The “residual frequency offset after the initial synchronization” corresponds to “(i) a feeder link delay at a reference time”, the “Doppler frequency offset caused by satellite movement” corresponds to “(ii) a feeder link delay drift rate at that reference time”, and the “sum[ming]” of these terms together to calculate the total Doppler shift corresponds to “(iii) deriving a feeder link delay at a given time based on an amount of time elapsed from the reference time”. Thus, both Ren and the claimed invention involve (i) an initial synchronization value based on the satellite’s starting position, (ii) a further synchronization term required by the satellite’s subsequent movement, and (iii) synchronizing the terminal with the satellite at any given moment based on the combination of these terms. The only difference between Ren and the claimed invention is that Ren expresses the synchronization terms and calculation in terms of frequency, whereas the claimed invention expresses these values in the time domain. However, as noted in past Office Actions, units of time and frequency are two interchangeable ways of describing a signal. A skilled artisan could easily convert between a quantity of seconds (time) and Hertz (frequency) by taking the inverse of the original measurement.
Regarding this last point, the Applicant attempts to argue on page 14 of their Remarks that “Doppler shift and propagation delay are distinct physical quantities associated with different aspects of signal transmission” and that, furthermore, “the Examiner’s apparent position that frequency-domain quantities ... and time-domain quantities ... may be interchangeable does not render the claimed subject matter obvious” because “[t]he claimed invention is directed to a specific time-referenced modeling and update mechanism, not merely to the existence of related physical measurements” (Remarks, p. 14).
However, the Examiner respectfully disagrees with this analysis. A skilled artisan would recognize that Doppler shift and propagation delay are not “associated with different aspects of signal transmission”; rather, they are two equivalent and interchangeable measures of a satellite’s changing position relative to a terminal. This also belies the distinction the Applicant attempts to draw between Ren and the claimed “specific time-referenced modeling and update mechanism” because a skilled artisan would recognize that Ren’s synchronization calculations would become identical to the claimed invention after an elementary mathematical transformation. Thus, the obviousness rejection based on Ren is properly maintained.
Next, on page 14, the Applicant reiterates their earlier argument that “Ren does not disclose or suggest that synchronization-related information is defined as being valid at ... an implicit reference, nor does Ren disclose determining such a reference without signaling time information” (Remarks, p. 14).
However, as stated above in response to arguments against Claim 1, this argument is unpersuasive because it does not comport with Ren’s description of determining “downlink timing synchronization” based on “a periodic position of a frame structure” (Ren, 0038-0039). Thus, the obviousness rejection based on Ren is properly maintained.
The Applicant then attempts to discredit the Examiner’s previous argument that the relationship between Doppler shift and delay is analogous to the relationship between pounds and kilograms, writing, “[p]ounds and kilograms are merely different units of the same scalar quantity and are directly convertible” whereas “Doppler shift and propagation delay are distinct physical quantities associated with different aspects of signal transmission” (Remarks, p. 14-15).
However, the bare facts of this summary are incorrect. Pounds measure weight, and kilograms measure mass, meaning they are clearly related, but not the same. Therefore, although they are not identical, a skilled artisan could easily convert between mass and weight in a normal context, and any disclosure of computations in kilograms would render obvious a similar description using pounds, and vice versa. Similarly, although the Examiner agrees that time and frequency measurements are “distinct physical quantities”, they are, contrary to the Applicant’s assertion, “directly convertible” via an inverse relationship, meaning the analogy remains valid.
To summarize, the Examiner respectfully disagrees with the Applicant’s assertion of an “absence of [the] claimed modeling and update mechanism in Ren” (Remarks, p. 15), and the obviousness rejection based on Ren is properly maintained.
Lastly, the Applicant reapplies an argument made previously against Claim 1 to Claim 10, writing that “Claim 10, as amended, recites that the implicit time reference corresponds to a frame boundary associated with a system information window in which a corresponding system information block (SIB) is transmitted” and that “Ren does not disclose or suggest any such system information transmission context” (Remarks, p. 15). In a further attempt to distinguish this claim limitation from Xu, the Applicant adds that “Xu does not remedy the deficiencies of Ren” because “Xu relies on explicitly signaled time information ... to indicate a moment associated with system information transmission” (Remarks, p. 16).
However, as explained above, the combination of Ren and Xu, not one reference in isolation, renders the claimed invention obvious. Ren describes a SIB and using a frame boundary to implicitly signal timing information, and Xu teaches using the SIB to implicitly indicate the position of other downlink signaling, so these references’ complementary teachings about SIBs would make it obvious to a skilled artisan to make the “periodic position of a frame structure” that implicitly shows the location of timing information in Ren the frame boundary of a SIB, as described in Xu. Thus, the rejection based on Ren in view of Xu is properly maintained.
Finally, because of the parallels between Claim 13 and Claims 1 and 10, the inability of the Applicant’s arguments to distinguish the prior art from Claims 1 and 10 mean they also don’t distinguish Claim 13. Thus, the obviousness rejection of Claim 13 based on Ren and Xu is properly maintained.
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) 1, 5-6, 10, 13, 17, and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ren et al. (US 2022/0132593 A1, hereinafter “Ren”) in view of Speidel et al. (US 10,084,535 B1, hereinafter “Speidel”) and further in view of Xu et al. (US 2021/0337491 A1, hereinafter “Xu”).
As to Claim 1 and Claim 10:
Ren describes a method for synchronizing a user equipment with a satellite.
Specifically, Ren teaches:
Determining, by a processor of an apparatus, synchronization information with respect to an implicit time reference associated with a wireless network, without signaling time information
Ren describes a “terminal” that performs “downlink cell search according to a periodic position of a frame structure where a downlink synchronization signal and/or reference signal predefined by a protocol is/are located” (Ren, 0035, 0038-0039). Here, the “periodic position of a frame structure” is analogous to the “synchronization information with respect to an implicit time reference associated with a wireless network, without signaling time information”. Also, paragraph 0065 of Ren states that “an embodiment of the application provides a terminal for random access, which includes: a processor and a memory” (Ren, 0065).
Maintaining, by the processor, synchronization using the synchronization information in performing non-terrestrial network (NTN) communications with the wireless network
Ren teaches that the terminal may “obtain the downlink synchronization signal and/or reference signal” based on “a periodic position of a frame structure” (Ren, 0039). Figs. 1 and 2 in Ren also show the base station communicating with an extraterrestrial satellite.
The synchronization information comprises all of: a position of a non-terrestrial (NT) network node of the wireless network, a velocity of the NT network node, and a feeder link delay associated with a feeder link between the terrestrial network node and the NT network node
Ren teaches that the “downlink cell search” performed “to obtain the downlink synchronization signal and/or reference signal” derives information to create “the generated PRACH Preamble sequence” (Ren, 0038-0039).
Furthermore, Ren states that the “PRACH Preamble format includes plurality of CPs [cyclic prefixes]” that have “a total duration” that “is greater than a sum of a transmission delay introduced by a movement distance of a satellite” (Ren, 0032). Ren further elaborates that “the PRACH Preamble sequence is determined according to a Doppler frequency offset range corresponding to the terminal at different moving speeds and/or ... a Doppler frequency offset caused by satellite movement” (Ren, 0035). This shows that this information about satellite position, speed, etc. is derived during synchronization.
Here, the “PRACH Preamble format” maps to “the synchronization information”,
“satellite movement” maps to “a position of a non-terrestrial (NT) network node of the wireless network”,
“satellite ... speed” maps to “a velocity of the NT network node”, and
“a transmission delay” corresponds to “a feeder link delay associated with a feeder link between the terrestrial network node and the NT network node”.
The synchronization information is valid at the implicit time reference which is a fixed reference corresponding to the NT network node
Ren describes a “terminal” that performs “downlink cell search according to a periodic position of a frame structure where a downlink synchronization signal and/or reference signal predefined by a protocol is/are located” (Ren, 0035, 0038-0039).
Here, the “periodic position of a frame structure” in a “downlink synchronization signal” corresponds to “the implicit time reference which is a fixed reference corresponding to the NT network node”.
Ren does not explicitly disclose:
The position and the velocity of the NT network node are according to Earth-Centered, Earth-Fixed (ECEF) coordinates
However, Speidel does describe a transceiver capable of communicating with a satellite in extraordinary conditions that exceed a normal mobile station’s design assumptions.
Specifically, Speidel teaches:
The position and the velocity of the NT network node are according to Earth-Centered, Earth-Fixed (ECEF) coordinates
Speidel describes “
r
B
T
S
” which “represents the position vector of the satellite in ECEF coordinates ...
v
B
T
S
represents the velocity vector of the satellite in ECEF coordinates” (Speidel col. 30, lines 21-22, 25-26).
Speidel also teaches more clearly than Ren taking a measurement of:
A velocity of the NT network node
Speidel describes “
v
B
T
S
” which “represents the velocity vector of the satellite in ECEF coordinates and
v
M
S
represents the velocity vector of the MS in ECEF coordinates” (Speidel col. 30, lines 25-27).
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 the ECEF position and velocity described in Speidel into Ren’s method for synchronizing a user equipment and a satellite. The satellite velocity is a useful parameter for achieving synchronization, and ECEF is a useful format for storing this and other parameters.
The combination of Ren and Speidel also does not explicitly disclose:
The implicit time reference corresponds to a frame boundary associated with a system information window in which a corresponding system information block (SIB) is transmitted
However, Xu does describe a method for synchronizing two devices using the end boundary of a window for sending a system information block.
Specifically, Xu teaches:
The implicit time reference corresponds to a frame boundary associated with a system information window in which a corresponding system information block (SIB) is transmitted
Xu describes locating “a system frame number SFN” at “an end boundary of a system information SI window for sending the SIB” (Xu, 0007).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the SIB boundary described in Xu as the implicit frame boundary used to locate a downlink synchronization signal in Ren. Ren also describes transmitting a SIB downlink (e.g., Ren 0144, 0146), and this provides an opportunity to use the SIB boundary for synchronization, a potential advantage a skilled artisan would recognize.
Claim 10 includes all of the subject matter of Claim 1 as well as an additional limitation requiring:
The maintaining of the synchronization using the feeder link delay comprises:
Deriving, by the processor, the feeder link delay at a given time based on:
The feeder link delay at a reference time,
A feeder link delay drift rate at the reference time, and
An amount of time elapsed from the reference time to the given time
Ren teaches that “[t]he subcarrier interval occupied by the PRACH Preamble sequence is determined according to a Doppler frequency offset range corresponding to the terminal at different moving speeds and/or a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035).
Here, the “frequency offset” maps to the claimed “feeder link delay at a given time” because frequency offset and delay are two interchangeable measurements of a moving satellite’s change in position,
“initial synchronization” maps to “the reference time”,
“a Doppler frequency caused by satellite movement” maps to “the feeder link delay at the reference time”,
“moving speeds” maps to “feeder link delay drift rate at the reference time”, and
“the residual frequency offset” maps to “the feeder link delay drift rate at the reference time, and an amount of time elapsed from the reference time to the given time” because the total offset is equivalent to the product of the delay drift rate and the time elapsed since synchronization.
As to Claim 5:
Ren teaches:
The implicit time reference corresponds to the frame boundary
Ren teaches that a terminal performs “downlink cell search according to a periodic position of a frame structure”, i.e. a “frame boundary”.
The combination of Ren and Speidel does not explicitly disclose:
The frame boundary at an ending boundary of a system information window in which the corresponding SIB is transmitted from the wireless network to the apparatus
However, Xu does teach:
The frame boundary at an ending boundary of a system information window in which the corresponding SIB is transmitted from the wireless network to the apparatus
Xu describes locating “a system frame number SFN” at “an end boundary of a system information SI window for sending the SIB” (Xu, 0007).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the end of the system information frame taught in Xu as the time reference for Ren’s synchronization method. The SIB window is a common feature of most, if not all communication between a base station and a terminal, meaning it can similarly serve as a reference point to determine transmission delay and synchronize both devices.
As to Claim 6:
Ren teaches:
The implicit time reference corresponds to the frame boundary
Ren teaches that a terminal performs “downlink cell search according to a periodic position of a frame structure”, i.e. a “frame boundary”.
Ren does not explicitly disclose:
The frame boundary immediately after an ending boundary of the system information window in which a corresponding SIB is transmitted from the wireless network to the apparatus
However, Xu does teach:
The frame boundary immediately after an ending boundary of the system information window in which a corresponding SIB is transmitted from the wireless network to the apparatus
Xu describes locating “a system frame number SFN” at “an end boundary of a system information SI window for sending the SIB” (Xu, 0007).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the end of the system information frame taught in Xu as the time reference for Ren’s synchronization method. The SIB window is a common feature of most, if not all communication between a base station and a terminal, meaning it can similarly serve as a reference point to determine transmission delay and synchronize both devices.
As to Claim 13:
Ren teaches:
Determining, by a processor of an apparatus ... synchronization information with respect to an implicit time reference associated with a wireless network, wherein the implicit time reference is used to avoid signaling of time information
Ren describes a “terminal” that performs “downlink cell search according to a periodic position of a frame structure where a downlink synchronization signal and/or reference signal predefined by a protocol is/are located” (Ren, 0035, 0038-0039). Here, the “periodic position of a frame structure” is analogous to the “synchronization information with respect to an implicit time reference associated with a wireless network, without signaling time information”. Also, paragraph 0065 of Ren states that “an embodiment of the application provides a terminal for random access, which includes: a processor and a memory” (Ren, 0065).
Determining, by a processor of an apparatus ... a feeder link delay associated with a feeder link between a terrestrial network node and a non-terrestrial (NT) network node of the wireless network
Ren teaches that “the subcarrier interval occupied by the PRACH Preamble sequence is determined according to ... a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035). Figs. 1 and 2 in Ren also depict a UE and base station communicating with an extraterrestrial satellite.
Here, the “sum of a residual frequency offset ... and a Doppler frequency offset” corresponds to “a feeder link delay” because the frequency difference here is analogous to and interchangeable with a time domain feeder link delay.
Maintaining, by the processor, synchronization using either or both of the synchronization information and the feeder link delay in performing non-terrestrial network (NTN) communications with the wireless network
Ren teaches that a UE should use “downlink timing synchronization position estimation” and “downlink frequency offset estimation” to “obtain the downlink synchronization signal and/or reference signal” (Ren, 0038-0039). Furthermore, this synchronization helps convey a “plurality of CPs which is greater than a sum of a transmission delay” (Ren, 0032).
Here, “obtain[ing] the downlink synchronization” is analogous to “maintaining ... synchronization” since this is the purpose of obtaining the downlink synchronization in the first place.
The synchronization information comprises all of: a position of a non-terrestrial (NT) network node of the wireless network, a velocity of the NT network node, and a feeder link delay associated with a feeder link between the terrestrial network node and the NT network node
Ren teaches that the “downlink cell search” performed “to obtain the downlink synchronization signal and/or reference signal” derives information to create “the generated PRACH Preamble sequence” (Ren, 0038-0039).
Furthermore, Ren states that the “PRACH Preamble format includes plurality of CPs [cyclic prefixes]” that have “a total duration” that “is greater than a sum of a transmission delay introduced by a movement distance of a satellite” (Ren, 0032). Ren further elaborates that “the PRACH Preamble sequence is determined according to a Doppler frequency offset range corresponding to the terminal at different moving speeds and/or ... a Doppler frequency offset caused by satellite movement” (Ren, 0035). This shows that this information about satellite position, speed, etc. is derived during synchronization.
Here, the “PRACH Preamble format” maps to “the synchronization information”,
“satellite movement” maps to “a position of a non-terrestrial (NT) network node of the wireless network”,
“satellite ... speed” maps to “a velocity of the NT network node”, and
“a transmission delay” corresponds to “a feeder link delay associated with a feeder link between the terrestrial network node and the NT network node”.
The synchronization information is valid at the implicit time reference which is a fixed reference corresponding to the NT network node
Ren describes a “terminal” that performs “downlink cell search according to a periodic position of a frame structure where a downlink synchronization signal and/or reference signal predefined by a protocol is/are located” (Ren, 0035, 0038-0039).
Here, the “periodic position of a frame structure” is analogous to the “synchronization information” because it is an “implicit time reference” and is sent “downlink” (i.e. “corresponding to the NT network node”).
Deriving, by the processor, the feeder link delay at a given time based on the feeder link delay at the reference time, the feeder link delay drift rate at the reference time, and an amount of time elapsed from the reference time to the given time
Ren states that “[t]he subcarrier interval occupied by the PRACH Preamble sequence is determined according to a Doppler frequency offset range corresponding to the terminal at different moving speeds and/or a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035).
Here, “[t]he subcarrier interval” for “the PRACH Preamble sequence” corresponds to “the feeder link delay at a given time” because this frequency shift is analogous to shifting a transmission in the time domain,
“a residual frequency offset after the initial synchronization of the terminal” maps to “the feeder link delay at the reference time”,
“a Doppler frequency offset range corresponding to the terminal at different moving speeds” maps to “the feeder link delay drift rate at the reference time”, and
“the residual frequency offset” maps to “the feeder link delay drift rate at the reference time, and an amount of time elapsed from the reference time to the given time” because the total offset is equivalent to the product of the delay drift rate and the time elapsed since synchronization.
Furthermore, although Ren does not explicitly disclose the following limitations from Claim 13 as arranged in the claim, Ren does elsewhere disclose and thus render obvious:
Receiving, from the wireless network, a ... signaling indicating
Ren describes several examples of the terminal receiving a message from the network such as “a feedback RAR message within an RAR time window” (Ren, 0027-0028).
The feeder link delay at a reference time and a feeder link delay drift rate at the reference time
Ren teaches that “the subcarrier interval occupied by the PRACH Preamble sequence is determined according to ... a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035). Figs. 1 and 2 in Ren also depict a UE and base station communicating with an extraterrestrial satellite.
Here, “residual frequency offset after the initial synchronization” corresponds to “the feeder link delay at a reference time” because frequency offset and time delay are two equivalent ways of measuring the initial distance to a satellite, and
similarly, “a Doppler frequency offset caused by satellite movement” corresponds to “a feeder link delay drift rate at the reference time” because both measure the change in distance that results from satellite movement.
And:
Broadcast signaling
Ren states that “cell public delay information is the public transmission delay of the beam area where the terminal is located obtained according to a system broadcast message” (Ren, 0162).
Here, “a system broadcast message” corresponds to “broadcast signaling”.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Ren’s method for calculating feeder link delay to perform the calculation at a network device and transmit it to the terminal, as other data already is sent to the terminal in Ren’s method. Calculating the feeder link delay and sending it to the terminal frees compute power on the terminal to perform other tasks while this calculation occurs.
Ren does not explicitly disclose:
The position and the velocity of the NT network node are according to Earth-Centered, Earth-Fixed (ECEF) coordinates
However, Speidel does teach:
The position and the velocity of the NT network node are according to Earth-Centered, Earth-Fixed (ECEF) coordinates
Speidel describes “
r
B
T
S
” which “represents the position vector of the satellite in ECEF coordinates ...
v
B
T
S
represents the velocity vector of the satellite in ECEF coordinates” (Speidel col. 30, lines 21-22, 25-26).
Speidel also teaches more clearly than Ren taking a measurement of:
A velocity of the NT network node
Speidel describes “
v
B
T
S
” which “represents the velocity vector of the satellite in ECEF coordinates and
v
M
S
represents the velocity vector of the MS in ECEF coordinates” (Speidel col. 30, lines 25-27).
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 the ECEF position and velocity described in Speidel into Ren’s method for synchronizing a user equipment and a satellite. The satellite velocity is a useful parameter for achieving synchronization, and ECEF is a useful format for storing this and other parameters.
The combination of Ren and Speidel also does not explicitly disclose:
The implicit time reference corresponds to a frame boundary associated with a system information window in which a corresponding system information block (SIB) is transmitted
However, Xu does teach:
The implicit time reference corresponds to a frame boundary associated with a system information window in which a corresponding system information block (SIB) is transmitted
Xu describes locating “a system frame number SFN” at “an end boundary of a system information SI window for sending the SIB” (Xu, 0007).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the SIB boundary described in Xu as the implicit frame boundary used to locate a downlink synchronization signal in Ren. Ren also describes transmitting a SIB downlink (e.g., Ren 0144, 0146), and this provides an opportunity to use the SIB boundary for synchronization, a potential advantage a skilled artisan would recognize.
As to Claim 17:
Ren teaches:
The implicit time reference corresponds to the frame boundary
Ren teaches that a terminal performs “downlink cell search according to a periodic position of a frame structure”, i.e. a “frame boundary”.
Ren does not explicitly disclose:
The frame boundary at or immediately after an ending boundary of the system information window in which the corresponding SIB is transmitted from the wireless network to the apparatus
However, Xu does teach:
The frame boundary at or immediately after an ending boundary of the system information window in which the corresponding SIB is transmitted from the wireless network to the apparatus
Xu describes locating “a system frame number SFN” at “an end boundary of a system information SI window for sending the SIB” (Xu, 0007).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the end of the system information frame taught in Xu as the time reference for Ren’s synchronization method. The SIB window is a common feature of most, if not all communication between a base station and a terminal, meaning it can similarly serve as a reference point to determine transmission delay and synchronize both devices.
As to Claim 20:
Deriving the feeder link delay at a given time based on the feeder link delay at the reference time, the feeder link delay drift rate at the reference time, and an amount of time elapsed from the reference time to the given time
Ren states that “[t]he subcarrier interval occupied by the PRACH Preamble sequence is determined according to a Doppler frequency offset range corresponding to the terminal at different moving speeds and/or a sum of a residual frequency offset after the initial synchronization of the terminal and a Doppler frequency offset caused by satellite movement” (Ren, 0035).
Here, “[t]he subcarrier interval” for “the PRACH Preamble sequence” corresponds to “the feeder link delay at a given time” because this frequency shift is analogous to shifting a transmission in the time domain,
“a residual frequency offset after the initial synchronization of the terminal” maps to “the feeder link delay at the reference time”,
“a Doppler frequency offset range corresponding to the terminal at different moving speeds” maps to “the feeder link delay drift rate at the reference time”, and
“the residual frequency offset” maps to “the feeder link delay drift rate at the reference time, and an amount of time elapsed from the reference time to the given time” because the total offset is equivalent to the product of the delay drift rate and the time elapsed since synchronization.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Benjamin Peter Welte whose telephone number is (703)756-5965. The examiner can normally be reached Monday - Friday, EST.
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, Chirag G Shah can be reached at (571) 272-3144. 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.
BENJAMIN PETER WELTE
Examiner
Art Unit 2477
/CHIRAG G SHAH/Supervisory Patent Examiner, Art Unit 2477
Prosecution Insights