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 2/16/2026 is being considered by the examiner.
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. In Fig. 1, Applicant uses two separated RRU controller (146 and 156) to control the signal processing: RRU 146 for controlling signal transmission from BBU to antenna, but RRU 156 for controlling signal transmission from antenna to BBU; also refer to Figures 2A and 2D, the RRU for downlink (BBU->RRU) and a RRU for uplink (RRU->BBU) are different and separated units; but, according to claims 1 and 4 and 11-12, a single “RRU controller” is used for both downlink and uplink data traffics; and drawings do not show a single RRU controller is used for both downlink transmission and uplink transmission.
Therefore, a single “RRU controller” (claimed in claims 1 and 4, and claims 11-12), which is used to control the signals coming from the baseband unit (BBU) (downlink) and to control the signals received from an antenna and sent to BBU (uplink), must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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 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, 7 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb et al (WO 2024/086942; hereinafter Zeb ‘942) in view of Miyasugi et al (Miyasugi et al: “Optical Signal Delay Processor for a Beamforming Antenna in a Radio over Fiber System”, 2024 IEEE Photonics Society Summer Topicals Meeting Series (SUM), 15-17 July 2024, paper no. TuA1.3) and Zeb et al (Zeb et al: “High Capacity Mode Division Multiplexing Based MIMO Enabled All-Optical Analog Millimeter-Wave Over Fiber Fronthaul Architecture for 5G and Beyond”, IEEE Access, SPECIAL SECTION ON ROADMAP TO 5G: RISING TO THE CHALLENGE, July 2019, pages 89522-89533; hereinafter Zeb NPL).
1). With regard to claim 1, Zeb ‘942 discloses a system (Figures 1-4) for implementing improved cellular fronthauling, the system comprising:
a baseband unit (“BBU”) (the central office CO 12 in Figure 1, CO 104 in Figure 3, CO 202 in Figure 3, or CO 404 in Figure 4; [0021]) comprising a BBU controller (102 in Figure 2, Baseband Signal Processing unit BBU; and BBU in Figures 3-4), a data network interface (as shown in Figures 2-4, data signals are input, shown with “->” symbol, and output, shown with “<-” symbol, from the BBU; also since it is a BBU, it is commonly that a BBUs connect to a core network (backhaul); and a BBU acts as an interface between the radio equipment (like Remote Radio Units, RRUs) and the wired network infrastructure, enabling voice and data transmission between mobile devices and the core network; therefore, it is obvious to one skilled in the art that CO/BBU has a data network interface used to input/output data signals), a signal processing system (DSP module and baseband signal processing in the BBU and DAC in Figure 2), a first electrical to optical transducer (an optical modulator, e.g., OM 117/118 in Figure 2), a first laser (QD-MWL 101), a first optical amplifier (e.g., OA 114 in Figure 2), and a first multiplexer (e.g., 122);
a first demultiplexer (e.g., 132 in Figure 2);
a plurality of remote radio units (“RRUs”) (a plurality of RRH/RRU in Figure 1, [0019] “remote radio heads/units (RRHs)Z(RRUs) 24”; or 108 in Figure 2, [0021], “The system design of Figure 2 can be used to realize SISO and/or M-MIMO without or with OBF configuration in various frequency bands with single or multi-beam operation with few or large number of RRHs/RRUs depending on the network requirements”, and [0027]) each comprising a RRU controller (since it is a RRH/RRU, it is obvious to one skilled in the art that the RRH/RRU has a controller to control the components of the RRH/RRU; also as shown in Figure 2, an optical beam forming network, OBFN 110 is used; and [0021], “The OBFN 110 may comprise of variable optical attenuators and optical true time delay lines (OTTDLs) for controlling the relative amplitudes and relative time delays of the signals that excite the antenna elements in accordance with the intended beam shape and beam direction”; then, the OBFN is a portion of RRU controller), a first photodetector (134), a first optical to electrical transducer (including the photodetector 134. Note: according to applicant’s Spec. “the O/E transducer(s) 148 includes (or is the same as) photodetector(s) 150”, [0027], the O/E transducer is the same as the photodetector. Then in light of Spec., the photodetector 134 of Zeb ‘942 is also an O/E transducer), and a first antenna (112, [0021]); and
a plurality of fiber-based fronthaul links ([0019], “The plurality of modulated optical signals and optical LOs may be multiplexed over a long standard single mode fiber (s) (SSFM) or spatial few/multi-mode/core or spatial modes fiber (s) 20 for transmission to remote radio heads/units (RRHs)Z(RRUs) 24”) each established between the first multiplexer (122) and the first demultiplexer (132);
wherein the BBU performs first operations comprising:
receiving, by the BBU controller and using the data network interface, a first data signal (Figure 2, “->” symbol, the BBU receives data signal) for transmission to one of the plurality of RRUs for radio frequency (“RF”) transmission;
determining, by the BBU controller, which RRU among the plurality of RRUs to send the first data signal ([0022], “The wavelength selective switch (WSS) 106 thus provides a plurality of optical channels of differing wavelengths from which individual channels can be selected. For example, two channels, Xi and may be selected based on the desired MMW frequency at the remote radio unit or remote radio head (RRU)/(RRH) 108”);
routing, by the BBU controller, the first data signal to the signal processing system (the DSP module and baseband signal processing and DAC), based on the determined RRU to send the first data signal;
converting, by the signal processing system, the first data signal from digital data into a first analog data signal (by the DAC in Figure 2);
converting, by the first electrical to optical transducer (117), the first analog data signal into a first optical control signal;
generating, by the first laser (101), a first optical data signal based on the first optical control signal (optical modulator OM 117 modulates the data signal on to optical carrier);
causing, by the first optical amplifier, amplification of the first optical data signal to produce a first amplified optical data signal (in Figure 1, an optical amplifier 114 is used before the optical modulator 117; however, it is obvious to one skilled in the art that an amplifier can be place after the optical modulator so to obtain an amplified optical data signal); and
sending the first amplified optical data signal to the determined RRU via the first multiplexer (122), over a corresponding fronthaul link among the plurality of HCF-based fronthaul links (Figures 1 and 2), and via the first demultiplexer (e.g., 132);
wherein each RRU performs second operations comprising:
receiving, by the first photodetector (134) and from the first demultiplexer (132), the first amplified optical data signal;
converting, by the first optical to electrical transducer (transducer including the photodetector 134 and amplifier 135), the first amplified optical data signal into a second analog data signal (the output from the amplifier 135); and
sending, by the RRU controller (OBFN 110 etc.) and over the first antenna (112), a first RF signal (output from the antenna) based on the second analog data signal (Figure 2, the outputs from the amplifier 135 are sent to antenna 112).
But, Zeb ‘942 does not expressly disclose: the fiber-based fronthaul links are a plurality of hollow core fiber (“HCF”)-based fronthaul link, and the data signal is a data packet, an amplifier amplifies the first optical data signal to produce a first amplified optical data signal.
Regarding the HCF, it is commonly known that the HCF has the advantages of high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects. And the HCF has been used in radio-over-fiber system; e.g., Miyasugi et al discloses a radio-over-fiber (ROF) system/method (Figure 1 etc.), in which a plurality of hollow-core fibers are used for signal transmissions between a base station (radio unit at the left side of Figure 1) and remote radio heads.
Regarding data packet and amplification of the first optical data signal, first, as shown in Figure 1 of Miyasugi et al, an optical amplifier (EDFA) can be implemented after an optical modulator. Second, Zeb NPL (same research group as Zeb ‘942) discloses a high capacity ROF system (Figures 1-4), and teaches that the data signal can be a data packet (page 89523 right column “The RRHs transmit and receive the radio frequency (RF) signals over the air interface, whereas the BBUs perform the base band and packet processing in a cloud environment as shown in Figure 1(c)”), and an amplifier (OA in Figure 2 and Figure 4) can be used to amplify optical data signals to produce an amplified optical data signal. And in Figures 1 and 3, Zeb NPL also discloses that the BBU connects to core network, that is, the CO/BBU has a data network interface for signal transmission to/from the core network.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Miyasugi et al and Zeb NPL to the system/method of Zeb ‘942 so that a ROF system with high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects can be obtained, and the system can be used to transmit data packet, and a desired power level of each modulated data signal can be obtained by a respective optical amplifier.
2). With regard to claim 7, Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL further discloses wherein the first RF signal is sent over one of a thousand band (“T-band”) channel, an original band (“O-band”) channel, a conventional band (“C-band”) channel, a long wavelength band (“L-band”) channel, a 4G spectrum channel, a 5G spectrum channel, or a millimeter wave (“mmWave”) channel (Zeb ‘942: [0002], [0008], [0019]. Zeb NPL: section “I. Introduction”).
3). With regard to claim 11, Zeb ‘942 discloses a computer-implemented method ([0042], “can generally be integrated together in a single software product or packaged into multiple software products”) for implementing improved cellular fronthauling (Figures 1-2), the method comprising:
converting, by a baseband unit (“BBU”) controller (102 in Figure 2, Baseband Signal Processing unit BBU; and BBU in Figures 3-4) at a BBU (the central office CO 12 in Figure 1, CO 104 in Figure 3, CO 202 in Figure 3, or CO 404 in Figure 4; [0021]), a first data signal (as shown in Figures 2-4, data signals are input, shown with “->” symbol, and output, shown with “<-” symbol, from the BBU; also since it is a BBU, it is commonly that a BBUs connect to a core network (backhaul); and a BBU acts as an interface between the radio equipment (like Remote Radio Units, RRUs) and the wired network infrastructure, enabling voice and data transmission between mobile devices and the core network; therefore, data signal is received from a core network) into a first analog data signal (the outputs from the BBU 102 are converted into analog signal by the DAC in Figure 2);
converting, by a first electrical to optical transducer (an optical modulator, e.g., OM 117/118 in Figure 2) at the BBU, the first analog data signal into a first optical data signal (the outputs from the OM 117/118);
causing, by a first optical amplifier at the BBU, amplification of the first optical data signal to produce a first amplified optical data signal (in Figure 1, an optical amplifier 114 is used before the optical modulator 117; however, it is obvious to one skilled in the art that an amplifier can be place after the optical modulator so to obtain an amplified optical data signal);
sending the first amplified optical data signal to a remote radio unit (“RRU”) (Figure 1, the RRH/RRU, and 108 in Figure 2) via a first multiplexer (122), over a fiber-based fronthaul link (e.g., 124 in Figure 2; and [0019], “The plurality of modulated optical signals and optical LOs may be multiplexed over a long standard single mode fiber (s) (SSFM) or spatial few/multi-mode/core or spatial modes fiber (s) 20 for transmission to remote radio heads/units (RRHs)Z(RRUs) 24”), and via a first demultiplexer (e.g., 132);
receiving, by a first photodetector (134) at the RRU, the first amplified optical data signal;
converting, by a first optical to electrical transducer (including the photodetector 134. Note: according to applicant’s Spec. “the O/E transducer(s) 148 includes (or is the same as) photodetector(s) 150”, [0027], the O/E transducer is the same as the photodetector. Then in light of Spec., the photodetector 134 of Zeb ‘942 is also an O/E transducer) at the RRU, the first amplified optical data signal into a second analog data signal (the output from the power amplifier 135); and
sending, by an RRU controller (since it is a RRH/RRU, it is obvious to one skilled in the art that the RRH/RRU has a controller to control the components of the RRH/RRU; also as shown in Figure 2, an optical beam forming network, OBFN 110 is used; and [0021], “The OBFN 110 may comprise of variable optical attenuators and optical true time delay lines (OTTDLs) for controlling the relative amplitudes and relative time delays of the signals that excite the antenna elements in accordance with the intended beam shape and beam direction”; then, the OBFN is a type of RRU controller) and over a first antenna (112) at the RRU, a first radio frequency (“RF”) signal (RF signal is output from the antenna 112) based on the second analog data signal (output from the power amplifier 135).
But, Zeb ‘942 does not expressly disclose: the fiber-based fronthaul link is a hollow core fiber (“HCF”)-based fronthaul link, and the data signal is a data packet, an amplifier amplifies the first optical data signal to produce a first amplified optical data signal.
Regarding the HCF, it is commonly known that the HCF has the advantages of high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects. And the HCF has been used in radio-over-fiber system; e.g., Miyasugi et al discloses a radio-over-fiber (ROF) system/method (Figure 1 etc.), in which a plurality of hollow-core fibers are used for signal transmissions between a base station (radio unit at the left side of Figure 1) and remote radio heads.
Regarding data packet and amplification of the first optical data signal, first, as shown in Figure 1 of Miyasugi et al, an optical amplifier (EDFA) can be implemented after an optical modulator. Second, Zeb NPL (same research group as Zeb ‘942) discloses a high capacity ROF system (Figures 1-4), and teaches that the data signal can be a data packet (page 89523 right column “The RRHs transmit and receive the radio frequency (RF) signals over the air interface, whereas the BBUs perform the base band and packet processing in a cloud environment as shown in Figure 1(c)”), and an amplifier (OA in Figure 2 and Figure 4) can be used to amplify optical data signals to produce an amplified optical data signal. And in Figures 1 and 3, Zeb NPL also discloses that the BBU connects to core network, that is, the CO/BBU has a data network interface for signal transmission to/from the core network.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Miyasugi et al and Zeb NPL to the system/method of Zeb ‘942 so that a ROF system with high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects can be obtained, and the system can be used to transmit data packet, and a desired power level of each modulated data signal can be obtained by a respective optical amplifier.
Claims 2-3 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claim 1 above, and further in view of Hijimiri (US 2022/0085886) and Nishimoto et al (US 2020/0112372).
1). With regard to claim 2, Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL discloses wherein the first operations further comprise converting, by the signal processing system, a data signal produced by the system into a first analog signal; converting, by the first electrical to optical transducer, the first analog signal into a second optical signal; generating, by the first laser, a first optical signal based on the second optical signal; causing, by the first optical amplifier, amplification of the first optical signal to produce a first amplified optical signal; and sending the first amplified optical signal to the plurality of RRUs via the first multiplexer, over the plurality of HCF-based fronthaul links, and via the first demultiplexer.
But, Zeb ‘942 and Miyasugi et al and Zeb NPL do not expressly disclose that the same operations are used to send a clock signal.
However, to send a clock signal from base station to a remote radio unit is known an common in the art. E.g., Hijimiri discloses a ROF system/method (Figures 1 and 3-5), in which the base station (left side of Figures 1 and 5; and Figure 4) comprises a system clock (clock 30 in Figure 1; Ref_ck in Figure 4; 530 in Figure 5), and operations comprise: converts, by a first electrical to optical transducer (modulator 12 in Figures 1; or 425 in Figure 4; or Mod in Figure 5), a clock signal (30 in Figure 1; Ref_ck in Figure 4; 530 in Figure 5) into a second optical control signal (output from modulator 12); generating, by a first laser (lr in Figures 1 and 5; Sck in Figure 4), a first optical clock signal based on the second optical control signal; sending the first optical clock signal to the plurality of RRUs (right side of Figures 1 and 3-5) via a first multiplexer (14 in Figure 1; 430 in Figure 4; 514 in Figure 5), over the plurality of fiber-based fronthaul links (16), and via a first demultiplexer (205 in Figure 3; [0033], [0035]-[0036] and [0048] etc.). Another prior art, Nishimoto et al, discloses a similar radio-over-fiber system/method (Figures 4, 7, 10, 13, 16 and18-19), in which reference clock signal is sent from the base station to the remote radio unit, and Nishimoto et al discloses that the base station can perform digital-analog conversion, and the “The reference clock signal generating section 130 generates a sine- or rectangular-wave analog periodic signal, and outputs the signal to the ground station side optical converting unit 150 as a reference clock electrical signal sc(t). Here, the reference clock electrical signal sc(t) is a periodic signal of 10 MHz or more”; that is, Nishimoto et al teaches/suggest that a common clock signal produced by a system clock is converted into a first analog clock signal. Nishimoto et al also discloses that an optical amplifier (145 in Figure 12) causes amplification of the first optical clock signal to produce a first amplified optical clock signal (Oc(t) in Figure 12); and sending the first amplified optical clock signal to the plurality of RRUs via the first multiplexer (155; 156), over fiber-based fronthaul links (Figure 5 etc.), and via a demultiplexer (211; 212).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Hijimiri and Nishimoto et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL to so that the remote radio unit/head can use the clock reference sent from the base station for synchronization etc., the reliability is enhanced.
2). With regard to claim 3, Zeb ‘942 and Miyasugi et al and Zeb NPL and Hijimiri and Nishimoto et al disclose all of the subject matter as applied to claims 1-2 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL and Hijimiri and Nishimoto et al further discloses wherein each RRU further comprises a local clock, wherein the second operations further comprise:
receiving, by the first photodetector (e.g., Hijimiri: 170. Nishimoto: 210c in Figure 18; 215-3 in Figure 19) and from the first demultiplexer, the first amplified optical clock signal;
converting, by the first optical to electrical transducer (e.g., Hijimiri: 170 and TIA 222. Nishimoto: 210c in Figure 18; 215-3 in Figure 19), the first amplified optical clock signal into a second analog clock signal (Hijimiri: the output from the 170/22; or Nishimoto: the output from 210c in Figure 18, or from 215-3 in Figure 19);
converting, by the RRU controller (e.g., Hijimiri: PLL 230; or Nishimoto: 230 in Figures 6 and 18), the second analog clock signal into a clock synchronization signal (Hijimiri: the ck from the PLL 230; or Nishimoto: the output from PLL 230 in Figure 6, or from 230 in Figure 19); and
synchronizing, by the RRU controller, the local clock using the clock synchronization signal (Hijimiri: Figures 1 and 3-5, [0004], [0031] and [0050]. Nishimoto: [0006]-[0007], [0009], [0035], [0046], [0049], [0052] and [0056] etc.).
Claims 4-6 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claims 1 and 11 above, and further in view of Li et al (US 2022/0303020) and Sulzberger et al (US 2005/0152695).
1). With regard to claim 4, Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL further discloses the system of claim 1, further comprising a second multiplexer (Zeb ‘942: 142 in Figure 1), wherein each RRU further comprises a second optical amplifiers (OA (k) at RRH in Figure 4 of Zeb NPL), a second laser wavelength (Zeb ‘942: from OC 131 and WSS 137), a second electrical to optical transducer (Zeb ‘942: optical modulator 138), and a second antenna (Zeb ‘942: same antenna 112, which is used for transmission and receiving), wherein the BBU further comprises a second demultiplexer (Zeb ‘942: 144),
wherein one of the RRUs performs third operations comprising:
receiving, by the second antenna, a second RF signal (Zeb ‘942: Figures 1-2, the antenna receives a second RF signal from user equipment UE, [0019] and [0025] etc.);
converting, by the RRU controller (Zeb ‘942: LNA etc. in Figure 2; and Zeb NPL: Figures 2 and 4, with LNA etc., then it is obvious to one skilled in the art that the RRH/RRU has a controller to control the components of the RRH/RRU), the second RF signal into a third analog data signal (Zeb NPL: Abstract “an entirely analog-radio-over fiber (A-RoF) based fronthual”);
converting, by the second electrical to optical transducer (Zeb ‘942: optical modulator 138), the third analog data signal into a third optical control signal (output from the optical modulator 138);
generating, by the second laser wavelength, a second optical data signal based on the third optical control signal (the data signals from the LNA are carried on the laser wavelengths; Zeb ‘942: Figure 2);
causing, by the second optical amplifier, amplification of the second optical data signal to produce a second amplified optical data signal (Zeb ‘942: optical signals output from the OA (k) in Figure 4); and
sending the second amplified optical data signal to the BBU via a second multiplexer (e,g., Zeb ‘942: multiplexer 142), over one of the corresponding HCF fronthaul link or another HCF fronthaul link among the plurality of HCF-based fronthaul links, and via a second demultiplexer (e,g., Zeb ‘942: demultiplexer 144).
In Figure 2 of Zeb ‘942, the laser wavelengths are from a splitter OC 131, which splits portion of received optical signals from the Central Office to the WSS 140; that is, the RRH/RRU does not have an individual “second laser”; and Zeb ‘942 also shows that the same antenna is used for transmission and reception.
Regarding the second laser in the RRH/RRU, Li et al discloses a radio over fiber system/method (Figures 5 and 9-10 etc.), and in each remote radio unit (e.g., 520 in Figure 5, there is a laser (e.g., in the electrical-to-optical conversion module 523); and in Figure 6-8, Li et al teaches that the electrical-to-optical conversion module can be a directly modulated laser source, or can include an external modulator (5122 or 5124) that modulates optical carrier from a laser source (5123 or 5125).
Regarding the second antenna, however, to use separated radio antennas for transmission and reception is known in the art, E.g., Sulzberger et al discloses a radio over fiber system/method (Figures 1-3), and as shown in Figure 1, radio transmitter 17 is separated from a radio receiver 24.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Li et al and Sulzberger et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so that each remote radio unit/head can use its own laser to transmit optical signals to the central office, and each remote radio unit/head can use individual transmission antenna and reception antenna for signal transmission to reduce conflict and interference, and the capacity can be increased.
2). With regard to claim 5, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Sulzberger et al disclose all of the subject matter as applied to claims 1 and 4 above, and the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Sulzberger et al further discloses wherein the BBU further comprises a second optical to electrical transducer (Zeb ‘942: Figure 2, 150 and ADC 154/156) and a second photodetector (164; or 160),
wherein the first operations further comprise:
receiving, by a second photodetector (Zeb ‘942: Figure 2, 164; also Zeb NPL: “E/O” or PD in Figures 2 and 4) and from the second demultiplexer (Zeb ‘942: 144. Zeb NPL: Mode Demux), the second amplified optical data signal;
converting, by a second optical to electrical transducer (Zeb ‘942: Figure 2, 150 and ADC 154/156), the second amplified optical data signal into a fourth analog data signal (the outputs from the ADC);
converting, by a second signal processing system (Zeb ‘942: 102. Or Zeb NPL: the Baseband Signal Processing), the fourth analog data signal into a second data packet (the output from the Baseband Signal Processing); and
sending, by the BBU controller and via the data network interface, the second data packet through a data network (Zeb NPL: e.g., backhaul and the core network).
3). With regard to claim 6, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Sulzberger et al disclose all of the subject matter as applied to claims 1 and 4 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Sulzberger et al do not expressly disclose wherein an amplitude of the first amplified optical data signal that is sent from the BBU to the determined RRU is greater than an amplitude of the second amplified optical data signal that is sent from the one of the RRUs to the BBU.
However, as disclosed by Zeb ‘942, Li et al and Sulzberger et al, the central office (CO) or BBU needs to send optical signals to a plurality of RRU/RRH, but a RRU/RRH just sends optical signals to the CO/BBU, not another RRU/RRH; therefore, it is obvious to one skilled in the art that the amplitude of the first amplified optical data signal that is sent from the BBU to the determined RRU is greater than an amplitude of the second amplified optical data signal that is sent from the one of the RRUs to the BBU, so that an enough signal strength can be received by any one of the plurality of RRU/RRH.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claim 1 above, and further in view of Zeng et al (US 2016/0308641).
Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL do not expressly disclose the corresponding signal processing system converts a third data packet and a fourth data packet into in-phase and quadrature (“I/Q”) analog data signals.
However, first, as discussed in claim 1 rejection, the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL discloses wherein the first operations further comprise: receiving, by the BBU controller and using the data network interface, data packets for transmission to the one of the plurality of RRUs; converting, by the corresponding signal processing system, the data packets into analog data signals, respectively; converting, by the corresponding first electrical to optical transducer, the analog data signals into optical control signals; generating, by the corresponding first laser, optical data signals based on the optical control signals; causing, by the corresponding first optical amplifier, amplification of the optical data signal to produce amplified optical data signals; and sending the amplified optical data signal to the determined RRU via the corresponding first multiplexer, over the corresponding HCF fronthaul link, and via the corresponding first demultiplexer. It is obvious to one skilled in the art that the same system can be used to convert the data packets into “I/Q” analog data signals and send “I/Q” optical data signal to corresponding RRU.
Second, Zeng et al discloses a radio-over-fiber system (Figures 1-5 etc.), in which received data packets ([0028], “transport packets, such as Ethernet packets, between the BBU pool 120 and the core network 150”, and [0032]-[0033]) are converted into in-phase and quadrature (“I/Q”) analog data signals (Figure 2, high-speed DAC 263 in Figure 2; and DAC 363 in Figure 3 etc.; [0027], [0036]-[0037] etc., and Figure 6, I/Q channel Data input, and then DAC 617 converts the digital I/Q into analog I/Q data signal).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the I/Q modulation format as taught by Zeng et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so to use the system to transmit I/Q signals to increase system capacity.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claim 1 above, and further in view of Wang et al (US 2022/0303013).
Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL do not expressly disclose wherein the BBU further comprises a first filter, wherein the first operations further comprise: filtering, using the first filter, the first optical data signal prior to amplification by the corresponding first optical amplifier.
However, to use an optical filter to obtain desired wavelength component is known in the art. E.g., Wang et al discloses a radio-over-fiber system (Figures 1, 3-4, 8, 14, 56A, 57A, 58A, 71A, 72A and 73A), in which the BBU further comprises a first filter (optical filter O-F1 etc.; the O-F filters an analog optical signal, [0137] etc.), wherein the first operations further comprise: filtering, using the first filter, the first optical data signal prior to amplification by the corresponding first optical amplifier (O-PA). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply an optical filter as taught by Wang et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so that a desired frequency/wavelength component can be obtained, and noise can be reduced.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claim 1 above, and further in view of Nishimoto et al (US 2020/0112372) and Sung et al (US 2018/0152245).
Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 1 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL do not expressly disclose wherein each RRU further comprises a second filter, wherein the second operations further comprise: filtering, using the second filter, the second analog signal prior to sending the first RF signal.
However, Nishimoto et al discloses a radio-over-fiber system/method (Figures 2,4, 6 and 8 etc.), in which the RRU comprises a second filter (e.g., 255 in Figure 8. [0047], “The band-pass filter 255 removes unnecessary frequency components from the input signal to generate a transmission electrical signal with a converted frequency in the RF band. The band-pass filter 255 outputs the frequency-converted transmission electrical signal to the multiplexing section 270 illustrated in FIG. 6 as a transmission RF signal v(t)”), wherein the second operations further comprise: filtering, using the second filter, a second analog signal (s(t)) prior to sending the first RF signal (Figure 6, from the frequency converting section 250 to the antenna 290). Another prior art, Sung et al discloses a similar system, and a RF filter (214 in Figure 2B, 317 in Figure 3B, 416 in Figure 4B, 517 in Figure 5B, 617 in Figure 6B, 720” in Figure 7B, 820” in Figure 8B, 922” in Figure 9B) is used “to filter the RF signal, and an antenna configured to output the filtered RF signal” and “the RF filters respectively corresponding to the frequency converters, and antennas each configured to output the filtered RF signal” ([0025]), “The RF filter 214 may filter the RF signal in view of a predetermined frequency band or a preset band” ([0073]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply an electrical filter as taught by Nishimoto et al and Sung et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so to removes unnecessary frequency components from the analog signal.
Claims 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL as applied to claim 11 above, and further in view of Sulzberger et al (US 2005/0152695).
1). With regard to claim 12, Zeb ‘942 and Miyasugi et al and Zeb NPL disclose all of the subject matter as applied to claim 11 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL further discloses computer-implemented method of claim 11, further comprising:
receiving, by a second antenna (Zeb ‘942: same antenna 112, which is used for transmission and receiving) at the RRU, a second RF signal (Zeb ‘942: Figures 1-2, the antenna receives a second RF signal from user equipment UE, [0019] and [0025] etc.);
converting, by the RRU controller (Zeb ‘942: LNA etc. in Figure 2; and Zeb NPL: LNA/DC/ADC/CPRI Framer), the second RF signal into a third analog data signal (Zeb NPL: Abstract “an entirely analog-radio-over fiber (A-RoF) based fronthual”);
converting, by a second electrical to optical transducer Zeb ‘942: optical modulator 138) at the RRU, the third analog data signal into a second optical data signal (output from the optical modulator 138);
causing, by a second optical amplifier at the RRU (OA (k) at RRH in Figure 4 of Zeb NPL), amplification of the second optical data signal to produce a second amplified optical data signal (Zeb ‘942: optical signals output from the OA (k) in Figure 4); and
sending the second amplified optical data signal to the BBU via a second multiplexer (e.g., Zeb ‘942: multiplexer 142), over one of the HCF-based fronthaul link or another HCF-based fronthaul link, and via a second demultiplexer (e,g., Zeb ‘942: demultiplexer 144);
receiving, by a second photodetector (Zeb ‘942: Figure 2, 164; also Zeb NPL: “E/O” or PD in Figures 2 and 4) at the BBU and from the second demultiplexer (Zeb ‘942: 144. Zeb NPL: Mode Demux), the second amplified optical data signal;
converting, by a second optical to electrical transducer (Zeb ‘942: Figure 2, 150 and ADC 154/156) at the BBU, the second amplified optical data signal into a fourth analog data signal (the outputs from the ADC);
converting, by the BBU controller, the fourth analog data signal into a second data packet (the output from the Baseband Signal Processing); and
sending, by the BBU controller and via a data network interface, the second data packet through a data network (Zeb NPL: e.g., backhaul and the core network).
In Figure 2, Zeb ‘942 also shows that the same antenna is used for transmission and reception; Zeb ‘942 does not expressly discloses a first antenna for transmission and second antenna for reception.
However, to use separated radio antennas for transmission and reception is known in the art, E.g., Sulzberger et al discloses a radio over fiber system/method (Figures 1-3), and as shown in Figure 1, radio transmitter 17 is separated from a radio receiver 24.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Sulzberger et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so that each remote radio unit/head can use individual transmission antenna and reception antenna for signal transmission to reduce conflict and interference, and the capacity can be increased.
2). With regard to claim 13, Zeb ‘942 and Miyasugi et al and Zeb NPL and Sulzberger et al disclose all of the subject matter as applied to claims 11 and 12 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Sulzberger et al do not expressly disclose wherein an amplitude of the first amplified optical data signal that is sent from the BBU to the RRU is greater than an amplitude of the second amplified optical data signal that is sent from the RRU to the BBU.
However, as disclosed by Zeb ‘942, Li et al and Sulzberger et al, the central office (CO) or BBU needs to send optical signals to a plurality of RRU/RRH, but a RRU/RRH just sends optical signals to the CO/BBU, not another RRU/RRH; therefore, it is obvious to one skilled in the art that the amplitude of the first amplified optical data signal that is sent from the BBU to the determined RRU is greater than an amplitude of the second amplified optical data signal that is sent from the one of the RRUs to the BBU, so that an enough signal strength can be received by any one of the plurality of RRU/RRH.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL and Sulzberger et al as applied to claims 11-12 above, and further in view of Zeng et al (US 2016/0308641)
Zeb ‘942 and Miyasugi et al and Zeb NPL and Sulzberger et al disclose all of the subject matter as applied to claim 1 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Sulzberger et al do not expressly disclose wherein the first analog data signal and the third analog data signals are each converted into at least one of a double-sideband modulated data signal or in-phase and quadrature (“I/Q”) analog data signals prior to transmission over corresponding HCF-based fronthaul link from the BBU and to the BBU, respectively.
However, Zeng et al discloses a radio-over-fiber system (Figures 1-5 etc.), in which in-phase and quadrature (“I/Q”) analog data signals are converted into in-phase and quadrature (“I/Q”) analog data signals prior to transmission over corresponding fiber-based fronthaul link (Figure 2, high-speed DAC 263 in Figure 2; and DAC 363 in Figure 3 etc.; [0027], [0036]-[0037] etc., and Figure 6, I/Q channel Data input, and then DAC 617 converts the digital I/Q into analog I/Q data signal. Figure 2: DAC 253 in RRU, and DAC 353 in RRU of Figure 3 etc., for converting the digital I/Q into analog I/Q data signal).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the I/Q modulation format as taught by Zeng et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so that the system can be more flexible, efficient, and versatile, and the system capacity can be increased with I/Q signals.
Claims 15-16 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb et al (WO 2024/086942; hereinafter Zeb ‘942) in view of Miyasugi et al (Miyasugi et al: “Optical Signal Delay Processor for a Beamforming Antenna in a Radio over Fiber System”, 2024 IEEE Photonics Society Summer Topicals Meeting Series (SUM), 15-17 July 2024, paper no. TuA1.3) and Zeb et al (Zeb et al: “High Capacity Mode Division Multiplexing Based MIMO Enabled All-Optical Analog Millimeter-Wave Over Fiber Fronthaul Architecture for 5G and Beyond”, IEEE Access, SPECIAL SECTION ON ROADMAP TO 5G: RISING TO THE CHALLENGE, July 2019, pages 89522-89533; hereinafter Zeb NPL) and Li et al (US 2022/0303020) and Wang et al (US 2025/0293773).
1). With regard to claim 15, Zeb ‘942 discloses a system (Figures 1-4), comprising:
a plurality of remote radio units (“RRUs”) (a plurality of RRH/RRU in Figure 1, [0019] “remote radio heads/units (RRHs)Z(RRUs) 24”; or 108 in Figure 2, [0021], “The system design of Figure 2 can be used to realize SISO and/or M-MIMO without or with OBF configuration in various frequency bands with single or multi-beam operation with few or large number of RRHs/RRUs depending on the network requirements”, and [0027]) each comprising a RRU controller (since it is a RRH/RRU, it is obvious to one skilled in the art that the RRH/RRU has a controller to control the components of the RRH/RRU; also as shown in Figure 2, an optical beam forming network, OBFN 110 is used; and [0021], “The OBFN 110 may comprise of variable optical attenuators and optical true time delay lines (OTTDLs) for controlling the relative amplitudes and relative time delays of the signals that excite the antenna elements in accordance with the intended beam shape and beam direction”; then, the OBFN is a type of RRU controller), laser wavelength (from OC 131 and WSS 140), an electrical to optical transducer (optical modulator 138), and an antenna (112);
a plurality of multiplexers (122 and 142 etc.);
a baseband unit (“BBU”) (the central office CO 12 in Figure 1, CO 104 in Figure 3, CO 202 in Figure 3, or CO 404 in Figure 4; [0021]) comprising a BBU controller (102 in Figure 2, Baseband Signal Processing unit BBU; and BBU in Figures 3-4), a data network interface (as shown in Figures 2-4, data signals are input, shown with “->” symbol, and output, shown with “<-” symbol, from the BBU; also since it is a BBU, it is commonly that a BBUs connect to a core network (backhaul); and a BBU acts as an interface between the radio equipment (like Remote Radio Units, RRUs) and the wired network infrastructure, enabling voice and data transmission between mobile devices and the core network; therefore, it is obvious to one skilled in the art that CO/BBU has a data network interface used to input/output data signals), a plurality of signal processing systems (DSP module and baseband signal processing in the BBU and DAC and ADC in Figure 2), a plurality of optical to electrical transducers (PDC 150, including an array of photo detectors along with other components such as couplers etc., “time delay or phase and amplitude adjustments, as shown by element 162”), a plurality of photodetectors (164 or 160), and a demultiplexer (144); and
a plurality of fiber-based fronthaul links ([0019], “The plurality of modulated optical signals and optical LOs may be multiplexed over a long standard single mode fiber (s) (SSFM) or spatial few/multi-mode/core or spatial modes fiber (s) 20 for transmission to remote radio heads/units (RRHs)Z(RRUs) 24”) each established between one of the plurality of multiplexers (e.g., 122 or 142) and one of the plurality of demultiplexers (e.g., 144);
wherein a first RRU (e.g., 108 in Figure 2) among the plurality of RRUs performs first operations comprising:
receiving, by the antenna, a first radio frequency (“RF”) signal (Figures 1-2, the antenna 112 receives a first RF signal from user equipment UE, [0019] and [0025] etc.);
converting, by the RRU controller (Figure 2 does not expressly show a RRU controller to control the RF signals from the antenna, however, as disclosed in [0026], the WSS is controlled; therefore, it is obvious to one skilled in the art that a control in the RRU is used to control the RF signal and amply the RF signal with LNA), the first RF signal into a first analog data signal (analog data signal from the LNA);
converting, by the electrical to optical transducer (OM 138), the first analog data signal into a first optical control signal (the outputs from the OM 138);
generating, by laser wavelength (from the OC 131 and WSS 140), a first optical data signal (output from the OM 138 and MUX 142) based on the first optical control signal (analog data signal is carried on the laser wavelength);
sending the first optical data signal to the BBU via a multiplexer (142) among the plurality of multiplexers, over a fiber fronthaul link (124) among the plurality of fiber-based fronthaul links, and via a demultiplexer (e.g., 144) among the plurality of demultiplexers;
wherein the BBU performs second operations comprising:
receiving, by a photodetector (164 or 160) among the plurality of photodetectors and from the demultiplexer (144), the first optical data signal;
converting, by an optical to electrical transducer (150 including photodetectors) among the plurality of optical to electrical transducers, the first optical data signal into a second analog data signal (the output from the PDC Module 150);
converting, by a signal processing system (ADC and DSP/Baseband Signal Processing 102) among the plurality of signal processing systems, the second analog data signal into a first data signal (the output from the BBU 102); and
sending, by the BBU controller (BBU 102) and via the data network interface, the first data signal through a data network (as shown in Figures 2-4, data signals are input, shown with “->” symbol, and output, shown with “<-” symbol, from the BBU; also since it is a BBU, it is commonly that a BBUs connect to a core network (backhaul); and a BBU acts as an interface between the radio equipment (like Remote Radio Units, RRUs) and the wired network infrastructure, enabling voice and data transmission between mobile devices and the core network; therefore, it is obvious to one skilled in the art that CO/BBU has a data network interface used to input/output data signals).
But, Zeb ‘942 does not expressly disclose: the RRU has an optical amplifier that causes amplification of the first optical data signal to produce a first amplified optical data signal, and a laser; the BBU has a plurality of demultiplexers; the fiber-based fronthaul links are a plurality of hollow core fiber (“HCF”)-based fronthaul link, and a data packet is sent through the data network.
Regarding the HCF, it is commonly known that the HCF has the advantages of high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects. And the HCF has been used in radio-over-fiber system; e.g., Miyasugi et al discloses a radio-over-fiber (ROF) system/method (Figure 1 etc.), in which a plurality of hollow-core fibers are used for signal transmissions between a base station (radio unit at the left side of Figure 1) and remote radio heads.
Regarding the data packet and an optical amplifier in RRU, Zeb NPL (same research group as Zeb ‘942) discloses a high capacity ROF system (Figures 1-4), and teaches that the data signal can be a data packet (page 89523 right column “The RRHs transmit and receive the radio frequency (RF) signals over the air interface, whereas the BBUs perform the base band and packet processing in a cloud environment as shown in Figure 1(c)”), and an amplifier (OA (k) at RRH in Figure 4) can be used to amplify an optical data signal to produce an amplified optical data signal. And in Figures 1 and 3, Zeb NPL also discloses that the BBU connects to core network.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Miyasugi et al and Zeb NPL to the system/method of Zeb ‘942 so that a ROF system with high speed, lower attenuation, broader low-loss spectrum and reduced nonlinear effects can be obtained, and the system can be used to transmit data packet, and a desired power level of each modulated data signal in RRU can be obtained by a respective optical amplifier.
Regarding a laser in the RRU, in Figure 2 of Zeb ‘942, the laser wavelengths are from a splitter OC 131, which splits portion of received optical signals from the Central Office to the WSS 140; that is, the RRH/RRU does not have an individual laser for optical signal transmission from the RRU to BBU.
However, Li et al discloses a radio over fiber system/method (Figures 5 and 9-10 etc.), and in each remote radio unit (e.g., 520 in Figure 5, there is a laser (e.g., in the electrical-to-optical conversion module 523); and in Figure 6-8, Li et al teaches that the electrical-to-optical conversion module can be a directly modulated laser source, or can include an external modulator (5122 or 5124) that modulates optical carrier from a laser source (5123 or 5125).
Regarding a plurality of demultiplexers in BBU, first, Zeb NPL discloses that the Central Office is a “BBU pool” (Figure 1(c) and Figure 3), and each BBU can be correspond to a specific RRU/RRH group; and as shown in Figure 4, a BBU has a multiplexer and a demultiplexer, and a RRH also has a demultiplexer and multiplexer; therefore, for the systems shown in Figure 1(c) and Figure 3, it is obvious to one skilled in the art that the system has a plurality of RRUs, a plurality of multiplexer, a plurality of demultiplexer etc. Also, Li et al discloses that a base unit in the central office (Figures 9A and 11A) has a multiplexer (MUX) and demultiplexer (Demux), and other multiplexer and demultiplexer (Figures 9B and 11B) are associated with remote radio unit (Figures 9B-9E and Figures 11B-11D). Another prior art, Wang et al, discloses a radio over fiber system (Figure 5), as shown in Figure 5, in Manner 3, “the BBU may be connected to one or more RRUs/AAUs via components such as multiplexers/demultiplexers and distribution frames” ([0132]), a plurality of multiplexers/demultiplexers are in BBU, and also a plurality of multiplexers/demultiplexers are associated with RRUs; and Wang et al also discloses that a radio unit can have a controller (processor 1211 in Figure 12) to control/process the signal in the radio unit ([0239]-[0240] etc.).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Li et al and Wang et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL so that each remote radio unit/head can use its own laser to transmit optical signals to the central office with a RRU controller, and a plurality multiplexers/demultiplexers can be used to connect plurality baseband units and remote radio units so to increasing system capacity and cover more service areas.
2). With regard to claim 16, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al disclose all of the subject matter as applied to claim 1 above. And the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al further discloses wherein the first RF signal is received over one of a thousand band (“T-band”) channel, an original band (“O-band”) channel, a conventional band (“C-band”) channel, a long wavelength band (“L-band”) channel, a 4G spectrum channel, a 5G spectrum channel, or a millimeter wave (“mmWave”) channel (Zeb ‘942: [0002], [0008], [0019]. Zeb NPL: section “I. Introduction”).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al as applied to claim 15 above, and further in view of Zeng et al (US 2016/0308641).
Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al disclose all of the subject matter as applied to claim 15 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al do not expressly disclose wherein the first analog data signal is converted into in-phase and quadrature (“I/Q”) analog data signals that are converted into I/Q optical data signals that are transmitted over I/Q channels over the HCF fronthaul link to the BBU.
However, first, as discussed in claim 15 rejection, the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al discloses that the RF signal received by the antenna is converted into optical signals that are transmitted over the HCF fronthaul link to the BBU. An “I/Q” signal is a type of signal representation and modulation format, and I/Q signal has been widely used in RF applications; it is obvious to one skilled in the art that the same system as disclosed by the combination of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al can be used to convert the data packets into “I/Q” analog data signals and send “I/Q” optical data signal to corresponding RRU.
Second, Zeng et al discloses a radio-over-fiber system (Figures 1-5 etc.), in which received data packets ([0028], “transport packets, such as Ethernet packets”, and [0032]-[0033]) are converted into in-phase and quadrature (“I/Q”) analog data signals (Figure 2, high-speed DAC 253 in Figure 2; and DAC 353 in Figure 3 etc.; [0027], [0035]-[0040] etc., and Figures 4 and 5 show a transmitter and a receiver, which are “employed by an RRU such as the RRUs 110, 210, and 310”, and “FIG. 7 is a schematic diagram of a structure of a wireless fronthaul data frame 700 according to an embodiment of the disclosure. The frame 700 may be employed by an RRU such as the RRUs 110, 210, and 310”, 711 is the I/Q channel; I/Q data signals are transmitted over I/Q channels).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the I/Q signal format as taught by Zeng et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al so that the system can be more flexible, efficient, and versatile, and the system capacity can be increased with I/Q signals.
Claims 18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al as applied to claim 15 above, and further in view of Mazarathy et al (US 2019/0280774).
1). With regard to claim 18, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al disclose all of the subject matter as applied to claim 15 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al do not expressly disclose wherein the first analog data signal is converted into a double-sideband modulated data signal.
However, double-sidebband modulation has been widely used in radio-over-fiber (RoF) system, e.g., Mazarathy et al discloses a RoF system (Figures 1-2, 5, 7-10 etc.), and “the optical transport link is fed at its Tx side by a bandpass information-bearing electrical message signal b(t) (to be further DSB modulated onto an optical carrier)” (DSB: Double Sideband [0112]. [0079], [0127], [0145]-[0147], [0163], [0182], [0285] and [0294]-[0301] etc.).
It is commonly known that double-sideband signal has the advantages of higher power efficiency, simpler bandwidth and spectral efficiency, reduced interference etc. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the double-sideband modulated as taught by Mazarathy et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al so that the system can be more power efficient, and intermodulation interference can be reduced.
2). With regard to claim 20, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al disclose all of the subject matter as applied to claim 15 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al do not expressly disclose wherein the BBU further comprises a plurality of second filters, wherein the second operations further comprise: filtering, using a corresponding second filter among the plurality of second filters, the second analog data signal prior to conversion into the first data packet.
However, to use an electrical filter to filter desired analog signal and remove noise etc. is well known in the art. E.g., Mazarathy et al discloses a RoF system (Figures 2, 5, 7, 12-14 and 19-20 etc.), the TX (140, 400, 600 and 1100 etc.) is a remote radio unit that receives RF signal from an antenna (102; [0118]) and converts the RF signal into an optical signal (by E-O IQ MOD), and sends the optical signal to the RX vis multiplexer (118) and demultiplexer (124); and the RX (150 etc.) can be viewed as a base unit, which “includes a de-multiplexer 124, multiple photodiodes (PD) {such as PD 126} that may be followed by at least one of (i) amplifier 128 and band pass filter BPF 130 and (ii) analog to digital converter 132” ([0555]); that is, an electrical filter (BPF) is used in the base unit to extract desired/useful band and remove undesired frequency components.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply an electrical filter as taught by Mazarathy et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al so that the central office (BBU) can use the electrical filter to filter the desired analog data signal after the optical-to-electrical conversion, and remove noise and undesired frequency components.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al as applied to claim 15 above, and further in view of Wang et al (US 2022/0303013).
Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al disclose all of the subject matter as applied to claim 15 above. But, Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al do not expressly disclose wherein each RRU further comprises a first filter, wherein the first operations further comprise: filtering, using the first filter, the first optical data signal prior to amplification by the optical amplifier.
However, to use an optical filter to remove noise and obtain desired wavelength/frequency component is well known in the art. E.g., Wang et al discloses a radio-over-fiber system (Figures 1, 16-25), in which the RRU comprises a first filter (OF-F4 in Figures 16 and 18-25) to filter an optical data signal (from the E/O module 221-22M) prior to amplification by an optical amplifier (O-PA44).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply an optical filter as taught by Wang et al to the system/method of Zeb ‘942 and Miyasugi et al and Zeb NPL and Li et al and Wang et al so to reduce noise and obtain desired wavelength/frequency component.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
WO 2026021047 A1
EP 4231548 A1
US 20180152244 A1
US 20150031316 A1
US 20140355991 A1
US 20140153919 A1
US 20140010548 A1
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/LI LIU/Primary Examiner, Art Unit 2634 June 26, 2026
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