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 .
1. This office action, in response to the amendment filed 2/9/2026, is a final office action.
Response to Amendment and Arguments
2. The amendments to claims 1, 8 and 14 are addressed in the rejections stated below. Applicant states the previously cited references do not disclose the newly added features on page 8 of the remarks. The examiner disagrees. Yoshido discloses the circuit shown in figure 3. Figure 3 shows channel estimation unit 101 conducting channel estimation. After the channel estimation has been determined, an output from the channel estimation unit 101 is provided to the delayed wave detector 103 and then to the ISI replica generator 104 to provide the input to subtractor 102. Figure 3 of Yoshido was cited in the previous rejections of claims 1, 8 and 14.
Applicant states Martinez does not disclose the amended features of claims 1, 8 and 14 on pages 8-10 of the remarks. However, the previous rejections of the claims cited Martinez in view of Yoshido and Dhakai. These references disclose the amended claims.
Applicant states Yoshido does not disclose the amended features on pages 10-11 of the remarks. Applicant states Yoshido mentions the application of a channel estimation but only after the ISI replica has already been determined. The examiner disagrees. Yoshido discloses the receiver shown in figure 3. The receiver comprises channel estimation unit 101 coupled to GI-exceed delayed wave detector 103, ISI replica generator 104 and subtractor 102. Paragraph 0046 discloses signal processing in a time domain is executed before FFT processing. Paragraph 0046 further discloses delay profile measurement by the channel estimation unit 101 is input to the GI exceeded delay wave detector 103 to perform monitoring to determine whether a delayed wave has exceeded the guard interval length of the data symbol has been observed. Paragraph 0047 describes a method of generating an ISI replica. The data symbol partially overlaps the pilot symbol of the delayed wave and sustains ISI from the pilot symbol P of the delayed wave. It is necessary to remove this portion of the pilot symbol from the receive symbol. Figure 4A and 4B shows direct wave A and delayed wave B, which includes the pilot P and the ISI. Paragraph 0047 further discloses the time (number of samples) subjected to interference is y. Accordingly, the ISI replica generator 104 cuts the y portion out of the known pilot-signal waveform and generates it as the ISI replica. A first channel compensator 105 multiplies the ISI replica by the channel estimation value to thereby apply channel compensation and inputs the result to subtractor 102. The latter subtracts the ISI replica from the receive signal and input the difference to an FFT arithmetic unit 106. Yoshido discloses applying the channel estimation in the time domain (Figure 3: channel estimation unit 101. Paragraph 0046: signal processing in a time domain is executed before FFT processing.) to the as-transmitted version of the pilot and data symbols (Figure 3. Figure 4A direct wave) to determine an as-transmitted version of the pilot symbol that includes a delayed portion of the pilot symbol (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.), wherein the delayed portion of the pilot results in inter-symbol interference (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.).
The rejections of the amended claims is stated below.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
3. Claims 1, 2, 4, 5, 7-9, 11-15, 17, 18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Martinez et al (US 2020/0015111) in view of Yoshido (EP 1 523 143 A1) further in view of Dhakal et al (US 2016/0352539).
Regarding claim 1, Martinez discloses a radio frequency (RF) receiver, comprising:
an antenna configured to receive a received RF signal (Figure 3: antenna IQ samples 340), the received RF signal including a first RF signal encoding a first orthogonal frequency-division multiplexing (OFDM) symbol of a first long-term evolution (LTE) vehicle-to-everything(V2X) data packet (Paragraph 0028: Vehicles, such as automobiles, can include vehicular communications circuitry such as wireless communicating with other vehicles and/or circuitry using vehicular communications protocol, sometimes referred to as vehicle-to-everything (V2X) communications. Figures 1 and 2 shows the communication systems. Figure 5 shows the packet.); and
a signal processing system electrically connected to the antenna and being configured to receive the received RF signal (Figure 3A), the signal processing system being configured to perform steps including:
determining a channel estimation in a time domain using the received signal (Figure 3A: the signal is received and input to channel estimation block 346.);
determining an as-transmitted version of the reference L-LTF symbol, wherein the as-transmitted version of the L-LTF symbol is in the time domain (figure 3A: the signal is received and input to L-LTF samples block to determine the transmitted version of the L-LTF symbol. This block is in the time domain.),
applying the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol to determine an as-transmitted version of the L-LTF symbol (Figure 3A: the signal output from the L-LTF samples block 344 is input to the channel estimation block 346. These blocks are in the time domain. Paragraph 0064: the receiver side divides the signal into blocks of samples and separates the data field from the preamble (e.g., L-STF, L-LTF, and SIG) fields. The channel coefficient are estimated based on the preamble fields and based on the channel coefficients, an equalizer compensates the fading effects introduced by the channel. Therefore, the transmitted version of the L-LTF symbol exhibits channel fading.);
determining a legacy signal (L-SIG) field from the second received RF signal (Figure 3A: SIG samples 348 and SIG decoding 350), and
decoding a data field from at least one of the received RF signal and the second received RF signal using the L-SIG field (Figure 3A: SIG samples block 348 and SIG decoding block 350 is disclosed for determining a legacy signal field and for decoding that field. DATA samples block 352 is also disclosed in the receiver.). .
Martinez does not disclose applying a channel estimation that includes a delayed portion of the known symbol, wherein the delayed portion of the known symbol results in ISI and subtracting the delayed portion of the known symbol from a second portion of the received RF signal to remove inter-symbol interference from the received signal and to generate a second received RF signal.
Yoshido discloses a receiver in an OFDM transmission system including a channel estimation unit 101 and an ISI replica generator 104 for generating a ISI replica and for subtracting the ISI replica from a received signal (abstract) as shown in figure 3. Figure 3 shows a signal is received and input to the channel estimation unit 101. The channel estimation unit is used to determine the ISI replica in ISI replica generator 104. The received signal is input to subtractor 102. A second portion of the received signal is fed back to the ISI replica generator 104 and is subtracted from the received signal in subtractor 102 to remove the ISI replica from the received signal. This will remove inter-symbol interference (ISI) from the received signal. Paragraph 0046 discloses signal processing in a time domain is executed before FFT processing. Paragraph 0046 further discloses delay profile measurement by the channel estimation unit 101 is input to the GI exceeded delay wave detector 103 to perform monitoring to determine whether a delayed wave has exceeded the guard interval length of the data symbol has been observed. Paragraph 0047 describes a method of generating an ISI replica. The data symbol partially overlaps the pilot symbol of the delayed wave and sustains ISI from the pilot symbol P of the delayed wave. It is necessary to remove this portion of the pilot symbol from the receive symbol. Figure 4A and 4B shows direct wave A and delayed wave B, which includes the pilot P and the ISI. Paragraph 0047 further discloses the time (number of samples) subjected to interference is y. Accordingly, the ISI replica generator 104 cuts the y portion out of the known pilot-signal waveform and generates it as the ISI replica. A first channel compensator 105 multiplies the ISI replica by the channel estimation value to thereby apply channel compensation and inputs the result to subtractor 102. The latter subtracts the ISI replica from the receive signal and input the difference to an FFT arithmetic unit 106. Yoshido discloses applying the channel estimation in the time domain (Figure 3: channel estimation unit 101. Paragraph 0046: signal processing in a time domain is executed before FFT processing.) to the as-transmitted version of the pilot and data symbols (Figure 3. Figure 4A direct wave) to determine an as-transmitted version of the pilot symbol that includes a delayed portion of the pilot symbol (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.), wherein the delayed portion of the pilot results in inter-symbol interference (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of removing inter-symbol interference (ISI) from received signal as taught by Yoshido into the receiver of Martinez. By removing interference, the receiver can better process and recover the information of the received signal, improving the efficiency of the communication system.
The combination of Martinez and Yoshido does not disclose converting the received RF signal into a received RF signal in a frequency domain; calculating a channel estimation in the frequency domain using a reference legacy long training field (L-LTF) symbol and the received RF signal in the frequency domain; converting the channel estimation in the frequency domain to a channel estimation in a time domain.
Dhakal discloses the receiver shown in figure 4. Dhakal discloses an antenna for receiving an RF signal. An FFT 302 converts the RF signal into a received RF signal in a frequency domain. A channel estimation in the frequency domain using a known training signal and the received RF signal in the frequency domain is calculated in the frequency domain channel estimation block 306. The channel estimation in the frequency domain is converted to a channel estimation in a time domain in IFFT 416. A channel estimation in a time domain is determined and applied in time domain channel estimation block 420. The time domain channel estimation is output on line 422. Paragraph 0002 discloses estimation of the channel conditions between the transmitter and the receiver is a necessary step for many communication systems to enable detection and optimal processing of a data stream received from a signal source. So as to enable the necessary channel estimation, most of these systems embed references symbols in the data stream that are known a priori to the receiver. Paragraph 0011 discloses the method includes receiving raw time domain data representing a plurality of known reference symbols.
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the method of determining the channel estimation as disclosed in Dhakal for the channel estimation of the method of the combination of Martinez and Yoshido to accomplish the goals stated in paragraph 0009 of Dhakal and to overcome previous issues with channel estimation as stated in paragraphs 0005-0008. This will allow the method of the combination to operate more efficiently and effectively.
Regarding claim 2, the combination discloses wherein the signal processing system is configured to perform the step of determining the as-transmitted version of the L-LTF symbol by performing steps including applying an inverse discrete Fourier transform on the reference L- LTF symbol to generate a time domain version of the reference L-LTF symbol (Martinez: figure 3A: the received signal is provided to the L-LTF samples block 344 and the channel estimation block 346. Dhakal: figure 4: the received signal is input to the FFT 302, the frequency domain channel estimation 306, IFFT 416, time domain channel estimation 420 and outputs signal 422.).
Regarding claim 4, the combination discloses wherein the received RF signal includes a second RF signal encoding a second OFDM symbol of a second LTE V2X data packet (The method of the combination may be repeated for any number of packets. Martinez shows the plurality of data packets in figure 5. Yoshido discloses the packets in figures 1 , 4A and 4B. Figure 2 shows the delay profile and duration of the guard intervals. Where the data packets originate does not limit the claim in terms of scope since it does not require a step to be performed at a receiver or limits a receiver in terms of structure. The receiver does not control the origin of the content of a transmission to be received.).
Regarding claim 5, the combination discloses wherein the second RF signal is delayed with respect to the first RF signal by a time period greater than a duration of a cyclic prefix encoded into the first RF signal (Martinez shows the plurality of data packets in figure 5. Yoshido discloses the packets in figures 1 , 4A and 4B. Figure 2 shows the delay profile and duration of the guard intervals.).
Regarding claim 7, the data or message content of a received signal does not limit the scope of the claim since it does not require a step to be performed or limits an apparatus in terms of structure. The receiver does not control what data content is sent to the receiver. The encoding takes place at a transmitter, not the receiver.
Regarding clam 8, Martinez discloses a method, comprising:
receiving a received RF signal, the received RF signal including a first RF signal encoding a first orthogonal frequency-division multiplexing (OFDM) symbol of a first long-term evolution (LTE) V2X data packet (Paragraph 0028: Vehicles, such as automobiles, can include vehicular communications circuitry such as wireless communicating with other vehicles and/or circuitry using vehicular communications protocol, sometimes referred to as vehicle-to-everything (V2X) communications. Figures 1 and 2 shows the communication systems. Figure 5 shows the packet.);
determining a channel estimation in a time domain using the received signal (Figure 3A: the signal is received and input to channel estimation block 346.);
determining an as-transmitted version of an L-LTF symbol in the time domain (figure 3A: the signal is received and input to L-LTF samples block to determine the transmitted version of the L-LTF symbol. This block is in the time domain.); and
applying the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol to determine an as-transmitted version of the L-LTF symbol (Figure 3A: the signal output from the L-LTF samples block 344 is input to the channel estimation block 346. These blocks are in the time domain. Paragraph 0064: the receiver side divides the signal into blocks of samples and separates the data field from the preamble (e.g., L-STF, L-LTF, and SIG) fields. The channel coefficient are estimated based on the preamble fields and based on the channel coefficients, an equalizer compensates the fading effects introduced by the channel. Therefore, the transmitted version of the L-LTF symbol exhibits channel fading.).
Martinez does not disclose applying a channel estimation that includes a delayed portion of the known symbol, wherein the delayed portion of the known symbol results in ISI and subtracting the delayed portion of the known symbol from a second portion of the received RF signal to remove inter-symbol interference from the received signal and to generate a second received RF signal.
Yoshido discloses a receiver in an OFDM transmission system including a channel estimation unit 101 and an ISI replica generator 104 for generating a ISI replica and for subtracting the ISI replica from a received signal (abstract) as shown in figure 3. Figure 3 shows a signal is received and input to the channel estimation unit 101. The channel estimation unit is used to determine the ISI replica in ISI replica generator 104. The received signal is input to subtractor 102. A second portion of the received signal is fed back to the ISI replica generator 104 and is subtracted from the received signal in subtractor 102 to remove the ISI replica from the received signal. This will remove inter-symbol interference (ISI) from the received signal. Paragraph 0046 discloses signal processing in a time domain is executed before FFT processing. Paragraph 0046 further discloses delay profile measurement by the channel estimation unit 101 is input to the GI exceeded delay wave detector 103 to perform monitoring to determine whether a delayed wave has exceeded the guard interval length of the data symbol has been observed. Paragraph 0047 describes a method of generating an ISI replica. The data symbol partially overlaps the pilot symbol of the delayed wave and sustains ISI from the pilot symbol P of the delayed wave. It is necessary to remove this portion of the pilot symbol from the receive symbol. Figure 4A and 4B shows direct wave A and delayed wave B, which includes the pilot P and the ISI. Paragraph 0047 further discloses the time (number of samples) subjected to interference is y. Accordingly, the ISI replica generator 104 cuts the y portion out of the known pilot-signal waveform and generates it as the ISI replica. A first channel compensator 105 multiplies the ISI replica by the channel estimation value to thereby apply channel compensation and inputs the result to subtractor 102. The latter subtracts the ISI replica from the receive signal and input the difference to an FFT arithmetic unit 106. Yoshido discloses applying the channel estimation in the time domain (Figure 3: channel estimation unit 101. Paragraph 0046: signal processing in a time domain is executed before FFT processing.) to the as-transmitted version of the pilot and data symbols (Figure 3. Figure 4A direct wave) to determine an as-transmitted version of the pilot symbol that includes a delayed portion of the pilot symbol (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.), wherein the delayed portion of the pilot results in inter-symbol interference (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of removing inter-symbol interference (ISI) from received signal as taught by Yoshido into the receiver of Martinez. By removing interference, the receiver can better process and recover the information of the received signal, improving the efficiency of the communication system.
The combination of Martinez and Yoshido does not disclose converting the received RF signal into a received RF signal in a frequency domain; calculating a channel estimation in the frequency domain using a reference legacy long training field (L-LTF) symbol and the received RF signal in the frequency domain; converting the channel estimation in the frequency domain to a channel estimation in a time domain.
Dhakal discloses the receiver shown in figure 3. Dhakal discloses an antenna for receiving an RF signal. An FFT 302 converts the RF signal into a received RF signal in a frequency domain. A channel estimation in the frequency domain using a known training signal and the received RF signal in the frequency domain is calculated in the frequency domain channel estimation block 306. The channel estimation in the frequency domain is converted to a channel estimation in a time domain in IFFT 416. A channel estimation in a time domain is determined and applied in time domain channel estimation block 420. The time domain channel estimation is output on line 422. Paragraph 0002 discloses estimation of the channel conditions between the transmitter and the receiver is a necessary step for many communication systems to enable detection and optimal processing of a data stream received from a signal source. So as to enable the necessary channel estimation, most of these systems embed references symbols in the data stream that are known a priori to the receiver. Paragraph 0011 discloses the method includes receiving raw time domain data representing a plurality of known reference symbols.
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the method of determining the channel estimation as disclosed in Dhakal for the channel estimation of the method of the combination of Martinez and Yoshido to accomplish the goals stated in paragraph 0009 of Dhakal and to overcome previous issues with channel estimation as stated in paragraphs 0005-0008. This will allow the method of the combination to operate more efficiently and effectively.
Regarding claim 9, the combination discloses wherein the signal processing system is configured to perform the step of determining the as-transmitted version of the L-LTF symbol by performing steps including applying an inverse discrete Fourier transform on the reference L- LTF symbol to generate a time domain version of the reference L-LTF symbol (Martinez: figure 3A: the received signal is provided to the L-LTF samples block 344 and the channel estimation block 346. Dhakal: figure 4: the received signal is input to the FFT 302, the frequency domain channel estimation 306, IFFT 416, time domain channel estimation 420 and outputs signal 422.).
Regarding claim 11, the combination discloses determining a legacy signal (L-SIG) field from the second received RF signal, and decoding a data field from at least one of the received RF signal and the second received RF signal using the L-SIG field (Martinez: Figure 3A: SIG samples block 348 and SIG decoding block 350 is disclosed for determining a legacy signal field and for decoding that field. DATA samples block 352 is also disclosed in the receiver.).
Regarding claim 12, the data or message content of a received signal does not limit the scope of the claim since it does not require a step to be performed or limits an apparatus in terms of structure. The receiver does not control what data content is sent to the receiver. The encoding takes place at a transmitter, not the receiver.
Regarding claim 13, the combination discloses wherein the received RF signal includes a second RF signal encoding a second OFDM symbol of a second LTE V2X data packet transmitted by a second remote transmitter and the second RF signal is delayed with respect to the first RF signal by a time period greater than a duration of a cyclic prefix encoded into the first RF signal and subtracting the delayed portion of the as-transmitted version of the L-LTF symbol to remove inter-symbol interference from the received signal further comprises removing the inter-symbol interference caused by the delay of the second RF signal (The method of the combination may be repeated for any number of packets. Martinez shows the plurality of data packets in figure 5. Yoshido discloses the packets in figures 1 , 4A and 4B. Figure 2 shows the delay profile and duration of the guard intervals. Where the data packets originate does not limit the claim in terms of scope since it does not require a step to be performed at a receiver or limits a receiver in terms of structure. The receiver does not control the origin of the content of a transmission to be received.).
Regarding claim 14, Martinez discloses a radio frequency (RF) receiver (Figure 3A), comprising:
an antenna configured to receive a received RF signal (Figure 3A: antenna IQ samples.), the received RF signal including a first RF signal encoding a first orthogonal frequency-division multiplexing (OFDM) symbol of a first long-term evolution (LTE) V2X data packet (Paragraph 0028: Vehicles, such as automobiles, can include vehicular communications circuitry such as wireless communicating with other vehicles and/or circuitry using vehicular communications protocol, sometimes referred to as vehicle-to-everything (V2X) communications. Figures 1 and 2 shows the communication systems. Figure 5 shows the packet.);
a signal processing system coupled to the antenna (Figure 3A), the signal processing system configured to:
determine a channel estimation in a time domain using the received signal (Figure 3A: the signal is received and input to channel estimation block 346.);
determine an as-transmitted version of an L-LTF symbol in the time domain (figure 3A: the signal is received and input to L-LTF samples block to determine the transmitted version of the L-LTF symbol. This block is in the time domain.); and
apply the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol to determine an as-transmitted version of the L-LTF symbol (Figure 3A: the signal output from the L-LTF samples block 344 is input to the channel estimation block 346. These blocks are in the time domain. Paragraph 0064: the receiver side divides the signal into blocks of samples and separates the data field from the preamble (e.g., L-STF, L-LTF, and SIG) fields. The channel coefficient are estimated based on the preamble fields and based on the channel coefficients, an equalizer compensates the fading effects introduced by the channel. Therefore, the transmitted version of the L-LTF symbol exhibits channel fading.).
Martinez does not disclose applying a channel estimation that includes a delayed portion of the known symbol, wherein the delayed portion of the known symbol results in ISI and subtracting the delayed portion of the known symbol from a second portion of the received RF signal to remove inter-symbol interference from the received signal and to generate a second received RF signal.
Yoshido discloses a receiver in an OFDM transmission system including a channel estimation unit 101 and an ISI replica generator 104 for generating a ISI replica and for subtracting the ISI replica from a received signal (abstract) as shown in figure 3. Figure 3 shows a signal is received and input to the channel estimation unit 101. The channel estimation unit is used to determine the ISI replica in ISI replica generator 104. The received signal is input to subtractor 102. A second portion of the received signal is fed back to the ISI replica generator 104 and is subtracted from the received signal in subtractor 102 to remove the ISI replica from the received signal. This will remove inter-symbol interference (ISI) from the received signal. Paragraph 0046 discloses signal processing in a time domain is executed before FFT processing. Paragraph 0046 further discloses delay profile measurement by the channel estimation unit 101 is input to the GI exceeded delay wave detector 103 to perform monitoring to determine whether a delayed wave has exceeded the guard interval length of the data symbol has been observed. Paragraph 0047 describes a method of generating an ISI replica. The data symbol partially overlaps the pilot symbol of the delayed wave and sustains ISI from the pilot symbol P of the delayed wave. It is necessary to remove this portion of the pilot symbol from the receive symbol. Figure 4A and 4B shows direct wave A and delayed wave B, which includes the pilot P and the ISI. Paragraph 0047 further discloses the time (number of samples) subjected to interference is y. Accordingly, the ISI replica generator 104 cuts the y portion out of the known pilot-signal waveform and generates it as the ISI replica. A first channel compensator 105 multiplies the ISI replica by the channel estimation value to thereby apply channel compensation and inputs the result to subtractor 102. The latter subtracts the ISI replica from the receive signal and input the difference to an FFT arithmetic unit 106. Yoshido discloses applying the channel estimation in the time domain (Figure 3: channel estimation unit 101. Paragraph 0046: signal processing in a time domain is executed before FFT processing.) to the as-transmitted version of the pilot and data symbols (Figure 3. Figure 4A direct wave) to determine an as-transmitted version of the pilot symbol that includes a delayed portion of the pilot symbol (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.), wherein the delayed portion of the pilot results in inter-symbol interference (figure 3 shows the channel estimation used to remove the ISI portion of the signal utilizing the subtractor.).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of removing inter-symbol interference (ISI) from received signal as taught by Yoshido into the receiver of Martinez. By removing interference, the receiver can better process and recover the information of the received signal, improving the efficiency of the communication system.
The combination of Martinez and Yoshido does not disclose converting the received RF signal into a received RF signal in a frequency domain; calculating a channel estimation in the frequency domain using a reference legacy long training field (L-LTF) symbol and the received RF signal in the frequency domain; and converting the channel estimation in the frequency domain to a channel estimation in a time domain.
Dhakal discloses the receiver shown in figure 3. Dhakal discloses an antenna for receiving an RF signal. An FFT 302 converts the RF signal into a received RF signal in a frequency domain. A channel estimation in the frequency domain using a known training signal and the received RF signal in the frequency domain is calculated in the frequency domain channel estimation block 306. The channel estimation in the frequency domain is converted to a channel estimation in a time domain in IFFT 416. A channel estimation in a time domain is determined and applied in time domain channel estimation block 420. The time domain channel estimation is output on line 422. Paragraph 0002 discloses estimation of the channel conditions between the transmitter and the receiver is a necessary step for many communication systems to enable detection and optimal processing of a data stream received from a signal source. So as to enable the necessary channel estimation, most of these systems embed references symbols in the data stream that are known a priori to the receiver. Paragraph 0011 discloses the method includes receiving raw time domain data representing a plurality of known reference symbols.
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the method of determining the channel estimation as disclosed in Dhakal for the channel estimation of the method of the combination of Martinez and Yoshido to accomplish the goals stated in paragraph 0009 of Dhakal and to overcome previous issues with channel estimation as stated in paragraphs 0005-0008. This will allow the method of the combination to operate more efficiently and effectively.
Regarding claim 15, the combination discloses wherein the signal processing system is configured to perform the step of determining the as-transmitted version of the L-LTF symbol by performing steps including applying an inverse discrete Fourier transform on the reference L- LTF symbol to generate a time domain version of the reference L-LTF symbol (Martinez: figure 3A: the received signal is provided to the L-LTF samples block 344 and the channel estimation block 346. Dhakal: figure 4: the received signal is input to the FFT 302, the frequency domain channel estimation 306, IFFT 416, time domain channel estimation 420 and outputs signal 422.).
Regarding claim 17, the combination discloses wherein the received RF signal includes a second RF signal encoding a second OFDM symbol of a second LTE V2X data packet (The method of the combination may be repeated for any number of packets. Martinez shows the plurality of data packets in figure 5. Yoshido discloses the packets in figures 1 , 4A and 4B. Figure 2 shows the delay profile and duration of the guard intervals. Where the data packets originate does not limit the claim in terms of scope since it does not require a step to be performed at a receiver or limits a receiver in terms of structure. The receiver does not control the origin of the content of a transmission to be received.).
Regarding claim 18, the combination discloses wherein the second RF signal is delayed with respect to the first RF signal by a time period greater than a duration of a cyclic prefix encoded into the first RF signal (Martinez shows the plurality of data packets in figure 5. Yoshido discloses the packets in figures 1 , 4A and 4B. Figure 2 shows the delay profile and duration of the guard intervals.).
Regarding claim 20, the data or message content of a received signal does not limit the scope of the claim since it does not require a step to be performed or limits an apparatus in terms of structure. The receiver does not control what data content is sent to the receiver. The encoding takes place at a transmitter, not the receiver.
4. Claims 3, 10 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Martinez et al (US 2020/0015111) in view of Yoshido (EP 1 523 143 A1) in view of Dhakal et al (US 2016/0352539) further in view of Auer (US 2005/0147025).
Regarding claim 3, the combination of Martinez, Yoshida and Dhakal discloses the receiver stated above. The combination does not disclose wherein the signal processing system is configured to apply the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol by applying the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol as a finite impulse response filter.
Auer discloses a method of receiving MIMO-OFDM signals. The time domain channel response is obtained by filtering with a finite impulse response (FIR) filter as stated in paragraph 0021. FIR filters are low cost and well known. It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the FIR filter of Auer into the method of the combination of Martinez, Yoshida and Dhakal to reduce cost and complexity of the method and receiver.
Regarding claim 10, the combination of Martinez, Yoshida and Dhakal discloses the method stated above. The combination does not disclose applying the channel estimation to the as-transmitted version of the L-LTF symbol as a finite impulse response filter.
Auer discloses a method of receiving MIMO-OFDM signals. The time domain channel response is obtained by filtering with a finite impulse response (FIR) filter as stated in paragraph 0021. FIR filters are low cost and well known. It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the FIR filter of Auer into the method of the combination of Martinez, Yoshida and Dhakal to reduce cost and complexity of the method and receiver.
Regarding claim 16, the combination of Martinez, Yoshida and Dhakal discloses the receiver stated above. The combination does not disclose wherein the signal processing system is configured to apply the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol by applying the channel estimation in the time domain to the as-transmitted version of the L-LTF symbol as a finite impulse response filter.
Auer discloses a method of receiving MIMO-OFDM signals. The time domain channel response is obtained by filtering with a finite impulse response (FIR) filter as stated in paragraph 0021. FIR filters are low cost and well known. It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to combine the FIR filter of Auer into the method of the combination of Martinez, Yoshida and Dhakal to reduce cost and complexity of the method and receiver.
5. Claims 6 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Martinez et al (US 2020/0015111) in view of Yoshido (EP 1 523 143 A1) in view of Dhakal et al (US 2016/0352539) further in view of Manica et al (US 2021/0229952).
Regarding claims 6 and 19, the combination of Martinez, Yoshida and Dhakal discloses the receiver stated above including the guard interval in the packet to be received. The combination does not disclose wherein the duration of the cyclic prefix is equal to or less than 1.6 microseconds.
Manica discloses as a general rule, with a higher delay spread, a longer guard interval is used. In some examples, the wireless communication protocol includes a guard interval duration of at least 1.6 micro seconds. The IEEE 802.11p standard specifies the use of a 1.6 microsecond guard interval duration in paragraph 0030. It would have been obvious for one of ordinary skill in the art before the effective date of the claimed invention to combine the standard guard interval duration as disclosed by Manica into the communication system using the guard interval of the combination of Martinez, Yoshido and Dhakal. Using values specified by a standard will allow the system to be efficient and effective.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN M. BURD whose telephone number is (571)272-3008. The examiner can normally be reached 9:30 - 5:00.
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/KEVIN M BURD/Primary Examiner, Art Unit 2632 3/12/2026