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 .
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Eberlein et al. (US 6,931,084 B1), hereinafter “EBERLEIN” in view of Abdi et al. (US 2016/0316445 A1), hereinafter “ABDI” in view of Sakai et al. (US 2010/0202552 A1), hereinafter “SAKAI” .
Regarding claim 1, EBERLEIN teaches, ‘A method to enhance Gaussian and Rayleigh sensitivity performance of Digital Audio Broadcast (DAB) receivers, the method comprises the steps of:’ (Col. 1, lines 23-27, the present invention is particularly useful in multipath environments with low channel
coherence time… applied to systems implementing a multicarrier modulation scheme. Col. 2, lines 56-58, A system applying such a mapping scheme is defined in the European Telecommunication standard ETS 300 401 (EU147-DAB)):
‘dropping samples in a cyclic prefix and forming a set of complex samples of length K, where K is a number of frequency subcarriers in a DAB transmission mode are formed from the next K complex samples;’ (Col. 8, lines 39-42, One MCM symbol comprising NFFT subcarriers is assembled from NFFT-K-1 guard band symbols… K DQPSK subcarrier symbols. Col. 2, lines 13-18, a reference symbol extracting unit 136 extracts the framing information, i.e. the reference symbol, from the MCM symbol coming from the receiver front end 132. After the extraction of the reference symbol, the MCM signal is applied to a guard interval removal unit 138);
‘evaluating a subsequent step FFT of length K to generate frequency domain samples;’ (Col. 2, lines 21-23, MCM symbols output from the guard interval removal unit 138 are provided to a fast Fourier transform unit 140 in order to provide a sequence of spectra);
‘differentially demodulating the frequency domain samples of successive OFDM symbols (100) to estimate subcarrier level Quadrature Phase Shift Keying (QPSK) symbols and the set of complex samples are marked as r1k (109); (Col. 9, lines 38-54, The output of the fast Fourier transformator is applied to the de-mapper, which performs a differential de-mapping along the frequency axis. The output of the de-mapper are the respective phase shifts for the subcarriers. The output of the de-mapper 142… is shown… only the encoded phase shifts, 0°, 90°, 180° or 270° are present);
‘differentially demodulating output frequency domain samples of successive OFDM symbols (100) corresponding to this FFT to estimate a second set of subcarrier level QPSK symbols r2k (110);’ (Col. 11, lines 20-23, A second embodiment of an echo phase offset correction algorithm… used in connection with multipath channels that have up to two strong path echoes);
‘and processing the resultant K complex samples (111) of the demodulator by the channel splitter and subsequently, the channel decoded to retrieve the information bit stream.’ (Col. 2, lines 24-26, Thereafter, the sequence of spectra is provided to a carrier-bit mapper 142 in which the serial bitstream is recovered).
EBERLEIN does not explicitly teach but ABDI teaches, ‘evaluating Fast Fourier Transforms (FFT) at multiple positions of Orthogonal Frequency Division Multiplexing (OFDM) symbols (100);’ (ABDI – Paragraph [0042], Use frequency-domain processing over two FFT windows… to cover timing ranges beyond the CP. Paragraph [0051], carrying out one FFT per OFDM symbol for each FFT window (10));
‘computing differential demodulation and subsequently combining post differential demodulation subcarrier constellation symbols;’ (ABDI – Paragraph [0052], Non-coherent or coherent combining of the two output vectors per OFDM symbol can then be performed… contains an iFFT (20) that is used to convert the frequency domain signal to a time domain signal);
‘wherein a second peak position in the channel impulse response is additionally utilized and the K complex samples beginning from the second peak position are collected;’ (ABDI – Paragraph [0047], Multiple instances of the algorithm can be run in parallel with different FFT windows (for example for search windows of different cells). Paragraph [0042], Use frequency-domain processing over two FFT windows and combine the signals to cover timing ranges beyond the CP [cyclic prefix]);
‘evaluating FFT of size K (104, 105) on the K complex samples;’ (ABDI – Paragraph [0051], first stage of the processing… comprises carrying out one FFT per OFDM symbol for each FFT window (10)… ‘from window 2' (12) represents the second window);
‘performing Subcarrier QPSK combination (108) on r2k (110) and r1k (109);’ (ABDI – Paragraph [0115], weight each iFFT output by the amplitude of its max value, and perform coherent combining before taking the power of the output);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have known to combine the teachings of ABDI with EBERLEIN because both are in the same/similar field of endeavor. The advantage of incorporating the above limitation(s) of ABDI into EBERLEIN is that ABDI provides time domain accumulation or interpolation carried out per FFT window based on the first FFT output vectors to obtain a second output vector per FFT window; and wherein the
combining is coherent combining carried out between the two second vectors to obtain an iFFT input; and executing the iFFT on the input. (See paragraph [0010], ABDI)
EBERLEIN and ABDI do not explicitly teach but SAKAI teaches, ‘retrieving peak positions (102, 103) of a channel impulse response using the channel impulse response peak estimator (101);’ (SAKAI – Paragraph [0033], The maximum value detecting circuit 124 detects a peak position of the amplitude component found by the amplitude finding circuit 123. Paragraph [0066], symbol timing that precisely indicates the boundary between the transmission symbols);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have known to combine the teachings of SAKAI with EBERLEIN and ABDI because both are in the same/similar field of endeavor. The advantage of incorporating the above limitation(s) of SAKAI into EBERLEIN and ABDI is that SAKAI provides an OFDM demodulator including a symbol integration circuit (131) for integrating a guard correlation signal in a symbol number direction, and an offset removal circuit (132) for removing an offset from the guard correlation signal integrated in the symbol number direction. An amplitude component due to the disturbing wave, which amplitude component is included in the guard correlation signal, is cancelled by the integration in the symbol number direction, so that it is possible to successfully remove the offset from the guard correlation signal. Therefore, it is possible to obtain symbol timing more precisely by use of a maximum value detecting circuit (124), and further, calculate a phase rotation amount more precisely by use of a phase
finding circuit (125). (See Abstract, SAKAI)
Regarding claim 2, EBERLEIN, ABDI and SAKAI teach, The method to enhance Gaussian and Rayleigh sensitivity performance of Digital Audio Broadcast receivers, as claimed in claim 1,
EBERLEIN does not explicitly teach but ABDI teaches, ‘wherein, the method includes utilizing more than two peaks from the channel impulse response’ (ABDI – Paragraph [0127], If necessary ( e.g. if the time region spread by the different values of Expected-RSTD and RSTD-Uncertainty for different cells is large), the measured Cells can be grouped in groups… and the method applied to different pairs of FFT windows in parallel)
‘and adding corresponding computational blocks FFT, DQPSK (106, 107)’ (ABDI – Paragraph [0135], To measure the Ncell eNodeBs, we have 2 common FFT then one iFFT per Cell. We also need to add the pilot compensation per Cell)
‘and the subcarrier QPSK combiner.’ (ABDI – Paragraph [0115], We can thus weight each iFFT output by the amplitude of its max value, and perform coherent combining before taking the power of the output).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have known to combine the teachings of ABDI with EBERLEIN because both are in the same/similar field of endeavor. The advantage of incorporating the above limitation(s) of ABDI into EBERLEIN is that ABDI provides time domain accumulation or interpolation carried out per FFT window based on the first FFT output vectors to obtain a second output vector per FFT window; and wherein the
combining is coherent combining carried out between the two second vectors to obtain an iFFT input; and executing the iFFT on the input. (See paragraph [0010], ABDI)
Regarding claim 3, EBERLEIN, ABDI and SAKAI teach, The method to enhance Gaussian and Rayleigh sensitivity performance of Digital Audio Broadcast receivers, as claimed in claim 1,
EBERLEIN further teaches, ‘wherein, the method includes transmission schemes which involves OFDM’ (Col. 1, lines 28-29, Multi-carrier modulation (MCM) is also known as orthogonal frequency division multiplexing (OFDM))
‘and Differential Multi Phase Shift Keying (DMPSK) instead of DQPSK.’ (Col. 7, lines 53-57, According to FIG. 2, a quadrature phase shift keying (QPSK) is used for mapping... However, other M-ary mapping schemes (MPSK) like 2-PSK, 8-PSK… are possible).
Regarding claim 4, EBERLEIN teaches, ‘A method to enhance digital audio broadcast (DAB) receivers, the method comprising:’ (Col. 2, lines 56-58, A system applying such a mapping scheme is defined in the European Telecommunication standard ETS 300 401 (EU147-DAB)):
‘differentially demodulating using demodulators the frequency domain samples of successive OFDM symbols to estimate subcarrier level QPSK symbols’ (Col. 2, lines 59-61, Differential Quadrature Phase Shift Keying (DQPSK) to encode every two bits into a 0, 90, 180 or 270 degrees phase difference between two subcarriers)
‘and processing the K complex samples of the demodulators to retrieve an information bit stream.’ (Col. 2, lines 24-25, Thereafter, the sequence of spectra is provided to a carrier-bit mapper 142 in which the serial bitstream is recovered).
EBERLEIN does not explicitly teach but ABDI teaches, ‘forming a first set of K samples starting from a first peak position;’ (ABDI – Paragraph [0061], The timing of the FFT window (40) is selected so that it preferably starts at the beginning of the earliest search window. Paragraph [0062], …the UE collects the resource elements corresponding to the PRS positions);
‘forming a second set of K samples starting from a second peak position;’ (ABDI – Paragraph [0127], If necessary… the measured Cells can be grouped… the method applied to different pairs of FFT windows in parallel. Paragraphs [0109]-[0110], choosing the start of the first FFT window at ExpectedRSTD-RSTDUncertainty);
‘evaluating Fast Fourier Transforms (FFT) of the first set of K samples and the second set of K samples to generate frequency domain samples;’ (ABDI – Paragraph [0051], the first stage of the processing… comprises carrying out one FFT per OFDM symbol for each FFT window (10)… This results in two FFT output vectors per OFDM symbol);
‘to mark the first set of K samples as r1k and the second set of K samples as r2k;’ (ABDI – Paragraphs [0072]-[0074], Let us denote: X1 (n) and X2(n) the corresponding values we have on 1st FFT window (40…) and 2nd FFT window (41…), respectively);
‘performing subcarrier combination on r1k and r2k;’ (ABDI – A more efficient combination method is the well-known maximum ratio combining where each contribution is weighted by a coefficient. Paragraph [0053], Coherent combining (16) is carried out between these two vectors);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have known to combine the teachings of ABDI with EBERLEIN because both are in the same/similar field of endeavor. The advantage of incorporating the above limitation(s) of ABDI into EBERLEIN is that ABDI provides time domain accumulation or interpolation carried out per FFT window based on the first FFT output vectors to obtain a second output vector per FFT window; and wherein the
combining is coherent combining carried out between the two second vectors to obtain an iFFT input; and executing the iFFT on the input. (See paragraph [0010], ABDI)
EBERLEIN and ABDI do not explicitly teach but SAKAI teaches, ‘receiving a plurality of peak positions of a channel impulse response at a channel impulse response peak estimator;’ (SAKAI – Paragraph [0033], The maximum value detecting circuit 124 detects a peak position of the amplitude component found by the amplitude finding circuit 123. Paragraph [0132], it possible to precisely detect a boundary between transmission symbols);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have known to combine the teachings of SAKAI with EBERLEIN and ABDI because both are in the same/similar field of endeavor. The advantage of incorporating the above limitation(s) of SAKAI into EBERLEIN and ABDI is that SAKAI provides an OFDM demodulator including a symbol integration circuit (131) for integrating a guard correlation signal in a symbol number direction, and an offset removal circuit (132) for removing an offset from the guard correlation signal integrated in the symbol number direction. An amplitude component due to the disturbing wave, which amplitude component is included in the guard correlation signal, is cancelled by the integration in the symbol number direction, so that it is possible to successfully remove the offset from the guard correlation signal. Therefore, it is possible to obtain symbol timing more precisely by use of a maximum value detecting circuit (124), and further, calculate a phase rotation amount more precisely by use of a phase
finding circuit (125). (See Abstract, SAKAI)
Conclusion
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/HAESHIL JESSICA CHOI/Examiner, Art Unit 2479 /JAE Y LEE/Supervisory Patent Examiner, Art Unit 2479