WO2004068749A1 - フェ−ジング周波数推定装置 - Google Patents
フェ−ジング周波数推定装置 Download PDFInfo
- Publication number
- WO2004068749A1 WO2004068749A1 PCT/JP2003/000896 JP0300896W WO2004068749A1 WO 2004068749 A1 WO2004068749 A1 WO 2004068749A1 JP 0300896 W JP0300896 W JP 0300896W WO 2004068749 A1 WO2004068749 A1 WO 2004068749A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- fading
- fusing
- estimating
- difference
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/391—Modelling the propagation channel
- H04B17/3911—Fading models or fading generators
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
Definitions
- Fading Frequency Estimation Apparatus ⁇ ⁇ - The present invention provides a fading method for estimating a fading frequency generated in a radio transmission line by performing predetermined signal processing on a radio frequency signal arriving via the radio transmission line.
- the present invention relates to a frequency estimation device.
- channel control, transmission power control, and traffic are achieved by linking radio base stations and terminals in a form adapted to frequency allocation, zone configuration, channel allocation, multiple access, modulation, and other configurations. Control is being performed.
- various services for transmitting image information and other digital information at high speed are being provided by actively utilizing the advantages of the CDMA system.
- the above-described channel control, transmission power control, and traffic control are realized in a form that flexibly and quickly adapts to, for example, fading frequency fluctuations and other characteristics of the wireless transmission path.
- signals output from a plurality of despreaders that perform despreading for each multipath are used. Are synthesized while retaining the phase difference generated for each of the multipaths, and the correlation time interval at which the autocorrelation value of the resulting signal is minimized is substituted into a known formula. Is required.
- Patent Documents 3 to 5 As prior art related to the present invention, for example, there are techniques disclosed in Patent Documents 3 to 5 described below.
- the pilot signal extracted from the received signal is subjected to fast Fourier transform, and the gradient of the obtained frequency spectrum is minimized. As the frequency, the maximum Doppler shift of the pilot signal is detected.
- the frequency at which the above-mentioned gradient becomes minimum is such that the frequency spectrum is “a large number of instantaneous signals indicating the pilot signal extracted from the received signal. If it was not found for the "value" column, it could not be obtained with sufficient accuracy.
- a frequency power spectrum of a carrier is obtained from a received signal, and a peak frequency corresponding to a peak value of the frequency spectrum is obtained. (Corresponding to the maximum Doppler shift.)
- the carrier frequency is obtained as the average value of the frequency at which the power is low over a predetermined level in the high band and the low band.
- the frequency at which the value of power (power density) has the maximum value in the frequency spectrum obtained by fast Fourier transform is determined as the maximum Topler frequency.
- the value of the frequency spectrum (frequency spectrum) at a frequency other than the above-mentioned pitch frequency may include a value that does not greatly differ from the above-described peak value (maximum value).
- Patent No. 3296421 Japanese Unexamined Patent Publication No. 2000-106576 • Patent document 5
- Another object of the present invention is to effectively utilize existing hardware and to achieve inexpensive, accurate, and efficient estimation of fading frequency. Another object of the present invention is to improve the accuracy compared to a case where a frequency corresponding to an estimated value of a fading frequency is obtained based on a signal arriving via only a single path.
- a further object of the present invention is to accurately and stably estimate a fusing frequency even in a state where transmission quality fluctuates greatly.
- an object of the present invention is to provide a wireless communication system that is capable of superimposing interference waves and interfering waves at a high level, such as fuzzing that occurs in a multipath with stable characteristics and is formed on a wireless transmission path. The point is that the fading frequency of fusing, in which the fusing frequency is concentrated and distributed in a narrow band, can be accurately estimated.
- the object of the present invention is to reduce the fading frequency as long as the increase in the amount of processing, storage capacity, and other resources provided for obtaining the latest frequency spectrum and the decrease in responsiveness are acceptable. The point is that the accuracy of the estimated value is improved.
- the purpose of the above is to determine the difference between the instantaneous value of the envelope component at two time points separated by the time when the characteristics of the wireless transmission path are considered to be steady among the components of the signal arriving in time series via the wireless transmission path.
- the fading is characterized by estimating the frequency of fusing generated in this radio transmission line as the frequency at which the size of the frequency spectrum is maximized. This is achieved by a frequency estimator.
- the above-mentioned frequency spectrum is obtained without including most of the stationary amplitude component of the signal arriving via the wireless transmission path. It takes a local maximum sharply at the fusing frequency of the generated fusing. '
- the above-mentioned object is to provide a wireless transmission path for two or more periods in which the start point and / or the end point are separated on the time axis over the time when the characteristics of the wireless transmission path are considered to be steady.
- the frequency spectrum of each signal arriving in the order of the time series through the system and the frequency at which the magnitude of the frequency spectrum difference becomes the maximum is the frequency of the fading generated in this radio transmission path.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimation device described earlier.
- the above-described object is to provide a frequency spectrum of a sequence of a difference between channel estimation values of a wireless transmission channel estimated in a time series at two time points separated by time at which the characteristics of the wireless transmission channel are considered to be stationary. This is achieved by a fading frequency estimating apparatus characterized by estimating the frequency of fusing generated in this radio transmission path as the frequency at which the magnitude of the frequency spectrum is maximized.
- the difference between the channel estimation values included in the above-described column of the difference between the channel estimation values is based on the fact that these channel estimation values are “the radio transmission path of the signal transmitted as described above. As long as the level at which the transmission wave corresponding to this signal is transmitted from the transmitting end of the signal is constant or is known, the amplitude in the first fusing frequency estimation device described above is used. Can be considered equivalent to the difference of '
- the above-mentioned object is to individually and chronologically arrange two or more of the start point and the end point in two periods separated on the time axis over the time when the characteristics of the wireless transmission path are considered to be steady.
- the difference in the frequency spectrum of the sequence of channel estimation values of the estimated radio transmission path is defined as the frequency at which the magnitude of the difference in the frequency spectrum is the maximum. This is achieved by a fusing frequency estimating apparatus characterized by estimating the frequency of paging.
- the above-described frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimation device described earlier.
- the above-described object is to obtain a frequency spectrum of a column of a difference of channel estimation values for each path forming the above-described wireless transmission path, and calculate the sum of these frequency spectra as the wireless transmission
- a fading frequency estimator that is characterized in that it obtains the frequency spectrum of the sequence of differences between the channel estimation values of the road.
- the estimated value of the fusing frequency is obtained by summing up the frequency spectrum of a signal arriving via a main path formed as a multipath in a wireless transmission path. It is determined as the frequency at which the power is maximized. Further, the above-mentioned object is to obtain a difference between the frequency spectrums of the sequence of channel estimation values for each path forming the wireless transmission path, and to obtain a sum of these frequency spectrum small sums as a channel estimation value of the wireless transmission path. This is achieved by a fading frequency estimator that is characterized in that the difference in the frequency spectrum of a sequence of values is determined.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimating apparatus described earlier. .
- the above-mentioned object is to provide two coefficients at which the frequency spectrum is steep at the frequency where the magnitude of the frequency spectrum is maximum, and to obtain these coefficients and the two
- a fading frequency estimator which is characterized in that a frequency spectrum is obtained for a sequence of differences in instantaneous values given as a product sum with an envelope component.
- the frequency spectrum does not include an excessively large component of the stationary amplitude of the signal described above according to the two coefficients described above, and Obtained in form.
- the fluctuation superimposed due to fading and the noise superimposed similarly due to factors other than this fading can be distinguished based on the maximum value of the power.
- the above-described object is to provide two coefficients in advance where the difference becomes steep at the frequency where the magnitude of the frequency spectrum difference is maximum, and to obtain these coefficients and the frequency spectrum of each signal described above.
- the difference is obtained as the sum of products of....
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimation device described earlier.
- the above-described object is to provide two coefficients that make the frequency spectrum sharp at a frequency where the magnitude of the frequency spectrum is maximum. This is achieved by a fading frequency estimator characterized by the fact that a frequency spectrum is obtained for a sequence of differences between instantaneous values given as the product sum of the coefficient of You.
- the frequency spectrum does not include an excessively large amount of the stationary amplitude component of the signal described above according to the above two coefficients, and Obtained in form.
- the fluctuation superimposed due to fading and the noise superimposed similarly due to factors other than this fading can be distinguished based on the maximum value of the power.
- the above-mentioned purpose is that two coefficients whose difference becomes steep at the frequency where the magnitude of the frequency spectrum difference is maximum are given in advance, and these coefficients and the coefficients are individually estimated in different periods described above.
- a fading frequency estimating apparatus characterized in that the difference is obtained as a product sum with the frequency spectrum of a sequence of channel estimation values of a wireless transmission channel.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimation device described earlier.
- the above-described object is to register in advance two coefficients at which the frequency spectrum has a maximum, at which the frequency spectrum becomes steep in a form corresponding to the transmission quality of the wireless transmission path described above. It is characterized in that the frequency spectrum is obtained for the sequence of the instantaneous value differences given as the product sum of the two coefficients registered in association with the transmission quality and the envelope components at the two points in time. This is achieved by a fusing frequency estimator.
- the frequency spectrum can be obtained with high accuracy in the following form even when the preferable values of the above two coefficients change according to the change in transmission quality. .
- the noise can be distinguished from the superimposed noise according to factors other than the above based on the maximum value of the power.
- the above-described object is to register two coefficients in advance where the difference becomes steep in a form corresponding to the transmission quality of the wireless transmission line at the frequency where the magnitude of the difference between the frequency spectra is the largest, and This is achieved by a fusing frequency estimating apparatus characterized in that the difference is obtained as the product sum of two coefficients registered in association with the transmission quality and the frequency spectrum of each signal.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the eleventh fusing frequency estimation device described above.
- the purpose is that two coefficients are registered in advance so that the frequency spectrum becomes steep in a form corresponding to the transmission quality of the radio transmission line at the frequency where the magnitude of the frequency spectrum is maximum, and Calculate the frequency spectrum for the sequence of instantaneous value differences given as the product sum of the two coefficients registered in association with the transmission quality and the channel estimation values estimated at the two points described above. This is achieved by a fading frequency estimator characterized by points.
- the frequency spectrum can be obtained with high accuracy in the following form even when the preferable values of the above two coefficients change according to the change in transmission quality. .
- the above-mentioned purpose is that two coefficients are registered in advance, in which the difference becomes steep in a form corresponding to the transmission quality of the wireless transmission line at a frequency where the magnitude of the frequency spectrum difference is maximum, and corresponds to the transmission quality. Is different from the two registered coefficients.
- a fusing frequency estimating apparatus characterized in that a difference is obtained as a product sum with a frequency spectrum of a sequence of channel estimation values of a radio transmission path individually estimated in a certain period.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained in the fading frequency estimating device described earlier.
- the above-mentioned purpose is to estimate the frequency of fusing that occurs in the wireless transmission path as the frequency giving the maximum value in the frequency band where the rate of change of the frequency spectrum is the maximum.
- the fading frequency estimator achieved by the characteristic fading frequency estimator c is such that the frequency at which the rate of change is closest to the above-mentioned band on the frequency axis and the power has the maximum value is obtained. Is estimated as the fading frequency.
- the above-mentioned object is achieved by a fading frequency estimating apparatus characterized in that the latest frequency spectrum is obtained by integrating a plurality of frequency spectra obtained in advance.
- the above-described object is to achieve a fusing frequency estimation characterized in that the fusing frequency is estimated as an average value of the frequency having the maximum value for each frequency spectrum or difference described above. Achieved by the device.
- the fusing frequency has the largest magnitude for each of these frequency spectra or differences without simply integrating the frequency spectra or differences. It is accurately estimated as the average value of the frequency.
- the above-mentioned object is achieved by a fading frequency estimating apparatus characterized in that the obtained frequency spectrum or the frequency at which the magnitude of the difference is maximum is obtained for each path.
- the fading frequency is calculated as the above-mentioned frequency spectrum or the average value of the frequency at which the magnitude of the difference is the maximum. It is estimated every time.
- FIG. 1 is a first principle block diagram of the present invention.
- FIG. 2 is a second principle block diagram of the present invention. .
- FIG. 3 is a third principle block diagram of the present invention.
- FIG. 4 is a fourth principle block diagram of the present invention.
- FIG. 5 is a diagram showing the first and third embodiments of the present invention.
- FIGS. 6A and 6B are diagrams for explaining the operation of the first embodiment of the present invention.
- FIG. 7 is a diagram showing a second embodiment of the present invention.
- FIG. 8 is a diagram showing a fourth embodiment of the present invention.
- FIG. 9 is a diagram showing a fifth embodiment of the present invention.
- FIG. 10 is a diagram showing another configuration of the first to fifth embodiments of the present invention. ⁇ Bird-shaped bear for skewering
- FIG. 1 is a first principle block diagram of the present invention.
- the fading frequency estimating apparatus shown in FIG. 1 includes frequency analyzing means 11, estimating means 12, and storage means 13.
- the principle of the first fading frequency estimation device according to the present invention is as follows.
- the frequency analysis means 11 calculates the instantaneous value of the envelope component at two time points separated by time when the characteristics of the wireless transmission path are considered to be steady among the signal components arriving in time series via the wireless transmission path. Find the frequency spectrum of the sequence of value differences.
- the estimating means 12 estimates the frequency of fading occurring in the above-described radio transmission path as the frequency at which the magnitude of the frequency spectrum is maximized.
- the above-mentioned frequency spectrum does not include most of the stationary amplitude components of the signal arriving via the wireless transmission path. It takes the maximum value sharply at the fading frequency of fading generated in this wireless transmission path.
- the number of differences between the above-mentioned instantaneous values to be referred to in order to obtain the frequency spectrum is smaller. Even if the number is small, the fading frequency can be estimated accurately.
- FIG. 2 is a second principle block diagram of the present invention.
- the fading frequency estimating device shown in FIG. 2 includes frequency analyzing means 11 A, estimating means 12 A, and storage means 13 A.
- the principle of the second fusing frequency estimation device according to the present invention is as follows.
- the frequency analysis means 11A is configured such that both the start point and the end point are separated on the time axis over two periods separated by ⁇ time when the characteristics of the wireless transmission path are considered to be stationary ''
- the frequency spectrum of each signal arriving in the order of time series via the wireless transmission path is obtained.
- the estimating means 12A estimates the above-mentioned fading frequency generated in the radio transmission path as the frequency at which the magnitude of the difference between these frequency spectra is maximized.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained by the frequency analysis means 11 in the above-described first fading frequency estimation device.
- FIG. 3 is a third principle block diagram of the present invention.
- the fading frequency estimating device shown in FIG. 3 includes frequency analyzing means 11 B, estimating means 12 B, and storage means 13 B.
- the principle of the third fading frequency estimation device is as follows.
- the frequency analysis means 1 IB calculates the frequency spectrum of the sequence of the difference between the channel estimation values of the wireless transmission path estimated in time series at two time points separated by time at which the characteristics of the wireless transmission path are considered to be steady. Ask for a cram.
- the estimating means 12B estimates a fading frequency generated in the above-described wireless transmission path as a frequency at which the magnitude of the frequency spectrum is maximum.
- the difference between the channel estimation values included in the above-described column of the channel estimation value As long as the level at which the transmission wave corresponding to this signal is transmitted from the transmitting end of the signal is constant or is known, the amplitude of the above-described first fading frequency estimation device is It can be considered equivalent to the difference.
- the existing hardware can be effectively used, and the fading frequency can be estimated at low cost, with high accuracy, and efficiently.
- FIG. 4 is a fourth principle block diagram of the present invention.
- the fading frequency estimating apparatus shown in FIG. 4 includes frequency analyzing means 11 C, estimating means 12 C, and storage means 13 C. ,
- the principle of the fourth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis means 11 C is used to determine whether the start point and / or the end point are separated on a time axis in two periods separated by the time when the characteristics of the wireless transmission path are considered to be steady.
- the difference of the frequency spectrum of the column of the estimated channel estimation value of the wireless transmission path is obtained.
- the estimating means 12C estimates the frequency of fusing that has occurred in the above-described wireless transmission path, as the frequency at which the magnitude of the difference in the frequency spectrum is maximized.
- the above-mentioned frequency spectrum is mathematically combined with the frequency spectrum obtained by the frequency analysis means 11 B in the above-described third fusing frequency estimation device.
- the existing harder is effectively used, and the fading frequency can be estimated inexpensively, accurately, and efficiently.
- the principle of the fifth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis means 11 B obtains the frequency spectrum of the sequence of the difference between the channel estimation values for each path forming the above-described wireless transmission path, and calculates the sum of these frequency spectra as the sum of these frequency spectra. Then, the frequency spectrum of the sequence of the difference between the channel estimation values of the wireless transmission path is obtained.
- the estimated value of the fusing frequency is calculated based on the sum of the frequency spectrum of a signal arriving via a main path formed as a multipath in a wireless transmission path. It is determined as the frequency at which the power is maximum. Therefore, according to the present invention, accuracy is improved as compared with the case where such a frequency is obtained based on a signal arriving via only a single path.
- the principle of the sixth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis unit 11c obtains the difference between the frequency spectra of the column of channel estimation values for each path forming the above-described wireless transmission line, and calculates the sum of these frequency spectra as the sum of these frequency spectra. Find the difference between the frequency spectra in the column of channel estimation values.
- the above-mentioned frequency spectrum is obtained by the frequency spectrum obtained by the frequency analyzing means 11C in the above-described fifth fusing frequency estimating apparatus.
- the accuracy of the estimated value of the fading frequency is improved.
- the principle of the seventh fusing frequency estimation device according to the present invention is as follows.
- the frequency analysis means 11 is given in advance two coefficients at which the frequency spectrum becomes steep at the frequency at which the magnitude of the frequency spectrum is maximum, and these coefficients and the two Given as the product sum with the envelope component at A frequency spectrum is obtained for the sequence of the difference between the instantaneous values.
- the frequency spectrum does not include an excessively large amount of the stationary amplitude component of the signal described above according to the above two coefficients, and Obtained in form.
- the eighth fading frequency estimating apparatus As long as the above two coefficients are set to appropriate values, such a sequence of mere differences between the instantaneous values of the envelope components at the different points in time described above is Fourier-transformed. Compared to the case where a frequency spectrum is required, the fading frequency can be accurately and stably estimated even in a state where the transmission quality fluctuates greatly.
- the principle of the eighth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis means 11A is given in advance two coefficients at which the difference becomes steep at the frequency where the magnitude of the frequency spectrum difference is the largest, and these coefficients and the frequencies of the individual signals described above are given. This difference is calculated as the sum of products with the spectrum.
- the above-described frequency spectrum is mathematically equivalent to the frequency spectrum obtained by the frequency analysis means 11 in the seventh fading frequency estimation device described above. is there.
- the frequency analysis means 11 B is given in advance two coefficients at which the frequency spectrum becomes steep at the frequency at which the magnitude of the frequency spectrum is maximum, This frequency spectrum is obtained for the sequence of the difference between the instantaneous values given as the product sum of these coefficients and the channel estimation values estimated at the two points described above.
- the frequency spectrum does not include an excessively large amount of the stationary amplitude component of the signal described above according to the two coefficients described above, and Obtained in form.
- the fusing frequency can be accurately and stably estimated even in a state where the transmission quality fluctuates greatly.
- the principle of the tenth fading frequency estimation device according to the present invention is as follows.
- the frequency analysis means 11 C is given in advance two coefficients at which the difference becomes steep at the frequency at which the magnitude of the difference between the frequency spectra is the largest, and the coefficients are individually assigned to these coefficients and the different periods described above. This difference is obtained as the product sum with the frequency spectrum of the sequence of the channel estimation values of the radio transmission path estimated in step (1).
- the above-mentioned frequency spectrum is mathematically combined with the frequency spectrum obtained by the frequency analyzing means 11B in the above-described ninth fading frequency estimating apparatus. Is equivalent to
- the principle of the eleventh fading frequency estimation device is as follows.
- the storage means 13 has two coefficients at which the frequency spectrum becomes steep in a form corresponding to the transmission quality of the above-mentioned radio transmission line at the frequency where the magnitude of the frequency spectrum is maximum. Is registered in advance.
- the frequency analysis unit 11 calculates the sequence of instantaneous value differences given as the product sum of the two coefficients registered in the storage unit 13 associated with the transmission quality and the envelope components at the two time points. Find the frequency spread drum. .
- the difficulty in determining whether the noise superimposed on the envelope component due to fading is due to fading is reduced.
- the fading frequency can be accurately and stably estimated even when the transmission quality varies widely.
- the principle of the twelfth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis means 11A obtains the difference as the sum of products of the two coefficients registered in the storage means 13A in association with the transmission quality and the frequency spectrum of each signal.
- the above-mentioned frequency spectrum is mathematically equivalent to the frequency spectrum obtained by the frequency analysis means 11 in the eleventh fading frequency estimating apparatus described above. Are equivalent.
- the principle of a thirteenth fading frequency estimating apparatus according to the present invention is as follows. .
- the storage means 13B two coefficients are registered in advance, at which the frequency spectrum has the maximum magnitude, at which the frequency spectrum becomes steep in a form corresponding to the transmission quality of the wireless transmission path. .
- the frequency analysis means 11B is stored in the storage means 13B in association with the transmission quality. Estimated for the two registered coefficients and the two time points. Find the frequency spectrum for the sequence of the instantaneous value differences.
- the fusing frequency can be accurately and stably estimated even when the transmission quality varies widely.
- the principle of a fourteenth fading frequency estimating apparatus according to the present invention is as follows.
- the frequency analysis means 11C calculates the two coefficients registered in the storage means 13C in association with the transmission quality and the frequency of the column of the channel estimation value of the wireless transmission channel estimated individually in two periods. Find the difference as the sum of products with the spectrum.
- the above-mentioned frequency spectrum is obtained by the frequency analysis means 11A in the thirteenth fading frequency estimation device described above. Is mathematically equivalent to the frequency spectrum determined as follows.
- the fusing frequency can be stably and accurately even if the transmission quality varies widely. Is estimated.
- the principle of the fifteenth fading frequency estimating apparatus according to the present invention is as follows. .
- the estimating means 12 estimates the fading frequency generated in the wireless transmission path as the frequency giving the maximum value in the frequency band in which the rate of change of the frequency spectrum is maximum.
- the frequency at which the above-described rate of change is closest to the band on the frequency axis and at which the power has the maximum value is estimated as the fading frequency.
- the fading frequency is not reduced as in fusing generated in a multipath with a stable characteristic formed on a wireless transmission path.
- the fading frequency of fading that is concentrated and distributed in a narrow band is accurately estimated.
- the principle of a sixteenth fading frequency estimating apparatus according to the present invention is as follows.
- the estimating means 12.A estimates the frequency of fading occurring in the wireless transmission path as the frequency giving the maximum value in the frequency band in which the rate of change of the frequency spectrum difference is the maximum.
- the frequency at which the above-described rate of change is closest to the band on the frequency axis and at which the power has the maximum value is estimated as the fading frequency.
- the fading frequency of fading in which the fading frequency is concentrated and distributed in a narrow band can be accurately estimated.
- the principle of a seventeenth fusing frequency estimation device is as follows.
- the estimating means 12B estimates the frequency of faging generated in the wireless transmission path as the frequency that gives the maximum value of the dog in the frequency band in which the rate of change of the frequency spectrum is the maximum.
- the frequency closest to the above-mentioned band where the rate of change is maximum on the frequency axis and having the maximum power is estimated as the fusing frequency.
- the fading frequency is narrow in a band such as fading that is formed in wireless transmission and occurs in multipath with stable characteristics.
- the fusing frequency of fusing distributed in a concentrated manner is accurately estimated.
- the principle of an eighteenth fading frequency estimating apparatus according to the present invention is as follows.
- the estimating means 12C estimates the frequency of fading generated in the wireless transmission path as the frequency giving the maximum value in the frequency band where the rate of change of the frequency spectrum difference is the maximum.
- the frequency at which the above-described rate of change is closest to the band on the frequency axis and at which the power has the maximum value is estimated as the fading frequency.
- the fading frequency of the fading in which the fading frequency is concentrated and distributed in a narrow band is accurately estimated.
- the frequency analysis means 11, 11 A, 11 B, and 11 C obtain the latest frequency spectrum by integrating a plurality of frequency spectra obtained in advance.
- the frequency analysis means 11, 11 A, 11 B, and 11 C repeatedly obtain the above-mentioned frequency spectrum by repeating the order of 'and' time series.
- the estimating means 12, 12 A 12 B, and 12 C calculate the plurality of frequency spectra obtained in this way, or the individual difference of the two frequency spectra among these frequency spectrums.
- the fusing frequency is estimated as the average value of the frequency having the largest magnitude.
- the fading frequency is estimated as the average value of the frequency having the largest magnitude for each of these frequency spectra or differences without simply integrating the above frequency spectrum or difference.
- the frequency analysis means 11 B and 11 C repeatedly obtain a frequency spectrum for each path forming a wireless transmission path by repeating in time series.
- the estimating means 12B, 12C Calculates a plurality of frequency spectrums obtained for each path in this way, or two frequency spectrums out of the plurality of frequency spectrums.
- the fading frequency is estimated as the average value of the frequencies at which the individual differences of the maximum are the largest.
- the fusing frequency is estimated for each path as an average value of the frequency at which the magnitude of the frequency spectrum or the difference becomes the maximum.
- the fading frequency is accurately estimated for these paths ⁇ .
- FIG. 5 is a diagram showing first and third embodiments of the present invention.
- a feeding end of an antenna 21 is connected to an input of a receiving unit 22, and a demodulated signal is obtained at one output of the receiving unit 22.
- the other output of the receiving unit 22 is connected to the input of the signal processing unit 26 via the cascade-connected A / D converter 23, difference operation unit 24, and FFT operation unit 25, and the signal A fusing frequency is obtained from the output of the processing unit 26. .
- FIGS. 6A and 6B are diagrams for explaining the operation of the first embodiment of the present invention.
- the receiving unit 22 performs heterodyne detection (homodyne detection) of the received wave arriving at the antenna 21 via a specific radio channel formed based on the CDMA method, and spreads the signal in conformity with the specific radio channel. By multiplying by a code, a baseband signal indicating this received wave is generated in the baseband region.
- heterodyne detection homodyne detection
- the octave / 0 converter 23 samples the baseband signal at a sampling frequency fs at which the sampling theorem holds for the occupied band of the baseband signal, thereby obtaining a sequence of amplitudes of the baseband signal. Then, a discrete signal is generated that indicates the discrete signals in time series.
- the difference calculation section 24 satisfies all of the following conditions (hereinafter, referred to as “window conditions”), fetches in parallel the above-described amplitude columns in two windows that are different on the time axis, and obtains these amplitudes.
- the two amplitudes that are included in the sequence of the time series in the same order (in this case, for the sake of simplicity, it is assumed that the time series i is represented by "A u" and "A 2 i ", respectively).
- the length of the period W is equal to the product of the “predetermined odd integer N” and the “sampling period T s equal to the reciprocal of the sampling frequency fs described above”, and
- the statistical properties of jitter are short enough to be considered stationary.
- the interval on the time axis is equal to “an integer multiple of the sampling period T s”, and is short enough that the above-mentioned statistical properties are regarded as stationary.
- the FFT operation unit 25 obtains the frequency spectrum of the sequence of the difference by subjecting the sequence of the difference to fast Fourier transform.
- the signal processing unit 26 identifies a frequency slot having the highest power among the frequency slots indicating the frequency spectrum, and determines a frequency corresponding to the midpoint between the maximum frequency and the minimum frequency of the frequency slot on the frequency axis. Find fd.
- the frequency f d corresponds to the “fogging frequency” that indicates the highest frequency at which the amplitude of the received wave actually fluctuates due to the faging that has occurred in the above-described specific wireless channel. .
- the steady (ideal) amplitude component of the received wave is excluded from the subject of the above-described fast Fourier transform with high accuracy, so that in the above-described frequency spectrum,
- the swaging frequency is obtained as a frequency that sharply indicates the maximum value of the frequency spread drum.
- the fast Fourier transform is performed as compared with the case where the “stationary (ideal) amplitude component of the received wave” is not excluded from the target of the above-described fast Fourier transform.
- Power window width number of differences in difference column ⁇
- the fading frequency can be estimated with high accuracy, or the width of the window that allows estimation of the fading frequency with desired accuracy can be reduced.
- the two windows described above are set to different periods on the time axis that do not include a common period.
- the load on the difference calculation unit 24 may be reduced by partially overlapping periods on the time axis.
- the interval between these two windows on the time axis is Is set to a value equal to “an integer multiple of the sampling period T s”.
- the above-mentioned statistical property of the specific wireless channel may be set to a value that is short enough to be regarded as simply stationary. .
- the start point and the end point of the above-described two windows are determined without any synchronization with the received wave.
- the start point and / or the end point are set at the time of synchronizing in the symbol unit under the modulation method applied to the generation of the received wave, the above-described two windows are set.
- the error caused by the lack of synchronization with the received wave may be reduced.
- FIG. 7 is a diagram showing a second embodiment of the present invention.
- a weighted difference calculation unit 31 is provided in place of the difference calculation unit 24 described above.
- the feature of the present embodiment lies in the following processing procedure performed by the weighted difference calculation unit 31 to obtain the difference column ⁇ .
- the weighted difference calculator 31 as in the first embodiment described above, satisfies all of the “window conditions” and has the above-mentioned amplitudes “A”, “ A 2 i ”columns are fetched in parallel.
- the difference sequence ⁇ is caused by fusing. It is difficult to distinguish between the superimposed amplitude fluctuation and the noise superimposed similarly due to factors other than this fading because there is a correlation between the two.
- the weighted difference calculation unit 31 is selected by considering the characteristics of these frequency spectra, and has two weights (0 ⁇ W i ⁇ 1) and w 2 that satisfy all of the following conditions: (-1 ⁇ w 2 ⁇ 0) is given in advance.
- the weighted difference calculation unit 31 generates a product-sum column represented by the following equation with respect to the weights “w,“ w 2 ”and the above-described columns of the amplitudes“ A ⁇ , “A 2 i ” Then, a column ⁇ of the difference described above is obtained.
- both the high band and the low band of the frequency spectrum obtained by the FFT unit 25 are appropriately weighted according to the weights W i and w 2 described above.
- the transmission quality greatly fluctuates compared to the first embodiment in which the sequence of the difference ⁇ is simply obtained as “the sequence of the difference between the two amplitudes described above”. Even if there is, the fusing frequency can be accurately and stably estimated.
- the weights W i and w 2 are given in advance as known values.
- the present embodiment for example, by adding the following elements indicated by dotted lines in FIG. 7, it is possible to improve the transmission quality (SN ratio) of the received wave which can vary widely.
- the accuracy of the estimation value of the single frequency may be kept high.
- Transmission quality monitoring unit that monitors
- the feature of the present embodiment lies in the following processing procedure performed by the signal processing unit 26.
- the signal processor 26 has a power greater than “power of any adjacent frequency slot” among the frequency slots indicating the frequency spectrum obtained by the FFT operation unit 25, and The specific frequency slot having the maximum relative value to the power is specified instead of the above-mentioned frequency slot.
- the signal processing unit 26 estimates the frequency f d corresponding to the midpoint between the maximum frequency and the minimum frequency of the specific frequency slot on the frequency axis as the fusing frequency. .
- the center frequency of the frequency slot closest to the band where the rate of change of power is the highest on the frequency axis and corresponding to the maximum value of the power is estimated as the fusing frequency.
- the fading frequency of fading which is concentrated and distributed in a narrow band, can be accurately estimated.
- FIG. 8 is a diagram showing a fourth embodiment of the present invention.
- a difference calculation unit 41 is provided in place of the difference calculation unit 2 shown in FIG. 5, and a channel estimation unit 42 is provided between the AD converter 23 and the difference calculation 41.
- a channel estimation unit 42 is provided between the AD converter 23 and the difference calculation 41.
- the feature of the present embodiment lies in the following processing mode performed in cooperation with the channel estimation unit 42 and the difference calculation unit 41.
- the reception wave arriving at the antenna 21 is configured as a train of slots in which a predetermined field (pilot channel) includes a known pilot signal.
- the channel estimator 42 is generated by the A / D converter 23 and receives the above-described signal. By correlating a discrete signal that discretely represents a signal wave with the above-described pilot signal, a sequence of channel estimation values indicating the transmission characteristics of the radio transmission path from which the received wave has arrived is arranged in chronological order. Ask.
- the difference calculation unit 41 captures in parallel the columns of “the above-described channel estimation values in two different windows” in which “the window conditions” are all satisfied and Two channel estimates that are included in the column of channel estimation values in the same order in the time series order (here, for simplicity, the time series i is represented by “CH” and “C 2 ..i”, respectively) Generate a sequence ⁇ of differences.
- the FFT operation unit 25 obtains the frequency spectrum of the sequence of the difference by subjecting the sequence of the difference ⁇ to fast Fourier transform.
- the “difference in channel estimation value” included in such a sequence of differences ⁇ indicates the “transmission characteristics of the radio transmission path from which the received wave arrived”, since these channel estimation values indicate the transmission end of the received wave. Therefore, as long as the level at which the transmitted wave corresponding to the received wave is transmitted is constant or is known, it can be regarded as equivalent to the amplitude difference in the above-described first embodiment.
- channel estimates are generally likely to be inherently determined by existing hardware in the receiving system to which the present invention should be applied.
- the present embodiment it is possible to efficiently and inexpensively and efficiently estimate a fusing cycle by effectively using existing hardware.
- the present embodiment is configured by changing the configuration of the above-described first embodiment.
- the present invention is not limited to such a configuration, and can be applied not only to the above-described second and third embodiments, but also to a fifth embodiment described later.
- the pilot signals referred to as the reference for calculating the above-described channel estimation value are concentrated on the time axis for each slot described above.
- the present invention is not limited to such a configuration, and the above-mentioned field (pilot channel) may be a specific small field of a plurality of slots (not necessarily adjacent slots in chronological order).
- the deviation of the channel estimation values obtained in the order of the time series may be equalized.
- FIG. 9 is a diagram showing a fifth embodiment of the present invention.
- a receiving unit 22 A is provided in place of the receiving unit 22 described above. :
- a despreading unit 52 is added between the 8/0 conversion unit 23 and the path corresponding units 5 1-:! to 5 1 -N.
- ⁇ 'Averaging unit 53 is added at the subsequent stage of the path corresponding unit 5 1-:! .
- the receiving section 22 A performs heterodyne detection (homodyne detection) of the received wave arriving at the antenna 21, thereby generating a baseband signal indicating the received wave in the paceband region.
- the A / D converter 23 samples the baseband signal by sampling the spanned signal at the sampling frequency fs where the sampling theorem holds for the occupied band of such a paceband signal. Generate a discrete signal that indicates the sequence discretely in chronological order.
- the despreading unit 52 is configured to transmit a spread code conforming to the above-mentioned radio channel which is the propagation path of the received wave (here, for simplicity, it is assumed that the spread code is formed based on the above-described CDMA system.) And the discrete signal, the component of the discrete signal that arrives individually via the main path formed as a multipath in this propagation path (hereinafter, such component Are called “individual discrete signals.”) Are generated in parallel.
- the averaging unit 53 averages these frequencies fd to produce fading. Obtain the frequency estimate.
- the estimated value of the fading frequency is obtained by calculating the frequency fd at which the power becomes maximum in the frequency spectrum of each received wave arriving via the main path formed as a multipath in the wireless transmission path. It is calculated as a moving average.
- the despreading unit 52 and the path corresponding unit 5 1-:! To 51-N and the processing performed by the averaging unit 53 are all realized as signal processing in the digital domain.
- DSP Digital Signal Processor
- the averaging unit 53 obtains the estimated value of the fading frequency as a moving average of the frequency f d obtained for each path.
- smoothing based on such a moving average for example, smoothing based on exponential smoothing or another algorithm may be performed.
- the sampling frequency fs and the fast Fourier transform described above are subject to calculation; the number n of amplitude values, the number of main paths, and the validity of the arithmetic operation to be performed in each unit.
- digits (word length) is given by a weight W l, W 2 other parameters Isseki are both constants.
- the present invention is not limited to such a configuration.
- suitable responsiveness to be achieved according to the operation status of each unit, transmission quality for each channel, and other factors, calculation accuracy, and load distribution ( (Processing amount required) A parameter for achieving the others is given in advance, and a control unit 61 for appropriately providing parameters for each factor to each unit as shown in FIG. 10 is provided. This may allow for flexible adaptation to various configurations, specifications and environments.
- the above-described sequence of differences ⁇ is subjected to the fast Fourier transform.
- the fusing frequency is estimated by referring to the frequency spectrum obtained by the calculation.
- the present invention is not limited to such a configuration.
- the fusing frequency may be estimated based on an arithmetic operation that is mathematically equivalent to “the fast Fourier transform of the sequence of differences ⁇ ” as in “Process for calculating”.
- the width W of the two windows described above does not necessarily have to be the same.
- the width of the window to which the result of the fast Fourier transform performed separately corresponds After normalization by (the total number of channel estimation values and the amplitude to be calculated), the fusing frequency may be estimated as a difference between the results of these normalizations.
- the present invention is applied to the receiving end where the RAKE combining is performed in the wireless transmission system to which the CDMA scheme is applied.
- the present invention is not limited to such a configuration.
- the present invention is applicable not only to a multiple access system but also to a receiving end of a wireless transmission system to which any modulation system, frequency allocation, and channel configuration is applied. .
- the fusing frequency is estimated based only on the power of the frequency spectrum obtained as a result of the fast Fourier transform.
- the present invention is not limited to such a configuration.
- two weights adapted to the form of fusing, the configuration of the wireless transmission path, the characteristics, and the like may be applied to adaptive algorithms, etc.
- the fading frequency of the fading may be estimated based on the frequency spectrum calculated as the product sum of the amplitude spectrum and the phase spectrum.
- the present invention is applied to estimating the fading frequency of multipath fading in a high frequency band equal to or higher than the UHF band.
- the present invention is not limited to such a frequency band or fading form, and it is required that the fading frequency can be efficiently and accurately estimated without complicating the configuration. As long as it is compatible with any wireless transmission system and wireless application equipment. Softly applicable.
- the above-described frequency spectrum is obtained based on the fast Fourier transform.
- such a frequency spectrum is not limited to the fast Fourier transform, and may be obtained by any of the following methods if desired accuracy and responsiveness are ensured.
- the fading frequency can be accurately determined even when the number of instantaneous values to be referred to is small because the frequency spectrum is obtained. Presumed.
- the existing hardware can be effectively used, and the fading frequency can be estimated inexpensively, accurately, and efficiently.
- the accuracy of the estimated value of the fading frequency is improved.
- the seventh and eighth fading frequency estimating apparatuses as long as the coefficient is set to an appropriate value, the sequence of simple differences between the instantaneous values of the envelope components at the different time points described above is Fourier-transformed. As a result, compared to the case where the frequency spectrum is required, even when the transmission quality fluctuates greatly, accurate The switching frequency is estimated.
- the mere difference sequence of the channel estimation values at the different time points described above is Fourier-transformed.
- the fading frequency can be accurately and stably estimated even in the state where the transmission quality fluctuates greatly.
- the fading frequency can be accurately and stably estimated even in a state where the transmission quality varies widely.
- the fusing frequency estimating apparatus is formed on a radio transmission path even if a large level of interference wave or interference wave can be superimposed, and
- the amount of processing, storage capacity and other resources necessary for obtaining the latest frequency spectrum are increased, and the responsiveness is reduced. As long as is acceptable, the accuracy of the fading frequency estimate is increased.
- the transmission characteristics of the radio transmission path and the path formed in the radio transmission path are not always sufficiently steady, or Even when the accuracy on the frequency axis for which the frequency spectrum is required is not sufficiently high, the accuracy of estimating the fusing frequency is ensured to be high.
- the fading frequency estimating apparatuses even if the transmission characteristics of the individual paths formed in the radio transmission path do not always have high correlation, the fading The frequency is accurately estimated for each of these paths.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Quality & Reliability (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE60335496T DE60335496D1 (de) | 2003-01-30 | 2003-01-30 | Fading-frequenzschätzvorrichtung |
EP20030815585 EP1589681B1 (en) | 2003-01-30 | 2003-01-30 | Fading frequency estimation apparatus |
JP2004567531A JP4011582B2 (ja) | 2003-01-30 | 2003-01-30 | フェージング周波数推定装置 |
PCT/JP2003/000896 WO2004068749A1 (ja) | 2003-01-30 | 2003-01-30 | フェ−ジング周波数推定装置 |
US11/034,629 US7043207B2 (en) | 2003-01-30 | 2005-01-13 | Fading frequency estimating apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2003/000896 WO2004068749A1 (ja) | 2003-01-30 | 2003-01-30 | フェ−ジング周波数推定装置 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/034,629 Continuation US7043207B2 (en) | 2003-01-30 | 2005-01-13 | Fading frequency estimating apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2004068749A1 true WO2004068749A1 (ja) | 2004-08-12 |
Family
ID=32800817
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2003/000896 WO2004068749A1 (ja) | 2003-01-30 | 2003-01-30 | フェ−ジング周波数推定装置 |
Country Status (5)
Country | Link |
---|---|
US (1) | US7043207B2 (ja) |
EP (1) | EP1589681B1 (ja) |
JP (1) | JP4011582B2 (ja) |
DE (1) | DE60335496D1 (ja) |
WO (1) | WO2004068749A1 (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007117026A1 (ja) * | 2006-04-11 | 2007-10-18 | Mitsubishi Electric Corporation | 移動体端末の移動速度検出装置 |
EP1928096A2 (en) | 2006-11-30 | 2008-06-04 | Fujitsu Limited | Interference power estimating device and interference power estimating method |
US9344851B2 (en) | 2013-06-26 | 2016-05-17 | Fujitsu Limited | Speed estimation method in a mobile terminal according to a result of determining a given satisfying condition |
JP2017041896A (ja) * | 2011-12-16 | 2017-02-23 | ミツビシ・エレクトリック・アールアンドディー・センター・ヨーロッパ・ビーヴィMitsubishi Electric R&D Centre Europe B.V. | 複数のストリームを表すofdmシンボルを転送する方法及びデバイス |
Families Citing this family (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4358686B2 (ja) * | 2004-06-17 | 2009-11-04 | 富士通株式会社 | フェージング周波数推定装置およびその推定方法 |
JP4917956B2 (ja) * | 2007-04-26 | 2012-04-18 | 京セラ株式会社 | 無線通信装置及び信号処理方法 |
US20110105036A1 (en) * | 2009-11-04 | 2011-05-05 | Motorola, Inc. | Method and apparatus for sensing presence of an incumbent signal on a secondary radio channel |
US8995658B2 (en) | 2013-02-13 | 2015-03-31 | Honeywell International Inc. | Physics-based key generation |
US8787836B1 (en) | 2013-03-15 | 2014-07-22 | DGS Global Systems, Inc. | Systems, methods, and devices having databases and automated reports for electronic spectrum management |
US10244504B2 (en) | 2013-03-15 | 2019-03-26 | DGS Global Systems, Inc. | Systems, methods, and devices for geolocation with deployable large scale arrays |
US10271233B2 (en) | 2013-03-15 | 2019-04-23 | DGS Global Systems, Inc. | Systems, methods, and devices for automatic signal detection with temporal feature extraction within a spectrum |
US10219163B2 (en) | 2013-03-15 | 2019-02-26 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management |
US9288683B2 (en) | 2013-03-15 | 2016-03-15 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management |
US8805292B1 (en) | 2013-03-15 | 2014-08-12 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management for identifying signal-emitting devices |
US11646918B2 (en) | 2013-03-15 | 2023-05-09 | Digital Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management for identifying open space |
US8750156B1 (en) | 2013-03-15 | 2014-06-10 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management for identifying open space |
US10122479B2 (en) | 2017-01-23 | 2018-11-06 | DGS Global Systems, Inc. | Systems, methods, and devices for automatic signal detection with temporal feature extraction within a spectrum |
US8798548B1 (en) | 2013-03-15 | 2014-08-05 | DGS Global Systems, Inc. | Systems, methods, and devices having databases for electronic spectrum management |
US10257727B2 (en) | 2013-03-15 | 2019-04-09 | DGS Global Systems, Inc. | Systems methods, and devices having databases and automated reports for electronic spectrum management |
US10257728B2 (en) | 2013-03-15 | 2019-04-09 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management |
US10257729B2 (en) | 2013-03-15 | 2019-04-09 | DGS Global Systems, Inc. | Systems, methods, and devices having databases for electronic spectrum management |
US10299149B2 (en) | 2013-03-15 | 2019-05-21 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management |
US10237770B2 (en) | 2013-03-15 | 2019-03-19 | DGS Global Systems, Inc. | Systems, methods, and devices having databases and automated reports for electronic spectrum management |
US10231206B2 (en) | 2013-03-15 | 2019-03-12 | DGS Global Systems, Inc. | Systems, methods, and devices for electronic spectrum management for identifying signal-emitting devices |
US9465960B2 (en) | 2013-12-04 | 2016-10-11 | Honeywell International Inc. | Physics-based authentication |
US10459020B2 (en) | 2017-01-23 | 2019-10-29 | DGS Global Systems, Inc. | Systems, methods, and devices for automatic signal detection based on power distribution by frequency over time within a spectrum |
US10529241B2 (en) | 2017-01-23 | 2020-01-07 | Digital Global Systems, Inc. | Unmanned vehicle recognition and threat management |
US10700794B2 (en) | 2017-01-23 | 2020-06-30 | Digital Global Systems, Inc. | Systems, methods, and devices for automatic signal detection based on power distribution by frequency over time within an electromagnetic spectrum |
US10498951B2 (en) | 2017-01-23 | 2019-12-03 | Digital Global Systems, Inc. | Systems, methods, and devices for unmanned vehicle detection |
US10943461B2 (en) | 2018-08-24 | 2021-03-09 | Digital Global Systems, Inc. | Systems, methods, and devices for automatic signal detection based on power distribution by frequency over time |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07162360A (ja) * | 1993-12-10 | 1995-06-23 | Japan Radio Co Ltd | フェージング変動量推定器 |
JPH08223108A (ja) * | 1995-02-14 | 1996-08-30 | Fujitsu Ltd | フェージングピッチ推定装置 |
JPH09135215A (ja) * | 1995-11-09 | 1997-05-20 | Fujitsu Ltd | フェージング周波数測定装置 |
JP2001345760A (ja) * | 2000-05-31 | 2001-12-14 | Nec Saitama Ltd | フェージング周波数検出方法および回路 |
JP2001358621A (ja) * | 2000-06-15 | 2001-12-26 | Fujitsu Ltd | フェージング周波数推定回路及び該回路を備えたcdma受信装置 |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5375143A (en) * | 1990-11-14 | 1994-12-20 | Motorola, Inc. | Method for channel adaptive detecting/equalizing |
JPH07140232A (ja) | 1993-11-19 | 1995-06-02 | Nippon Motorola Ltd | 受信装置を搭載した移動体の移動速度検出装置 |
JP3442156B2 (ja) * | 1994-08-31 | 2003-09-02 | 富士通株式会社 | 多重伝搬特性測定装置 |
JP2953959B2 (ja) | 1994-09-06 | 1999-09-27 | 富士通株式会社 | フェージングピッチ推定装置 |
JP3366141B2 (ja) | 1994-12-06 | 2003-01-14 | 沖電気工業株式会社 | 同期追跡装置 |
GB9818378D0 (en) * | 1998-08-21 | 1998-10-21 | Nokia Mobile Phones Ltd | Receiver |
JP3296421B2 (ja) | 1998-09-28 | 2002-07-02 | 日本電気株式会社 | 周波数推定装置 |
US6563861B1 (en) * | 1999-03-22 | 2003-05-13 | Ericsson, Inc. | Doppler spread estimation system |
US6680969B1 (en) * | 1999-03-22 | 2004-01-20 | Ericsson, Inc. | Methods for estimating doppler spreads including autocorrelation function hypotheses and related systems and receivers |
JP2001223671A (ja) | 2000-02-14 | 2001-08-17 | Mitsubishi Electric Corp | フェージングピッチ検出装置およびこれを用いた携帯情報端末 |
US6922452B2 (en) * | 2001-03-27 | 2005-07-26 | Telefonaktiebolaget L M Ericsson (Publ) | Method and apparatus for estimating Doppler spread |
-
2003
- 2003-01-30 DE DE60335496T patent/DE60335496D1/de not_active Expired - Lifetime
- 2003-01-30 EP EP20030815585 patent/EP1589681B1/en not_active Expired - Fee Related
- 2003-01-30 WO PCT/JP2003/000896 patent/WO2004068749A1/ja active Application Filing
- 2003-01-30 JP JP2004567531A patent/JP4011582B2/ja not_active Expired - Fee Related
-
2005
- 2005-01-13 US US11/034,629 patent/US7043207B2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07162360A (ja) * | 1993-12-10 | 1995-06-23 | Japan Radio Co Ltd | フェージング変動量推定器 |
JPH08223108A (ja) * | 1995-02-14 | 1996-08-30 | Fujitsu Ltd | フェージングピッチ推定装置 |
JPH09135215A (ja) * | 1995-11-09 | 1997-05-20 | Fujitsu Ltd | フェージング周波数測定装置 |
JP2001345760A (ja) * | 2000-05-31 | 2001-12-14 | Nec Saitama Ltd | フェージング周波数検出方法および回路 |
JP2001358621A (ja) * | 2000-06-15 | 2001-12-26 | Fujitsu Ltd | フェージング周波数推定回路及び該回路を備えたcdma受信装置 |
Non-Patent Citations (1)
Title |
---|
See also references of EP1589681A4 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007117026A1 (ja) * | 2006-04-11 | 2007-10-18 | Mitsubishi Electric Corporation | 移動体端末の移動速度検出装置 |
EP1928096A2 (en) | 2006-11-30 | 2008-06-04 | Fujitsu Limited | Interference power estimating device and interference power estimating method |
JP2017041896A (ja) * | 2011-12-16 | 2017-02-23 | ミツビシ・エレクトリック・アールアンドディー・センター・ヨーロッパ・ビーヴィMitsubishi Electric R&D Centre Europe B.V. | 複数のストリームを表すofdmシンボルを転送する方法及びデバイス |
US9344851B2 (en) | 2013-06-26 | 2016-05-17 | Fujitsu Limited | Speed estimation method in a mobile terminal according to a result of determining a given satisfying condition |
Also Published As
Publication number | Publication date |
---|---|
US20050118960A1 (en) | 2005-06-02 |
JPWO2004068749A1 (ja) | 2006-05-25 |
JP4011582B2 (ja) | 2007-11-21 |
US7043207B2 (en) | 2006-05-09 |
EP1589681A1 (en) | 2005-10-26 |
EP1589681B1 (en) | 2010-12-22 |
EP1589681A4 (en) | 2007-05-30 |
DE60335496D1 (de) | 2011-02-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4011582B2 (ja) | フェージング周波数推定装置 | |
US8335283B1 (en) | Weak signal detection in wireless communication systems | |
US7167456B2 (en) | Apparatus for estimating propagation path characteristics | |
US8457177B2 (en) | System and method for fast code phase and carrier frequency acquisition in GPS receiver | |
JP4446606B2 (ja) | ドップラ拡散評価システム | |
US6922452B2 (en) | Method and apparatus for estimating Doppler spread | |
US8401487B2 (en) | Radio channel analyzer to determine doppler shifts across multiple frequencies of a wideband signal | |
JP4560510B2 (ja) | 周波数偏移変調受信機の同期方法及び同期システム | |
EP1856811B1 (en) | Method and apparatus for synchronizing wireless receiver | |
JP3523236B2 (ja) | 電力スペクトル密度推定に基づくデータ伝送速度の決定 | |
JP4358686B2 (ja) | フェージング周波数推定装置およびその推定方法 | |
JP2008537590A (ja) | チャープ信号を用いて送受信機間の電磁波多重経路特性に対するチャネル推定方法およびチャネル推定装置 | |
JPH09511893A (ja) | 受信器、及び受信器に拡散コードを発生する方法 | |
JPH07170225A (ja) | 無線通信システム | |
US20120033768A1 (en) | Non-coherent detection apparatus and method for ieee 802.15.4 lr-wpan bpsk receiver | |
JP2011223546A (ja) | 受信装置 | |
JP2007512762A (ja) | 多次元統合探索チャネル推定器 | |
TWI487335B (zh) | 數位資料輔助頻率偏移估計 | |
US7003415B2 (en) | Delay profile estimation apparatus and a correlating unit | |
CN112953593B (zh) | LoRa高级接收器 | |
US6330431B1 (en) | Method and apparatus for measuring signal quality in a wireless communication system | |
US6993093B2 (en) | OFDM receiving apparatus with reduced bit error rate after demodulation | |
KR101828835B1 (ko) | 무선통신 시스템에서 다중 경로 신호 수신 장치 및 방법 | |
JP2618094B2 (ja) | マルチパス伝送路の遅延時間の測定方法及び測定システム | |
CN117579443A (zh) | 一种基于同步头信号的信道探测方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT SE SI SK TR |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2004567531 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2003815585 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 11034629 Country of ref document: US |
|
WWP | Wipo information: published in national office |
Ref document number: 2003815585 Country of ref document: EP |