WO2014012352A1 - Procédé et dispositif d'estimation de canal - Google Patents

Procédé et dispositif d'estimation de canal Download PDF

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Publication number
WO2014012352A1
WO2014012352A1 PCT/CN2013/000834 CN2013000834W WO2014012352A1 WO 2014012352 A1 WO2014012352 A1 WO 2014012352A1 CN 2013000834 W CN2013000834 W CN 2013000834W WO 2014012352 A1 WO2014012352 A1 WO 2014012352A1
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Prior art keywords
sequence
channel estimation
copy
timing information
channel
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PCT/CN2013/000834
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English (en)
Chinese (zh)
Inventor
陈立俊
邓单
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京信通信系统（中国）有限公司
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Publication of WO2014012352A1 publication Critical patent/WO2014012352A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0212—Channel estimation of impulse response
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/022—Channel estimation of frequency response
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/024—Channel estimation channel estimation algorithms
    • H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only

Definitions

  • the present invention relates to the field of mobile communications technologies, and in particular, to a channel estimation method and apparatus. Background technique
  • Orthogonal Frequency Division Multiplexing is a multi-carrier modulation technique.
  • the main idea is to divide the non-flat frequency selective channel into many orthogonal sub-ranges in the frequency domain.
  • the channel, the signal bandwidth on each subchannel is smaller than the relevant bandwidth of the channel, so that each subchannel is relatively flat, and the purpose of reducing intersymbol interference caused by multipath effects is achieved.
  • the receiving end needs to perform coherent demodulation on the received signal. Therefore, channel estimation is needed to obtain information such as the amplitude and phase of the channel.
  • pilot-based channel estimation method generally transmits a specific sequence in the frequency domain known by both communicating parties at the transmitting end to continuously track channel changes. Since the pilot-based channel estimation method is relatively simple and easy to implement, it is widely used.
  • the receiving end uses the pilot sequences known by both the transmitting and receiving parties to accurately reflect the delay of each path of the channel in the time domain.
  • Amplitude phase time domain channel impulse response
  • the amplitude phase of each subcarrier of the channel in the frequency domain frequency domain channel impulse response.
  • PUSCH Physical Uplink Shared Channel
  • the receiving end first needs to estimate the channel response at the pilot position, and then uses the channel response at the pilot position to perform averaging or interpolation in the time domain to obtain a sub- The channel response value of a frame or a time slot.
  • the Least Square (LS) algorithm is often used for channel estimation based on pilots.
  • the LS algorithm is relatively simple to implement.
  • the channel estimation can be obtained by directly dividing the frequency domain form of the received sequence by the transmission sequence.
  • the noise in the received signal and the interference between the subcarriers are not considered, the obtained channel estimation includes noise. And interference, resulting in the accuracy of the results as the noise and interference increase, so the estimation accuracy is limited.
  • time domain denoising technique to improve the performance of the LS algorithm to some extent by removing the noise as much as possible by performing domain transformation on the frequency domain channel response.
  • the main idea of the LS algorithm after time domain denoising is to convert the frequency domain channel impulse response into a time domain channel impulse response, estimate the noise in the time domain, and then set the threshold according to the estimated noise and pass The threshold denoises and filters the time domain channel impulse response, and then converts the filtered time domain channel impulse response into a frequency domain channel impulse response to obtain a final channel estimation value.
  • the frequency domain denoising operation if the frequency domain length of the OFDM pilot sequence is not a power of 2, an inverse Fourier inverse Fourier transform (Nove 2) is required.
  • IDFT / Discrete Fourier Transform (DFT) operation to transform the frequency domain channel impulse response of the pilot sequence to a time domain channel impulse response; however, due to a power-based power of 2
  • IFFT Inver se Fa st Four Ier Transform
  • FFT Fast Fourier Transform
  • the frequency domain channel impulse response is complemented by a power of 1 to perform an IFFT/FFT operation using a two-sided zero-padding method.
  • the frequency domain channel impulse response after zero-padding can be regarded as the original frequency domain channel impulse response multiplied by an ideal rectangular window, and according to the Fourier transform property, the time domain form of the ideal rectangular window is the sine function.
  • the time-domain channel impulse response corresponding to the frequency domain channel impulse response after zero-padding is equal to the original time-domain channel impulse response convolved with a sine function, and the more zero-padding points, the closer the time-domain channel impulse response is to continuous s ine function.
  • the obtained frequency domain channel impulse response is a 12-point unit impact corresponding to the 12 subcarriers shown in FIG. 2, That is, the all-one sequence of length 12, after the 12-point DFT operation, the obtained time domain channel impulse response is as shown in FIG. 3, and no side lobes appear in the time domain channel impulse response;
  • the two-side equal-length zero-padding method fills the pilot sequence to 16 points and still passes the ideal noise-free and time-delay-free channel.
  • the resulting frequency domain channel impulse response is shown in Figure 4, after 16-point FFT operation. After that, the obtained time domain channel impulse response is as shown in FIG. 5.
  • the length of the frequency domain channel impulse response of the pilot sequence can also be increased by zero-padding the frequency domain channel impulse response of the pilot sequence, thereby increasing the number of times of the pilot sequence time domain channel impulse response.
  • the effect of improving the timing estimation accuracy to a certain extent is achieved, but if the length of the frequency domain channel impulse response is increased by zero-padding the frequency domain channel impulse response, the frequency domain channel will still be rushed.
  • the response is transformed into the time domain to perform time domain denoising, a power leakage occurs, which results in partial information loss of the real time domain channel impulse response, which causes the channel estimation performance to be degraded.
  • the frequency domain channel impulse response of the pilot sequence is zero-padded to improve the accuracy of the channel timing estimation. If the frequency domain channel impulse response after zero-padding is converted to the time domain, the converted time-domain channel impact will result. In response to the power leakage phenomenon, that is, the converted time domain channel impulse response has a large side lobes, and the side lobes contain useful signals. If the time domain channel impulse response is time-domain denoised, the real time will be caused. Part of the information of the domain channel impulse response is lost, thereby reducing the accuracy of the channel estimation.
  • the embodiment of the present invention provides a channel estimation method and device, which are used to solve the problem of zero-frequency channel impulse response in the prior art and perform power-time denoising operation on the frequency domain channel impact response. Part of the information of the time domain channel impulse response is lost, thereby reducing the problem of channel estimation accuracy.
  • a channel estimation method includes:
  • Timing information indicating a phase offset of each channel estimate in the first sequence in the frequency domain; Performing a copy operation on the first sequence, and respectively obtaining a first copy and a second copy according to the copied first sequence, respectively performing phase adjustment on the first copy and the second copy by using the determined timing information, and Adding the adjusted first copy to the low frequency end of the first sequence, and adding the adjusted second copy to the high frequency end of the first sequence to obtain a second sequence of frequency domain channel estimation;
  • a channel estimation apparatus After transforming the second sequence into the time domain for time domain denoising, transforming it into the frequency domain to obtain a channel estimation result.
  • a channel estimation apparatus includes:
  • a frequency domain channel estimation module configured to perform channel estimation on the received pilot sequence, to obtain a first sequence of frequency domain channel estimates, where the first sequence includes at least one channel estimation value that is consecutively arranged;
  • timing information determining module configured to determine timing information indicating a phase offset of each channel estimation value in the frequency domain in the frequency domain
  • a first sequence adding module configured to perform a copy operation on the first sequence obtained by the frequency domain channel estimation module, and obtain a first copy and a second copy respectively according to the copied first sequence, and respectively use the determined timing information Phase-adjusting the first copy and the second copy, adding the adjusted first copy to the low frequency end of the first sequence, and adding the adjusted second copy to the high of the first sequence At the frequency end, obtaining a second sequence of frequency domain channel estimates;
  • a second sequence processing module configured to transform the second sequence into a time domain for time domain denoising, and then transform the frequency into a frequency domain to obtain a channel estimation result.
  • An embodiment of the present invention provides a channel estimation method and apparatus, which obtains a first sequence of frequency domain channel estimation by performing channel estimation on a received pilot sequence, and obtains a first copy and a first copy according to the copied first sequence, respectively. a second copy, and determining, by using the determined timing information indicating a phase offset of each channel estimation value in the frequency domain in the frequency domain, phase adjustment of the first copy and the second copy, respectively, and adjusting the A copy and a second copy are respectively added to the low frequency end and the high frequency end of the first sequence to obtain a second sequence of frequency domain channel estimation, so that the second sequence is transformed into the time domain for time domain denoising
  • the obtained time domain sequence conforms to the real time domain channel impulse response of the first sequence, thereby avoiding power leakage, thereby solving the frequency domain channel of the pilot sequence existing in the prior art while improving channel channel estimation accuracy.
  • FIG. 1 is a schematic diagram of a PUSCH block pilot structure of an LTE system in the prior art
  • Figure 2 is a diagram showing a frequency domain channel impulse response of a 12-point pilot sequence under an ideal channel
  • Figure 3 shows the time domain channel impulse response of the 12-point pilot sequence under the ideal channel
  • Figure 4 shows the resulting frequency domain channel impulse response when the 12-point pilot sequence is zeroed to 16 points on the ideal channel.
  • Figure 5 shows the resulting time domain channel impulse response when the 12-point pilot sequence is zeroed to 16 points on the ideal channel.
  • Figure 6 shows the resulting frequency domain channel impulse response when the 12-point pilot sequence is zeroed to 128 points on the ideal channel.
  • Figure 7 shows the time-domain channel impulse response of the 12-point pilot sequence when it is zeroed to 128 points on the ideal channel.
  • FIG. 8 is a schematic flowchart diagram of a channel estimation method according to Embodiment 1 of the present invention.
  • FIG. 9 is a schematic structural diagram of a channel estimation apparatus according to Embodiment 2 of the present invention. detailed description
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • FIG. 8 is a schematic flowchart diagram of a channel estimation method according to Embodiment 1 of the present invention, where the method includes the following steps:
  • Step 101 Perform channel estimation on the received pilot sequence to obtain a first sequence of frequency domain channel estimates, where the first sequence includes at least one channel estimation value that is consecutively arranged.
  • the received pilot sequence may be subjected to channel estimation by using an LS channel estimation method, and the obtained first sequence of the frequency domain channel estimation may be expressed as:
  • Step 102 Determine timing information indicating a phase offset of each channel estimation value in the first sequence in the frequency domain.
  • the timing information is a phase offset added to the first sequence caused by the timing error, and may be an average phase offset of each channel estimation value in the frequency domain in the first sequence.
  • timing information can be determined by:
  • Manner 1 According to the order of the channel estimation values in the first sequence, the first sequence is divided into two sub-sequences including the same number of channel estimation values, and each channel estimation value in the subsequent sub-sequence is determined respectively. The sum of the determined phase offsets is averaged with respect to the phase offset of the channel estimation values of the same position in the previous subsequence, and the obtained average phase offset is used as timing information.
  • the timing information may be expressed as: 1
  • Mode 2 determining the phase-bias complex number of the average phase offset, and determining according to the phase-bias complex number The phase offset base number is used as timing information.
  • the extracted channel estimation value in the first sequence in the frequency domain After determining an average phase offset of each channel estimation value in the first sequence in the frequency domain, the extracted
  • phase-bias complex number a + _y'.b i ⁇ ra+jV( . /2 .(A ffl ) , where ⁇ is the real part of the phase-biased complex number, and 6 is the imaginary part of the phase-biased complex number, and
  • Step 103 Perform a copy operation on the first sequence, and obtain a first copy and a second copy respectively according to the copied first sequence, and respectively phase the first copy and the second copy by using the determined timing information. Adjusting, adding the adjusted first copy to the low frequency end of the first sequence, and adding the adjusted second copy to the high frequency end of the first sequence to obtain a second sequence of frequency domain channel estimation .
  • the channel estimation values included in the first sequence are subjected to a copy operation to obtain a copied first sequence (or referred to as a first sequence copy;), and the channel estimation included in the copied first sequence
  • a copied first sequence or referred to as a first sequence copy;
  • the value is the same as the order of the channel estimation values included in the first sequence and the number is equal.
  • the channel estimation value included in the obtained first sequence of the replica is also ⁇ 2 ⁇ ⁇ ⁇ ).
  • the first copy is obtained according to the first sequence of the copy, the first copy is phase-adjusted by using the determined timing information, and the adjusted first copy is added to the low-frequency end of the first sequence, including:
  • the C channel estimation values are consecutive last C channel estimation values in the first sequence of the copy
  • obtaining a second copy according to the copied first sequence, and performing phase adjustment on the second copy by using the determined timing information, and adding the adjusted second copy to the high frequency end of the first sequence including:
  • a distance between the first copied A sequence and the first sequence is smaller than a distance between the C channel estimated values and the first sequence; and, in the first copy And in the second copy, for the first sequence of A replicas, the copied sequence of the first sequence is located at a farther distance from the first sequence, the phase adjustment amplitude is larger, and the phase adjustment amplitude is greater than the C channel estimation values.
  • the adjusted first copy VL that needs to be added at the low end of the first sequence 0 according to the timing information and the first sequence may be Expressed as:
  • the adjusted first copy VL that needs to be added at the low frequency end of the first sequence according to the timing information and the first sequence H ts may be Expressed as:
  • the number of channel estimation values of the adjusted first copy that need to be added at the low frequency end of the first sequence and the adjusted second copy of the channel that need to be added at the high frequency end of the first sequence is equal.
  • the obtained second sequence of frequency domain channel estimates can be expressed as:
  • H LS VL H LS VR
  • VL is the first replica added at the low frequency end
  • VR is the second replica added at the high frequency end
  • VL and the VR are equal in length
  • the adjusted first copy or the second copy is added to the After the low frequency end or the high frequency end of the first sequence, the number of channel estimation values of the obtained second sequence, that is, the sequence number of the second sequence is N e + 2 'N pad .
  • the sequence number of the second sequence may be a power of 2 or a power of 2, and preferably, the number of sequence points of the second sequence is a power of 2.
  • the sequence number of the second sequence is a power of 2
  • the sequence number of the second sequence + 2 . ⁇ is not limited to the nearest power of 2 to N e , but may be the number of sequence points determined according to the system timing estimation, for example, if the system is TDD-LTE (Time Division Duplexing - Long Term) Evolution, time division duplex-long-term evolution system, and the bandwidth is 10MHz, the sequence number of the second sequence may be 128, so that the channel timing estimation is maximized under the premise of ensuring a high channel estimation operation rate. Precision.
  • the sequence number N of the first sequence is 12 and the sequence number N c +2' N pad of the second sequence is 128, it is known from the calculation that the low frequency end of the first sequence is needed. Or the number of sequence points N pad in the adjusted first copy or the adjusted second copy added at the high frequency end is 58.
  • the adjusted first copy VL added at the low frequency end of the first sequence may be represented. for:
  • VL VL VL
  • the adjusted first replica is obtained by using the remaining 10 channel estimation values obtained by 58/12 in a sequence of replicas as the first replica, and performing phase adjustment using the determined timing information, where the 10 channels are obtained.
  • the estimated value is consecutively arranged in the first sequence of copies 10 channel estimates;
  • the distance between the four first sequence copies (or the adjusted first sequence copy) and the first sequence is smaller than the first sequence copy (or adjusted)
  • the distance between the 10 channel estimates in the first sequence of copies and the first sequence; for example, in the adjusted first copy VL, the four adjusted copies of the first sequence e_ ( AW >.0) LS , E - 3 ' (A ' RT -H LS , e - J - 2iN ⁇ -H LS and e - ⁇ ⁇ ! ⁇ are spaced from the first sequence by less than the 10 adjusted channel estimates, eg E ⁇ '(K , e - H ⁇ ). ⁇ 4 and e - 5(AW ). 12 The distance from the first sequence.
  • the phase sequence adjustment amplitude is larger as the first sequence copy located farther from the first sequence, for example, the phase adjustment range of ⁇ is larger than
  • Phase adjustment amplitude for the 10 channel estimation values, the phase adjustment amplitude is greater than any of the first sequence copies, for example, the phase adjustment amplitude of e -ford / ⁇ 2 is greater than e - H , e - / 3 ' ( ⁇ -H LS , e— (K LS and
  • the adjusted first copy VR added at the high frequency end of the first sequence can be expressed as:
  • 58 / 12 obtained the first sequence of the quotient and the remaining 10 channel estimates obtained by 58 / 12 in the first sequence of copies as the second copy, and using the determined timing information for phase adjustment, The adjusted second copy, wherein the 10 channel estimation values are consecutively ranked first 10 channel estimation values in the first sequence of copies;
  • the distance between the four first sequence copies and the first sequence is smaller than the distance between the ten channel estimation values and the first sequence
  • the phase sequence adjustment amplitude is larger for the first sequence of the further position of the first sequence; and the phase adjustment is performed for the ten channel estimation values.
  • the amplitude is greater than the phase adjustment amplitude of any of the first sequence of copies.
  • VL VL
  • Step 104 Transform the frequency domain channel estimated second sequence into a time domain for time domain denoising, and then transform the frequency domain to a frequency domain to obtain a channel estimation result.
  • this step 104 includes the following three sub-steps:
  • Step 1 Perform an inverse discrete Fourier transform on the second sequence of the frequency domain channel estimation to obtain a first sequence of time domain channel estimates.
  • the resulting first sequence of time domain channel estimates can be expressed as
  • an inverse discrete Fourier transform is performed on a vector, which is a second sequence of frequency domain channel estimation.
  • the inverse discrete Fourier transform may be a normal inverse discrete Fourier transform, and if the first copy and the second copy are added after the continuous phase adjustment, the second sequence of the obtained frequency domain channel estimation is obtained.
  • the number of sequence points is 2 . N2013/000834
  • the inverse discrete Fourier transform in this step may be a fast Fourier transform in the discrete Fourier transform.
  • the second step performing a time domain denoising operation on the first sequence of the time domain channel estimation to obtain a second sequence of time domain channel estimation.
  • the second sequence of time domain channel estimates after noise can be expressed as:
  • the time domain denoising operation may be performed on the first sequence of the time domain channel estimation by:
  • h " h n, ⁇ . + 2. ⁇ ⁇ +, ⁇ ⁇ ⁇ + 2 ⁇ ⁇ ⁇ , wherein ⁇ is the CP length.
  • Step 3 Perform a discrete Fourier transform on the second sequence of the time domain channel estimation to obtain a channel estimation result.
  • the obtained channel estimation result can be expressed as specifically! ! ⁇ - ⁇ , where (*) indicates a discrete Fourier transform on a vector, which is the second sequence of time domain channel estimation.
  • the discrete Fourier transform may be a normal discrete Fourier transform. If the first copy and the second copy are added after the continuous phase adjustment, the sequence number of the second sequence of the obtained frequency domain channel estimation is obtained. When the power is 2, the discrete Fourier transform in this step may be a fast Fourier transform in the discrete Fourier transform.
  • Embodiment 2 :
  • FIG. 9 is a schematic structural diagram of a channel estimation apparatus according to Embodiment 2 of the present invention, where the channel estimation apparatus includes a frequency domain channel estimation module 11, a timing information determining module 12, a first sequence adding module 13, and a second sequence processing.
  • Module 14 wherein:
  • the frequency domain channel estimation module 11 is configured to perform channel estimation on the received pilot sequence to obtain a first sequence of frequency domain channel estimation, where the first sequence includes at least one channel estimation value that is consecutively arranged; specifically Channel estimation
  • the meter can be estimated for the LS channel.
  • ⁇ , represents the channel estimate on the subcarrier.
  • the timing information determining module 12 is configured to determine timing information indicating a phase offset of each channel estimation value in the frequency domain in the frequency domain; specifically, the timing information is added to the first sequence caused by a timing error
  • the phase offset may be an average phase offset of the channel estimates in the first sequence in the frequency domain.
  • the timing information determining module 12 may determine the timing information by: manner 1: dividing the first sequence into the same quantity according to an order of arrangement of channel estimation values in the first sequence The two sub-sequences of the channel estimation value respectively determine the phase offset of each channel estimation value in the subsequent sub-sequence relative to the channel estimation value of the same position in the previous sub-sequence, and average the sum of the determined phase offsets, The resulting average phase offset is used as timing information.
  • Manner 2 determining a phase offset complex number of the average phase offset, and using the phase offset base number determined according to the phase offset complex number as timing information.
  • phase-offset base number T N2013/000834
  • the first sequence adding module 13 is configured to perform a copy operation on the first sequence obtained by the frequency domain channel estimation module 11, and obtain the first copy and the second copy respectively according to the copied first sequence, and use the determined timing information. Phase adjusting the first copy and the second copy respectively, adding the adjusted first copy to the low frequency end of the first sequence, and adding the adjusted second copy to the first At the high frequency end of the sequence, a second sequence of frequency domain channel estimates is obtained.
  • the first sequence adding module 13 is configured to perform a copy operation on each channel estimation value included in the first sequence, to obtain a copied first sequence, that is, a first sequence copy, where the first sequence is copied.
  • the included channel estimate is the same as the order of the channel estimates included in the first sequence and the number is equal.
  • the first sequence adding module 13 is configured to obtain a first copy according to the copied first sequence, and perform phase adjustment on the first copy by using the determined timing information, where the adjusted first A copy is added at the low end of the first sequence:
  • the first sequence adding module 13 is configured to obtain a second copy according to the copied first sequence, and perform phase adjustment on the second copy by using the determined timing information, and the adjusted second copy is performed. Added at the high frequency end of the first sequence:
  • the distance between the first sequence of A copies and the first sequence is less than Determining the distance between the C channel estimation values and the first sequence; and, in the first copy and the second copy, for the first sequence of the A copies, the first copy of the first sequence is located farther away
  • the sequence has a larger phase adjustment amplitude; for the C channel estimation values, the phase adjustment amplitude is greater than any of the copied first sequences.
  • the timing information determining module 12 performs the extraction of the timing information according to the mode 1
  • the first sequence adding module 13 obtains the required sequence in the first sequence H ts according to the timing information and the first sequence.
  • the adjusted first copy VL added at the low end can be expressed as:
  • VL VL ... VL VL
  • the first sequence adding module 13 is based on the timing information and the A sequence of adjusted second copies VR that need to be added at the high frequency end of the first sequence 0 can be expressed as: P
  • the timing information determining module 12 performs timing information extraction according to the second method, and the first sequence adding force 'block 13 according to the timing information and the first sequence, obtains the need in the first sequence ⁇ ' 6 6 LS
  • the frequency of the end of the adjustment 'the first copy of the VL is:
  • VL ⁇ VL VL
  • the first sequence adding module 13 obtains an adjusted second required at the high frequency end of the first sequence H ts according to the timing information and the first sequence
  • the copy VR is:
  • the number of channel estimation values of the first replica that need to be added at the low frequency end of the first sequence is equal to the number of channel estimation values of the second replica that need to be added at the high frequency end of the first sequence.
  • the second sequence of the frequency domain channel estimation obtained by the first sequence adding module 13 is obtained. It can be expressed as:
  • VL is the adjusted first copy added at the low frequency end
  • VR is the adjusted second copy added at the high frequency end
  • the VL and the VR are equal in length
  • sequence number of the first sequence is N e and the length of VL and VR is N ⁇
  • the sequence number of the second sequence is N e + 2.N .
  • sequence number of the second sequence may be a power of 2 or a power of 2, and preferably, the number of sequence points of the second sequence is a power of 2.
  • sequence number of the second sequence is a power of 2
  • sequence number of the second sequence ⁇ + 2 ⁇ ⁇ / is not limited to the nearest power of 2 , but may also be determined according to the system timing estimation needs, for example, if the system is a TDD-LTE system and the bandwidth is 10MHz, then The sequence number of the second sequence may be I 28 , so that the accuracy of the channel timing estimation is maximized under the premise of ensuring a high channel estimation operation rate.
  • the second sequence processing module 14 is configured to transform the second sequence into a time domain for time domain denoising, and then transform it into a frequency domain to obtain a channel estimation result.
  • the second sequence processing module 14 includes a conversion submodule 141 and a time domain denoising submodule 142.
  • the conversion sub-module 141 is configured to transform the second sequence of the frequency domain channel estimation into a time domain, and transform a second sequence after transforming into a time domain and performing a time domain denoising operation to the frequency domain;
  • the time domain denoising sub-module 142 is configured to perform time domain denoising on the second sequence of the frequency domain channel estimation transformed into the time domain.
  • the conversion sub-module 141 is configured to perform inverse discrete Fourier transform on the second sequence of the frequency domain channel estimation to obtain a first sequence of time domain channel estimation, and, for the time domain denoising sub-module 142.
  • the second sequence of the obtained time domain channel estimation is subjected to discrete Fourier transform to obtain a channel estimation result.
  • fi LS is a second sequence of frequency domain channel estimation;
  • the inverse discrete Fourier transform may be a normal inverse discrete Fourier transform, if the first copy and the second copy are added after continuous phase adjustment
  • the sequence number of the second sequence of the obtained frequency domain channel estimation is a power of 2
  • the inverse discrete Fourier transform may be a fast Fourier transform in the discrete Fourier transform.
  • the channel estimation result obtained by the conversion sub-module 141 may be H), where
  • a vector performs a discrete Fourier transform, and ⁇ 8 is a second sequence of time domain channel estimates; the discrete Fourier transform can be a normal discrete Fourier transform, if the continuous phase is continuously phase adjusted After the addition operation of the copy and the second copy, the discrete Fourier transform may be fast in the discrete Fourier transform when the sequence number of the second sequence of the obtained frequency domain channel estimation is a power of 2 Fourier transform.
  • the time domain denoising sub-module 142 is specifically configured to perform a time domain denoising operation on the first sequence of the time domain channel estimation obtained by the conversion sub-module 141 to obtain a second sequence of time domain channel estimation.
  • the time domain denoising sub-module 142 may perform a time domain denoising operation on the first sequence of the time domain channel estimation by:
  • h.. h n (N c + 2 - N pad - L cp + l) - (N c + 2 - N pad ) , where ' CT is CP length.
  • An embodiment of the present invention provides a channel estimation method and apparatus, which obtains a first sequence of frequency domain channel estimation by performing channel estimation on a received pilot sequence, and obtains a first copy and a first copy according to the copied first sequence, respectively. a second copy, and determining, by using the determined timing information indicating a phase offset of each channel estimation value in the frequency domain in the frequency domain, phase adjustment of the first copy and the second copy, respectively, and adjusting the A copy and a second copy are respectively added to the low frequency end and the high frequency end of the first sequence to obtain a second sequence of frequency domain channel estimation, so that the frequency domain channel estimation second sequence is transformed into the time domain
  • the obtained time domain channel impulse response has no side lobes, which conforms to the real time domain channel impulse response of the first sequence of frequency domain channel estimation, avoiding power leakage, thereby improving the accuracy of channel timing estimation.
  • the invention solves the problem that the frequency domain channel impulse response of the pilot sequence existing in the prior art is zero-padded and time-domain denoising is performed, because the time domain channel Hit exist side lobe response contains useful signal, resulting in power leakage leading to real time domain channel impulse response of partial information loss and reduce the problem of channel estimation accuracy, improved channel estimate was accurate.
  • the timing information extraction operation is adopted in the embodiment of the present invention, the direct calculation of the phase is avoided, the implementation efficiency of the system hardware is improved, and the resource consumption is reduced.
  • embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) in which computer usable program code is embodied.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • the computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device.
  • the apparatus implements the functions specified in one or more of the flow or in one or more of the flow charts and/or block diagrams of the flowchart.
  • These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device.
  • the instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

Abstract

L'invention concerne un procédé et un dispositif d'estimation de canal comprenant : la réalisation d'une estimation de canal sur une séquence de fréquences pilotes reçue pour obtenir la première séquence de l'estimation de canal de domaine fréquentiel ; la duplication de la première séquence, l'obtention d'un premier double et d'un second double respectivement selon la première séquence dupliquée, l'utilisation des informations de temporisation déterminées représentant le décalage de phase du domaine fréquentiel de chaque valeur d'estimation de canal dans la première séquence pour adapter les phases du premier double et du second double, et la superposition respective des premier et second doubles adaptés à l'extrémité de basse fréquence et à l'extrémité de haute fréquence de la première séquence, de manière à obtenir la seconde séquence de l'estimation de canal de domaine fréquentiel, de telle sorte que lorsque la seconde séquence est convertie en un domaine temporel pour le débruitage de domaine temporel, la séquence de domaine temporel obtenue est cohérente avec la réponse d'impulsions du canal de domaine temporel réel de la première séquence, ce qui évite la perte de puissance, et améliore la précision de l'estimation du canal tout en améliorant la précision de l'estimation de temporisation de canal.
PCT/CN2013/000834 2012-07-17 2013-07-11 Procédé et dispositif d'estimation de canal WO2014012352A1 (fr)

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CN112511470B (zh) * 2020-12-04 2022-04-05 上海交通大学 一种信道估计方法及装置

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CN101150346A (zh) * 2000-10-02 2008-03-26 三菱电机株式会社 电信系统及其传输信道特性的估计方法
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WO2010022007A2 (fr) * 2008-08-20 2010-02-25 Qualcomm Incorporated Estimation de pilote sdma de liaison montante
WO2010144973A1 (fr) * 2009-06-19 2010-12-23 Cohda Wireless Pty Ltd Estimation d'un milieu ambiant d'un système de communications sans fil

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CN1980201A (zh) * 2005-12-05 2007-06-13 松下电器产业株式会社 多天线正交频分复用系统的信道估计方法
CN101601244A (zh) * 2006-11-24 2009-12-09 法国电信公司 使用训练序列的多载波多天线系统的传输/接收方法和模块
WO2010022007A2 (fr) * 2008-08-20 2010-02-25 Qualcomm Incorporated Estimation de pilote sdma de liaison montante
WO2010144973A1 (fr) * 2009-06-19 2010-12-23 Cohda Wireless Pty Ltd Estimation d'un milieu ambiant d'un système de communications sans fil

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CN115695094A (zh) * 2021-07-26 2023-02-03 中移物联网有限公司 信道估计方法、装置及通信设备

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