WO2020052683A1 - 频偏估计补偿方法、装置、通信设备及计算机可读存储介质 - Google Patents

频偏估计补偿方法、装置、通信设备及计算机可读存储介质 Download PDF

Info

Publication number
WO2020052683A1
WO2020052683A1 PCT/CN2019/105918 CN2019105918W WO2020052683A1 WO 2020052683 A1 WO2020052683 A1 WO 2020052683A1 CN 2019105918 W CN2019105918 W CN 2019105918W WO 2020052683 A1 WO2020052683 A1 WO 2020052683A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency offset
group
symbol
offset estimation
symbol group
Prior art date
Application number
PCT/CN2019/105918
Other languages
English (en)
French (fr)
Inventor
张良俊
Original Assignee
中兴通讯股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中兴通讯股份有限公司 filed Critical 中兴通讯股份有限公司
Priority to EP19858803.0A priority Critical patent/EP3849147B1/en
Priority to KR1020217009910A priority patent/KR102464665B1/ko
Publication of WO2020052683A1 publication Critical patent/WO2020052683A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • H04B10/6164—Estimation or correction of the frequency offset between the received optical signal and the optical local oscillator
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end
    • H04L2027/0026—Correction of carrier offset
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present disclosure relates to the field of optical communications.
  • An aspect of the embodiments of the present disclosure provides a frequency offset estimation compensation method, which includes: determining a search angle of symbols in each symbol group within a Kth symbol group in a received signal; wherein any symbol group is determined by At least two phase noises can be regarded as the same symbol composition.
  • the Kth symbol group includes at least one symbol group, and K is greater than or equal to 1.
  • Each code is determined according to the search angle of the symbols in each symbol group.
  • Group frequency offset estimation of the meta group determine the frequency offset estimation of the Kth symbol large group based on the group frequency offset estimation of each symbol group; and according to the frequency offset estimation of the Kth symbol large group,
  • the K + 1th symbol group performs frequency offset compensation.
  • a frequency offset estimation and compensation device including: a search angle determination module configured to determine a search angle of symbols in each symbol group in a K-th symbol group in a received signal Among them, any symbol group is composed of at least two symbols whose phase noise can be regarded as the same, and the K-th symbol large group includes at least one symbol group, and K is greater than or equal to 1; group frequency offset estimation module, configuration In order to determine the group frequency offset estimation of each symbol group according to the search angle of each symbol group in the symbol group; the large group frequency offset estimation module is configured to determine the Kth symbol according to the group frequency offset estimation of each symbol group Large group frequency offset estimation; and a frequency offset compensation module configured to perform frequency offset compensation on the K + 1th symbol large group based on the frequency offset estimation of the Kth symbol large group.
  • Another aspect of the embodiments of the present disclosure further provides a communication device, including a processor, a memory, and a communication bus, wherein the communication bus is configured to implement connection and communication between the processor and the memory; and the processor is configured to execute storage in the memory.
  • a communication device including a processor, a memory, and a communication bus, wherein the communication bus is configured to implement connection and communication between the processor and the memory; and the processor is configured to execute storage in the memory.
  • Another aspect of the embodiments of the present disclosure further provides a computer-readable storage medium on which one or more programs are stored, and the one or more programs can be executed by one or more processors to implement the frequency offset described above. Estimate compensation method.
  • FIG. 1 is a flowchart of a frequency offset estimation compensation method according to an embodiment of the present disclosure.
  • FIG. 2 is another flowchart of a frequency offset estimation compensation method according to an embodiment of the present disclosure.
  • FIG. 3 is a schematic diagram showing a comparison between the performance of the frequency offset estimation compensation scheme provided by the embodiment of the present disclosure and the frequency offset estimation performance of the Vertebi-Vertebi algorithm.
  • FIG. 4 is another flowchart of a frequency offset estimation compensation method according to an embodiment of the present disclosure.
  • FIG. 5 is a schematic structural diagram of a frequency offset estimation and compensation device according to an embodiment of the present disclosure.
  • FIG. 6 is another schematic structural diagram of a frequency offset estimation and compensation device according to an embodiment of the present disclosure.
  • FIG. 7 is a schematic diagram of a hardware structure of a communication device according to an embodiment of the present disclosure.
  • mainstream frequency offset estimation compensation algorithms include V-V (Vertebi-Vertebi, Viterbi-Viterbi) algorithm, FFT (Fast Fourier Transformation) algorithm, and the like.
  • V-V algorithm is suitable for QPSK (Quadrature Phase Shift Keying) modulation format, but has limited compensation capability for high-order QAM (Quadrature Amplitude Modulation).
  • QPSK Quadrature Phase Shift Keying
  • QAM Quadadrature Amplitude Modulation
  • the FFT algorithm is transparent to the modulation format, but the algorithm complexity is too high, which is not conducive to hardware implementation. It can be seen that the existing frequency offset estimation and frequency offset compensation algorithms generally have low compensation accuracy.
  • an embodiment of the present disclosure provides a frequency offset estimation compensation method, as shown in FIG. 1, which is a flowchart of a frequency offset estimation compensation method provided by an embodiment of the present disclosure.
  • the frequency offset estimation compensation method may include steps S102 to S108.
  • step S102 a search angle of symbols in each symbol group in the K-th symbol group in the received signal is determined.
  • the large group of symbols mentioned herein refers to a group of symbols that includes multiple symbols.
  • the large group of symbols may refer to a "frame", and a large group of symbols is also a signal frame.
  • the received signal received by the communication device from the transmitting end includes at least one large group of symbols, and under normal circumstances, the received signal should include multiple large groups of symbols.
  • the large group of symbols of the Kth receiving frequency offset compensation process in the received signal is referred to as the Kth large group of symbols
  • the large group of symbols of the K + 1th receiving frequency offset compensation process is referred to as the Kth A large group of 1 symbols, where K is greater than or equal to 1.
  • a symbol group refers to a method of dividing a symbol group under a large group of symbols. Therefore, at least one symbol group is included in a large group of symbols.
  • one symbol group is composed of at least two symbols in which phase noise can be regarded as the same. It can be understood that in a group of symbols, the phase noise of each symbol cannot be completely the same, but because the symbols are close, the phase noise is not much different, so they can be regarded as the same.
  • a large group of symbols is a frame. In a signal frame, it can include 6400 symbols, and each symbol group can include 64 consecutive symbols. Therefore, in a signal frame, Can include 100 symbol groups; the phase noise of 64 symbols in a symbol group can be approximated as
  • a search angle of a symbol in a symbol group may be determined according to a Blind Phase Search (BPS) algorithm.
  • BPS Blind Phase Search
  • the communication device may calculate and determine the search angle of each symbol. For example, in an example, assuming that there are 100 symbol groups in a signal frame, and each symbol group includes 64 symbols, for each symbol group, the communication device needs to determine 64 The search angle of the symbol. For the entire signal frame, the communication device needs to calculate the search angle of 6400 symbols.
  • the search angle of these 6400 symbols can be expressed in sequence as ⁇ 1 , ⁇ 2 , ⁇ 3 , ⁇ 4 ... ⁇ 6400 .
  • the communication device determines the symbol search angle in each symbol group in the Kth symbol group, it is not necessary to calculate the search angle of all the symbols, because, in the subsequent calculation process, In some cases, the search angle of all symbols may not be used.
  • the communication device only needs to calculate the search angle of the first and last symbols. Assuming that the k-th symbol group includes the q-th symbol group, and there are m symbols in the symbol group, the communication device only needs to calculate the search angle ⁇ of the first symbol in the symbol group. 1 and the search angle ⁇ m of the last symbol in the symbol.
  • the symbols targeted by the communication device for calculating the search angle are not limited to the first and last symbols in the symbol group, and may also be any at least two symbols in the symbol group.
  • the manner in which the communication device determines the search angle of each symbol is not limited to BPS. In other examples, the communication device may also determine the search angle of each symbol according to other algorithms.
  • step S104 the group frequency offset estimation of each symbol group is determined according to the search angle of the symbols in each symbol group.
  • the communication device after the communication device determines a search angle of a symbol in a certain symbol group, it can determine a group frequency offset estimation of the symbol group.
  • the following uses the communication device to determine the group frequency offset estimation of the q-th symbol group in the K-th symbol group as an example for description.
  • n should be greater than or equal to 1, and less than or equal to m.
  • the group frequency offset estimate ⁇ f q of the q-th symbol group can be expressed as Among them, ⁇ m is the search angle of the m-th symbol in the q-th symbol group, ⁇ 1 is the search angle of the first symbol in the q-th symbol group, and R s is the baud rate of the received signal.
  • step S106 the frequency offset estimation of the K-th symbol large group is determined according to the group frequency offset estimation of each symbol group.
  • the frequency of the Kth symbol group can be determined according to the frequency offset estimation of each symbol group. Partial estimation.
  • the communication device may perform an average calculation on the group frequency offset estimation of each symbol group in the K-th symbol group to obtain the group frequency offset estimation average value, and then the group frequency offset estimation average value. As the frequency offset estimation of the K-th symbol group.
  • the communication device may first screen the group frequency offset estimates of each symbol group, remove the middle separated group point, and then average the remaining group frequency offset estimates, and then obtain the average value. As the frequency offset estimation of the K-th symbol group.
  • the communication device may determine the group frequency offset estimation of each symbol group without For calculation, a medium-frequency group offset estimation is directly selected as the frequency offset estimation of the K-th symbol group.
  • the communication device may directly estimate the group frequency offset after calculating the group frequency offset estimate of the symbol group. As the frequency offset estimation of the large group of symbols.
  • step S108 frequency offset compensation is performed on the K + 1th symbol group in the received signal based on the frequency offset estimation of the Kth symbol group.
  • the communication device may perform frequency offset compensation on the K + 1-th symbol large group of the received signal.
  • a specific frequency offset compensation scheme is provided, and the communication device can perform frequency offset compensation on the K + 1th symbol large group according to the following formula: Among them, S (K + 1) represents the frequency offset of the K + 1th symbol group before frequency offset compensation, and S ′ (K + 1) represents the K + 1th symbol group after frequency offset compensation.
  • the communication device performs frequency offset compensation on the K + 1th symbol group based on the frequency offset estimation of the Kth symbol group, which is actually based on the frequency offset of the previous symbol group. It is estimated that frequency offset compensation is performed on the next large group of symbols: when K is equal to 1, the communication device performs frequency offset compensation on the second large group of symbols according to the frequency offset estimation of the first large group of symbols; when K When it is equal to 2, the communication device performs frequency offset compensation for the third symbol group based on the frequency offset estimation of the second symbol group ... and so on, until it is based on the penultimate symbol group in the received signal.
  • the frequency offset estimation completes the frequency offset compensation of the last large group of symbols in the received signal.
  • the phase noise of each symbol in a symbol group is close, which can be regarded as the same characteristic.
  • the search angle of the symbol is determined according to the BPS algorithm, the search angle is based on the search angle.
  • Determine the group frequency offset estimation of the symbol group and then determine the frequency offset estimation of a large group of symbols based on the group frequency offset estimation of multiple symbol groups, and then perform the next symbol large group based on the frequency offset estimation.
  • Frequency offset compensation and then repeat the process for the large group of symbols that have been frequency offset compensated, and then cycle through them to achieve frequency offset compensation for all large groups of symbols in the received signal.
  • This method has low processing complexity. However, compared with the existing VV algorithm, the accuracy can be greatly improved.
  • the frequency offset estimation and compensation method provided in the embodiment of the present disclosure can estimate a relatively small frequency offset, so that the frequency offset estimation and the frequency offset compensation accuracy reach a higher accuracy.
  • the frequency offset estimation compensation method provided in the embodiment of the present disclosure is referred to herein as a "fine frequency offset estimation compensation scheme".
  • the fine frequency offset estimation compensation scheme has the advantage of higher estimation accuracy, the range of this algorithm for frequency offset estimation is relatively small. Therefore, if the frequency offset of the received signal is high, it is not suitable to use this scheme. Frequency offset estimation compensation.
  • the frequency offset estimation of the K-th symbol large group before determining the frequency offset estimation of the K-th symbol large group according to the fine frequency offset estimation compensation scheme, the frequency offset estimation of the K-1th symbol large group (that is, the K-1th The residual frequency offset of the large group of symbols after frequency offset compensation is smaller than a preset frequency offset threshold.
  • this embodiment also provides a solution: if it is determined that the frequency offset estimate of the K-1th symbol group is greater than or equal to a preset frequency offset threshold, the communication device is using the Kth Frequency offset estimation of -1 symbol large group After frequency offset compensation is performed on the Kth symbol large group, the frequency offset estimation of the Kth large symbol group can be determined according to at least one of the VV algorithm and the FFT algorithm. .
  • the frequency offset estimation scheme based on this type of algorithm is called "rough Frequency offset estimation compensation scheme ".
  • the K + 1-th symbol large group is subjected to frequency offset compensation according to the frequency offset estimation of the K-th symbol large group.
  • FIG. 2 shows another flowchart of a frequency offset estimation compensation method provided by an embodiment of the present disclosure. Assume that there are a large group of Q symbols in a received signal, and Q is a positive integer greater than 1.
  • the frequency offset estimation compensation method may be Including steps S202-S212.
  • step S202 it is determined whether the frequency offset estimation of the K-1th symbol group is smaller than a preset frequency offset threshold; if yes, go to step S204; if no, go to step S206.
  • the frequency offset estimation of the K-1th symbol group refers to the residual frequency offset after frequency offset compensation; but when the K-1th symbol group is actually When it refers to the first large group of symbols, that is, when K is equal to 2, the frequency offset estimation of the K-1th large group of symbols refers to the frequency offset estimation without frequency offset compensation, that is, the first symbol Estimate of the frequency offset of the large group itself.
  • step S204 frequency offset estimation is performed on the K-th symbol large group according to the fine frequency offset estimation scheme (fine frequency offset estimation compensation scheme); proceed to step S208.
  • fine frequency offset estimation scheme fine frequency offset estimation compensation scheme
  • the communication device may use the fine frequency offset estimation compensation scheme introduced in the foregoing embodiment to perform frequency offset estimation on the large group of K symbols, that is, the communication device may first determine the The search angle of the symbols in each symbol group in the K-th symbol group, and then the group frequency offset estimation of each symbol group is determined based on the determined search angle, and then the K-th symbol is determined according to the frequency offset estimation of each group. Large group frequency offset estimation.
  • step S206 frequency offset estimation is performed on the K-th symbol large group according to the coarse frequency offset estimation scheme (coarse frequency offset estimation compensation scheme); proceed to step S208.
  • the communication device may use the coarse frequency offset estimation compensation scheme provided in this embodiment to perform frequency offset estimation on the K-th symbol large group.
  • step S208 frequency offset compensation is performed on the K + 1th symbol group based on the frequency offset estimation of the Kth symbol group; and step S210 is performed.
  • the frequency offset of the K + 1th symbol large group may be performed according to the frequency offset estimation of the Kth symbol large group. make up.
  • the communication device may perform frequency offset compensation on the K + 1th symbol group according to the following formula: Among them, S (K + 1) represents the frequency offset of the K + 1th symbol group before frequency offset compensation, and S ′ (K + 1) represents the K + 1th symbol group after frequency offset compensation.
  • step S210 it is determined whether K + 1 is less than Q, where Q is the total number of large groups of symbols in the received signal; if yes, go to step S212; if not, end the process.
  • the communication device needs to determine whether there are currently large groups of symbols to be processed for frequency offset processing, that is, whether the value of K + 1 is smaller than the total number Q of the large groups of symbols in the received signal. If the determination result is yes, the process proceeds to S212. , Otherwise, the process ends.
  • step S212 the value of K is incremented by one.
  • a coarse frequency offset estimation compensation scheme such as an FFT algorithm or a VV algorithm is used to perform a large group of previous symbols that have been frequency offset compensated. Frequency offset estimation, and then frequency offset compensation for the next large group of symbols according to the determined frequency offset estimation.
  • FFT Fast Fourier transform
  • Frequency offset estimation and then frequency offset compensation for the next large group of symbols according to the determined frequency offset estimation.
  • the characteristics of the wide frequency offset estimation range of FFT, VV and other algorithms can be used to achieve fast convergence of the frequency offset of the received signal, thereby This allows the frequency offset of the received signal to converge to a smaller range.
  • the communication device uses a fine frequency offset estimation compensation scheme based on the BPS algorithm to perform frequency offset estimation on the previous group of symbols that has been frequency offset compensated, and then performs frequency offset on the next group of symbols based on the determined frequency offset estimation. Compensation, thereby ensuring the accuracy of frequency offset estimation for large groups of symbols and improving the accuracy of frequency offset compensation.
  • the V-V algorithm is used for frequency offset estimation and frequency offset compensation, and the accuracy can only reach about 10 MHz.
  • the frequency offset estimation compensation method provided in the embodiment of the present disclosure the accuracy can reach 1 MHz.
  • FIG. 3 is a schematic diagram showing a comparison between performance of frequency offset estimation compensation of a conventional V-V algorithm and performance of a frequency offset estimation compensation scheme provided by an embodiment of the present disclosure.
  • the left side of the dotted line in FIG. 3 shows the error of frequency offset estimation using the V-V algorithm
  • the right side of the dotted line shows the error of frequency offset estimation using the frequency offset estimation compensation method provided by the embodiment of the present disclosure. It can be clearly seen from FIG. 3 that the frequency offset estimation compensation method provided by the embodiment of the present disclosure has higher frequency offset estimation accuracy.
  • the frequency offset estimation compensation method provided by the embodiment of the present disclosure comprehensively utilizes the advantages of fast frequency offset convergence of the coarse frequency offset estimation compensation scheme and the advantage of high frequency offset estimation accuracy of the fine frequency offset estimation compensation scheme.
  • FIG. 4 shows still another flowchart of a frequency offset estimation compensation method provided by an embodiment of the present disclosure. Assuming that a large group of symbols is a frame, and assuming that each symbol group includes 64 symbols, the frequency offset estimation compensation is performed. The method may include steps S402 to S416.
  • step S402 front-end digital signal processing is performed on the received signal; and step S404 is performed.
  • the so-called front-end digital signal processing may include delay adjustment, DC removal, dispersion compensation, clock synchronization, and polarization demultiplexing. After the front-end digital signal processing, a received signal with frequency offset and phase noise can be obtained.
  • step S404 it is determined whether the received signal is sent by a preset sending end; if so, the process proceeds to step S406; if not, the process proceeds to step S408.
  • the laser frequency offset between the transmitting end and the receiving end is relatively small, and even without frequency offset estimation, it can be determined that the frequency offset between the two is not large.
  • the frequency offset estimation and compensation of the signal frame can be directly adopted by the fine frequency offset estimation compensation scheme. For example, in a data center, the frequency offset between the data sender and the data receiver is not large.
  • the receiving end can directly use the fine frequency offset estimation compensation scheme to perform frequency offset estimation without first using
  • the coarse frequency offset estimation compensation scheme performs frequency offset estimation and compensation until the frequency offset is smaller than a preset frequency offset threshold, and then uses a fine frequency offset estimation compensation scheme to perform frequency offset estimation on a large group of symbols.
  • step S406 a fine frequency offset estimation scheme (fine frequency offset estimation compensation scheme) is used to perform frequency offset estimation on the K-th signal frame; proceed to step S410.
  • fine frequency offset estimation scheme fine frequency offset estimation compensation scheme
  • the communication device may first determine a search angle corresponding to each symbol according to the BPS algorithm.
  • the search angle ⁇ 1 satisfies the following relationship:
  • the frequency offset phase, phase noise, and search angle of the 2nd to 64th symbols satisfy the following relationships in order:
  • the group frequency offset estimate of this symbol group can be calculated as: Assume that there are 10 symbol groups in the Kth signal frame, and after calculation, the group frequency offsets of these 10 symbol groups are respectively ⁇ f 1 , ⁇ f 2 ... ⁇ f 10 , then the frequency offset of the Kth signal frame Estimated as:
  • step S408 a coarse frequency offset estimation scheme (coarse frequency offset estimation compensation scheme) is used to perform frequency offset estimation on the K-th signal frame; proceed to step S410.
  • coarse frequency offset estimation scheme coarse frequency offset estimation compensation scheme
  • the received signal is not sent by a preset transmitting end
  • its current frequency offset estimation may be relatively large (frequency offset estimation is greater than or equal to a preset frequency offset threshold), so FFT or Algorithms such as VV perform frequency offset estimation in order to achieve fast convergence and stability of the received signal frequency offset.
  • FFT or Algorithms such as VV perform frequency offset estimation in order to achieve fast convergence and stability of the received signal frequency offset.
  • step S410 frequency offset compensation is performed on the K + 1th signal frame according to the frequency offset estimation of the Kth signal frame; proceed to step S412.
  • step S412 it is determined whether K + 1 is less than Q, where Q is the total number of signal frames in the received signal; if yes, go to step S414; if not, end the process.
  • the communication device needs to determine whether there are currently signal frames to be processed for frequency offset processing, that is, whether the value of K + 1 is less than the total number of signal frames Q in the received signal. If the determination result is yes, the process proceeds to S414, otherwise, the process ends Process.
  • step S414 the value of K is incremented by 1; the process proceeds to step S416.
  • step S416 it is determined whether the frequency offset of the K-1th signal frame is less than a preset frequency offset threshold; if yes, go to step S406; if no, go to step S408.
  • the frequency offset estimation and compensation method provided by the embodiment of the present disclosure has the advantages of low processing complexity, fast convergence speed of frequency offset estimation, and high accuracy of frequency offset compensation.
  • FIG. 5 shows a schematic structural diagram of the frequency offset estimation compensation device 50.
  • the frequency offset estimation compensation device 50 may include a search angle determination module 502, a group frequency offset estimation module 504, a large group frequency offset estimation module 506, and a frequency offset compensation module 508.
  • the search angle determining module 502 is configured to determine a search angle of a symbol in each symbol group in a K-th large group of symbols in a received signal; wherein any symbol group can be regarded as the same by at least two phase noises.
  • the symbol composition, the K-th symbol group includes at least one symbol group, and K is greater than or equal to 1;
  • the group frequency offset estimation module 504 is configured to determine the symbol group according to the search angle of the symbols in each symbol group.
  • the large group frequency offset estimation module 506 is configured to determine the frequency offset estimation of the K-th symbol large group based on the group frequency offset estimation of each symbol group; the frequency offset compensation module 508 is configured to be based on the Kth code Elementary group frequency offset estimation, frequency offset compensation is performed on the K + 1th symbol large group.
  • the large group of symbols mentioned herein refers to a group of symbols that includes multiple symbols.
  • the large group of symbols may refer to a "frame", and a large group of symbols is also a signal frame.
  • the received signal received by the frequency offset estimation and compensation device 50 from the transmitting end includes at least one large group of symbols, and under normal circumstances, the received signal should include multiple large groups of symbols.
  • the large group of symbols of the Kth receiving frequency offset compensation process in the received signal is referred to as the Kth large group of symbols
  • the large group of symbols of the K + 1th receiving frequency offset compensation process is referred to as the Kth A large group of 1 symbols, where K is greater than or equal to 1.
  • a symbol group refers to a method of dividing a symbol group under a large group of symbols. Therefore, at least one symbol group is included in a large group of symbols.
  • one symbol group is composed of at least two symbols in which phase noise can be regarded as the same. It can be understood that in a group of symbols, the phase noise of each symbol cannot be completely the same, but because the symbols are close, the phase noise is not much different, so they can be regarded as the same.
  • a large group of symbols is a frame. In a signal frame, it can include 6400 symbols, and each symbol group can include 64 consecutive symbols. Therefore, in a signal frame, Can include 100 symbol groups; the phase noise of 64 symbols in a symbol group can be approximated as
  • the search angle determination module 502 may determine the search angle of the symbols in each symbol group according to the BPS algorithm.
  • the search angle determination module 502 may calculate and determine the search angle of each symbol. For example, assuming that there are 100 symbol groups in a signal frame, and each symbol group includes 64 symbols, the search angle determination module 502 can determine 64 symbols for each symbol group. For the entire signal frame, the search angle determination module 502 can calculate the search angle of 6400 symbols, and the search angle of these 6400 symbols can be expressed in sequence as ⁇ 1 , ⁇ 2 , ⁇ 3 , ⁇ 4 ... ... ⁇ 6400 .
  • the search angle determining module 502 determines the symbol search angles of each symbol group in the K-th symbol group, it is not necessary to calculate the search angles of all the symbols. Because in the subsequent calculation process, the search angle of all symbols may not be used. For example, in one example, for a group of symbols, the search angle determination module 502 may calculate only the search angles of the first and last symbols. Assuming that the k-th symbol group includes the q-th symbol group, and there are m symbols in the symbol group, the search angle determination module 502 can only calculate the search of the first symbol in the symbol group. The angle ⁇ 1 and the search angle ⁇ m of the last symbol in the symbol. Undoubtedly, the symbol for which the search angle determination module 502 calculates the search angle is not limited to the first and last symbols in the symbol group, and may be at least two symbols in the symbol group.
  • the manner in which the search angle determination module 502 determines the search angle of each symbol is not limited to the BPS. In some other examples, the search angle determination module 502 may also determine the Search corner.
  • the group frequency offset estimation module 504 may determine the group frequency offset estimation of the symbol group.
  • the following uses the group frequency offset estimation module 504 to determine the group frequency offset estimation of the q-th symbol group in the K-th symbol group as an example for description.
  • the q-th symbol group includes m symbols, of which the nth Frequency offset phase ⁇ f of each symbol, phase noise And the search angle ⁇ n satisfies the following relationship: Among them, n should be greater than or equal to 1, and less than or equal to m.
  • the relationship between the frequency offset phase, phase noise, and search angle of each symbol in the q-th symbol group can be expressed as follows:
  • the group frequency offset estimation module 504 can determine the group frequency offset estimation ⁇ f q of the q-th symbol group as: Among them, ⁇ m is the search angle of the m-th symbol in the q-th symbol group, ⁇ 1 is the search angle of the first symbol in the q-th symbol group, and R s is the baud rate of the received signal.
  • the large group frequency offset estimation module 506 may determine the group frequency offset according to the frequency of each symbol group.
  • the bias estimation determines the frequency offset estimation of the K-th symbol large group:
  • the large-group frequency offset estimation module 506 may perform a group frequency offset of each symbol group in the K-th symbol large group. The average is calculated by the estimation to obtain the average value of the group frequency offset estimation, and then the average value of the group frequency offset estimation is used as the frequency offset estimation of the large group of the Kth symbol.
  • the large group frequency offset estimation module 506 may first filter the group frequency offset estimates of each symbol group, remove the middle separated group point, and then average the remaining group frequency offset estimates, and The obtained mean value is used as the frequency offset estimate of the K-th symbol group.
  • the large group frequency offset estimation module 506 may also determine the group frequency offset estimation of each symbol group. After that, without calculation, a medium-frequency group frequency offset estimation is directly selected as the frequency offset estimation of the K-th symbol large group.
  • the large group frequency offset estimation module 506 may directly calculate the group frequency offset estimation of the symbol group, The frequency offset estimation is used as the frequency offset estimation of the large group of symbols.
  • the frequency offset compensation module 508 may perform the K + 1th symbol of the received signal Large groups perform frequency offset compensation.
  • the embodiment of the present disclosure provides a specific frequency offset compensation scheme.
  • the frequency offset compensation module 508 can perform frequency offset compensation on the K + 1th large group of symbols according to the following formula: Among them, S (K + 1) represents the frequency offset of the K + 1th symbol group before frequency offset compensation, and S ′ (K + 1) represents the K + 1th symbol group after frequency offset compensation.
  • Frequency offset ⁇ f is the frequency offset estimate of the K-th symbol group
  • R s is the baud rate of the received signal.
  • the frequency offset compensation module 508 performs frequency offset compensation on the K + 1th symbol group based on the frequency offset estimation of the Kth symbol group, which is actually based on the previous symbol group Frequency offset estimation for frequency offset compensation of the next large group of symbols: when K is equal to 1, the frequency offset compensation module 508 performs the second large group of symbols according to the frequency offset estimation of the first large group of symbols Frequency offset compensation; when K is equal to 2, the frequency offset compensation module 508 performs frequency offset compensation on the third symbol group based on the frequency offset estimation of the second symbol group ... and so on, until it is based on the received signal The frequency offset estimation of the penultimate symbol group in the middle completes the frequency offset compensation for the last symbol group in the received signal.
  • the frequency offset estimation compensation device 50 may be deployed on a communication device, in which the functions of a search angle determination module 502, a group frequency offset estimation module 504, a large group frequency offset estimation module 506, and a frequency offset compensation module 508 Both can be implemented by the processor of the communication device.
  • the frequency offset estimation and compensation device uses the phase noise of each symbol in a symbol group to be close and can be regarded as the same characteristic.
  • the search angle is based on the search angle.
  • Determine the group frequency offset estimation of the symbol group and then determine the frequency offset estimation of a large group of symbols based on the group frequency offset estimation of multiple symbol groups, and then perform the next symbol large group based on the frequency offset estimation.
  • Frequency offset compensation and then repeat the process for the large group of symbols that have been frequency offset compensated, and then cycle through them to achieve frequency offset compensation processing for all large groups of symbols in the received signal.
  • the compensation scheme has low processing complexity, but compared with the existing VV algorithm, the accuracy can be greatly improved.
  • the frequency offset estimation and compensation scheme provided by the embodiment of the present disclosure can estimate a relatively small frequency offset, so that the frequency offset estimation and the frequency offset compensation accuracy reach a higher accuracy.
  • the frequency offset estimation compensation scheme provided by the embodiments of the present disclosure is referred to as a "fine frequency offset estimation compensation scheme".
  • the fine frequency offset estimation compensation scheme has the advantage of higher estimation accuracy, the range of this algorithm for frequency offset estimation is relatively small. Therefore, if the frequency offset of the received signal is high, it is not suitable to use this scheme. Frequency offset estimation compensation.
  • the frequency offset estimation before the frequency offset estimation is performed on a large group of symbols by using a fine frequency offset estimation compensation scheme, it may be first determined that the current residual frequency offset is less than a preset frequency offset threshold. That is, before determining the frequency offset estimation of the K-th symbol large group according to the fine frequency offset estimation compensation scheme, the frequency offset estimation of the K-1th symbol large group (that is, the K-1th The residual frequency offset of the large group of symbols after frequency offset compensation is smaller than a preset frequency offset threshold.
  • the frequency offset estimation compensation device may use the frequency offset estimation of the K-1th symbol group to perform frequency offset compensation on the Kth symbol group, and then may use the VV algorithm, At least one of the FFT algorithms is used to determine the frequency offset estimation of the K-th symbol large group.
  • the frequency offset estimation scheme based on this type of algorithm is called "rough Frequency offset estimation compensation scheme ".
  • the K + 1-th symbol large group is subjected to frequency offset compensation according to the frequency offset estimation of the K-th symbol large group.
  • FIG. 6 is another schematic structural diagram of a frequency offset estimation and compensation apparatus according to an embodiment of the present disclosure.
  • the frequency offset estimation and compensation device 60 may include a frequency offset determination module 600, a coarse frequency offset estimation module 602, a fine frequency offset estimation module 604, and a frequency offset compensation module 606.
  • the frequency offset determination module 600 may be configured to determine whether the frequency offset estimation of the K-1th symbol group is smaller than a preset frequency offset threshold, and the coarse frequency offset estimation module 602 may be configured to adjust the frequency offset.
  • the judgment result of the judgment module 600 is no, an algorithm such as VV or FFT is used to estimate the frequency offset of the K-th symbol group; and the fine frequency deviation estimation module 604 may be configured to determine that the judgment result of the frequency deviation judgment module 600 is yes.
  • the fine frequency offset estimation compensation scheme provided by the embodiment of the present disclosure is used to determine the frequency offset estimation of the K-th symbol large group.
  • the fine frequency offset estimation module 604 may include a search angle determination module 6042, a group frequency offset estimation module 6044, and a large group frequency offset estimation module 6046.
  • the search angle determination module 6042, the group frequency offset estimation module 6044, and the large group frequency offset estimation module 6046 have the same functions as the search angle determination module 502, the group frequency offset estimation module 504, and the large group frequency offset estimation module in FIG. 5 in the embodiment of the present disclosure.
  • the function of 506 is the same.
  • the frequency offset compensation module 606 may perform frequency offset compensation on the K + 1th symbol group according to the frequency offset estimation of the Kth symbol group.
  • the frequency offset estimation compensation device 60 implements the frequency offset estimation compensation method, refer to the frequency offset estimation compensation method provided by the embodiment of the present disclosure, and details are not described herein again.
  • the frequency offset estimation compensation device 60 may be deployed on a communication device, and the functions of the frequency offset determination module 600, the coarse frequency offset estimation module 602, the fine frequency offset estimation module 604, and the frequency offset compensation module 606 are all It may be implemented by a processor of a communication device.
  • a coarse frequency offset estimation compensation scheme such as an FFT algorithm or a VV algorithm is used to perform a large group of previous symbols that have been frequency offset compensated. Frequency offset estimation, and then frequency offset compensation for the next large group of symbols according to the determined frequency offset estimation.
  • FFT Fast Fourier transform
  • the frequency offset estimation compensation device uses a fine frequency offset estimation compensation scheme based on the BPS algorithm to perform frequency offset estimation on the previous group of symbols that has been subjected to frequency offset compensation, and then performs the next group of symbols based on the determined frequency offset estimation.
  • Frequency offset compensation is performed to ensure the accuracy of frequency offset estimation for large groups of symbols and improve the accuracy of frequency offset compensation.
  • the V-V algorithm is used for frequency offset estimation and frequency offset compensation only, and its accuracy can only reach about 10 MHz.
  • the accuracy can reach 1 MHz.
  • FIG. 3 is a schematic diagram showing a comparison between the performance of the traditional V-V algorithm frequency offset estimation compensation and the performance of the frequency offset estimation compensation scheme in the embodiment of the present disclosure.
  • the left side of FIG. 3 shows the error of frequency offset estimation using the V-V algorithm, and the right side shows the error of frequency offset estimation using the solution provided by the embodiment of the present disclosure. It is apparent from FIG. 3 that the frequency offset estimation accuracy of the frequency offset estimation compensation device provided by the embodiment of the present disclosure is higher.
  • the frequency offset estimation compensation device provided by the embodiment of the present disclosure comprehensively utilizes the advantages of fast frequency offset convergence of the coarse frequency offset estimation compensation scheme and the advantage of high frequency offset estimation accuracy of the fine frequency offset estimation compensation scheme.
  • An embodiment of the present disclosure further provides a computer-readable storage medium.
  • the computer-readable storage medium may store one or more computer programs that can be read, compiled, and executed by one or more processors.
  • the computer-readable storage medium may store a frequency offset estimation compensation program, and the frequency offset estimation compensation program may be used by one or more processors to implement any one of the frequency offset estimation compensation methods provided by the embodiments of the present disclosure. .
  • FIG. 7 shows a schematic diagram of a hardware structure of the communication device 7.
  • the communication device 7 may include a processor 71, a memory 72, and a communication bus 73 for implementing a communication connection between the processor 71 and the memory 72.
  • the memory 72 may be the foregoing computer-readable storage medium storing a frequency offset estimation compensation program.
  • the processor 71 may read the frequency offset estimation compensation program stored in the memory 72, compile and execute any frequency offset estimation compensation method provided by the embodiment of the present disclosure.
  • the processor 71 may first determine a search angle of the symbols in each symbol group in the K-th symbol group in the received signal, and then determine a group frequency offset estimation of each symbol group according to the search angle of the symbols in each symbol group. And determine the frequency offset estimation of the Kth symbol group based on the group frequency offset estimation of each symbol group, and finally the processor 71 performs the K + 1th on the received signal according to the frequency offset estimation of the Kth symbol group.
  • the large group of symbols performs frequency offset compensation.
  • the processor 71 executes a frequency offset estimation compensation program, and for specific details of a method for realizing the frequency offset estimation compensation, refer to the frequency offset estimation compensation method provided in the embodiment of the present disclosure, and details are not described herein again.
  • the signal receiving end can calculate the group frequency offset estimate based on the search angle of the symbol, and then obtain the frequency offset estimate of the large group of symbols.
  • the frequency offset estimation and compensation scheme used by the communication device provided by the embodiments of the present disclosure has higher accuracy and lower complexity, which is beneficial to reducing the complexity of the frequency offset compensation processing at the receiving end while improving system performance. To ensure the communication quality between the local end and the transmitting end.
  • Such software may be distributed on a computer-readable medium, executed by a computing device, and in some cases, the steps shown or described may be performed in a different order than described here, and the computer-readable medium may include computer storage Medium (or non-transitory medium) and communication medium (or transient medium).
  • computer storage Medium includes volatile and non-volatile implemented in any method or technology used to store information, such as computer-readable instructions, data structures, program modules or other data. Removable, removable and non-removable media.
  • Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or may Any other medium used to store desired information and which can be accessed by a computer.
  • a communication medium typically contains computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and may include any information delivery medium . Therefore, the present disclosure is not limited to any particular combination of hardware and software.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

本公开实施例提供一种频偏估计补偿方法、装置、通信设备及计算机可读存储介质，可确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，第K个码元大组包括至少一个码元小组，且K大于等于1；根据各码元小组内码元的搜索角，确定各码元小组的小组频偏估计；根据各码元小组的小组频偏估计，确定第K个码元大组的频偏估计；以及根据第K个码元大组的频偏估计，对接收信号中第K+1个码元大组进行频偏补偿。

Description

频偏估计补偿方法、装置、通信设备及计算机可读存储介质 技术领域
本公开涉及光通信领域。
背景技术
在相干光通信系统中，由于不能保证发射端激光器和接收端激光器的光载波波长完全一致，因此，在接收端会产生一定的频率偏移。载波频偏会导致系统性能严重劣化，所以，正确地估计频率偏移的大小并进行对应的补偿对保证系统性能和通信质量是非常重要的。
发明内容
本公开实施例的一个方面提供了一种频偏估计补偿方法，包括：确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，第K个码元大组内包括至少一个码元小组，且K大于等于1；根据各码元小组内码元的搜索角，确定各码元小组的小组频偏估计；根据各码元小组的小组频偏估计，确定第K个码元大组的频偏估计；以及根据第K个码元大组的频偏估计，对接收信号中第K+1个码元大组进行频偏补偿。
本公开实施例的另一方面还提供了一种频偏估计补偿装置，包括：搜索角确定模块，配置为确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，第K个码元大组包括至少一个码元小组，且K大于等于1；小组频偏估计模块，配置为根据各码元小组内码元的搜索角，确定各码元小组的小组频偏估计；大 组频偏估计模块，配置为根据各码元小组的小组频偏估计，确定第K个码元大组的频偏估计；以及频偏补偿模块，配置为根据第K个码元大组的频偏估计，对第K+1个码元大组进行频偏补偿。
本公开实施例的又一方面还提供了一种通信设备，包括处理器、存储器及通信总线，其中：通信总线配置为实现处理器和存储器之间的连接通信；处理器配置为执行存储器中存储的一个或者多个程序，以实现上述的频偏估计补偿方法。
本公开实施例的再一方面还提供了一种计算机可读存储介质，其上存储有一个或者多个程序，一个或者多个程序可被一个或者多个处理器执行，以实现上述的频偏估计补偿方法。
附图说明
图1为本公开实施例提供的一种频偏估计补偿方法的一种流程图。
图2为本公开实施例提供的一种频偏估计补偿方法的另一种流程图。
图3为本公开实施例提供的频偏估计补偿方案的性能同Vertebi-Vertebi算法的频偏估计性能的对比示意图。
图4为本公开实施例提供的一种频偏估计补偿方法的又一种流程图。
图5为本公开实施例提供的一种频偏估计补偿装置的一种结构示意图。
图6为本公开实施例提供的一种频偏估计补偿装置的另一种结构示意图。
图7为本公开实施例提供的一种通信设备的一种硬件结构示意图。
具体实施方式
为了使本公开的目的、技术方案及优点更加清楚明白，下面通过具体实施方式结合附图对本公开实施例作进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本公开，并不用于限定本公开。
在相干光通信系统中，由于不能保证发射端激光器和接收端激光器的光载波波长完全一致，因此，在接收端会产生一定的频率偏移。载波频偏会导致系统性能严重劣化，因此，正确地估计频率偏移的大小并进行对应的补偿对保证系统性能和通信质量是非常重要的。
目前主流的频偏估计补偿算法有V-V(Vertebi-Vertebi，维特比-维特比)算法，FFT(Fast Fourier Transformation，快速傅里叶变换)算法等。V-V算法适用于QPSK(Quadrature Phase Shift Keyin，正交相移键控)调制格式，但是对于高阶QAM(Quadrature Amplitude Modulation，正交振幅调制)补偿能力有限。FFT算法对调制格式透明，但是算法复杂度太高，不利于硬件实现。可见，现有的频偏估计及频偏补偿算法普遍补偿精度不高。
有鉴于此，本公开实施例提供一种频偏估计补偿方法，如图1所示，其为本公开实施例提供的频偏估计补偿方法的流程图。该频偏估计补偿方法可包括步骤S102-步骤S108。
在步骤S102中，确定接收信号中第K个码元大组内各码元小组内码元的搜索角。
这里所说的码元大组是指包括多个码元的码元组，在本实施例的一些示例中，码元大组可以指“帧”，一个码元大组也即一个信号帧。可以理解的是，通信设备从发送端接收到的接收信号中，至少包括一个码元大组，而在通常情况下，接收信号中应当 包括多个码元大组。这里，将接收信号中第K个接收频偏补偿处理的码元大组称为第K个码元大组，将第K+1个接收频偏补偿处理的码元大组称为第K+1个码元大组，这里K的大于等于1。
码元小组是指码元大组下一种码元分组的划分方式，所以，一个码元大组中至少包括一个码元小组。根据本公开提供的实施例，一个码元小组由至少两个相位噪声可以视为相同的码元构成。可以理解的是，一个码元小组中，各码元的相位噪声不可能完全一致，但是因为码元相近，因此相位噪声相差不大，因此，可以被视为相同。例如，在一个示例当中，码元大组为帧，在一个信号帧中，可以包括6400个码元，而每一个码元小组中可以包括64个连续的码元，所以，在一个信号帧中可以包括100个码元小组；其中，一个码元小组中64个码元的相位噪声都可以近似表示为
Figure PCTCN2019105918-appb-000001
根据本公开提供的实施例，通信设备在对接收信号进行处理的时候，可以根据BPS(Blind Phase Search，盲相位搜索)算法确定码元小组中码元的搜索角。
根据本公开提供的实施例，通信设备在确定码元小组中码元搜索角的时候，可以计算确定每一个码元的搜索角。例如，在一个示例当中，假定一个信号帧中存在100个码元小组，而每一个码元小组中又都包括有64个码元，则针对每一个码元小组，通信设备需要确定出64个码元的搜索角，对于整个信号帧，通信设备需要计算出6400个码元的搜索角，这6400个码元的搜索角可以依次被表示为φ 1,φ 2,φ 3,φ 4……φ 6400。
根据本公开提供的实施例，通信设备在确定第K个码元大组内各码元小组中码元搜索角的时候，可以不必计算出全部的码元的搜索角，因为，在后续计算过程中，可能并不需要用到所有码元的搜索角。例如，在一个示例当中，针对一个码元小组，通信设备只需要计算出其首尾两个码元的搜索角即可。假定第K个码 元大组中包括第q个码元小组，该码元小组中共有m个码元，则通信设备可以只需要计算出该码元小组中第一个码元的搜索角φ 1以及该码元中最后一个码元的搜索角φ m。毫无疑义的是，通信设备计算搜索角所针对的码元也不限于码元小组中首尾码元，也可以是码元小组中任意的至少两个码元。
根据本公开提供的实施例，通信设备确定各码元搜索角的方式也不限于BPS一种，在其它一些示例中，通信设备也可以根据其它算法来确定各码元的搜索角。
在步骤S104中，根据各码元小组内码元的搜索角，确定各码元小组的小组频偏估计。
根据本公开提供的实施例，通信设备确定出某一个码元小组中码元的搜索角之后，可以确定该码元小组的小组频偏估计。下面以通信设备确定第K个码元大组中的第q个码元小组的小组频偏估计为例进行说明。
假设第q个码元小组包括m个码元，其中，第n个码元的频偏相位θ f、相位噪声
Figure PCTCN2019105918-appb-000002
以及搜索角φ n满足以下关系：
Figure PCTCN2019105918-appb-000003
Figure PCTCN2019105918-appb-000004
其中，n应当大于等于1，小于等于m。
由于一个码元小组中各码元的相位噪声
Figure PCTCN2019105918-appb-000005
可以视为相同，因此，在本示例中，第q个码元小组中各码元的频偏相位、相位噪声以及搜索角之间的关系可以分别作如下表示：
Figure PCTCN2019105918-appb-000006
根据上述式(1)至式(m)，可以推导得出：
Figure PCTCN2019105918-appb-000007
因此，第q个码元小组的小组频偏估计Δf q可以表示为
Figure PCTCN2019105918-appb-000008
Figure PCTCN2019105918-appb-000009
其中，φ m为第q个码元小组中第m个码元的搜索角，φ 1为第q个码元小组中第1个码元的搜索角，R s为接收信号的波特率。
在步骤S106中，根据各码元小组的小组频偏估计，确定第K个码元大组的频偏估计。
根据本公开提供的实施例，确定出第K个码元大组中各码元小组的小组频偏估计之后，可以根据各码元小组的频偏估计确定出第K个码元大组的频偏估计。
在本公开实施例的一个示例当中，通信设备可以对第K个码元大组中各码元小组的小组频偏估计进行均值计算，从而得到小组频偏估计均值，然后将小组频偏估计均值作为第K个码元大组的频偏估计。
在本公开实施例的另一个示例当中，通信设备可以先对各码元小组的小组频偏估计进行筛选，剔除其中部分离群点之后再对剩余小组频偏估计取均值，并将得到的均值作为第K个码元大组的频偏估计。
在本公开实施例的其它示例当中，除了通过计算均值的方式确定第K个码元大组的频偏估计以外，通信设备还可以在确定出各码元小组的小组频偏估计之后，不经计算，直接从中选择一个中等取值的小组频偏估计作为第K个码元大组的频偏估计。
在本公开实施例的一个示例当中，如果在一个码元大组中仅包括一个码元小组，则通信设备在计算出该码元小组的小组频偏估计之后，可以直接将该小组频偏估计作为该码元大组的频偏估计。
在步骤S108中，根据第K个码元大组的频偏估计，对接收 信号中第K+1个码元大组进行频偏补偿。
根据本公开提供的实施例，通信设备计算出接收信号中第K个码元大组的频偏估计之后，可以对接收信号第K+1个码元大组进行频偏补偿。
根据本公开提供的实施例，提供一种具体的频偏补偿方案，通信设备可以根据以下公式对第K+1个码元大组进行频偏补偿：
Figure PCTCN2019105918-appb-000010
其中，S(K+1)表征频偏补偿前的第K+1个码元大组的频率偏移，S′(K+1)表征频偏补偿后的第K+1个码元大组的频率偏移；Δf为第K个码元大组的频偏估计，R s为接收信号的波特率。
根据本公开提供的实施例，通信设备根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿，实际上就是根据前一个码元大组的频偏估计对后一个码元大组进行频偏补偿：当K等于1的时候，通信设备就是根据第一个码元大组的频偏估计对第二个码元大组进行频偏补偿；当K等于2的时候，通信设备就是根据第二个码元大组的频偏估计对第三个码元大组进行频偏补偿……依次类推，直到根据接收信号中倒数第二个码元大组的频偏估计完成对接收信号中的最后一个码元大组的频偏补偿。
可以理解的是，当K大于1的时候，在计算第K个码元大组的频偏估计时，第K个码元大组是已经经历过频偏补偿的，即第K个码元大组已经根据第K-1个码元大组的频偏估计进行过频偏补偿。所以，确定第K个码元大组的频偏估计，实际上就是计算第K个码元大组经频偏补偿后的残余频偏。对第K+1个码元大组进行频偏补偿，实际上也就是根据第K个码元大组的残余频偏对第K+1个码元大组进行频偏补偿。
根据本公开实施例提供的频偏估计补偿方法，利用一个码元 小组中各码元的相位噪声接近，可视为相同的特点，在根据BPS算法确定出码元的搜索角之后，基于搜索角确定出该码元小组的小组频偏估计，再根据多个码元小组的小组频偏估计确定出一个码元大组的频偏估计，进而根据该频偏估计对下一个码元大组进行频偏补偿，然后再对已经频偏补偿的码元大组重复该处理过程，依次循环，就可以实现对接收信号中所有码元大组的频偏补偿处理；该方法处理复杂度较低，但是相较于现有V-V算法，精度却可以得到极大的提升。
本公开实施例提供的频偏估计补偿方法能够对较为细小的频偏进行估计，从而使得频偏估计及频偏补偿精度达到较高的精度。为了便于介绍，这里将本公开实施例提供的频偏估计补偿方法称为“细频偏估计补偿方案”。不过细频偏估计补偿方案虽然具有估计精度较高的优点，但这种算法对频偏估计的范围相对较小，所以，如果接收信号的频偏较高，则不太适用采用这种方案进行频偏估计补偿。
根据本公开提供的实施例，在采用细频偏估计补偿方案对码元大组进行频偏估计前，可首先确定当前的残余频偏已经小于预设频偏阈值。也就是说，在根据细频偏估计补偿方案确定第K个码元大组的频偏估计前，可首先确定第K-1个码元大组的频偏估计(也即第K-1个码元大组经历频偏补偿后的残余频偏)小于预设频偏阈值。
根据本公开提供的实施例，如果经过判断，确定第K-1个码元大组的频偏估计大于等于预设频偏阈值，则说明接收信号当前的频偏尚不在可以采用细频偏估计补偿方案的范围内，对于这种情况，本实施例还提供一种方案：如果确定第K-1个码元大组的频偏估计大于等于预设频偏阈值，则通信设备在采用第K-1个码元大组的频偏估计对第K个码元大组进行频偏补偿后，可以根据 V-V算法、FFT算法中的至少一种来确定第K个码元大组的频偏估计。由于V-V算法、FFT算法能够估计的频偏范围较大，但精度不高，因此，为了和前述细频偏估计补偿方案区分，这里将根据这一类算法进行频偏估计的方案称为“粗频偏估计补偿方案”。在根据粗频偏估计补偿方案确定出第K个码元大组的频偏估计后，根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿。
图2示出了本公开实施例提供的频偏估计补偿方法的另一种流程图，假定接收信号中共有Q个码元大组，Q为大于1的正整数，该频偏估计补偿方法可包括步骤S202-步骤S212。
在步骤S202中，判断第K-1个码元大组的频偏估计是否小于预设频偏阈值；若是，则进入步骤S204；若否，则进入步骤S206。
可以理解的是，当K取值为1的时候，由于并不存在第K-1个码元大组，因此，在本实施例的一些示例当中，当K取值为1的时候，可以不必执行S202，而直接执行S204或者是执行S206。考虑到接收信号中第一个码元大组完全没有经过频偏补偿，因此频偏通常较大，所以，在本实施例中，当K取值为1的时候，可以执行S206。
可以理解的是，当K大于2时，第K-1个码元大组的频偏估计指的是经历过频偏补偿后的残余频偏；但当第K-1个码元大组实际是指第1个码元大组时，也即K等于2时，第K-1个码元大组的频偏估计是指未经频偏补偿的频偏估计，也即第1个码元大组本身的频偏估计。
在步骤S204中，根据细频偏估计方案(细频偏估计补偿方案)对第K个码元大组进行频偏估计；进入步骤S208。
根据本公开提供的实施例，如果经过判断确定第K-1个码元大组的频偏估计小于预设频偏阈值，则在根据第K-1个码元大组 的频偏估计对第K个码元大组进行频偏补偿之后，通信设备可以采用前述实施例中介绍的细频偏估计补偿方案对第K个码元大组进行频偏估计，即通信设备可以先采用BPS算法确定第K个码元大组中各码元小组内码元的搜索角，然后基于确定出的搜索角确定各码元小组的小组频偏估计，然后根据各小组频偏估计确定第K个码元大组的频偏估计。
在步骤S206中，根据粗频偏估计方案(粗频偏估计补偿方案)对第K个码元大组进行频偏估计；进入步骤S208。
根据本公开提供的实施例，如果经过判断确定第K-1个码元大组的频偏估计大于等于预设频偏阈值，则在根据第K-1个码元大组的频偏估计对第K个码元大组进行频偏补偿之后，通信设备可以采用本实施例提供的粗频偏估计补偿方案对第K个码元大组进行频偏估计。
根据本公开提供的实施例，通信设备根据V-V算法对第K个码元大组进行频偏估计的过程可如下：假定第K个码元大组中包括有N个码元，通过对相邻两个的码元做共轭相乘，以及四次方运算可以消除码元所携带的相位信息和激光器导致的相位噪声：C(k)＝[S(k)·S *(k-1)] 4，其中，S(k-1)表征第K个码元大组中第k-1个码元的频率偏移，S(k)表征第K个码元大组中第k个码元的频率偏移。然后对多个C(k)进行求和平均，消除白噪声的影响，这样可以得到第K个码元大组的频偏估计：
Figure PCTCN2019105918-appb-000011
Figure PCTCN2019105918-appb-000012
其中R s为接收信号的波特率，N表示第K个码元大组中码元的数目，arg表示取幅角运算。
根据本公开提供的实施例，根据FFT算法进行粗频偏估计的方案的过程可如下：通过运算获得数据码元四次方的频谱并且对 其分析发现，在频率为4*△f处存在最大的频谱分量，因此第K个码元大组的频偏估计△f可以通过搜寻数据码元四次方后的频谱的最大频谱分量求得，其表达式如下：Δf＝1/4max{FFT(S 4(k))}。
在步骤S208中，根据第K个码元大组的频偏估计，对第K+1个码元大组进行频偏补偿；进入步骤S210。
根据本公开提供的实施例，在确定出第K个码元大组的频偏估计后，可以根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿。
根据本公开提供的实施例，通信设备可以根据以下公式对第K+1个码元大组进行频偏补偿：
Figure PCTCN2019105918-appb-000013
其中，S(K+1)表征频偏补偿前的第K+1个码元大组的频率偏移，S′(K+1)表征频偏补偿后的第K+1个码元大组的频率偏移；Δf为第K个码元大组的频偏估计，R s为接收信号的波特率。
在步骤S210中，判断K+1是否小于Q，其中，Q为接收信号中码元大组的总数；若是，则进入步骤S212；若否，则结束流程。
根据本公开提供的实施例，在对第K+1个码元大组进行频偏补偿处理之后，需要根据第K+1个码元大组是否是接收信号中的最后一个码元大组来确定当前是否还存在其它码元大组待频偏补偿。所以，通信设备需要确定当前是否还存在待频偏处理的码元大组，也即K+1的取值是否小于接收信号中码元大组的总数Q，若判断结果为是，则进入S212，否则，结束流程。
在步骤S212中，将K的取值递增1。
根据本公开提供的实施例，在对第K+1个码元大组的进行频偏补偿之后，需要对第K+1个码元大组之后的码元大组进行频偏估计补偿处理，所以，在此时可以将K的取值按照公差1进行一 次递增。对K的取值进行递增之后，需要继续循环之间的流程，因此，通信设备执行步骤S202。
本公开实施例提供的频偏估计补偿方法，在接收信号的频偏较大的情况下，采用FFT算法、V-V算法等粗频偏估计补偿方案对已经频偏补偿的前一码元大组进行频偏估计，然后根据确定出的频偏估计对后一个码元大组进行频偏补偿，这样可以利用FFT、V-V等算法频偏估计范围大的特点，实现接收信号频偏的快速收敛，从而使得接收信号的频偏收敛到一个较小的范围内。随后，通信设备利用基于BPS算法的细频偏估计补偿方案对已经频偏补偿的前一码元大组进行频偏估计，然后根据确定出的频偏估计对后一个码元大组进行频偏补偿，从而保证对码元大组频偏估计的准确性，提升频偏补偿的精确程度。通常，单纯采用V-V算法进行频偏估计及频偏补偿，其精度只能到达10MHz左右，但是根据本公开实施例提供的频偏估计补偿方法，精度可以达到1MHz。图3示出了传统V-V算法频偏估计补偿的性能和本公开实施例提供的频偏估计补偿方案的性能对比示意图。
图3虚线左侧示出的是采用V-V算法进行频偏估计的误差，而虚线右侧是采用本公开实施例提供的频偏估计补偿方法进行频偏估计的误差。从图3可以明显看出本公开实施例提供的频偏估计补偿方法的频偏估计精度更高。
本公开实施例提供的频偏估计补偿方法综合利用了粗频偏估计补偿方案的频偏收敛快的优点，和细频偏估计补偿方案频偏估计精度高的优点。
图4示出了本公开实施例提供的频偏估计补偿方法的又一种流程图，假定码元大组为帧，并且假定每一个码元小组中包括64个码元，该频偏估计补偿方法可包括步骤S402-步骤S416。
在步骤S402中，对接收信号进行前端数字信号处理；进入步 骤S404。
根据本公开提供的实施例，这里所谓的前端数字信号处理可包括时延调整，去直流，色散补偿，时钟同步，以及偏振解复用等处理。经过前端数字信号处理，可以得到带有频偏和相位噪声的接收信号。
在步骤S404中，判断接收信号是否是由预设发送端发送；若是，则进入步骤S406；若否，则执行步骤S408。
根据本公开提供的实施例，在一些通信场景下，发送端和接收端的激光器频偏比较小，即使未经频偏估计，也能够确定二者之间频偏不大，在这种情况下，可以直接采用细频偏估计补偿方案对信号帧进行频偏估计及补偿。例如，在数据中心中，数据发端与数据收端间的频偏就不大。因此，如果信号接收端能够确定当前接收到的信号是由那些与本端激光器频偏不大的发送端发送，则接收端可以直接采用细频偏估计补偿方案进行频偏估计，而不必先采用粗频偏估计补偿方案进行频偏估计及补偿，直到频偏小于预设频偏阈值之后采用细频偏估计补偿方案对码元大组进行频偏估计。
在步骤S406中，采用细频偏估计方案(细频偏估计补偿方案)对第K个信号帧进行频偏估计；进入步骤S410。
根据本公开提供的实施例，对于信号帧中的某一个码元小组，其一共包括64个码元，通信设备可以先根据BPS算法确定出每一个码元对应的搜索角。其中，第1个码元的频偏相位θ f、相位噪声
Figure PCTCN2019105918-appb-000014
以及搜索角φ 1满足如下关系：
Figure PCTCN2019105918-appb-000015
第2～64个码元的频偏相位、相位噪声以及搜索角依次满足如下关系：
Figure PCTCN2019105918-appb-000016
Figure PCTCN2019105918-appb-000017
这里近似认为这64个码元的相位噪声一样或者变化很小，因此可以计算出这一码元小组的小组频偏 估计为：
Figure PCTCN2019105918-appb-000018
假定第K个信号帧中一共有10个码元小组，且经过计算，这10个码元小组的小组频偏估计分别为Δf 1，Δf 2…Δf 10，则第K个信号帧的频偏估计为：
Figure PCTCN2019105918-appb-000019
在步骤S408中，采用粗频偏估计方案(粗频偏估计补偿方案)对第K个信号帧进行频偏估计；进入步骤S410。
根据本公开提供的实施例，如果经过判断确定接收信号不是由预设发送端发送的，其当前的频偏估计可能比较大(频偏估计大于等于预设频偏阈值)，因此可以采用FFT或V-V等算法进行频偏估计，以便实现接收信号频偏的快速收敛稳定。对于采用粗频偏估计补偿方案对第K个码元大组进行频偏估计的具体过程，请参见前述介绍，这里不再赘述。
在步骤S410中，根据第K个信号帧的频偏估计对第K+1个信号帧进行频偏补偿；进入在步骤S412。
对于频偏补偿具体实现，本公开实施例已经做了比较具体的介绍，这里不再赘述。
在步骤S412中，判断K+1是否小于Q，其中，Q为接收信号中信号帧的总数；若是，则进入步骤S414；若否，结束流程。
根据本公开提供的实施例，在对第K+1个信号帧进行频偏补偿处理之后，需要根据第K+1个信号帧是否是接收信号中的最后一个信号帧来确定当前是否还存在其它信号帧待频偏补偿。所以，通信设备需要确定当前是否还存在待频偏处理的信号帧，也即K+1的取值是否小于接收信号中信号帧的总数Q，若判断结果为是，则进入S414，否则，结束流程。
在步骤S414中，将K的取值递增1；进入步骤S416。
根据本公开提供的实施例，在对第K+1个信号帧的进行频偏 补偿之后，需要对第K+1个信号帧之后的信号帧进行频偏估计补偿处理，所以，在此时可以将K的取值按照公差1进行一次递增。
在步骤S416中，判断第K-1个信号帧的频偏是否小于预设频偏阈值；若是，则进入步骤S406；若否，则进入步骤S408。
如此循环，直至处理完接收信号中所有的信号帧。
本公开实施例提供的频偏估计补偿方法，具有处理复杂度低，频偏估计收敛速度快，频偏补偿精度高的优点。
本公开实施例还提供一种频偏估计补偿装置，图5示出该频偏估计补偿装置50的结构示意图。
频偏估计补偿装置50可包括搜索角确定模块502、小组频偏估计模块504、大组频偏估计模块506以及频偏补偿模块508。其中，搜索角确定模块502配置为确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，第K个码元大组包括至少一个码元小组，且K大于等于1；小组频偏估计模块504配置为根据各码元小组内码元的搜索角，确定各码元小组的小组频偏估计；大组频偏估计模块506配置为根据各码元小组的小组频偏估计，确定第K个码元大组的频偏估计；频偏补偿模块508配置为根据第K个码元大组的频偏估计，对第K+1个码元大组进行频偏补偿。
这里所说的码元大组是指包括多个码元的码元组，在本实施例的一些示例中，码元大组可以指“帧”，一个码元大组也即一个信号帧。可以理解的是，频偏估计补偿装置50从发送端接收到的接收信号中，至少包括一个码元大组，而在通常情况下，接收信号中应当包括多个码元大组。这里，将接收信号中第K个接收频偏补偿处理的码元大组称为第K个码元大组，将第K+1个接收频偏补偿处理的码元大组称为第K+1个码元大组，这里K的大于等于1。
码元小组是指码元大组下一种码元分组的划分方式，所以，一个码元大组中至少包括一个码元小组。根据本公开提供的实施例，一个码元小组由至少两个相位噪声可以视为相同的码元构成。可以理解的是，一个码元小组中，各码元的相位噪声不可能完全一致，但是因为码元相近，因此相位噪声相差不大，因此，可以被视为相同。例如，在一个示例当中，码元大组为帧，在一个信号帧中，可以包括6400个码元，而每一个码元小组中可以包括64个连续的码元，所以，在一个信号帧中可以包括100个码元小组；其中，一个码元小组中64个码元的相位噪声都可以近似表示为
Figure PCTCN2019105918-appb-000020
根据本公开提供的实施例，频偏估计补偿装置50在对接收信号进行处理的时候，搜索角确定模块502可以根据BPS算法确定各码元小组中码元的搜索角。
在本公开实施例的一些示例当中，搜索角确定模块502在确定码元小组中码元搜索角的时候，可以计算确定每一个码元的搜索角。例如，假定一个信号帧中存在100个码元小组，而每一个码元小组中又都包括有64个码元，则针对每一个码元小组，搜索角确定模块502可确定出64个码元的搜索角，对于整个信号帧，搜索角确定模块502可计算出6400个码元的搜索角，这6400个码元的搜索角可以依次被表示为φ 1,φ 2,φ 3,φ 4……φ 6400。
在本公开实施例的另一些示例当中，搜索角确定模块502在确定第K个码元大组内各码元小组中码元搜索角的时候，可以不必计算出全部的码元的搜索角，因为，在后续计算过程中，可能并不需要用到所有码元的搜索角。例如，在一种示例当中，针对一个码元小组，搜索角确定模块502可仅计算出其首尾两个码元的搜索角即可。假定第K个码元大组中包括第q个码元小组，该码元小组中共有m个码元，则搜索角确定模块502可以只计算出该码元小组中第一个码元的搜索角φ 1以及该码元中最后一个码 元的搜索角φ m。毫无疑义的是，搜索角确定模块502计算搜索角所针对的码元也不限于码元小组中首尾码元，也可以是码元小组中任意的至少两个码元。
根据本公开提供的实施例，搜索角确定模块502确定各码元搜索角的方式也不限于BPS一种，在其它一些示例中，搜索角确定模块502也可以根据其它算法来确定各码元的搜索角。
根据本公开提供的实施例，搜索角确定模块502确定出某一个码元小组中码元的搜索角之后，小组频偏估计模块504可以确定该码元小组的小组频偏估计。下面以小组频偏估计模块504确定第K个码元大组中的第q个码元小组的小组频偏估计为例进行说明：第q个码元小组包括m个码元，其中，第n个码元的频偏相位θ f、相位噪声
Figure PCTCN2019105918-appb-000021
以及搜索角φ n满足以下关系：
Figure PCTCN2019105918-appb-000022
Figure PCTCN2019105918-appb-000023
其中，n应当大于等于1，小于等于m。
根据本公开提供的实施例，由于一个码元小组中各码元的相位噪声
Figure PCTCN2019105918-appb-000024
可以视为相同，因此，在本公开实施例中，第q个码元小组中各码元的频偏相位、相位噪声以及搜索角之间的关系可以分别作如下表示：
Figure PCTCN2019105918-appb-000025
根据上述式(1)至式(m)，可以推导得出：
Figure PCTCN2019105918-appb-000026
因此，小组频偏估计模块504可以确定第q个码元小组的小组频偏估计Δf q为：
Figure PCTCN2019105918-appb-000027
其中，φ m为第q个码元小组中第m个码元的搜索角，φ 1为第q个码元小组中第1个码元的搜索 角，R s为接收信号的波特率。
根据本公开提供的实施例，小组频偏估计模块504确定出第K个码元大组中各码元小组的小组频偏估计之后，大组频偏估计模块506可以根据各码元小组的频偏估计确定出第K个码元大组的频偏估计：在本实施例的一个示例当中，大组频偏估计模块506可以对第K个码元大组中各码元小组的小组频偏估计进行均值计算，从而得到小组频偏估计均值，然后将小组频偏估计均值作为第K个码元大组的频偏估计。在本实施例的另一个示例当中，大组频偏估计模块506可以先对各码元小组的小组频偏估计进行筛选，剔除其中部分离群点之后再对剩余小组频偏估计取均值，并将得到的均值作为第K个码元大组的频偏估计。在本实施例的其它示例当中，除了通过计算均值的方式确定第K个码元大组的频偏估计以外，大组频偏估计模块506还可以在确定出各码元小组的小组频偏估计之后，不经计算，直接从中选择一个中等取值的小组频偏估计作为第K个码元大组的频偏估计。
根据本公开提供的实施例，如果在一个码元大组中仅包括一个码元小组，则大组频偏估计模块506在计算出该码元小组的小组频偏估计之后，可以直接将该小组频偏估计作为该码元大组的频偏估计。
根据本公开提供的实施例，大组频偏估计模块506计算出接收信号中第K个码元大组的频偏估计之后，频偏补偿模块508可以对接收信号的第K+1个码元大组进行频偏补偿。本公开实施例提供一种具体的频偏补偿方案，频偏补偿模块508可以根据以下公式对第K+1个码元大组进行频偏补偿：
Figure PCTCN2019105918-appb-000028
Figure PCTCN2019105918-appb-000029
其中，S(K+1)表征频偏补偿前的第K+1个码元大组的频率偏移，S′(K+1)表征频偏补偿后的第K+1个码元大组的频 率偏移；Δf为第K个码元大组的频偏估计，R s为接收信号的波特率。
根据本公开提供的实施例，频偏补偿模块508根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿，实际上就是根据前一个码元大组的频偏估计对后一个码元大组进行频偏补偿：当K等于1的时候，频偏补偿模块508就是根据第一个码元大组的频偏估计对第二个码元大组进行频偏补偿；当K等于2的时候，频偏补偿模块508就是根据第二个码元大组的频偏估计对第三个码元大组进行频偏补偿……依次类推，直到根据接收信号中倒数第二个码元大组的频偏估计完成对接收信号中的最后一个码元大组的频偏补偿。
可以理解的是，当K大于1的时候，在计算第K个码元大组的频偏估计时，第K个码元大组是已经经历过频偏补偿的：第K个码元大组已经根据第K-1个码元大组的频偏估计进行过频偏补偿。所以，确定第K个码元大组的频偏估计，实际上就是计算第K个码元大组经频偏补偿后的残余频偏。对第K+1个码元大组进行频偏补偿，实际上也就是根据地K个码元大组的残余频偏对第K+1个码元大组进行频偏补偿。
根据本公开提供的实施例，频偏估计补偿装置50可以部署在通信设备上，其中搜索角确定模块502、小组频偏估计模块504、大组频偏估计模块506以及频偏补偿模块508的功能都可以由通信设备的处理器实现。
本公开实施例提供的的频偏估计补偿装置，利用一个码元小组中各码元的相位噪声接近，可视为相同的特点，在根据BPS算法确定出码元的搜索角之后，基于搜索角确定出该码元小组的小组频偏估计，再根据多个码元小组的小组频偏估计确定出一个码元大组的频偏估计，进而根据该频偏估计对下一个码元大组进行 频偏补偿，然后再对已经频偏补偿的码元大组重复该处理过程，依次循环，就可以实现对接收信号中所有码元大组的频偏补偿处理，这种频偏估计、频偏补偿方案处理复杂度低，但是相较于现有V-V算法，精度却可以得到极大的提升。
本公开实施例提供的频偏估计补偿方案能够对较为细小的频偏进行估计，从而使得频偏估计及频偏补偿精度达到较高的精度。为了便于介绍，这里本公开实施例提供的频偏估计补偿方案称为“细频偏估计补偿方案”。不过细频偏估计补偿方案虽然具有估计精度较高的优点，但这种算法对频偏估计的范围相对较小，所以，如果接收信号的频偏较高，则不太适用采用这种方案进行频偏估计补偿。在本公开实施例的一个示例中，在采用细频偏估计补偿方案对码元大组进行频偏估计前，可首先确定当前的残余频偏已经小于预设频偏阈值。也就是说，在根据细频偏估计补偿方案确定第K个码元大组的频偏估计前，可首先确定第K-1个码元大组的频偏估计(也即第K-1个码元大组经历频偏补偿后的残余频偏)小于预设频偏阈值。
根据本公开提供的实施例，如果经过判断，确定第K-1个码元大组的频偏估计大于等于预设频偏阈值，则说明接收信号当前的频偏尚不在可以采用细频偏估计补偿方案的范围内，对于这种情况，频偏估计补偿装置在采用第K-1个码元大组的频偏估计对第K个码元大组进行频偏补偿后，可以根据V-V算法、FFT算法中的至少一种来确定第K个码元大组的频偏估计。由于V-V算法、FFT算法能够估计的频偏范围较大，但精度不高，因此，为了和前述细频偏估计补偿方案区分，这里将根据这一类算法进行频偏估计的方案称为“粗频偏估计补偿方案”。在根据粗频偏估计补偿方案确定出第K个码元大组的频偏估计后，根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿。
图6示出本公开实施例提供的频偏估计补偿装置的另一种结构示意图。频偏估计补偿装置60可包括频偏判断模块600、粗频偏估计模块602、细频偏估计模块604以及频偏补偿模块606。
根据本公开提供的实施例，频偏判断模块600可配置为判断第K-1个码元大组的频偏估计是否小于预设频偏阈值，粗频偏估计模块602可配置为在频偏判断模块600的判断结果为否时，采用V-V或FFT等算法对第K个码元大组进行频偏估计；而细频偏估计模块604可配置为在频偏判断模块600的判断结果为是时，采用本公开实施例提供的细频偏估计补偿方案确定第K个码元大组的频偏估计。细频偏估计模块604可包括搜索角确定模块6042、小组频偏估计模块6044以及大组频偏估计模块6046。搜索角确定模块6042、小组频偏估计模块6044以及大组频偏估计模块6046的功能同本公开实施例图5中的搜索角确定模块502、小组频偏估计模块504以及大组频偏估计模块506的功能相同。频偏补偿模块606可根据第K个码元大组的频偏估计对第K+1个码元大组进行频偏补偿。
根据本公开提供的实施例，频偏估计补偿装置60实现频偏估计补偿方法的具体过程请参见本公开实施例提供的频偏估计补偿方法，这里不再赘述。
根据本公开提供的实施例，频偏估计补偿装置60可以部署在通信设备上，其中频偏判断模块600、粗频偏估计模块602、细频偏估计模块604以及频偏补偿模块606的功能都可以由通信设备的处理器实现。
本公开实施例提供的频偏估计补偿装置，在接收信号的频偏较大的情况下，采用FFT算法、V-V算法等粗频偏估计补偿方案对已经频偏补偿的前一码元大组进行频偏估计，然后根据确定出的频偏估计对后一个码元大组进行频偏补偿，这样可以利用FFT、 V-V等算法频偏估计范围大的特点，实现接收信号频偏的快速收敛，从而使得接收信号的频偏收敛到一个较小的范围内。随后，频偏估计补偿装置利用基于BPS算法的细频偏估计补偿方案对已经频偏补偿的前一码元大组进行频偏估计，然后根据确定出的频偏估计对后一个码元大组进行频偏补偿，从而保证对码元大组频偏估计的准确性，提升频偏补偿的精确程度。通常，单纯采用V-V算法进行频偏估计及频偏补偿，其精度只能到达10MHz左右，但是采用本公开实施例提供的频偏估计补偿装置，精度可以达到1MHz。图3示出了传统V-V算法频偏估计补偿的性能和本公开实施例中频偏估计补偿方案的性能的对比示意图。图3左侧示出的是采用V-V算法进行频偏估计的误差，而右侧是采用本公开实施例提供的方案进行频偏估计的误差。从图3可以明显看出本公开实施例提供的频偏估计补偿装置的频偏估计精度更高。
本公开实施例提供的频偏估计补偿装置综合利用了粗频偏估计补偿方案的频偏收敛快的优点，和细频偏估计补偿方案频偏估计精度高的优点。
本公开实施例还提供了一种计算机可读存储介质，该计算机可读存储介质中可以存储有一个或多个可供一个或多个处理器读取、编译并执行的计算机程序，根据本公开提供的实施例，该计算机可读存储介质可以存储有频偏估计补偿程序，该频偏估计补偿程序可供一个或多个处理器执行实现本公开实施例提供的任意一种频偏估计补偿方法。
本公开实施例还提供了一种通信设备，图7示出通信设备7的硬件结构示意图。通信设备7可包括处理器71、存储器72以及用于实现处理器71同存储器72间通信连接的通信总线73，其中存储器72可以为前述存储有频偏估计补偿程序的计算机可读存储介质。处理器71可以读取存储器72中存储的频偏估计补偿程序， 进行编译并执行实现实施本公开实施例提供的任意一种频偏估计补偿方法。
处理器71可以先确定接收信号中第K个码元大组内各码元小组内码元的搜索角，然后根据各码元小组内码元的搜索角确定各码元小组的小组频偏估计，并根据各码元小组的小组频偏估计确定第K个码元大组的频偏估计，最后处理器71根据第K个码元大组的频偏估计对接收信号中第K+1个码元大组进行频偏补偿。
处理器71执行频偏估计补偿程序，实现频偏估计补偿方法的具体细节请参见本公开实施例提供的频偏估计补偿方法，这里不再赘述。
由于码元大组中一个码元小组内的各码元之间，相位噪声能够被视为相同，因此，在确定该码元小组的小组频偏估计时，码元的相位噪声可以被直接抵消，从而使得信号接收端可以基于码元的搜索角计算出小组频偏估计，进而得到码元大组的频偏估计。本公开实施例提供的通信设备采用的频偏估计补偿方案相对于现有方案，精度更高，复杂度更低，有利于在减小接收端频偏补偿处理的复杂度的同时，提升系统性能，能够保证本端与发送端的通信质量。
显然，本领域的技术人员应该明白，上文中所公开方法中的全部或某些步骤、系统、装置中的功能模块/单元可以被实施为软件(可以用计算装置可执行的程序代码来实现)、固件、硬件及其适当的组合。在硬件实施方式中，在以上描述中提及的功能模块/单元之间的划分不一定对应于物理组件的划分；例如，一个物理组件可以具有多个功能，或者一个功能或步骤可以由若干物理组件合作执行。某些物理组件或所有物理组件可以被实施为由处理器，如中央处理器、数字信号处理器或微处理器执行的软件，或者被实施为硬件，或者被实施为集成电路，如专用集成电路。 这样的软件可以分布在计算机可读介质上，由计算装置来执行，并且在某些情况下，可以以不同于此处的顺序执行所示出或描述的步骤，计算机可读介质可以包括计算机存储介质(或非暂时性介质)和通信介质(或暂时性介质)。如本领域普通技术人员公知的，术语计算机存储介质包括在用于存储信息(诸如计算机可读指令、数据结构、程序模块或其它数据)的任何方法或技术中实施的易失性和非易失性、可移除和不可移除介质。计算机存储介质包括但不限于RAM,ROM,EEPROM、闪存或其它存储器技术、CD-ROM，数字多功能盘(DVD)或其它光盘存储、磁盒、磁带、磁盘存储或其它磁存储装置、或者可以用于存储期望的信息并且可以被计算机访问的任何其它的介质。此外，本领域普通技术人员公知的是，通信介质通常包含计算机可读指令、数据结构、程序模块或者诸如载波或其它传输机制之类的调制数据信号中的其它数据，并且可包括任何信息递送介质。所以，本公开不限制于任何特定的硬件和软件结合。
以上内容是结合具体的实施方式对本公开实施例所作的进一步详细说明，不能认定本公开的具体实施只局限于这些说明。对于本公开所属技术领域的普通技术人员来说，在不脱离本公开构思的前提下，还可以做出若干简单推演或替换，都应当视为属于本公开的保护范围。

Claims (10)

  1. 一种频偏估计补偿方法，包括：
    确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，所述第K个码元大组包括至少一个码元小组，且所述K大于等于1；
    根据所述各码元小组内码元的搜索角，确定所述各码元小组的小组频偏估计；
    根据所述各码元小组的小组频偏估计，确定所述第K个码元大组的频偏估计；以及
    根据所述第K个码元大组的频偏估计，对所述接收信号中第K+1个码元大组进行频偏补偿。
  2. 如权利要求1所述的频偏估计补偿方法，其中，确定所述接收信号中所述第K个码元大组内所述各码元小组内码元的搜索角，包括：根据盲相位搜索BPS算法，确定所述接收信号中所述第K个码元大组内所述各码元小组内码元的搜索角。
  3. 如权利要求1所述的频偏估计补偿方法，其中，根据所述各码元小组内码元的搜索角，确定所述各码元小组的小组频偏估计，包括：
    对于所述第K个码元大组中第q个码元小组，通过以下方式确定所述第q个码元小组的小组频偏估计：
    Figure PCTCN2019105918-appb-100001
    其中，所述Δf q为所述第q个码元小组的小组频偏估计，所述φ m为所述第q个码元小组中第m个码元的搜索角，所述φ 1为所述第q个码元小组中第1个码元的搜索角，所述R s为所述接收信 号的波特率。
  4. 如权利要求1所述的频偏估计补偿方法，其中，根据所述各码元小组的小组频偏估计，确定所述第K个码元大组的频偏估计，包括：
    确定所述各码元小组的小组频偏估计的均值作为所述第K个码元大组的频偏估计。
  5. 如权利要求1所述的频偏估计补偿方法，其中，根据所述第K个码元大组的频偏估计，对所述接收信号中所述第K+1个码元大组进行频偏补偿，包括：
    通过以下方式对所述第K+1个码元大组进行频偏补偿：
    Figure PCTCN2019105918-appb-100002
    其中，所述S(K+1)表征频偏补偿前的所述第K+1个码元大组的频率偏移，所述S′(K+1)表征频偏补偿后的所述第K+1个码元大组的频率偏移；所述Δf为所述第K个码元大组的频偏估计，所述R s为所述接收信号的波特率。
  6. 如权利要求1-5任一项所述的频偏估计补偿方法，在确定所述接收信号中所述第K个码元大组内各码元小组内码元的搜索角之前，还包括：
    确定所述接收信号中第K-1个码元大组的频偏估计小于预设频偏阈值，其中，所述K大于1；或，
    确定所述接收信号由预设发送端发送。
  7. 如权利要求1-5任一项所述的频偏估计补偿方法，若在确定所述接收信号中所述第K个码元大组内各码元小组内码元的搜索角之前，确定所述接收信号中第K-1个码元大组的频偏估计大于等于预设频偏阈值，则频偏估计补偿方法还包括：
    根据维特比-维特比Vertebi-Vertebi算法、快速傅里叶变换 FFT算法中的至少一种确定所述第K个码元大组的频偏估计。
  8. 一种频偏估计补偿装置，包括：
    搜索角确定模块，配置为确定接收信号中第K个码元大组内各码元小组内码元的搜索角；其中，任一码元小组由至少两个相位噪声能视为相同的码元构成，所述第K个码元大组包括至少一个码元小组，且所述K大于等于1；
    小组频偏估计模块，配置为根据所述各码元小组内码元的搜索角，确定所述各码元小组的小组频偏估计；
    大组频偏估计模块，配置为根据所述各码元小组的小组频偏估计，确定所述第K个码元大组的频偏估计；以及
    频偏补偿模块，配置为根据所述第K个码元大组的频偏估计，对第K+1个码元大组进行频偏补偿。
  9. 一种通信设备，包括处理器、存储器及通信总线，其中：
    所述通信总线配置为实现处理器和存储器之间的连接通信；
    所述处理器配置为执行存储器中存储的一个或者多个程序，以实现如权利要求1至7中任一项所述的频偏估计补偿方法。
  10. 一种计算机可读存储介质，存储有一个或者多个程序，所述一个或者多个程序可被一个或者多个处理器执行，以实现如权利要求1至7中任一项所述的频偏估计补偿方法。
PCT/CN2019/105918 2018-09-13 2019-09-16 频偏估计补偿方法、装置、通信设备及计算机可读存储介质 WO2020052683A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19858803.0A EP3849147B1 (en) 2018-09-13 2019-09-16 Frequency offset estimation and compensation method and apparatus, communication device, and computer readable storage medium
KR1020217009910A KR102464665B1 (ko) 2018-09-13 2019-09-16 주파수 오프셋 추정 및 보상 방법, 장치, 통신 설비 및 컴퓨터 판독 가능한 저장 매체

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811068358.2A CN110896384B (zh) 2018-09-13 2018-09-13 频偏估计补偿方法、装置、通信设备及存储介质
CN201811068358.2 2018-09-13

Publications (1)

Publication Number Publication Date
WO2020052683A1 true WO2020052683A1 (zh) 2020-03-19

Family

ID=69776939

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/105918 WO2020052683A1 (zh) 2018-09-13 2019-09-16 频偏估计补偿方法、装置、通信设备及计算机可读存储介质

Country Status (4)

Country Link
EP (1) EP3849147B1 (zh)
KR (1) KR102464665B1 (zh)
CN (1) CN110896384B (zh)
WO (1) WO2020052683A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113794666A (zh) * 2021-09-14 2021-12-14 深圳市极致汇仪科技有限公司 一种综测仪分析大频偏数据的方法及系统
CN114363133A (zh) * 2022-01-20 2022-04-15 武汉梦芯科技有限公司 一种频偏检测方法、系统、存储介质和电子设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102436575B1 (ko) 2021-02-04 2022-08-26 한국전자통신연구원 사이클릭 슬립에 강인한 위상 오차 보상 방법 및 장치

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1988526A (zh) * 2005-12-23 2007-06-27 中兴通讯股份有限公司 一种多输入多输出、正交频分复用无线系统的同步方法
US20070263712A1 (en) * 2006-05-15 2007-11-15 Qualcomm Incorporated System and method of calculating noise variance
CN101309248A (zh) * 2007-05-16 2008-11-19 富士通株式会社 适用于ofdm通信系统的频率同步方法及装置
CN103916357A (zh) * 2014-04-29 2014-07-09 西安电子科技大学 基于导频联合编码辅助的soqpsk载波同步方法
CN106936513A (zh) * 2017-03-22 2017-07-07 北京邮电大学 一种基于卡尔曼滤波算法的载波相位恢复方法及装置
CN107135182A (zh) * 2017-04-10 2017-09-05 上海顺久电子科技有限公司 调频信号的频偏计算方法及装置

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8908809B2 (en) * 2010-12-15 2014-12-09 At&T Intellectual Property I, L.P. Complexity reduced feed forward carrier recovery methods for M-QAM modulation formats
JP6156807B2 (ja) * 2013-11-15 2017-07-05 国立研究開発法人産業技術総合研究所 受信信号処理装置、通信システム及び受信信号処理方法
CN104378316A (zh) * 2014-10-30 2015-02-25 深圳市国创新能源研究院 一种多普勒频偏估计方法和装置
US9537683B1 (en) * 2015-10-06 2017-01-03 Huawei Technologies Co., Ltd. Method and apparatus for residual phase noise compensation
CN107769841B (zh) * 2017-10-19 2019-11-15 中国人民解放军陆军工程大学 高动态极低信噪比下卫星通信Turbo码迭代解调方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1988526A (zh) * 2005-12-23 2007-06-27 中兴通讯股份有限公司 一种多输入多输出、正交频分复用无线系统的同步方法
US20070263712A1 (en) * 2006-05-15 2007-11-15 Qualcomm Incorporated System and method of calculating noise variance
CN101309248A (zh) * 2007-05-16 2008-11-19 富士通株式会社 适用于ofdm通信系统的频率同步方法及装置
CN103916357A (zh) * 2014-04-29 2014-07-09 西安电子科技大学 基于导频联合编码辅助的soqpsk载波同步方法
CN106936513A (zh) * 2017-03-22 2017-07-07 北京邮电大学 一种基于卡尔曼滤波算法的载波相位恢复方法及装置
CN107135182A (zh) * 2017-04-10 2017-09-05 上海顺久电子科技有限公司 调频信号的频偏计算方法及装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3849147A4 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113794666A (zh) * 2021-09-14 2021-12-14 深圳市极致汇仪科技有限公司 一种综测仪分析大频偏数据的方法及系统
CN113794666B (zh) * 2021-09-14 2023-12-08 深圳市极致汇仪科技有限公司 一种综测仪分析大频偏数据的方法及系统
CN114363133A (zh) * 2022-01-20 2022-04-15 武汉梦芯科技有限公司 一种频偏检测方法、系统、存储介质和电子设备
CN114363133B (zh) * 2022-01-20 2023-10-03 武汉梦芯科技有限公司 一种频偏检测方法、系统、存储介质和电子设备

Also Published As

Publication number Publication date
KR20210053327A (ko) 2021-05-11
EP3849147A1 (en) 2021-07-14
KR102464665B1 (ko) 2022-11-09
CN110896384B (zh) 2023-04-11
CN110896384A (zh) 2020-03-20
EP3849147A4 (en) 2021-11-17
EP3849147B1 (en) 2024-05-01

Similar Documents

Publication Publication Date Title
WO2020052683A1 (zh) 频偏估计补偿方法、装置、通信设备及计算机可读存储介质
US10778496B2 (en) OFDM system synchronization tracking method and apparatus
US20140079407A1 (en) Updating apparatus and method for equalizer coefficient, receiver and otpical communication system
US8897412B2 (en) Method and apparatus for phase noise mitigation
WO2010138206A1 (en) Method and apparatus for iterative timing and carrier phase recovery
US20190372607A1 (en) Maximum likelihood error detection for decision feedback equalizers with pam modulation
US8938037B1 (en) High speed gain and phase recovery in presence of phase noise
CN111555819A (zh) 一种载波相位估计和补偿方法及系统
US10554309B2 (en) Pilot-aided carrier phase estimation for optical communications
US20180302168A1 (en) Adaptive demapper
US9258166B2 (en) Timing synchronization apparatus and method for multi-carrier modulation signals
EP3945700B1 (en) Method and system for adjusting the bandwidth of a frequency domain smoothing filter for channel tracking loop in ofdm communication system
US10771230B2 (en) Estimating apparatus for bias drift of transmitting end modulator, compensating apparatus and receiver
US10734950B2 (en) Phase noise compensation apparatus and method and receiver
TW200427240A (en) Reducing phase noise in phase-encoded communications signals
WO2016095261A1 (zh) 一种分布式iq不平衡估计与抑制方法
WO2015161720A1 (zh) 信道均衡和跟踪装置、方法以及接收机
CN114826858B (zh) 载波同步方法和装置、计算机设备、存储介质
JP4681637B2 (ja) 周波数誤差推定装置
JP6082125B2 (ja) マルチキャリア変調信号のための受信機
WO2024012164A1 (zh) 信号处理方法、电子设备及存储介质
CN107005259B (zh) 减少wlan系统中的相邻信道干扰的方法和设备
Chen et al. OFDM carrier frequency offset correction based on type-2 control loop
CN111064685A (zh) 一种载波同步方法、装置及设备
WO2022171293A1 (en) Signal processing device and signal processing method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19858803

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 20217009910

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2019858803

Country of ref document: EP

Effective date: 20210406