CN113541733A - Equalization and echo cancellation device, method, computer device and storage medium - Google Patents

Equalization and echo cancellation device, method, computer device and storage medium Download PDF

Info

Publication number
CN113541733A
CN113541733A CN202111089912.7A CN202111089912A CN113541733A CN 113541733 A CN113541733 A CN 113541733A CN 202111089912 A CN202111089912 A CN 202111089912A CN 113541733 A CN113541733 A CN 113541733A
Authority
CN
China
Prior art keywords
signal
current moment
equalizer
echo
equalized
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
CN202111089912.7A
Other languages
Chinese (zh)
Other versions
CN113541733B (en
Inventor
陆连伟
谈树峰
王孟奇
邓伯金
杨洋
徐义
杨晓宇
杨旭
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Tasson Science and Technology Co Ltd
Original Assignee
Beijing Tasson Science and Technology Co Ltd
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 Beijing Tasson Science and Technology Co Ltd filed Critical Beijing Tasson Science and Technology Co Ltd
Priority to CN202111089912.7A priority Critical patent/CN113541733B/en
Publication of CN113541733A publication Critical patent/CN113541733A/en
Application granted granted Critical
Publication of CN113541733B publication Critical patent/CN113541733B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers
    • H04B3/235—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers combined with adaptive equaliser

Abstract

The present application relates to an equalization and echo cancellation apparatus, method, computer device and storage medium. The device includes: the equalizer is used for carrying out equalization processing on the signal to be equalized corresponding to the current moment to obtain an initial signal equalized at the current moment; the echo eliminator is used for carrying out echo simulation on the sending signal at the current moment to obtain a simulated echo signal at the current moment; the decision device is used for acquiring a signal to be decided which is determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment, and performing decision processing on the signal to be decided to obtain an estimated signal corresponding to the original signal at the current moment; and the equalizer is also used for updating the tap coefficient of the equalizer according to the signal error determined by the estimated signal and the signal to be judged. The device combines the equalizer and the echo eliminator to work, adopts the signal to be judged which eliminates the analog echo signal to complete the updating of the tap coefficient of the follow-up equalizer, and is beneficial to improving the convergence speed of the equalizer.

Description

Equalization and echo cancellation device, method, computer device and storage medium
Technical Field
The present application relates to the field of signal processing technologies, and in particular, to an apparatus and a method for equalization and echo cancellation, a computer device, and a storage medium.
Background
With the development of the vehicle-mounted ethernet technology, channel equalization and echo cancellation technologies have emerged. The vehicle-mounted Ethernet adopts a single-pair five-type unshielded twisted pair, and can simultaneously receive and send data. When the vehicle-mounted ethernet is used for high-speed data transmission, because the non-ideal characteristics of the channel can be subjected to various interferences, channel compensation including intersymbol interference compensation, echo compensation and the like needs to be performed by adopting channel equalization and echo cancellation technologies, so that the signal-to-noise ratio meets the requirements.
The traditional channel equalization method and the echo cancellation method are independent, and the tap coefficient of the equalizer used in the channel equalization is updated according to the equalized signal in the convergence process.
However, with the conventional technique, since the equalized signal also includes an echo signal, the echo signal may cause the equalizer to oscillate, which may result in a slow convergence speed of the equalizer, and affect the equalization speed and the echo cancellation speed of the signal.
Disclosure of Invention
In view of the above, it is desirable to provide an equalization and echo cancellation apparatus, method, computer device, and storage medium capable of improving the convergence speed of an equalizer.
An equalization and echo cancellation device, the device comprising:
the equalizer is used for performing equalization processing on a signal to be equalized corresponding to the current moment to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
the echo eliminator is used for carrying out echo simulation on the sending signal at the current moment to obtain a simulated echo signal at the current moment;
the decision device is used for acquiring a signal to be decided which is determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment, and performing decision processing on the signal to be decided to obtain an estimated signal corresponding to the original signal at the current moment;
and the equalizer is also used for updating the tap coefficient of the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
In one embodiment, the echo canceller is further configured to update a tap coefficient of the echo canceller according to the signal error.
In one embodiment, the equalizer includes a feedforward equalizer and a decision feedback equalizer, the signal to be equalized includes a received signal at a current time and an estimated signal at a previous time, and the initial signal equalized at the current time includes a feedforward equalized signal at the current time and a feedback equalized signal at the current time;
the feedforward equalizer is used for performing feedforward equalization processing on the received signal at the current moment to obtain a signal subjected to feedforward equalization at the current moment;
and the decision feedback equalizer is connected with the decision device and used for carrying out feedback equalization processing on the estimation signal at the previous moment to obtain a signal after the feedback equalization at the current moment.
In one embodiment, the apparatus further comprises:
the first subtracter is respectively connected with the feedforward equalizer and the decision feedback equalizer and is used for subtracting the signal subjected to feedforward equalization at the current moment from the signal subjected to feedback equalization at the current moment to obtain a signal subjected to equalization at the current moment;
and the first subtracter is connected with the echo eliminator and is also used for subtracting the signal after being equalized at the current moment from the analog echo signal at the current moment to obtain the signal to be judged.
In one embodiment, the feedforward equalizer includes a feedforward filter, and the tap coefficients of the feedforward filter are updated by the following formula:
Figure 100002_DEST_PATH_IMAGE001
；
wherein the content of the first and second substances,
Figure 699753DEST_PATH_IMAGE002
is shown as
Figure 100002_DEST_PATH_IMAGE003
The tap coefficients of the feed-forward filter at the time instant,
Figure 736979DEST_PATH_IMAGE004
is shown as
Figure 100002_DEST_PATH_IMAGE005
The tap coefficients of the feed-forward filter at the time instant,
Figure 484356DEST_PATH_IMAGE006
which represents the step size of the update,
Figure 100002_DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 163599DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure 100002_DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 47241DEST_PATH_IMAGE010
representing the regression vector of the feedforward filter.
In one embodiment, the decision feedback equalizer includes a feedback filter, and tap coefficients of the feedback filter are updated by the following formula:
Figure 100002_DEST_PATH_IMAGE011
；
wherein the content of the first and second substances,
Figure 520948DEST_PATH_IMAGE012
is shown as
Figure 693303DEST_PATH_IMAGE003
The tap coefficients of the feedback filter are fed back at the time instants,
Figure 100002_DEST_PATH_IMAGE013
is shown as
Figure 910658DEST_PATH_IMAGE005
The tap coefficients of the feedback filter are fed back at the time instants,
Figure 117648DEST_PATH_IMAGE006
which represents the step size of the update,
Figure 762256DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 421907DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure 646215DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 770029DEST_PATH_IMAGE014
representing the regression vector of the feedback filter.
In one embodiment, the echo canceller includes an echo cancellation filter, and tap coefficients of the echo cancellation filter are updated by the following formula:
Figure 100002_DEST_PATH_IMAGE015
；
wherein the content of the first and second substances,
Figure 597257DEST_PATH_IMAGE016
is shown as
Figure 744205DEST_PATH_IMAGE003
The tap coefficients of the time-of-day echo cancellation filter,
Figure 100002_DEST_PATH_IMAGE017
is shown as
Figure 303362DEST_PATH_IMAGE005
The tap coefficients of the time-of-day echo cancellation filter,
Figure 219366DEST_PATH_IMAGE006
which represents the step size of the update,
Figure 471355DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 105599DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure 468447DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 238957DEST_PATH_IMAGE018
representing the regression vector of the echo cancellation filter.
An equalization and echo cancellation method applied to the apparatus according to any one of the above embodiments, the method comprising:
equalizing the signal to be equalized corresponding to the current moment through an equalizer to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
carrying out echo simulation on the sending signal at the current moment through an echo canceller to obtain a simulated echo signal at the current moment;
obtaining a signal to be judged determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment through a judging device, and judging the signal to be judged to obtain an estimated signal corresponding to the original signal at the current moment;
and updating the tap coefficient of the equalizer through the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
A computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:
equalizing the signal to be equalized corresponding to the current moment through an equalizer to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
carrying out echo simulation on the sending signal at the current moment through an echo canceller to obtain a simulated echo signal at the current moment;
obtaining a signal to be judged determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment through a judging device, and judging the signal to be judged to obtain an estimated signal corresponding to the original signal at the current moment;
and updating the tap coefficient of the equalizer through the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of:
equalizing the signal to be equalized corresponding to the current moment through an equalizer to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
carrying out echo simulation on the sending signal at the current moment through an echo canceller to obtain a simulated echo signal at the current moment;
obtaining a signal to be judged determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment through a judging device, and judging the signal to be judged to obtain an estimated signal corresponding to the original signal at the current moment;
and updating the tap coefficient of the equalizer through the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
The equalization and echo cancellation device, the equalization and echo cancellation method, the computer equipment and the storage medium adopt a combined framework of an equalizer and an echo canceller to generate an equalized initial signal and a simulated echo signal together, then carry out decision processing on a signal to be decided determined according to the equalized initial signal and the simulated echo signal through a decision device to obtain an estimated signal corresponding to the original signal, and finally update a tap coefficient of the equalizer according to a signal error determined by the estimated signal and the signal to be decided. It can be understood that the device combines the equalizer and the echo canceller to work, and adopts the signal to be judged which eliminates the analog echo signal to complete the updating of the tap coefficient of the subsequent equalizer, thereby reducing the adverse effect of the echo signal on the convergence of the equalizer, improving the convergence speed of the equalizer, being beneficial to improving the speed of the equalization and the echo cancellation of the signal, and meeting the requirement of the high-speed transmission of the Ethernet.
Drawings
FIG. 1 is a schematic diagram of an embodiment of an equalization and echo cancellation apparatus;
FIG. 2 is a schematic flow diagram of an equalization and echo cancellation method in one embodiment;
FIG. 3 is a diagram illustrating an internal structure of a computer device according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In one embodiment, as shown in fig. 1, there is provided an equalization and echo cancellation apparatus, which is applicable to an 100/1000BASE-T1 standard-based ethernet in a vehicle, the apparatus comprising:
the equalizer is used for carrying out equalization processing on the signal to be equalized corresponding to the current moment to obtain an initial signal equalized at the current moment;
an Echo Canceller (EC) configured to perform Echo simulation on a transmission signal at a current time to obtain a simulated Echo signal at the current time;
a determiner (Slicer) 108 for obtaining a signal to be determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment
Figure DEST_PATH_IMAGE019
Judging the signal to be judged to obtain the estimation signal corresponding to the original signal at the current moment
Figure 661848DEST_PATH_IMAGE020
；
An equalizer for determining signal error based on the estimated signal and the signal to be decided
Figure DEST_PATH_IMAGE021
The tap coefficients of the equalizer are updated.
The signal to be equalized corresponding to the current moment is determined according to the original signal. The tap coefficients of the equalizer are adjusted according to the adaptive filtering. The adaptive filtering algorithm includes a least mean square error algorithm (LMS), a Recursive Least Squares (RLS), and the like.
Optionally, the Equalizer comprises a Feed Forward Equalizer (FFE). Optionally, the Equalizer includes a Decision Feedback Equalizer (DFE). The signal to be equalized which is input into the feedforward equalizer comprises: original signal
Figure 580126DEST_PATH_IMAGE022
Output after channel, channel noise
Figure DEST_PATH_IMAGE023
And local transmission of signals
Figure 215506DEST_PATH_IMAGE024
Echo signal of
Figure DEST_PATH_IMAGE025
. The signal to be equalized of the input feedforward equalizer is the signal received by the equalizing and echo eliminating device
Figure 106102DEST_PATH_IMAGE026
。
In the equalization and echo cancellation device, a combined architecture of an equalizer and an echo canceller is adopted to generate an equalized initial signal and an analog echo signal together, then a decision device 108 is used for carrying out decision processing on a signal to be decided determined according to the equalized initial signal and the analog echo signal to obtain an estimated signal corresponding to an original signal, and finally a tap coefficient of the equalizer is updated according to a signal error determined by the estimated signal and the signal to be decided. It can be understood that the device combines the equalizer and the echo canceller to work, and adopts the signal to be judged which eliminates the analog echo signal to complete the updating of the tap coefficient of the subsequent equalizer, thereby reducing the adverse effect of the echo signal on the convergence of the equalizer, improving the convergence speed of the equalizer, being beneficial to improving the speed of the equalization and the echo cancellation of the signal, and meeting the requirement of the high-speed transmission of the Ethernet.
In one embodiment, the echo canceller is further configured to update a tap coefficient of the echo canceller based on the signal error. The echo canceller may operate in LMS mode. Since the interference of wrong decision is avoided at this time, the cold start problem does not exist. To reduce the variance of the LMS gradient estimate to reduce the excess Mean Square Error (MSE), components that are not coherent with the echo may be eliminated from the noise signal as much as possible. Thus using as much as possible cancellation of the remaining echo signal included in the transmitted signal as the desired response, but this signal need not be present to any significant extent, this can be achieved using the decision error as an error signal adjustment factor, when the echo canceller is operating in Decision Directed (DD) mode.
In one embodiment, the equalizer includes a feedforward equalizer and a decision feedback equalizer. The feed forward equalizer is a linear equalizer whose input is sampled data for the analog to digital converter. The structure of the decision feedback equalizer is similar to that of the feedforward equalizer, but the input is feedback of the decision result. The signal to be equalized comprises a received signal at the current moment and an estimated signal at the last moment. The equalized initial signal at the current moment comprises a feedforward equalized signal at the current moment and a feedback equalized signal at the current moment.
In one embodiment, the feedforward equalizer is configured to perform feedforward equalization processing on the received signal at the current time to obtain a feedforward equalized signal at the current time.
In an embodiment, the decision feedback equalizer is connected to the decision device 108, and configured to perform feedback equalization processing on the estimated signal at the previous time, so as to obtain a signal after feedback equalization at the current time.
In one embodiment, the apparatus further comprises:
the first subtracter is respectively connected with the feedforward equalizer and the decision feedback equalizer and is used for subtracting the signal subjected to feedforward equalization at the current moment from the signal subjected to feedback equalization at the current moment to obtain the signal subjected to equalization at the current moment;
and the first subtracter is connected with the echo eliminator and is also used for subtracting the signal after being equalized at the current moment from the analog echo signal at the current moment to obtain a signal to be judged.
In one embodiment, the means relating to equalization and echo cancellation are based on the working principle of the LMS algorithm.
First, the operation principle of the LMS algorithm is described.
The idea of the LMS algorithm is as follows: it is assumed that a reference signal related to an original signal is given
Figure DEST_PATH_IMAGE027
Then, first, FIR (Finite Impulse Response) Filter (for example, Feed Forward Filter (FFF) 102, Feedback Filter (FBF) 104, echo cancellation Filter (FBF)) is appliedFilter (ECF) 106, etc.) sets an initial value arbitrarily, and then an error between an output value obtained by passing a received signal through an FIR Filter and a reference signal is determined based on the error
Figure 434315DEST_PATH_IMAGE021
The weight is adjusted to reduce the next output error, and the process is repeated until the weight converges to the optimal value. It can be seen that the key of the LMS adaptive filtering is how to rely on the error
Figure 839889DEST_PATH_IMAGE021
The weights of the filter are adjusted to converge to the optimum values.
Setting the input signal of LMS adaptive filtering as
Figure 747802DEST_PATH_IMAGE022
The output signal is
Figure 758483DEST_PATH_IMAGE019
. Then
Figure 523177DEST_PATH_IMAGE019
、
Figure 353730DEST_PATH_IMAGE021
The calculation formula of (a) is as follows:
Figure 596492DEST_PATH_IMAGE028
；
Figure DEST_PATH_IMAGE029
；
wherein the content of the first and second substances,
Figure 461680DEST_PATH_IMAGE030
represents the weights at the nth moment of the filter, i.e., the tap coefficients of the filter, N represents the order of the filter,
Figure DEST_PATH_IMAGE031
is a sum of the original signal
Figure 131696DEST_PATH_IMAGE022
The associated reference signal may be, for example
Figure 511861DEST_PATH_IMAGE022
The decision signal of (1).
Order to
Figure 495998DEST_PATH_IMAGE032
；
Figure DEST_PATH_IMAGE033
；
Wherein W (n) represents the weight of the filter at the nth time,
Figure 278009DEST_PATH_IMAGE034
representing the received signal and T representing the transpose of the vector. Thereby to obtain
Figure DEST_PATH_IMAGE035
；
Figure 118926DEST_PATH_IMAGE036
；
The process of updating the LMS algorithm is to make the noise mean square error
Figure DEST_PATH_IMAGE037
A gradual decrease in the process.
Figure 720809DEST_PATH_IMAGE038
；
Through simplified derivation, the update formula for obtaining the filter weight vector is as follows:
Figure DEST_PATH_IMAGE039
；
wherein the content of the first and second substances,
Figure 508636DEST_PATH_IMAGE040
which represents the step size of the update,
Figure 145154DEST_PATH_IMAGE006
the value ranges are:
Figure DEST_PATH_IMAGE041
；
wherein the content of the first and second substances,
Figure 156972DEST_PATH_IMAGE042
. It is noted that
Figure DEST_PATH_IMAGE043
Represents the total average energy of the signal, and thus
Figure 980572DEST_PATH_IMAGE006
The value is less than the inverse of the total average energy. In the case where the LMS algorithm is used in practice,
Figure 572090DEST_PATH_IMAGE006
is typically of the order of 1/10 from the upper bound given by the above equation.
Then, the feed forward filter 102 tap coefficient vector is defined:
Figure 63114DEST_PATH_IMAGE044
；
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE045
is shown asnThe 0 th filter coefficient at a time instant,
Figure 449096DEST_PATH_IMAGE046
is shown asnThe 1 st filter coefficient at a time instant,
Figure DEST_PATH_IMAGE047
is shown asnThe 2 nd filter coefficient at a time instant,L f representing the filter coefficient length.
Defining the equivalent vector of the tap coefficients of the feedback filter 104:
Figure 25571DEST_PATH_IMAGE048
；
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE049
is shown asnThe 1 st filter coefficient at a time instant,
Figure 217518DEST_PATH_IMAGE050
is shown asnThe 2 nd filter coefficient at a time instant,
Figure DEST_PATH_IMAGE051
is shown asnThe 3 rd filter coefficient at a time instant,L g representing the filter coefficient length.
Defining the equivalent vector of the echo cancellation filter 106 tap coefficients:
Figure 297470DEST_PATH_IMAGE052
；
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE053
is shown asnThe 0 th filter coefficient at a time instant,
Figure 916670DEST_PATH_IMAGE054
is shown asnThe 1 st filter coefficient at a time instant,
Figure DEST_PATH_IMAGE055
is shown asnThe 2 nd filter coefficient at a time instant,L p representing the filter coefficient length.
The regression vector defining the feedforward filter 102:
Figure 714861DEST_PATH_IMAGE056
；
wherein the content of the first and second substances,
Figure 382603DEST_PATH_IMAGE026
is shown asnThe signals received at the time of day are,
Figure DEST_PATH_IMAGE057
is shown in (A)n-1) The signals received at the time of day are,
Figure 848220DEST_PATH_IMAGE058
is shown as
Figure DEST_PATH_IMAGE059
The signal received at the moment.
The regression vector defining the feedback filter 104:
Figure 638321DEST_PATH_IMAGE060
；
the regression vector defining the echo cancellation filter 106:
Figure DEST_PATH_IMAGE061
；
wherein the content of the first and second substances,
Figure 658230DEST_PATH_IMAGE024
is shown asnThe signals that are transmitted at the time of day,
Figure 395241DEST_PATH_IMAGE062
is shown in (A)n-1) The signals that are transmitted at the time of day,
Figure DEST_PATH_IMAGE063
is shown as
Figure 715364DEST_PATH_IMAGE064
The signals transmitted at the moment.
Thus, the total equalizer tap coefficients are defined as follows:
Figure DEST_PATH_IMAGE065
the total equalizer regression vector is defined as follows:
Figure 410788DEST_PATH_IMAGE066
the soft estimate, which represents the output of the joint architecture of equalization and echo cancellation in the form of an inner product, is as follows:
Figure DEST_PATH_IMAGE067
；
the soft estimate has a different magnitude to represent reliability compared to the three-valued decision { -1,0,1 }.
The errors are as follows:
Figure 183572DEST_PATH_IMAGE068
；
referring to the working principle of the LMS algorithm, the update expression of the tap coefficient of the equalization and echo cancellation combined architecture can be obtained as follows:
Figure DEST_PATH_IMAGE069
；
from the above equation, the update equations of the taps of the feedforward filter 102, the feedback filter 104 and the echo cancellation filter 106 under the LMS criterion are as follows:
the updated expression of the tap coefficients of the feedforward filter 102 is:
Figure 458695DEST_PATH_IMAGE070
；
wherein the content of the first and second substances,
Figure 633325DEST_PATH_IMAGE002
is shown as
Figure 968491DEST_PATH_IMAGE003
The tap coefficients of the feed forward filter 102 at the time,
Figure 228571DEST_PATH_IMAGE004
is shown as
Figure 307386DEST_PATH_IMAGE005
The tap coefficients of the feed forward filter 102 at the time,
Figure 602101DEST_PATH_IMAGE006
which represents the step size of the update,
Figure DEST_PATH_IMAGE071
which is indicative of a signal error,
Figure 842589DEST_PATH_IMAGE010
representing the regression vector of the feedforward filter 102.
The updated expression of the tap coefficients of the feedback filter 104 is:
Figure 855545DEST_PATH_IMAGE072
；
wherein the content of the first and second substances,
Figure 472471DEST_PATH_IMAGE012
is shown as
Figure 621692DEST_PATH_IMAGE003
The tap coefficients of the time instant feedback filter 104,
Figure 298661DEST_PATH_IMAGE013
is shown as
Figure 471017DEST_PATH_IMAGE005
The tap coefficients of the time instant feedback filter 104,
Figure DEST_PATH_IMAGE073
representing the regression vector of the feedback filter 104.
The updated expression of the tap coefficients of the echo cancellation filter 106 is:
Figure 688371DEST_PATH_IMAGE074
；
wherein the content of the first and second substances,
Figure 692100DEST_PATH_IMAGE016
is shown as
Figure 539970DEST_PATH_IMAGE003
The tap coefficients of the time-of-day echo cancellation filter 106,
Figure 261938DEST_PATH_IMAGE017
is shown as
Figure 486246DEST_PATH_IMAGE005
The tap coefficients of the time-of-day echo cancellation filter 106,
Figure 547743DEST_PATH_IMAGE018
representing the regression vector of the echo cancellation filter 106.
In one embodiment, the equalization and echo cancellation device is based on the principle of operation of the Sign DLMS algorithm.
First, the LMS algorithm according to the above embodiment is widely used in adaptive filtering, and the error signal updates the tap coefficient before the next sampling point arrives. In some practical applications, the LMS algorithm may be limited in implementation. For example, a pipeline structure often used in a high-speed VLSI (Very Large Scale Integration) circuit needs a delay in processing, and an error is often obtained after several symbol times, which introduces a delay in the LMS algorithm and also has the same problem when other adaptive algorithms are implemented using a parallel structure. Therefore, it is necessary to study the LMS algorithm that introduces delay in coefficient updating, which is the dlms (delayed LMS) algorithm.
The coefficient update of the DLMS algorithm can be represented by the following equation:
Figure DEST_PATH_IMAGE075
；
wherein the content of the first and second substances,
Figure 363252DEST_PATH_IMAGE008
representing processing latency.
It can be seen that the DLMS algorithm is equivalent to the basic LMS algorithm. Therefore, the optimal coefficient vector to minimize the mean square error is the same as the basic LMS algorithm.
In a specific implementation, in order to reduce the complexity of the implementation, the tap coefficient in the adjustment formula of the LMS algorithm
Figure 306938DEST_PATH_IMAGE021
、
Figure 69357DEST_PATH_IMAGE076
The respective polarities are used to replace the magnitudes, which is the Sign LMS algorithm, and the following three expressions are provided:
Figure DEST_PATH_IMAGE077
；
wherein the content of the first and second substances,
Figure 47677DEST_PATH_IMAGE078
；
through simulation verification, the performance of the second algorithm is basically not different from that of the original algorithm, and the second algorithm is adopted in the method, namely:
Figure DEST_PATH_IMAGE079
；
and combining the DLMS algorithm and Sign LMS algorithm to obtain a Sign LMS (Sign DLMS) algorithm with time delay. The coefficient updating formula of the Sign DLMS algorithm is as follows:
Figure 34088DEST_PATH_IMAGE080
；
then, the feed forward filter 102 tap coefficient vector is defined as follows:
Figure 668332DEST_PATH_IMAGE044
；
the equivalent vector defining the tap coefficients of the feedback filter 104 is as follows:
Figure 31180DEST_PATH_IMAGE048
；
the equivalent vector defining the tap coefficients of the echo cancellation filter 106 is as follows:
Figure 67269DEST_PATH_IMAGE052
；
the regression vector defining the feedforward filter 102 is as follows:
Figure 427843DEST_PATH_IMAGE056
；
the regression vector defining the feedback filter 104 is as follows:
Figure DEST_PATH_IMAGE081
；
the regression vector for the echo cancellation filter 106 is defined as follows:
Figure 80541DEST_PATH_IMAGE061
；
thus, the total equalizer tap coefficients are defined as follows:
Figure 247081DEST_PATH_IMAGE082
the total equalizer regression vector is defined as follows:
Figure DEST_PATH_IMAGE083
the soft estimate, which represents the output of the joint architecture of equalization and echo cancellation in the form of an inner product, is as follows:
Figure 137676DEST_PATH_IMAGE084
；
the soft estimate has a different magnitude to represent reliability compared to the three-valued decision { -1,0,1 }.
The errors are as follows:
Figure DEST_PATH_IMAGE085
；
by referring to the working principle of the Sign DLMS algorithm, the updating expression of the tap coefficient of the equalization and echo cancellation combined framework can be obtained as follows:
Figure 465889DEST_PATH_IMAGE086
；
from the above equation, the updating formulas of the taps of the feedforward filter 102, the feedback filter 104 and the echo cancellation filter 106 under the Sign DLMS criterion are as follows:
the updated expression of the tap coefficients of the feedforward filter 102 is:
Figure 871463DEST_PATH_IMAGE001
；
wherein the content of the first and second substances,
Figure 513797DEST_PATH_IMAGE009
representing a symbolic function.
The updated expression of the tap coefficients of the feedback filter 104 is:
Figure 321216DEST_PATH_IMAGE011
；
the updated expression of the tap coefficients of the echo cancellation filter 106 is:
Figure 289172DEST_PATH_IMAGE015
；
in the embodiment, the sign LMS algorithm with time delay is adopted, so that the use of a multiplier is reduced, a large amount of area and power consumption are saved, and the hardware implementation complexity is greatly simplified.
In one embodiment, as shown in fig. 2, there is provided an equalization and echo cancellation method applied to the equalization and echo cancellation apparatus in the above embodiment, the method includes the following steps:
step S202, carrying out equalization processing on a signal to be equalized corresponding to the current moment through an equalizer to obtain an initial signal equalized at the current moment;
step S204, performing echo simulation on the sending signal at the current moment through an echo canceller to obtain a simulated echo signal at the current moment;
step S206, acquiring a signal to be judged determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment through a judging device, and judging the signal to be judged to obtain an estimated signal corresponding to the original signal at the current moment;
and step S208, updating the tap coefficient of the equalizer through the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
The signal to be equalized corresponding to the current moment is determined according to the original signal.
In the equalization and echo cancellation method, a combined framework of an equalizer and an echo canceller is adopted to generate an equalized initial signal and an analog echo signal together, then a decision device is used for carrying out decision processing on a signal to be decided determined according to the equalized initial signal and the analog echo signal to obtain an estimated signal corresponding to an original signal, and finally a tap coefficient of the equalizer is updated according to a signal error determined by the estimated signal and the signal to be decided. It can be understood that the method combines the equalizer and the echo canceller to work, and adopts the signal to be judged which eliminates the analog echo signal to complete the updating of the tap coefficient of the subsequent equalizer, thereby reducing the adverse effect of the echo signal on the convergence of the equalizer, improving the convergence speed of the equalizer, being beneficial to improving the speeds of the equalization and the echo cancellation of the signal, and meeting the requirement of the high-speed transmission of the Ethernet.
In one embodiment, the method further comprises the steps of:
step S210, updating the tap coefficient of the echo canceller according to the signal error by the echo canceller.
In one embodiment, step S202 includes the steps of:
step S2022, performing feedforward equalization processing on the received signal at the current moment through a feedforward equalizer to obtain a signal subjected to feedforward equalization at the current moment;
step S2024, performing feedback equalization processing on the estimated signal at the previous time by using the decision feedback equalizer to obtain a signal after feedback equalization at the current time.
In one embodiment, the method further comprises the steps of:
step S2052, subtracting the signal after feedforward equalization at the current moment from the signal after feedback equalization at the current moment by using a first subtracter to obtain a signal after equalization at the current moment;
step S2054 is to subtract the equalized signal at the current time from the analog echo signal at the current time by the first subtractor to obtain a signal to be determined.
In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown in fig. 3. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface of the computer device is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, an operator network, NFC (near field communication) or other technologies. The computer program is executed by a processor to implement an equalization and echo cancellation method. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.
Those skilled in the art will appreciate that the architecture shown in fig. 3 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
In one embodiment, a computer device is further provided, which includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method embodiments when executing the computer program.
In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in the embodiments provided herein can include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. An equalization and echo cancellation apparatus, characterized in that said apparatus comprises:
the equalizer is used for performing equalization processing on a signal to be equalized corresponding to the current moment to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
the echo eliminator is used for carrying out echo simulation on the sending signal at the current moment to obtain a simulated echo signal at the current moment;
the decision device is used for acquiring a signal to be decided which is determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment, and performing decision processing on the signal to be decided to obtain an estimated signal corresponding to the original signal at the current moment;
and the equalizer is also used for updating the tap coefficient of the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
2. The apparatus of claim 1, wherein the echo canceller is further configured to update a tap coefficient of the echo canceller according to the signal error.
3. The apparatus of claim 1, wherein the equalizer comprises a feedforward equalizer and a decision feedback equalizer, the signal to be equalized comprises a received signal at a current time and an estimated signal at a previous time, and the initial signal after equalization at the current time comprises a feedforward equalized signal at the current time and a feedback equalized signal at the current time;
the feedforward equalizer is used for performing feedforward equalization processing on the received signal at the current moment to obtain a signal subjected to feedforward equalization at the current moment;
and the decision feedback equalizer is connected with the decision device and used for carrying out feedback equalization processing on the estimation signal at the previous moment to obtain a signal after the feedback equalization at the current moment.
4. The apparatus of claim 3, further comprising:
the first subtracter is respectively connected with the feedforward equalizer and the decision feedback equalizer and is used for subtracting the signal subjected to feedforward equalization at the current moment from the signal subjected to feedback equalization at the current moment to obtain a signal subjected to equalization at the current moment;
and the first subtracter is connected with the echo eliminator and is also used for subtracting the signal after being equalized at the current moment from the analog echo signal at the current moment to obtain the signal to be judged.
5. The apparatus of claim 3, wherein the feedforward equalizer comprises a feedforward filter, and wherein tap coefficients of the feedforward filter are updated by the following equation:
Figure DEST_PATH_IMAGE001
；
wherein the content of the first and second substances,
Figure 522144DEST_PATH_IMAGE002
is shown as
Figure DEST_PATH_IMAGE003
The tap coefficients of the feed-forward filter at the time instant,
Figure 747589DEST_PATH_IMAGE004
is shown as
Figure DEST_PATH_IMAGE005
The tap coefficients of the feed-forward filter at the time instant,
Figure 930309DEST_PATH_IMAGE006
which represents the step size of the update,
Figure DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 506784DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 433151DEST_PATH_IMAGE010
representing the regression vector of the feedforward filter.
6. The apparatus of claim 3, wherein the decision feedback equalizer comprises a feedback filter, and wherein tap coefficients of the feedback filter are updated according to the following formula:
Figure DEST_PATH_IMAGE011
；
wherein the content of the first and second substances,
Figure 513103DEST_PATH_IMAGE012
is shown as
Figure 397882DEST_PATH_IMAGE003
The tap coefficients of the feedback filter are fed back at the time instants,
Figure DEST_PATH_IMAGE013
is shown as
Figure 399336DEST_PATH_IMAGE005
The tap coefficients of the feedback filter are fed back at the time instants,
Figure 394974DEST_PATH_IMAGE006
which represents the step size of the update,
Figure 532695DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 588375DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure 77125DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 610875DEST_PATH_IMAGE014
representing the regression vector of the feedback filter.
7. The apparatus of claim 2, wherein the echo canceller comprises an echo cancellation filter, and wherein tap coefficients of the echo cancellation filter are updated by the following equation:
Figure DEST_PATH_IMAGE015
；
wherein the content of the first and second substances,
Figure 868681DEST_PATH_IMAGE016
is shown as
Figure 95263DEST_PATH_IMAGE003
The tap coefficients of the time-of-day echo cancellation filter,
Figure DEST_PATH_IMAGE017
is shown as
Figure 602468DEST_PATH_IMAGE005
The tap coefficients of the time-of-day echo cancellation filter,
Figure 877591DEST_PATH_IMAGE006
which represents the step size of the update,
Figure 521062DEST_PATH_IMAGE007
which is indicative of a signal error,
Figure 652966DEST_PATH_IMAGE008
which represents the time delay of the processing,
Figure 116309DEST_PATH_IMAGE009
the function of the symbol is represented by,
Figure 991861DEST_PATH_IMAGE018
representing the regression vector of the echo cancellation filter.
8. An equalization and echo cancellation method, characterized in that said method is applied to the device according to any of claims 1-7, said method comprising:
equalizing the signal to be equalized corresponding to the current moment through an equalizer to obtain an initial signal equalized at the current moment, wherein the signal to be equalized corresponding to the current moment is determined according to an original signal;
carrying out echo simulation on the sending signal at the current moment through an echo canceller to obtain a simulated echo signal at the current moment;
obtaining a signal to be judged determined according to the equalized initial signal at the current moment and the analog echo signal at the current moment through a judging device, and judging the signal to be judged to obtain an estimated signal corresponding to the original signal at the current moment;
and updating the tap coefficient of the equalizer through the equalizer according to the signal error determined by the estimated signal and the signal to be judged.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of claim 8 when executing the computer program.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method as claimed in claim 8.
CN202111089912.7A 2021-09-17 2021-09-17 Equalization and echo cancellation device, method, computer device and storage medium Active CN113541733B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111089912.7A CN113541733B (en) 2021-09-17 2021-09-17 Equalization and echo cancellation device, method, computer device and storage medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111089912.7A CN113541733B (en) 2021-09-17 2021-09-17 Equalization and echo cancellation device, method, computer device and storage medium

Publications (2)

Publication Number Publication Date
CN113541733A true CN113541733A (en) 2021-10-22
CN113541733B CN113541733B (en) 2022-01-28

Family

ID=78093317

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111089912.7A Active CN113541733B (en) 2021-09-17 2021-09-17 Equalization and echo cancellation device, method, computer device and storage medium

Country Status (1)

Country Link
CN (1) CN113541733B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114518911A (en) * 2022-02-21 2022-05-20 中国农业银行股份有限公司 Plug-in loading duration prediction method, device, equipment and storage medium
CN115987727A (en) * 2023-03-21 2023-04-18 荣耀终端有限公司 Signal transmission method and device
WO2023169304A1 (en) * 2022-03-07 2023-09-14 华为技术有限公司 Tap adjustment method for equalizer, device, storage medium, and system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1451225A (en) * 1999-07-29 2003-10-22 艾利森电话股份有限公司 Echo cancellation device for cancelling echos in a transceiver unit
CN1716931A (en) * 2004-06-28 2006-01-04 三星电子株式会社 Can adjust the equalizer and the equalization methods thereof of step-length
CN102404012A (en) * 2010-09-10 2012-04-04 上海明波通信技术有限公司 Training sequence using method in digital communication receiver and adaptive equalizer
CN209488618U (en) * 2018-10-26 2019-10-11 上海晟矽微电子股份有限公司 Adaptive equalizer in GFSK receiver
EP3340552B1 (en) * 2016-12-22 2020-03-18 Nxp B.V. Phy transceiver with adaptive tx driver and method of operating thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1451225A (en) * 1999-07-29 2003-10-22 艾利森电话股份有限公司 Echo cancellation device for cancelling echos in a transceiver unit
CN1716931A (en) * 2004-06-28 2006-01-04 三星电子株式会社 Can adjust the equalizer and the equalization methods thereof of step-length
CN102404012A (en) * 2010-09-10 2012-04-04 上海明波通信技术有限公司 Training sequence using method in digital communication receiver and adaptive equalizer
EP3340552B1 (en) * 2016-12-22 2020-03-18 Nxp B.V. Phy transceiver with adaptive tx driver and method of operating thereof
CN209488618U (en) * 2018-10-26 2019-10-11 上海晟矽微电子股份有限公司 Adaptive equalizer in GFSK receiver

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114518911A (en) * 2022-02-21 2022-05-20 中国农业银行股份有限公司 Plug-in loading duration prediction method, device, equipment and storage medium
CN114518911B (en) * 2022-02-21 2024-03-12 中国农业银行股份有限公司 Plug-in loading time length prediction method, device, equipment and storage medium
WO2023169304A1 (en) * 2022-03-07 2023-09-14 华为技术有限公司 Tap adjustment method for equalizer, device, storage medium, and system
CN115987727A (en) * 2023-03-21 2023-04-18 荣耀终端有限公司 Signal transmission method and device
CN115987727B (en) * 2023-03-21 2023-09-26 荣耀终端有限公司 Signal transmission method and device

Also Published As

Publication number Publication date
CN113541733B (en) 2022-01-28

Similar Documents

Publication Publication Date Title
CN113541733B (en) Equalization and echo cancellation device, method, computer device and storage medium
Comminiello et al. Nonlinear acoustic echo cancellation based on sparse functional link representations
JPH08265223A (en) Adaptive filter and echo canceller
US6430287B1 (en) Combined parallel adaptive equalizer/echo canceller
Li et al. A robust adaptive weighted constant modulus algorithm for blind equalization of wireless communications systems under impulsive noise environment
Ferrer et al. Transient analysis of the conventional filtered-x affine projection algorithm for active noise control
Geravanchizadeh et al. Dual-channel speech enhancement using normalized fractional least-mean-squares algorithm
JP4681813B2 (en) Tap coefficient updating method and tap coefficient updating circuit
Sahoo et al. Effect of BER performance in RLS adaptive equalizer
Shi et al. An efficient acoustic echo cancellation design for systems with long room impulses and nonlinear loudspeakers
Chien et al. A new variable step-size method for the M-max LMS algorithms
TWI385941B (en) Method and apparatus for canceling channel interference
US20130308771A1 (en) Method and apparatus for hierarchical adaptive filter
de Campos et al. Adaptive Filters
Kar et al. Adaptive channel equalization using variable step-size least mean fourth algorithm
Sivakumar et al. A new normalized block LMS based adaptive decision feedback equalizer for wireless communications
Zhang et al. l 0-norm penalized shrinkage LMS algorithm based DFE for underwater acoustic communication
Katwal et al. A simple Kalman channel Equalizer using adaptive algorithms for time variant channel
Ghadjati et al. Communication channel equalization based on Levenberg-Marquardt trained artificial neural networks
Aggarwal et al. Performance Analysis of Different Adaptive Algorithms for Equalization
Radhika et al. Architecture Design for an Adaptive Equalizer using LMS 2Tap filters
Yamazaki et al. Performance evaluation of a decision feedback equalizer with an adaptive error prediction filter
Kumar et al. Block based Partial update NLMS Algorithm for Adaptive Decision Feedback Equalization
Gomathi et al. Area Efficient Implementation of Adaptive Filters using High Level Transformation
Sun et al. Improving Blind Equalization Algorithm for Wireless Communication Systems

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CP03 Change of name, title or address
CP03 Change of name, title or address

Address after: 701, 7th Floor, Building 6, Courtyard 8, Kegu 1st Street, Beijing Economic and Technological Development Zone, Daxing District, Beijing, 100176

Patentee after: Beijing Tasson Technology Ltd.

Address before: Room 701, 7 / F, building 6, courtyard 8, KEGU 1st Street, Beijing Economic and Technological Development Zone, Daxing District, Beijing 100176

Patentee before: BEIJING TASSON TECHNOLOGY Ltd.