WO2018120615A1 - Mehod and device for adaptive decision feedback equalization, and storage medium - Google Patents

Abstract

Disclosed is a method for adaptive decision feedback equalization, comprising: a feedforward equalizer performing a filtering processing of an inputted first signal, according to a finite impulse response filtering strategy, to obtain a first filtering result, and outputting the first filtering result to a determiner; after the determiner outputs a second signal, a feedback equalizer receiving the second signal, and performing a filtering processing of the second signal, according to the finite impulse response filtering strategy, to obtain a second filtering result; and performing a filtering processing of the second signal, according to an infinite impulse response filtering strategy, to obtain a third filtering result; obtaining the difference between the third filtering result and the second filtering result as the first difference; the determiner receiving a third signal which is obtained according to the sum of the first filtering result and the first difference, and obtaining, according to the third signal, the second signal associated with the third signal; the second signal being the known transmission level closest to the third signal. Further disclosed are a device for adaptive decision feedback equalization, and a computer storage medium.

Description

Method and device for adaptive decision feedback equalization, storage medium

Cross-reference to related applications

The present application is based on a Chinese patent application filed on Jan. 29, 2016, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present invention relates to the field of twisted pair Ethernet communication, and in particular, to a method and apparatus for adaptive decision feedback equalization, and a computer storage medium.

Background technique

In digital communication systems, inter-symbol interference (ISI), or inter-symbol interference, inter-symbol interference, etc., is an important factor affecting communication performance when multipath propagation occurs in a channel. Among them, the multipath may lead the signal main path, or may lag behind the signal main path, causing forward inter-code interference and backward inter-code interference.

Ethernet is a typical communication system with inter-symbol interference. In high-speed Ethernet, since the signal symbol spacing becomes smaller, inter-symbol interference is more serious. As Ethernet technology continues to develop toward high-speed and large-capacity, higher and higher requirements are imposed on the receiver-side equalization technology. Through equalization, the influence of inter-symbol interference can be eliminated to ensure communication reliability; further, the time-varying of channel response can be solved by adaptive equalization technology.

In Ethernet, a feedforward equalizer plus a feedback equalizer is generally used to eliminate inter-symbol interference caused by multipath propagation in a channel; wherein the feedforward equalizer is used to eliminate forward inter-code interference, the feedback equalization It is used to eliminate backward inter-code interference.

The adaptive equalizer in Ethernet is usually designed only for inter-symbol interference. However, there is another factor in the Ethernet that affects the communication performance, that is, the baseline drift of the received signal due to the high-pass filtering effect of the isolation transformer on the signal. (BLW, Baseline Wander) effect, resulting in reduced communication performance.

An existing solution to the baseline drift problem is to consider its high-pass filtering effect as part of the channel distortion, still eliminating its effects with a conventional equalizer structure, and adding a high-pass filter to the analog portion in order to reduce the filter length. To shorten the length of the trailing tail; however, since the effect of the high-pass filter is equivalent to the form of Infinite impulse response (IIR), it is necessary to increase the order of the filter to eliminate its influence, which in turn leads to equalizer complexity. Greatly improve.

Summary of the invention

In order to solve the existing technical problems, embodiments of the present invention provide a method and apparatus for adaptive decision feedback equalization, which achieves the effect of eliminating baseline offset while reducing filter complexity.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

An embodiment of the present invention provides an apparatus for adaptive decision feedback equalization, where the apparatus includes: a feedforward equalizer, a decider, and a feedback equalizer;

The feedforward equalizer is configured to filter the input first signal according to a finite impulse response filtering strategy to obtain a first filtering result, and send the first filtering result to the determiner;

The determiner is configured to: after outputting the second signal to the feedback equalizer, receive a third signal obtained according to the sum of the first filtering result and the first difference, and obtain, according to the third signal, the third signal a second signal; the second signal being a known transmission level that is closest to the third signal;

The feedback equalizer is configured to receive the second signal, perform filtering processing on the second signal according to a finite impulse response filtering strategy, to obtain a second filtering result, and filter the second signal according to an infinite impulse response The strategy performs filtering processing to obtain a third filtering result; The difference between the third filtering result and the second filtering result is a first difference, and the first difference is fed back to the decider.

In the above solution, the device further includes: an error calculator;

The error calculator is configured to determine a difference between the third signal and the second signal as a second difference, and send the second difference to a first tap coefficient updater and a second tap Coefficient updater.

In the above solution, the device further includes: a first tap coefficient updater; the feedforward equalizer is a finite impulse response filter;

The first tap coefficient updater is configured to calculate a finite order filter coefficient from the first signal and the second difference as a tap coefficient provided to the finite impulse response filter.

In the above solution, the device further includes: a second tap coefficient updater;

The second tap coefficient updater is configured to calculate a finite order filter coefficient according to the second signal and the second difference as a tap coefficient of the feedback equalizer.

In the above solution, the feedback equalizer includes: an inter-symbol interference cancellation unit and a baseline drift cancellation unit;

The inter-code interference cancellation unit is a finite impulse response filter configured to receive the second signal, and combine the second signal input in the past N times to calculate a weighted summation result as a second filtering result;

The baseline drift cancellation unit is an infinite impulse response filter configured to receive the weighted summation result sent by the second signal and the inter-symbol interference cancellation unit, and obtain a third filtering result.

The embodiment of the invention provides a method for adaptive decision feedback equalization, the method comprising:

The feedforward equalizer filters the input first signal according to a finite impulse response filtering strategy And obtaining a first filtering result, and sending the first filtering result to the decider;

The determiner receives a third signal obtained according to the sum of the first filtering result and the first difference, and obtains a second signal related to the third signal according to the third signal; the second signal is a known transmission level that is closest to the third signal;

After the determiner outputs the second signal, the feedback equalizer receives the second signal, performs filtering processing on the second signal according to the finite impulse response filtering strategy, to obtain a second filtering result; and according to the second signal The infinite impulse response filtering strategy performs filtering processing to obtain a third filtering result; and the first difference is obtained according to a difference between the third filtering result and the second filtering result.

In the above solution, after the obtaining the second signal related to the third signal according to the third signal, the method further includes:

Determining a difference between the third signal and the second signal as a second difference, and determining a tap coefficient of the feedforward equalizer and the feedback equalizer according to the second difference.

In the above solution, the determining the tap coefficients of the feedforward equalizer according to the second difference comprises:

Calculating a finite order filter coefficient according to the first signal and the second difference value as a tap coefficient of the feedforward equalizer.

In the above solution, the determining the tap coefficients of the feedback equalizer according to the second difference comprises:

A finite order filter coefficient is calculated according to the second signal and the second difference as a tap coefficient of the feedback equalizer.

In the above solution, the second signal is filtered according to a finite impulse response filtering strategy to obtain a second filtering result, including:

Receiving the second signal, combining the second signal input in the past N times, and calculating the obtained weighted summation result as a second filtering result;

Performing filtering processing on the second signal according to an infinite impulse response filtering strategy The third filtering result; comprising:

Receiving the second signal and the weighted summation result, and calculating a third filtering result.

Embodiments of the present invention provide a computer storage medium in which computer executable instructions are stored, the computer executable instructions configuring a method for performing the adaptive decision feedback equalization described above.

In the solution of the feedback feedback equalization provided by the embodiment of the present invention, the feed forward equalizer filters the input first signal according to the finite impulse response filtering strategy to obtain a first filtering result, and sends the first filtering result to the decision. After the determiner outputs the second signal, the feedback equalizer receives the second signal, and performs filtering processing on the second signal according to the finite impulse response filtering strategy to obtain a second filtering result; The signal is filtered according to an infinite impulse response filtering strategy to obtain a third filtering result; the first difference is obtained according to a difference between the third filtering result and the second filtering result; the determiner receives according to the a third signal obtained by summing the filtered result and the first difference, and obtaining a second signal related to the third signal according to the third signal; the second signal being closest to the third signal The transmission level is known. The method and apparatus provided by the embodiments of the present invention propose an adaptive tap coefficient update method, which adds a baseline wander elimination unit based on a typical decision feedback equalizer, and uses a feedback structure with fewer operations (adder, multiplier) And the delay unit) achieves an infinite impulse response filtering effect, thereby eliminating the baseline drift caused by the infinite impulse response high-pass filtering of the transformer, compared to the conventional technique of eliminating the baseline drift by increasing the order of the decision feedback equalizer The effect of baseline drift cancellation is achieved while reducing the complexity of the filter.

DRAWINGS

1 is a schematic structural diagram of a conventional decision feedback equalization system;

2 is a schematic structural diagram of a conventional feedback equalizer;

3 is a schematic structural diagram of a conventional second tap coefficient updater;

FIG. 4 is a schematic structural diagram of an apparatus for adaptive decision feedback equalization according to an embodiment of the present invention; intention;

FIG. 5 is a schematic structural diagram of an adaptive decision feedback equalizer according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a feedback equalizer according to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a second tap coefficient updater according to an embodiment of the present invention;

FIG. 8 is a schematic flowchart diagram of a method for adaptive decision feedback equalization according to an embodiment of the present invention.

detailed description

In various embodiments of the present invention, the feedforward equalizer performs filtering processing on the input first signal according to a finite impulse response filtering strategy to obtain a first filtering result, and sends the first filtering result to the decider; After the determiner outputs the second signal, the feedback equalizer receives the second signal, performs filtering processing on the second signal according to the finite impulse response filtering strategy, to obtain a second filtering result; and according to the infinite The impulse response filtering algorithm performs filtering processing to obtain a third filtering result; and the first difference is obtained according to a difference between the third filtering result and the second filtering result; the determiner receives the first filtering result according to the first filtering result And a third signal obtained by summing the first difference, obtaining a second signal related to the third signal according to the third signal; the second signal is a known transmission closest to the third signal Level.

The present invention will be further described in detail below with reference to the embodiments.

1 is a schematic structural diagram of a conventional decision feedback equalizer. As shown in FIG. 1, the decision feedback equalizer includes: a feedforward equalizer, a first tap coefficient updater, an error calculator, a decider, and a feedback equalization. And a second tap coefficient updater; wherein

The feedforward equalizer is configured to filter the input signal v _k to obtain a filtering result u _k , and send the filtering result u _k to the determiner;

Here, the feedforward equalizer uses a finite impulse response filter whose transfer function is:

G _f =f ₀ +f ₁ z ^-1 +...+f _i z ^-i +...+f _M z ^-M ,i=0,1,...,M

Where f _i (i = 0, 1, ..., M) is the tap coefficient of the feedforward equalizer. At time k, the tap coefficient is denoted as f _i,k ; M+1 is the number of taps.

所述前馈均衡器的抽头系数f_i(i＝0,1,…,M)由所述第一抽头系数更新器提供。At time k, the input signal of the feedforward equalizer is v _k and the output signal is u _k .

The tap coefficients f _i (i = 0, 1, ..., M) of the feed forward equalizer are provided by the first tap coefficient updater.

At time k, the input signal of the feedback equalizer is I _k and the output signal is d _k .

将输入信号

映射为多个已知可能的电平值之一，输出判决结果I_k为与

最接近的已知发送电平。The determiner is configured to receive a _{sum of} an output signal u _{k of the} feedforward equalizer and an output signal d _k of the feedback equalizer as an input signal

Input signal

Mapping to one of a plurality of known possible level values, outputting the decision result I _k as

The closest known send level.

和输出信号I_k的差值e_k，

并将所述差值e_k发送到第一抽头系数更新器和第二抽头系数更新器。The error calculator configured to calculate an input signal of the decider

And the difference between the output signal I _k e _k,

And transmitting the difference e _k to the first tap coefficient updater and the second tap coefficient updater.

The first tap coefficient updater is configured to provide a tap coefficient update for the feed forward equalizer according to the received input signal v _k of the feedforward equalizer and the difference e _k calculated by the error calculator As a result, the result is the tap coefficient of the feedforward equalizer at time k+1;

Here, the update formula of the tap coefficients is: f _i,k+1 =f _i,k +Δ _f e _k v _ki ,i=0,1,...,M; wherein Δ _f is the feedforward equalization The coefficient is updated in steps.

The second tap coefficient updater is configured to provide a tap coefficient update result for the feedback equalizer according to the received decision result I _k output by the decider and the difference e _k calculated by the error calculator. The result is the tap coefficient of the feedback equalizer at time k+1.

2 is a schematic structural diagram of a conventional feedback equalizer; as shown in FIG. 2, the existing feedback equalizer includes N delay units (indicated by D in the figure) and tap coefficients corresponding to each delay unit. And summation unit;

The tap coefficients of the prior art feedback equalizer are b ₁ , b ₂ , ..., b _j , ... b _N (j = 1, 2, ..., N), and at time k, these tap coefficients are denoted as b _{1 , k} , b _{2, k} ,..., b _j,k ,...b _N,k (j=1,2,...,N).

At time k, the existing feedback equalizer receives the decision result I _k output by the _decider , and calculates and obtains the weighting request according to the decision results I _k-1 , I _k-2 , . . . , I _{kN of the} past N times. And the result δ _k . The transfer function of the existing feedback equalizer is:

3 is a schematic structural diagram of a conventional second tap coefficient updater; as shown in FIG. 3, the update formula of the second tap coefficient updater is: b _{j, k+1} = b _{j, k} + Δ _b e _k I _kj , i=1, 2,...,N;

Where N is the number of delay units; Δ _b is the feedback equalizer coefficient update step size, and e _k is the difference of the error calculator output.

FIG. 4 is a schematic structural diagram of an apparatus for adaptive decision feedback equalization according to an embodiment of the present invention. As shown in FIG. 4, the apparatus includes: a feedforward equalizer, a decider, and a feedback equalizer;

The feedforward equalizer is configured to filter the input first signal according to a finite impulse response filtering strategy to obtain a first filtering result, and send the first filtering result to the determiner;

The determiner is configured to: after outputting the second signal to the feedback equalizer, receive a third signal obtained according to the sum of the first filtering result and the first difference, and obtain, according to the third signal, the third signal a second signal; the second signal being a known transmission level that is closest to the third signal;

The feedback equalizer is configured to receive the second signal, perform filtering processing on the second signal according to a finite impulse response filtering strategy, to obtain a second filtering result, and filter the second signal according to an infinite impulse response And performing a filtering process to obtain a third filtering result; obtaining a first difference according to a difference between the third filtering result and the second filtering result, and feeding the first difference to the decider.

Specifically, the device further includes: an error calculator;

The error calculator is configured to determine a difference between the third signal and the second signal as a second difference, and send the second difference to a first tap coefficient updater and a second tap Coefficient updater.

Specifically, the device further includes: a first tap coefficient updater; the feedforward equalizer is a finite impulse response filter;

The first tap coefficient updater is configured to calculate a finite order filter coefficient based on the first signal and the second difference as a tap coefficient provided to the feed forward equalizer.

Specifically, the device further includes: a second tap coefficient updater;

The second tap coefficient updater is configured to calculate a finite order filter coefficient according to the second signal and the second difference as a tap coefficient of the feedback equalizer.

Specifically, the feedback equalizer includes: an inter-symbol interference cancellation unit and a baseline drift cancellation unit; wherein

The inter-symbol interference cancellation unit is a finite impulse response filter configured to receive the second signal, and combine the second signals input in the past N times to calculate and obtain a weighted summation result as a second filtering result;

The baseline drift cancellation unit is an infinite impulse response filter configured to receive the weighted summation result sent by the second signal and the inter-symbol interference cancellation unit, and obtain a third filtering result.

FIG. 5 is a schematic structural diagram of an adaptive decision feedback equalizer according to an embodiment of the present invention. As shown in FIG. 5, the adaptive decision feedback equalizer includes: a feedforward equalizer, a first tap coefficient updater, An error calculator, a decider, a feedback equalizer, and a second tap coefficient updater; wherein

The feedforward equalizer, the first tap coefficient updater, the error calculator, and the decider are the same as those in the existing decision feedback equalizer shown in FIG. 1; specifically,

将所述第一滤波结果发送给判决器； The feedforward equalizer is configured to filter the input first signal v _k according to a finite impulse response filtering strategy to obtain a first filtering result u _k ,

Transmitting the first filtering result to the decider;

根据所述第三信号

得到与所述第三信号

相关的第二信号I_k，所述第二信号I_k为与所述第三信号

最接近的已知发送电平；The determiner is configured to output a second signal I _k to the feedback equalizer, and receive a third signal obtained according to a _sum of the first filtering result u _k and the first difference d _k

According to the third signal

Obtaining the third signal

a second signal I _k , the second signal I _k being the third signal

The closest known send level;

和所述第二信号I_k的差值得到第二差值

并将所述第二差值e_k发送到第一抽头系数更新器和第二抽头系数更新器；The error calculator configured to determine the third signal

And a difference between the second signal I _k and a second difference

And transmitting the second difference e _k to the first tap coefficient updater and the second tap coefficient updater;

The first tap coefficient updater is configured to calculate a finite order filter coefficient according to the first signal v _k and the second difference e _k as a tap coefficient provided to the feed forward equalizer;

The feedback equalizer is configured to receive the second signal I _k , perform filtering processing on the second signal I _k according to a finite impulse response filtering strategy, to obtain a second filtering result; and to the second signal I _k Performing a filtering process according to an infinite impulse response filtering strategy to obtain a third filtering result; obtaining the first difference d _k according to a difference between the third filtering result and the second filtering result, and the first difference The value d _{k is} fed back to the decider;

Specifically, the feedback equalizer includes: an inter-symbol interference cancellation unit and a baseline drift cancellation unit; wherein

The inter-code interference cancellation unit is a finite impulse response filter configured to receive the second signal I _k and combine the second signals input in the past N times to calculate a weighted summation result as a second filtering result;

The baseline drift cancellation unit is configured to receive the weighted summation result sent by the second signal I _k and the inter-symbol interference cancellation unit, and obtain a third filtering result;

Here, the second tap coefficient updater is configured to calculate a finite order filter coefficient from the second signal I _k and the second difference e _k as a tap coefficient of the feedback equalizer.

FIG. 6 is a schematic structural diagram of a feedback equalizer according to an embodiment of the present invention; as shown in FIG. 6, the feedback equalizer includes: an inter-symbol interference cancellation unit and a baseline drift cancellation unit;

In FIG. 6, the upper dotted line frame is an inter-code interference cancellation unit, and the lower dotted line frame is a baseline drift elimination unit;

The inter-symbol interference cancellation unit includes N delay units (indicated by D in the figure) and respective corresponding tap coefficients, and a summation unit;

The tap coefficients of the inter-symbol interference unit are b ₁ , b ₂ , ..., b _j , ... b _N (j = 1, 2, ..., N), and at time k, the tap coefficients are recorded as b _{1, k} , b _2,k ,...,b _j,k ,...b _N,k (j=1,2,...,N);

At time k, the inter-symbol interference cancellation unit receives the decision result input by the feedback equalizer, that is, the second signal I _k that the decider outputs to the feedback equalizer, and according to the decision result I _k-1 input in the past N times, I _k-2 ,...,I _kN , calculating a weighted summation result δ _k and outputting;

The transfer function of the inter-symbol interference cancellation unit is:

The baseline drift elimination unit may multiplex the operation unit of the inter-symbol interference cancellation unit, and additionally add two delay units, two weighting operation units, and two summation units; here, the transfer function of the constructed filter is:

Among them, the alpha value can be set according to the pole range of the system isolation transformer.

At time k, the baseline wander elimination unit receives the decision result I _k input by the feedback equalizer and the weighted summation result δ _k output by the inter-symbol interference canceling unit, and calculates according to the decision result I _k and the weighted summation result δ _k The result is β _k .

Output beta] _k and the inter-code interference canceling unit taking the difference output beta] _k at time k, the feedback equalizer D _k output from said elimination unit baseline drift obtained: d _k = β _k -δ _k .

The total transfer function of the feedback equalizer is:

Where N is the number of delay units;

Here, the baseline drift canceling unit in the feedback equalizer adds a small number of computing units and multiplexes the operations of the inter-symbol interference canceling unit, and implements an infinite impulse response filtering function with a feedback structure to eliminate baseline drift.

FIG. 7 is a schematic structural diagram of a second tap coefficient updater according to an embodiment of the present invention; as shown in FIG. 7, the input part of the dashed box preprocesses the input decision result I _k to obtain I′ _k , and the transfer function is :

Preprocessing result I 'update formula of the second tap coefficient updater _k is:

b _j,k+1 =b _j,k +Δ _b e _k I' _kj ,j=1,2,...,N

Where Δ _b is the feedback equalizer coefficient update step size; the alpha value can be set according to the pole range of the system isolation transformer.

The effect of partial pre-processing in the dashed box in Figure 7 is to match the high-pass filtering of the system isolation transformer, filtering the output of the decider I _{k to the} low-frequency portion.

FIG. 8 is a schematic flowchart of a method for adaptive decision feedback equalization according to an embodiment of the present invention; as shown in FIG. 8, the method for adaptive decision feedback equalization includes:

Step 801: The feedforward equalizer performs filtering processing on the input first signal according to the finite impulse response filtering strategy to obtain a first filtering result, and sends the first filtering result to the decider.

Step 802: The determiner receives a third signal obtained according to a sum of the first filtering result and the first difference, and obtains a second signal related to the third signal according to the third signal; the second signal is The closest known transmission level of the third signal;

Step 803: After the determiner outputs the second signal, the feedback equalizer receives the second signal, and The second signal is filtered according to a finite impulse response filtering strategy to obtain a second filtering result; and the second signal is filtered according to an infinite impulse response filtering strategy to obtain a third filtering result; according to the third The difference between the filtered result and the second filtered result results in the first difference.

It should be noted that, in the initial decision, the first difference value is zero, the first filtering result is sent to the feedback equalizer as a third signal, and the feedback equalizer filters the third signal to obtain the first Filtering the result and the second filtering result, and obtaining the first difference according to a difference between the third filtering result and the second filtering result, the determiner according to the first filtering result and the first The sum of the differences, that is, the new third signal, obtains a new second signal and feeds back to the feedback equalizer, the second signal being the known transmission level closest to the third signal, thereby circulating .

Specifically, after the obtaining the second signal related to the third signal according to the third signal, the method further includes:

Determining a difference between the third signal and the second signal as a second difference, and determining a tap coefficient of the feedforward equalizer and the feedback equalizer according to the second difference.

Specifically, the determining, according to the second difference, a tap coefficient of the finite impulse response filter, including:

Calculating a finite order filter coefficient according to the first signal and the second difference value as a tap coefficient of the feedforward equalizer.

Specifically, the determining, according to the second difference, a tap coefficient of the feedback equalizer includes:

A finite order filter coefficient is calculated according to the second signal and the second difference as a tap coefficient of the feedback equalizer.

Specifically, the second signal is filtered according to a finite impulse response filtering strategy, and the second filtering result is obtained, including: receiving the second signal, combining the second signal input in the past N times, and calculating the obtained weighting request. And the result as a second filtering result;

And performing filtering processing on the second signal according to an infinite impulse response filtering strategy to obtain a third filtering result. The method includes: receiving the second signal and the weighted summation result, and calculating to obtain a third filtering result.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in Within the scope of protection of the present invention.

Industrial applicability

By adopting the embodiment of the present invention, by updating the adaptive tap coefficients, the baseline drift elimination unit is added on the basis of a typical decision feedback equalizer, and the feedback structure is used with fewer operations (adder, multiplier and delay). Unit) achieves an infinite impulse response filtering effect, thereby eliminating the baseline drift caused by the high-pass filtering of the infinite impulse response of the transformer, compared to the conventional technique of eliminating the baseline drift by increasing the order of the decision feedback equalizer. The complexity of the filter simultaneously achieves the effect of baseline drift cancellation.

Claims (11)

An apparatus for adaptive decision feedback equalization, the apparatus comprising: a feedforward equalizer, a decider, and a feedback equalizer; wherein The feedforward equalizer is configured to filter the input first signal according to a finite impulse response filtering strategy to obtain a first filtering result, and send the first filtering result to the determiner; The determiner is configured to: after outputting the second signal to the feedback equalizer, receive a third signal obtained according to the sum of the first filtering result and the first difference, and obtain, according to the third signal, the third signal a second signal; the second signal being a known transmission level that is closest to the third signal; The feedback equalizer is configured to receive the second signal, perform filtering processing on the second signal according to a finite impulse response filtering strategy, to obtain a second filtering result, and filter the second signal according to an infinite impulse response And performing a filtering process to obtain a third filtering result; obtaining a first difference according to a difference between the third filtering result and the second filtering result, and feeding the first difference to the decider. The apparatus according to claim 1, wherein said apparatus further comprises: an error calculator; The error calculator is configured to determine a difference between the third signal and the second signal as a second difference, and send the second difference to a first tap coefficient updater and a second tap Coefficient updater. The apparatus according to claim 2, wherein said apparatus further comprises: a first tap coefficient updater; said feed forward equalizer being a finite impulse response filter; The first tap coefficient updater is configured to calculate a finite order filter coefficient from the first signal and the second difference as a tap coefficient provided to the finite impulse response filter. The apparatus of claim 2, wherein the apparatus further comprises: a second tap coefficient updater; The second tap coefficient updater is configured to calculate a finite order filter coefficient according to the second signal and the second difference as a tap coefficient of the feedback equalizer. The apparatus according to claim 1, wherein the feedback equalizer comprises: an inter-symbol interference cancellation unit and a baseline drift cancellation unit; wherein The inter-code interference cancellation unit is a finite impulse response filter configured to receive the second signal, and combine the second signal input in the past N times to calculate a weighted summation result as a second filtering result; The baseline drift cancellation unit is an infinite impulse response filter configured to receive the weighted summation result sent by the second signal and the inter-symbol interference cancellation unit, and obtain a third filtering result. A method for adaptive decision feedback equalization, the method comprising: The feedforward equalizer performs filtering processing on the input first signal according to the finite impulse response filtering strategy to obtain a first filtering result, and sends the first filtering result to the decider; The determiner receives a third signal obtained according to the sum of the first filtering result and the first difference, and obtains a second signal related to the third signal according to the third signal; the second signal is a known transmission level that is closest to the third signal; After the determiner outputs the second signal, the feedback equalizer receives the second signal, performs filtering processing on the second signal according to the finite impulse response filtering strategy, to obtain a second filtering result; and according to the second signal The infinite impulse response filtering strategy performs filtering processing to obtain a third filtering result; and the first difference is obtained according to a difference between the third filtering result and the second filtering result. The method of claim 6 wherein said obtaining is based on said third signal After the second signal related to the third signal, the method further includes: Determining a difference between the third signal and the second signal as a second difference, and determining a tap coefficient of the feedforward equalizer and the feedback equalizer according to the second difference. The method of claim 7, wherein the determining the tap coefficients of the feedforward equalizer based on the second difference comprises: Calculating a finite order filter coefficient according to the first signal and the second difference value as a tap coefficient of the feedforward equalizer. The method of claim 7, wherein the determining the tap coefficients of the feedback equalizer based on the second difference comprises: A finite order filter coefficient is calculated according to the second signal and the second difference as a tap coefficient of the feedback equalizer. The method according to claim 6, wherein the second signal is filtered according to a finite impulse response filtering strategy to obtain a second filtering result, comprising: Receiving the second signal, combining the second signal input in the past N times, and calculating the obtained weighted summation result as a second filtering result; Performing filtering processing on the second signal according to an infinite impulse response filtering strategy to obtain a third filtering result; Receiving the second signal and the weighted summation result, and calculating a third filtering result. A computer storage medium having stored therein computer executable instructions configured to perform the method of adaptive decision feedback equalization of any of the preceding claims 6-10.

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