A coefficient initialization system and method for decision feedback equalizer

Abstract

The present invention discloses a coefficient initialization system and method for a decision feedback equalizer, comprising: a feedforward filter and a feedback filter, wherein an input signal is converted into a digital signal through the feedforward filter; the digital signal is subjected to coefficient convergence operation through an update component; the update component transmits the digital signal after operation to a decision module to judge the signal; an initialization control module can receive the coefficient signal of the feedforward filter, the initialization control module is provided with a timer, the coefficient convergence time can be limited, and the coefficient initialization operation can be performed, and the initialized coefficient signal is transmitted to the feedforward filter and the feedback filter, and at the time interval when the timer expires, the feedforward filter and the feedback filter are reinitialized in an interlaced manner, and the device is provided with a timer in the initialization control module, and the coefficient convergence cycle period is set by the timer, so as to realize the adaptive convergence of the decision feedback equalizer.

Description

Technical Field

[0001] The present invention relates to the field of communication systems, and in particular to a coefficient initialization system and method for a decision feedback equalizer. Background Art

[0002] A decision feedback equalizer (DFE) has two adaptive FIR filters, a feedforward filter (FFF) and a feedback filter (FBF), whose coefficients are adjusted according to the output decision; DFE has a coefficient convergence problem, especially when the initial coefficient is not close to the optimal coefficient, the output signal of the decision feedback equalizer will produce a large error. Publication No. CN 114070229 A provides a decision feedback equalizer and a related control method. Through a weight coefficient control unit, a minimum mean square error algorithm is adopted. At the initial convergence of the minimum mean square algorithm, the weight coefficient in the feedback equalizer is limited, thereby limiting the weight energy of the feedback equalizer. In this way, it is possible to avoid error propagation caused by the error being amplified when a decision error occurs, thereby preventing the minimum mean square algorithm from converging. However, if the weight coefficient is limited at the initial convergence stage, some data signals may be distorted after being amplified by the algorithm, or some initial coefficients that meet the requirements may be screened out to ensure that the weight coefficients within the limit are met. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings in the prior art and to propose a coefficient initialization system and method for a decision feedback equalizer.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: a coefficient initialization system of a decision feedback equalizer, comprising:

[0005] A feedforward filter, configured to receive an input signal and convert the input signal into a digital signal through the feedforward filter;

[0006] The digital signal performs coefficient convergence operation through the update component, so that the introduced coefficient of the digital signal is updated;

[0007] The updating component transmits the calculated digital signal to the decision module, and the decision module judges the signal;

[0008] The decision module converts the signal into an output signal and transmits it out, and at the same time performs feedback adjustment processing through a feedback filter during the output;

[0009] The feedback filter retransmits the signal to the update component, and the coefficient is further updated by the update component, and is transmitted to the decision module for judgment, and the signal is output again until the coefficient meets the requirements;

[0010] The initialization control module can receive the coefficient signal of the feedforward filter and perform regulation. The initialization control module is provided with a timer, which can limit the coefficient convergence time and perform coefficient initialization operation, and pass the initialized coefficient signal to the feedforward filter and the feedback filter. At the timer expiration interval, the feedforward filter and the feedback filter are reinitialized in an interlaced manner.

[0011] As a further description of the above technical solution: a feedback component is used to receive the coefficient signal fed back by the update component and the decision module.

[0012] As a further description of the above technical solution: the feedback component is used to transmit the coefficient signal to the initialization control module to perform the coefficient initialization operation.

[0013] As a further description of the above technical solution: after receiving the coefficient signal, the initialization control module controls the timer to accumulate the clock pulse signal.

[0014] As a further description of the above technical solution: a threshold is set by the timer, and after the clock pulse signal accumulates to the set threshold, convergence is determined by comparing the quantization difference, that is, the difference between the N-bit data of the feedback filter and the quantized result, to see whether it is less than the set threshold.

[0015] As a further description of the above technical solution: if the quantization difference reaches a specific threshold within a certain time range, it is considered to have converged. If not, the feedforward filter and the feedback filter are restarted to achieve coefficient convergence through the cross-coefficient adjustment step.

[0016] As a further description of the above technical solution: the timer is reset to zero after the pulse signal reaches the set value, and the pulse signal is accumulated again.

[0017] A coefficient initialization method for a decision feedback equalizer, comprising:

[0018] s1: The input signal enters the feedforward filter, through which the coefficients are generated and passed to the update component and the initialization control module;

[0019] S2: The initialization control module receives the signal and accumulates the clock pulse signal through the timer to perform timing; the update component receives the coefficient and performs calculation convergence on the coefficient, and transmits the converged coefficient signal to the decision module and the feedback component;

[0020] S3: The decision module receives the feedback signal of the update component to determine whether the coefficient can be output. If yes, the coefficient signal is output. If no, the coefficient signal is transmitted to the feedback filter and the feedback component.

[0021] S4: The feedback filter receives the coefficients and converts them into feedback signals, which are then passed to the update component to perform the next step of updating the coefficients. The feedback component is used to collect information about the coefficients after convergence from the update component and the decision module, and feed the information back to the initialization control module.

[0022] S5: After receiving the information of the feedback component, the initialization control module makes a judgment with the timer. If the coefficients have not converged within the set time, the trigger signal is initialized and sent to the feedforward filter and the feedback filter. If the coefficients have converged, the decision module outputs the converged coefficient signal;

[0023] S6: After receiving the trigger signal, the feedforward filter repeats the above steps until the decision module determines that the coefficient of the feedback signal is yes, and outputs a converged coefficient signal.

[0024] The above technical solution has the following advantages or beneficial effects:

[0025] 1. A timer is provided in the initialization control module. The coefficient convergence cycle period is set by the timer, so that the adaptive convergence of the decision feedback equalizer can be achieved.

[0026] 2. Within the time period set by the timer, the system performs coefficient convergence operations. After reaching the cycle period, the decision module determines whether the current coefficients have converged. If they have converged, the coefficient signal is output. If they have not converged, the initialization control module is used to initialize and correct the coefficients, and the coefficient convergence operation is performed again.

[0027] 3. After the timer expires, restart to determine whether the coefficients have converged. If they have converged, no reinitialization is required.

[0028] 4. After the timer expires, the feedforward filter and the feedback filter are reinitialized in an interleaved manner, so that the initialized coefficients are close to the optimal coefficients. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the connection structure of the initialization system proposed by the present invention.

[0030] Legend:

[0031] 1. Feedforward filter; 2. Update component; 3. Decision module; 4. Feedback filter; 5. Initialization control module; 6. Timer; 7. Feedback component. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Reference Figure 1 , an embodiment of the present invention provides: a coefficient initialization system for a decision feedback equalizer, comprising:

[0034] The feedforward filter 1 is used to receive an input signal and convert the input signal into a digital signal through the feedforward filter 1; the digital signal is subjected to coefficient convergence operation through the update component 2, so that the introduced coefficient of the digital signal is updated; the update component 2 transmits the digital signal after operation to the decision module 3, and the signal is judged through the decision module 3; the decision module 3 converts the signal into an output signal and transmits it, and at the same time, performs feedback adjustment processing through the feedback filter 4;

[0035] The feedback filter 4 retransmits the signal to the update component 2, which further updates the coefficients and transmits them to the decision module 3 for judgment until the coefficients meet the requirements and the signal is re-output;

[0036] The initialization control module 5 can receive the coefficient signal of the feedforward filter 1 and perform regulation. The initialization control module 5 is provided with a timer 6, which can limit the coefficient convergence time and perform coefficient initialization operation, and pass the initialized coefficient signal to the feedforward filter 1 and the feedback filter 4. At the timer expiration interval, the feedforward filter 1 and the feedback filter 4 are reinitialized in an interlaced manner.

[0037] In this embodiment, the logic for determining whether the coefficients have converged to the optimal point can calculate the degree of convergence by using the DFE error signal. If the DFE error (and quantization error) is lower than a certain threshold, it can be determined that convergence has occurred, otherwise it has not occurred. If the coefficients are determined to have converged, the DFE coefficients will no longer be reinitialized.

[0038] The initialization control module 5 can receive the coefficient signal of the feedforward filter 1 and perform regulation; the initialization control module 5 is provided with a timer 6, which can limit the coefficient convergence time, and can perform coefficient initialization operation, and pass the initialized coefficient signal to the feedforward filter 1 and the feedback filter 4.

[0039] In this embodiment, when the timer 6 expires and the coefficients have not converged, a coefficient re-initialization trigger signal is generated and fed back to the initialization control module 5 for coefficient initialization.

[0040] The feedback component 7 is used to receive the coefficient signal fed back by the update component 2 and the decision module 3, and transmit the coefficient signal to the initialization control module 5 to perform the coefficient initialization operation.

[0041] After receiving the coefficient signal, the initialization control module 5 controls the timer 6 to accumulate the clock pulse signal.

[0042] The threshold is set by timer 6. After the clock pulse signal accumulates to the set threshold, the convergence is determined by comparing the quantization difference, that is, the difference between the N-bit data of the feedback filter 4 and the quantized result, to see whether it is less than the set threshold. If the quantization difference reaches a specific threshold within a certain time range, it is considered to have converged. If not, the feedforward filter 1 and the feedback filter 4 are restarted to achieve coefficient convergence through the cross-coefficient adjustment step. The timer 6 is reset to zero after the pulse signal reaches the set value, and the pulse signal is accumulated again.

[0043] In this embodiment, after the timing of timer 6 expires, the feedforward filter 1 and the feedback filter 4 are reinitialized in an interlaced manner. Specifically, the initialized coefficient signal is transmitted to the feedback filter 4 through the initialization control module 5, and the signal is transmitted to the update component 2 through the feedback filter 4 to update the coefficient. After multiple feedback and update steps, a new initialized coefficient signal can be obtained, and the signal is transmitted to the feedforward filter 1 to re-perform the coefficient convergence operation.

[0044] That is, the initialization order can be:

[0045] FBF, FFF, FBF, FFF;

[0046] or FBF, FBF, FFF, FBF, FBF, FFF;

[0047] Or FBF, FBF, FBF, FFF, FBF, FBF, FBF, FFF, etc. perform periodic operations.

[0048] The coefficient initialization operation can be performed by passing the initialization coefficient signal to the feedback filter 4, and passing the coefficient signal to the initialization control module 5 through the feedback filter 4.

[0049] A coefficient initialization method for a decision feedback equalizer, comprising:

[0050] s1: The input signal enters the feedforward filter 1, generates coefficients through the feedforward filter 1, and passes the coefficients to the update component 2 and the initialization control module 5;

[0051] S2: Initialization control module 5 receives the signal and accumulates the clock pulse signal through timer 6 to perform timing; update component 2 receives the coefficient and performs calculation convergence on the coefficient, and transmits the converged coefficient signal to decision module 3 and feedback component 7;

[0052] S3: Decision module 3 receives the feedback signal of update component 2 to determine whether the coefficient can be output. If yes, it outputs it. If no, it transmits the coefficient signal to feedback filter 4 and feedback component 7.

[0053] S4: The feedback filter 4 receives the coefficients and converts them into feedback signals, which are then passed to the update component 2 for the next step of updating the coefficients. The feedback component 7 is used to collect information about the coefficients after convergence from the update component 2 and the decision module 3, and feed the information back to the initialization control module 5.

[0054] S5: After receiving the information from the feedback component 7, the initialization control module 5 makes a judgment with the timer 6. If the coefficients have not converged within the set time, the trigger signal is initialized and sent to the feedforward filter 1 and the feedback filter 4. If the coefficients have converged, the decision module 3 outputs the converged coefficient signal;

[0055] S6: After receiving the trigger signal, the feedforward filter 1 repeats the above steps until the decision module 3 determines the coefficient of the feedback signal as yes, and outputs a converged coefficient signal.

[0056] Working principle: The input signal enters through the feedforward filter 1, and the electrical signal is converted into a digital signal through the feedforward filter 1, and the signal is passed to the update component 2 and the initialization control module 5. The update component 2 performs a coefficient convergence operation after receiving the coefficient signal. After the operation is completed, the coefficient signal can be passed to the decision module 3 for judgment. If the coefficient is judged to have converged, the output signal is performed. If not, the signal is passed to the feedback filter 4, and the coefficient signal is passed to the update component 2 through the feedback filter 4. Then, the coefficient convergence operation is further performed. At the same time, the digital signal output by the update component 2 and the decision module 3 can be received through the feedback component 7, and fed back to the initialization control module 5. According to the judgment result, it is selected whether the initialization operation needs to be performed. The initialization control module 5 is internally provided with a timer 6. By setting the timing threshold, the initialization operation time is limited. If the initialized digital signal does not converge within a certain period of time, it is reinitialized; if it has converged, the output signal is performed.

[0057] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coefficient initialization system for a decision feedback equalizer, characterized in that: include: A feedforward filter (1) is used to receive an input signal and convert the input signal into a digital signal through the feedforward filter (1); The digital signal is subjected to coefficient convergence operation through the updating component (2), so that the introduced coefficient of the digital signal is updated; The updating component (2) transmits the calculated digital signal to the decision module (3), and the decision module (3) makes a judgment on the signal; The decision module (3) converts the signal into an output signal and transmits it, and at the same time performs feedback adjustment processing through a feedback filter (4); The feedback filter (4) transmits the signal to the update component (2) again, and the coefficients are further updated by the update component (2), and are transmitted to the decision module (3) for judgment, until the coefficients meet the requirements and the signal is output again; The initialization control module (5) can receive the coefficient signal of the feedforward filter (1) and perform regulation. The initialization control module (5) is provided with a timer (6) which can limit the coefficient convergence time and can perform coefficient initialization operation, and transmit the initialized coefficient signal to the feedforward filter (1) and the feedback filter (4). At the time when the timer expires, the feedforward filter (1) and the feedback filter (4) are reinitialized in an interleaved manner. A feedback component (7) is used to receive coefficient signals fed back by the update component (2) and the decision module (3); The feedback component (7) is used to transmit the coefficient signal to the initialization control module (5) to perform a coefficient initialization operation.

2. The coefficient initialization system of a decision feedback equalizer according to claim 1, characterized in that: After receiving the coefficient signal, the initialization control module (5) controls the timer (6) to accumulate the clock pulse signal.

3. The coefficient initialization system of a decision feedback equalizer according to claim 1, characterized in that: A threshold is set by the timer (6). After the clock pulse signal is accumulated to the set threshold, convergence is determined by comparing the quantization difference, that is, the difference between the N-bit data of the feedback filter (4) and the quantized result, to see whether it is less than the set threshold.

4. The coefficient initialization system of a decision feedback equalizer according to claim 3, characterized in that: If the quantized difference reaches a certain threshold within a certain time range, it is considered to have converged. If not, the feedforward filter (1) and the feedback filter (4) are restarted to achieve coefficient convergence through the cross coefficient adjustment step.

5. The coefficient initialization system of a decision feedback equalizer according to claim 1, characterized in that: The timer (6) is reset to zero after the pulse signal reaches a set value, and the pulse signal is accumulated again.

6. A coefficient initialization method for a decision feedback equalizer, characterized in that: include: s1: The input signal enters the feedforward filter (1), through which the coefficients are generated and passed to the update component (2) and the initialization control module (5); S2: the initialization control module (5) receives the signal and accumulates the clock pulse signal through the timer (6) to perform timing; the update component (2) receives the coefficient and performs calculation convergence on the coefficient, and transmits the converged coefficient signal to the decision module (3) and the feedback component (7); S3: The decision module (3) receives the feedback signal of the update component (2) to determine whether the coefficient can be output. If yes, the coefficient signal is output. If no, the coefficient signal is transmitted to the feedback filter (4) and the feedback component (7); S4: the feedback filter (4) receives the coefficients and converts them into feedback signals, which are then transmitted to the update component (2) for the next step of updating the coefficients; the feedback component (7) is used to collect information on the coefficients after convergence from the update component (2) and the decision module (3), and feed the information back to the initialization control module (5); S5: After receiving the information from the feedback component (7), the initialization control module (5) makes a judgment with the timer (6). If the coefficients have not converged within the set time, a trigger signal is initialized and sent to the feedforward filter (1) and the feedback filter (4). If the coefficients have converged, the decision module (3) outputs a converged coefficient signal; S6: After receiving the trigger signal, the feedforward filter (1) repeats the above steps until the decision module (3) determines the coefficient of the feedback signal as yes, and outputs a converged coefficient signal.

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