CTLE adaptive method applied to vehicle-mounted high-speed transmission system

Abstract

The invention discloses a CTLE self-adaption method applied to a vehicle-mounted high-speed transmission system. The CTLE self-adaption method specifically comprises the following steps of (1) CTLE gear division, (2) statistical processing and (3) self-adaption. The CTLE self-adaption method applied to the vehicle-mounted high-speed transmission system is easy to implement, high in convergence speed and good in performance.

Description

Technical Field

[0001] The present invention relates to the field of information transmission technology, and more specifically, to a CTLE self-adaptation method applied to a vehicle-mounted high-speed transmission system. Background Art

[0002] In high-speed transmission systems, CTLE (Continuous time linear equalizer) is usually used to equalize the received analog signal, that is, to boost the mid- and high-frequency losses caused by the insertion loss of the wiring harness, and to improve the demodulation performance of the receiving end through equalization.

[0003] In the vehicle transmission system, due to the different types and lengths of cable harnesses, the harness insertion loss is also different, and the optimal CTLE boost gain corresponding to different channel losses is also different. Therefore, in actual use, it is generally necessary to adaptively select the CTLE gain.

[0004] General SerDes adaptation algorithms such as LMS / SS-LMS are generally not used for CTLE adaptation, and it is difficult to establish a relationship between LMS and CTLE. The ZF / S-ZF adaptation scheme is more commonly used, and S-ZF is a simplified implementation scheme of ZF.

[0005] The traditional S-ZF algorithm adjusts the CTLE Gain to make the ISI based on S-ZF statistics approach zero. That is, if the residual ResISI>0, the CTLE is in the Over Compensated state and the CTLE Gain needs to be reduced. If the residual ResISI<0, the CTLE is in the Under Compensated state and the CTLE Gain needs to be increased. This solution has the advantages of small amount of calculation and simple implementation. However, in the tradition of vehicle transmission systems, the S-ZF solution does not work effectively. Because no matter whether the CTLE Gain is Over or Under, the residual ISI is greater than 0 and there will be no negative values. This makes it impossible to adjust the CTLE Gain through the traditional ResISI-based polarity.

[0006] The traditional S-ZF CTLE adaptive scheme estimates ResISI through a specific Pattern Filtering and makes the residual ISI tend to 0. Generally, h can be calculated based on the residual ISI calculated by S-ZF. -2 、h -1 The ISI of h1, h2, h3, and h4 is the residual ISI of one or two taps before the main mark of the channel impulse response and a few taps after the main mark. The so-called residual ISI tends to 0, which means that h -2 、h-1 , the ISI cumulative value or each value of h1, h2, h3, and h4 tends to 0. Therefore, the traditional S-ZF adaptive solution cannot be used in the vehicle-mounted high-speed transmission system because the minimum value of the residual ISI is not 0. When the CTLE Gain configuration is too large or too small, the residual ISI tends to a larger positive value. Therefore, the traditional S-ZF-based CTLE adaptive solution cannot be used in the vehicle-mounted high-speed transmission system.

[0007] In addition to the S-ZF adaptive solution, there is generally also a CTLE adaptive solution based on Max Eye Opening. The Max Eye Opening-based solution requires a longer training time because the statistical eye height converges slowly after switching the CTLE gear. In addition, the dynamic deviation of the statistical eye height is also relatively large, resulting in a large deviation in the adaptive result and failing to achieve the optimal effect. In addition, the eye height is generally statistically calculated by the EQ module, which results in a higher coupling between the CTLE and EQ modules during implementation, bringing difficulties to both implementation and verification.

[0008] There are also some solutions, such as Spectrum Matching, which are difficult to implement and control because they need to control multiple parameters and need to implement LPF and HPF in Analog.

[0009] Therefore, there is an urgent need to implement a simple, fast-converging, and high-performance in-vehicle high-speed transmission technology. Summary of the invention

[0010] The present invention overcomes the shortcomings of the prior art and provides a CTLE self-adaptation method applied to a vehicle-mounted high-speed transmission system, which is simple to implement, has a fast convergence speed and good performance.

[0011] The technical solution of the present invention is as follows:

[0012] A CTLE adaptive method applied to a vehicle-mounted high-speed transmission system comprises the following steps:

[0013] 1) CTLE gear division step: According to the range of boosting gain supported by CTLE, the gears that need training are divided, that is, the resolution of CTLE gain adaptation is determined according to the row in the CTLE gain range that affects the system performance, and the training time length T required by the residual ResISI statistics of each gear is determined;

[0014] 2) Statistical processing step: for each determined gear, switch CTLE to the corresponding Gain gear, count the residual ResISI value, count the required Training time length T, and record it as the statistical ISI value corresponding to the gear;

[0015] 3) Adaptive step: After completing the statistics of the ResISI value of each gear in step 2), select the appropriate CTLE Gain according to the ResISI value as the adaptive CTLE Gain result;

[0016] The specific method of selecting the appropriate one is: counting the average ResISIAvg of ResISI of all gears, and calculating the threshold to be compared Thres = ResISIAvg*Factor according to ResISIAvg, where Factor is the configured threshold factor; then, according to Thres, selecting the smallest or largest value that is smaller than the threshold as the result of CTLE Gain adaptation, and selecting the smallest or largest value is determined by whether the system tends to have a strategy of making the CTLE Gain larger or smaller.

[0017] Furthermore, when the residual ResISI is counted in step 2), the ResISI is counted based on the S-ZF algorithm, and the ResISI corresponding to several Taps is selected for counting when the ResISI is counted.

[0018] Furthermore, in step 3), the minimum ResISI value is directly selected as the result of CTLE Gain adaptation.

[0019] Furthermore, the GearNum required for training of the CTLE adaptation is calculated according to the dynamic range of the CTLE boosting gain supported by the CTLE circuit and the resolution sensitive to the system performance, and the training time length T of each gear is determined according to the S-ZF convergence time.

[0020] Furthermore, the dynamic range of the Boosting Gain of the CTLE is set to W dB, and the Step of each gear is set to S dB, so that the number of gears GearNum=Ceil(W / S), where Ceil(x) represents the rounding operation on x.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The present invention uses the principle of minimizing the residual ISI of S-ZF to realize CTLE adaptation, so as to achieve the purpose of simple implementation, fast convergence speed and good performance, so that the simple and easy-to-implement S-ZF solution can be effectively used in the vehicle transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a specific process of calculating ResISI based on the S-ZF scheme of the present invention;

[0024] Figure 2 This is a processing example diagram of the S-ZF module of the present invention detecting a received Pattern. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and cannot be used as a limitation of the present invention.

[0026] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0027] The reference numerals of the steps mentioned in each embodiment are only for the convenience of description and have no substantial sequence connection. Different steps in each specific embodiment can be combined in different sequences to achieve the purpose of the invention. In addition, some structures and modules not described in detail in the present invention can be implemented by conventional technical means, so they will not be described in detail.

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] As shown in the figure, in the vehicle transmission system, due to the existence of some unique interferences and non-ideal factors such as NBI, PoC, ToL, CrossTalk, CarNoise, etc., the traditional S-ZF CTLE adaptive solution based on residual ISI tending to 0 cannot be used. Therefore, a CTLE adaptive method for vehicle high-speed transmission system is proposed, which specifically includes the following steps:

[0030] 1) CTLE gear division step: According to the range of boosting gain supported by CTLE, the gears that need training are divided, that is, the resolution of CTLE gain adaptation is determined according to the row in the CTLE gain range that affects the system performance, and the training time length T required by the residual ResISI statistics of each gear is determined;

[0031] The number of gears GearNum required for training of CTLE adaptation is calculated according to the dynamic range of CTLE's BoostingGain supported by the CTLE circuit and the resolution sensitive to system performance. The training time length T of each gear is determined according to the S-ZF convergence time.

[0032] In the setting, the dynamic range of CTLE's BoostingGain is W dB, and the step of each gear is S dB, so the number of gears GearNum = Ceil(W / S), where Ceil(x) represents the rounding operation of x. The training time length T for each gear needs to be determined according to the actual system performance, for example, one gear needs 1ms.

[0033] 2) Statistical processing steps: For the determined number of gears GearNum and each gear Gear, after switching CTLE to the corresponding Gain gear, the residual ResISI value is counted. After counting the required Training time length T, it is recorded as the statistical ISI value corresponding to the gear. That is, for each determined CTLE Gear, switch and configure the CTLE module of Analog so that the Gain of CTLE switches to the corresponding trial gear. After configuration, it is necessary to wait until the behavior of Analog is stable before counting the ResISI value.

[0034] When counting the residual ResISI, the S-ZF algorithm is used to count the ResISI. When counting the ResISI, the ResISI corresponding to several Taps is selected. For example, h -2 、h -1 , h1, h2, h3, etc. If multiple Taps are counted, the residual value of each Tap can be accumulated to improve the accuracy of ResISI. However, the more statistics are counted, the greater the amount of calculation will be.

[0035] Specifically, select a filter pattern. For example, the pattern length is D0 to D6. Different patterns are selected for calculating ResISI of different taps. For example, if ResISI of h4 needs to be calculated, the selected pattern for FP0 is 0,0,1,1,0,1,0, and FP1 is 0,0,1,0,0,1,0.

[0036] When the S-ZF module detects the received Pattern, it determines whether it is FP0 and FP1. If so, ResISI is calculated, h1=E4FP0-E4FP1. In order to simplify the scheme, only the identification information of the error information and the identification information of ResISI are counted, that is, h1=sign(E4)*sign(D3). In this way, the average value of h1 reflects E4FP0-E4FP1, that is, the size of the residual h1.

[0037] When calculating h1 above, the only difference between FP0 and FP1 is D3, so h1 can be calculated. In the actual system, different FP0 and FP1 patterns can be selected to calculate h respectively. -2 、h -1 , h1, h2, h3, etc., the ResISI of different Taps also needs to be accumulated and averaged, and finally the average value of the ResISI corresponding to the CTLE gear is obtained. In actual processing, in order to speed up the convergence of the channel coefficient, more patterns need to be defined. When the pattern length is 7, there are a maximum of 64 groups of patterns, and each group has two patterns that differ by only 1 bit.

[0038] 3) Adaptive step: After completing the statistics of the ResISI value of each gear in step 2), select the appropriate CTLE Gain according to the ResISI value as the adaptive CTLE Gain result;

[0039] The specific method of selecting the appropriate one is: count the average ResISIAvg of ResISI of all gears, and calculate the threshold to be compared Thres = ResISIAvg*Factor according to ResISIAvg, where Factor is the configured threshold factor; then select the smallest or largest value less than the threshold according to Thres as the result of CTLE Gain adaptation, and the selection of the smallest or largest value is determined by whether the system tends to make the CTLE Gain too large or too small. When designing the system, you can also directly select the smallest ResISI value as the result of CTLE Gain adaptation. This will not cause too much error, but the statistical accuracy is slightly lost.

[0040] In summary, this scheme adopts the principle of S-ZF residual ISI minimization to realize CTLE adaptation, achieving a CTLE adaptation method applied to vehicle-mounted high-speed transmission systems with simple implementation, fast convergence speed and good performance.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the concept of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A CTLE adaptive method applied to a vehicle-mounted high-speed transmission system, characterized in that: The specific steps include: 1) CTLE gear division step: According to the range of boosting gain supported by CTLE, the gears that need training are divided, that is, the resolution of CTLE gain adaptation is determined according to the row in the CTLE gain range that affects the system performance, and the training time length T required by the residual ResISI statistics of each gear is determined; 2) Statistical processing step: for each determined gear, switch CTLE to the corresponding Gain gear, count the residual ResISI value, count the required Training time length T, and record it as the statistical ISI value corresponding to the gear; 3) Adaptive step: After completing the statistics of the ResISI value of each gear in step 2), select the appropriate CTLE Gain according to the ResISI value as the adaptive CTLE Gain result; The specific method of selecting the appropriate one is: counting the average ResISIAvg of ResISI of all gears, and calculating the threshold to be compared Thres = ResISIAvg*Factor according to ResISIAvg, where Factor is the configured threshold factor; then, according to Thres, selecting the smallest or largest value that is smaller than the threshold as the result of CTLE Gain adaptation, and selecting the smallest or largest value is determined by whether the system tends to have a strategy of making the CTLE Gain larger or smaller.

2. The CTLE adaptive method for a vehicle-mounted high-speed transmission system according to claim 1, characterized in that: When the residual ResISI is counted in step 2), the ResISI is counted based on the S-ZF algorithm, and the ResISI corresponding to several Taps is selected for counting when the ResISI is counted.

3. The CTLE adaptive method for a vehicle-mounted high-speed transmission system according to claim 1, characterized in that: In step 3), the minimum ResISI value is directly selected as the result of CTLE Gain adaptation.

4. The CTLE adaptive method for a vehicle-mounted high-speed transmission system according to claim 1, characterized in that: The GearNum required for training of CTLE adaptation is calculated based on the dynamic range of CTLE boosting gain supported by the CTLE circuit and the resolution sensitive to system performance. The training time length T of each gear is determined based on the S-ZF convergence time.

5. The CTLE adaptive method for a vehicle-mounted high-speed transmission system according to claim 4, characterized in that: The dynamic range of the Boosting Gain of the CTLE is set to W dB, and the Step of each gear is set to S dB, so that the number of gears GearNum = Ceil(W / S), where Ceil(x) represents the rounding operation on x.

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