Ultrahigh-order DSM coding mapping method and system based on three-dimensional constellation

Abstract

The invention discloses an ultrahigh-order DSM coding mapping method and system based on a three-dimensional constellation, and belongs to the technical field of Delta-sigma modulation. The mapping method comprises the following steps: performing three-dimensional constellation mapping on bit data, performing dimension reduction processing to obtain a two-dimensional constellation, and obtaining a QAM signal; performing inverse Fourier transform on the obtained QAM signal, and converting a frequency domain signal into a time domain signal; dSM modulation is carried out on the time domain signal, then a low-frequency signal and high-frequency noise are cut off through a low-pass filter, and a DSM signal is output; after the DSM signal is transmitted through a channel, reversely converting the two-dimensional constellation into the three-dimensional constellation again; judging and demodulating the three-dimensional constellation to obtain bit data; according to the method, DSM modulation is carried out on the time domain, the effective resolution of signals and the anti-interference capability of the signals to noise are improved, in constellation mapping, a three-dimensional constellation is used for replacing a two-dimensional constellation, the Euclidean distance between constellation points is increased, and the influence of quantization noise on the signals in DSM modulation is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of Delta-Sigma modulation, and in particular relates to an ultra-high-order DSM coding mapping method and system based on a three-dimensional constellation. Background Art

[0002] In recent years, with the rapid development of technologies such as the Internet, big data, and cloud computing, the fifth generation of communication technology (5G) has been popularized. The popularity of 5G has led to an increasing number of Internet users and a rapid increase in Internet traffic, which has led to an urgent need for larger capacity and higher-speed communication networks. In particular, due to the combination of mobile phones and 5G technology, mobile phones have become more comprehensive and intelligent, and the amount of data used by end users has also increased rapidly, placing higher and higher demands on communication technology.

[0003] Delta-sigma modulation (DSM) can be used to further improve signal transmission quality and signal transmission efficiency. DSM modulation is a digital signal processing technology that is commonly used in analog-to-digital (A / D) and digital-to-analog (D / A) converters, as well as in digital communication systems. DSM modulation adds the original analog signal to the noise and inputs it into an analog integrator that integrates modules such as operational amplifiers and feedback circuits. Over time, the noise will continue to accumulate and gradually convert into high-frequency pulse signals. Through a low-pass filter, these pulse signals are converted into high-precision digital signals for output. In other words, DSM modulation introduces noise and quantizes and oversamples the noise using a high-speed ADC analog-to-digital converter, while applying the negative feedback principle and integration process to improve the digital conversion accuracy of the analog signal, push the noise to the high-frequency range, thereby reducing the impact of noise on the signal, and making the DSM signal have the characteristics of high resolution and high signal-to-noise ratio. The advantage of the DSM modulation principle is that it can achieve different accuracy and speed requirements through different sampling rates and bit depths, and has higher noise resistance and linearity than traditional analog-to-digital conversion technology. Therefore, it is widely used in various industries, medical treatments, communications and other fields.

[0004] However, due to the existence of quantization noise, when demodulating the DSM system, the information has a process of transforming from low-order symbols to high-order symbols, and a small amount of errors will occur in the transformed high-order symbols. As the modulation order increases, the relative minimum Euclidean distance between the two-dimensional constellation points will further decrease, and the probability of erroneous judgment between symbols will inevitably increase, resulting in an increase in the probability of errors in the transformed high-order symbols. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide an ultra-high-order DSM coding mapping method and system based on a three-dimensional constellation, which solves the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A super-high-order DSM coding mapping method based on a three-dimensional constellation comprises the following steps:

[0008] The bit data is mapped to a three-dimensional constellation, and then a dimensionality reduction process is performed to obtain a two-dimensional constellation, and a QAM signal is obtained;

[0009] After inverse Fourier transforming the obtained QAM signal, the frequency domain signal is converted into a time domain signal;

[0010] Perform DSM modulation on the time domain signal, and then use a low-pass filter to cut off the low-frequency signal and high-frequency noise to output the DSM signal;

[0011] After the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely converted into a three-dimensional constellation;

[0012] The three-dimensional constellation is judged and demodulated to obtain bit data.

[0013] Furthermore, the process of the dimensionality reduction process is: after converting the coordinates of the three-dimensional constellation into a long sequence, they are grouped in pairs to form the coordinates of the two-dimensional constellation.

[0014] Furthermore, the expression for inverse Fourier transform of QAM signal is:

[0015]

[0016] Among them, F(ω) represents the frequency domain signal, f(t) represents the time domain signal, and e jωt is a complex exponential function, Represents the integral from negative infinity to positive infinity.

[0017] Furthermore, a fourth-order delta-sigma modulator based on a cascade resonator feedback structure is used to perform DSM modulation on the time domain signal.

[0018] Furthermore, the fourth-order delta-sigma modulator based on the cascade resonator feedback structure includes four integrators, and every two integrators are cascaded together to form a resonator.

[0019] Furthermore, in the three-dimensional constellation decision, the received symbol coordinates are compared with the standard symbol coordinates; by comparing the distance between the received symbol coordinates and the standard coordinates, the standard symbol coordinates closest to the received coordinates are selected as the decision result.

[0020] An ultra-high-order DSM coding mapping system based on a three-dimensional constellation, comprising:

[0021] Dimensionality reduction module: performs 3D constellation mapping on the bit data, then performs dimensionality reduction processing to obtain a 2D constellation and obtain a QAM signal;

[0022] Signal conversion module: After inverse Fourier transform of the obtained QAM signal, the frequency domain signal is converted into a time domain signal;

[0023] DSM modulation module: performs DSM modulation on the time domain signal, and then uses a low-pass filter to cut off the low-frequency signal and high-frequency noise, and outputs the DSM signal;

[0024] Reverse transformation module: After the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely transformed into a three-dimensional constellation;

[0025] And, the decision module: makes a decision on the three-dimensional constellation and demodulates to obtain bit data.

[0026] A computer storage medium stores a readable program, which can execute the above-mentioned ultra-high-order DSM coding mapping method based on three-dimensional constellation when the program is running.

[0027] An electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0028] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the above-mentioned ultra-high-order DSM coding mapping method based on a three-dimensional constellation.

[0029] A computer program product includes computer instructions, wherein the computer instructions instruct a computing device to perform operations corresponding to the above-mentioned ultra-high-order DSM coding mapping method based on a three-dimensional constellation.

[0030] Beneficial effects of the present invention:

[0031] 1. The present invention proposes an ultra-high-order DSM coding mapping method based on a three-dimensional constellation. Through the three-dimensional constellation and DSM modulation, the transmission quality and transmission efficiency are improved in the communication system.

[0032] 2. The present invention performs DSM modulation in the time domain, which improves the effective resolution of the signal and the signal's ability to resist noise interference, so it is more efficient and safer;

[0033] 3. In the constellation mapping, the present invention uses a three-dimensional constellation instead of a two-dimensional constellation, which increases the Euclidean distance between constellation points and reduces the influence of quantization noise on the signal in DSM modulation, so that the signal quality is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 It is the process of the ultra-high-order DSM coding mapping method based on three-dimensional constellation of the present invention;

[0036] Figure 2 It is a schematic diagram of the structure of a fourth-order Delta-Sigma modulator based on a cascade resonator feedback structure of the present invention;

[0037] Figure 3 The two-dimensional and three-dimensional constellation diagrams of 16QAM of the present invention;

[0038] Figure 4 It is the 8 hexagram diagrams of the ultra-high-order three-dimensional constellation of the present invention;

[0039] Figure 5 It is a schematic diagram of dimensionality reduction of a three-dimensional constellation according to the present invention. DETAILED DESCRIPTION

[0040] 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.

[0041] Example 1

[0042] like Figure 1 As shown, a super-high-order DSM coding mapping method based on a three-dimensional constellation includes the following steps:

[0043] S1, perform three-dimensional constellation mapping on the bit data, then perform dimensionality reduction processing to obtain a two-dimensional constellation, and obtain a QAM (Quadrature Amplitude Modulation) signal;

[0044] like Figure 3 As shown in the figure, taking 16QAM as an example, the difference between the two-dimensional constellation diagram and the three-dimensional constellation diagram is shown. Figure 3As shown in the three-dimensional constellation in FIG, the constellation points are set in different shapes according to the different distances between the constellation points and the origin, so that the distribution of the constellation points in the three-dimensional space can be more intuitively seen. The three-dimensional constellation used in the present invention is composed of standard cubic units. The advantage of this is that the distribution of the constellation points is more regular and can meet the conditions of Gray coding.

[0045] In the process of using ultra-high-order three-dimensional constellations for communication, it should be noted that ultra-high-order three-dimensional constellations will contain a large number of constellation points. However, in the current reports on three-dimensional constellations, 16QAM or 32QAM is usually used. The number of constellation points in these schemes is relatively small, so the coordinates of the constellation points can be directly designed to generate a complete three-dimensional constellation. Since the ultra-high-order three-dimensional constellation adopted by the present invention can have the number of symbol points reaching tens of millions, this increases the difficulty of demodulation and judgment at the receiving end. Therefore, the present invention adopts a new three-dimensional constellation design scheme, such as Figure 4 As shown in the figure, the three-dimensional space is divided into 8 hexagrams by the coordinate axis, 8 sub-constellations are generated in each of the 8 hexagrams, and then they are combined into a complete three-dimensional constellation. In this way, the constellation points can be divided into 8 sub-constellations first, and then the constellation points in the 8 sub-constellations are judged, thereby reducing the complexity of the calculation.

[0046] After designing the three-dimensional constellation, the binary bit data stream is first mapped into the constellation symbol. Since the three-dimensional constellation diagram is used, the coordinates of each constellation point are composed of three elements. However, there is an obvious problem, that is, when processing the subsequent transmitting digital signal, the three-dimensional data cannot be directly processed. Therefore, it is necessary to reduce the dimension of the three-dimensional constellation and convert it into a two-dimensional constellation for further processing.

[0047] like Figure 5 As shown, the process of dimensionality reduction processing is to transform the coordinates of the three-dimensional constellation into the coordinates of the two-dimensional constellation through changes, that is, after transforming the coordinates of the three-dimensional constellation into a long sequence, they are grouped in pairs in sequence to form new two-dimensional coordinates;

[0048] It should be noted that Figure 5The display of the three-dimensional constellation and the two-dimensional constellation in the figure cannot represent the corresponding relationship between the coordinates of the three-dimensional point and the two-dimensional point in actual processing. Because in actual situations, the x-axis, y-axis, and z-axis coordinates of the three-dimensional constellation symbol points may be repeated, so after the dimensionality reduction transformation, the types of two-dimensional constellation symbols will not increase. For example, such as (A,A,A), (A,-A,A), (A,A,-A), (A,-A,-A), (-A,A,A), (-A,-A,A), (-A,A,-A), (-A,-A,-A), there are a total of 8 symbol positions in the three-dimensional coordinate system, which are called 8 symbols here. However, after the two-dimensional transformation, it can only generate 4 symbols: (A,A), (A,-A), (-A,A), and (-A,-A). Although the number of occurrences of each symbol will increase, the types of symbols will decrease.

[0049] S2, after performing inverse Fourier transform on the obtained QAM signal, the frequency domain signal is converted into a time domain signal;

[0050] The expression for inverse Fourier transform (IFFT) of QAM signal is:

[0051]

[0052] Among them, F(ω) represents the frequency domain signal, f(t) represents the time domain signal, and e jωt is a complex exponential function, Represents the integral from negative infinity to positive infinity.

[0053] S3, performing DSM modulation on the time domain signal, and then using a low-pass filter to cut off the low-frequency signal and high-frequency noise, and outputting a DSM signal;

[0054] In the present invention, a fourth-order delta-sigma modulator based on a cascade resonator feedback structure is used to perform DSM modulation on the time domain signal; Figure 2 As shown, the fourth-order delta-sigma modulator based on the cascade resonator feedback structure includes four integrators. A resonator can be formed by cascading a 1 / (z-1) integrator and a z / (z-1) integrator.

[0055] The ultra-high-order QAM signal is modulated by a fourth-order delta-sigma modulator. The following two methods are usually used to quantize the ultra-high-order QAM signal:

[0056] 1) Under 1-bit quantization, an on-off keying (OOK) signal is obtained; the density of "1" in the bit signal is positively correlated with the amplitude of the analog signal; when the amplitude of the analog signal is the largest, the DSM outputs continuous "1"; when the amplitude of the analog signal is the smallest, the DSM outputs continuous "0". When the input value is in the middle amplitude, the DSM outputs "0" and "1" at the same time.

[0057] 2) Under 2-bit quantization, the output of DSM is in the form of a PAM4 signal, that is, the output is a signal composed of "±1" and "±3". However, in the process of converting analog signals to digital signals, since the continuously changing signal amplitude is converted into a discretely transformed amplitude, an amplitude error is bound to occur. This error is called quantization noise. Even if the quantization noise is very small in ultra-high-order QAM, it will have a greater impact on the final result. The present invention designs a three-dimensional constellation for symbol decision, which can effectively reduce the negative impact of quantization noise.

[0058] DSM modulation technology introduces noise and uses a high-speed ADC analog-to-digital converter to quantize and oversample the noise. At the same time, it applies the negative feedback principle and integration process to improve the digital conversion accuracy of the analog signal, push the noise to the high-frequency range, and then use a low-pass filter to cleverly cut off the low-frequency signal and high-frequency noise, thereby reducing the impact of noise on the signal, making the DSM signal have the characteristics of high resolution and high signal-to-noise ratio.

[0059] S4, after the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely converted into a three-dimensional constellation;

[0060] The steps to reversely transform a two-dimensional constellation into a three-dimensional constellation are:

[0061] by Figure 5 Taking the two-dimensional and three-dimensional constellations in the example, the coordinates of the two-dimensional constellation symbols are spliced ​​one by one to form a long sequence. Then, this sequence is processed in an orderly manner, and every three coordinate values ​​are grouped together to restore and reconstruct the three-dimensional coordinates.

[0062] S5, judging the three-dimensional constellation and demodulating to obtain bit data.

[0063] During signal transmission, the signal is often interfered by various noises, and the coordinates of these symbols may have certain deviations due to the influence of noise. In order to accurately restore the original signal, it is necessary to judge the received symbol coordinates at the receiving end. In the three-dimensional constellation judgment, the received symbol coordinates are compared with the standard symbol coordinates. By comparing the distance between the received symbol coordinates and the standard coordinates, the standard symbol coordinates closest to the received coordinates are selected as the judgment result. This method can minimize the impact of noise on signal transmission and improve the reliability and accuracy of the communication system.

[0064] Judging the three-dimensional constellation will have a gain in Euclidean distance; in conventional QAM transmission, since high-order symbols are transmitted in the channel, the judgment is greatly affected by channel noise, so the effect of this gain is difficult to reflect. However, in DSM-based ultra-high-order QAM transmission, since low-order symbols are transmitted in the channel, these low-order signals can easily meet the bit error rate of 0. At this time, the source of DSM system bit errors is the conversion process between low-order symbols and high-order symbols, and the factor that has the greatest impact on this process is quantization noise. Even if quantization noise shaping has been performed in DSM, even very small noise in ultra-high-order QAM will have a greater impact on the final result. Using three-dimensional constellations for judgment can effectively reduce the negative impact of quantization noise.

[0065] Based on similar inventive concepts, an embodiment of the present invention further provides a computer storage medium storing a readable program, which can execute the above-mentioned ultra-high-order DSM coding mapping method based on a three-dimensional constellation when the program is running.

[0066] Based on similar inventive concepts, an embodiment of the present invention provides an electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0067] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the above-mentioned ultra-high-order DSM coding mapping method based on a three-dimensional constellation.

[0068] Based on similar inventive concepts, an embodiment of the present invention further provides a computer program product, including computer instructions, which instruct a computing device to perform operations corresponding to the above-mentioned ultra-high-order DSM coding mapping method based on a three-dimensional constellation.

[0069] Example 2

[0070] In this embodiment, a super-high-order DSM coding mapping system based on a three-dimensional constellation is proposed, which specifically includes:

[0071] Dimensionality reduction module: performs 3D constellation mapping on the bit data, then performs dimensionality reduction processing to obtain a 2D constellation and obtain a QAM signal;

[0072] Signal conversion module: After inverse Fourier transform of the obtained QAM signal, the frequency domain signal is converted into a time domain signal;

[0073] DSM modulation module: performs DSM modulation on the time domain signal, and then uses a low-pass filter to cut off the low-frequency signal and high-frequency noise, and outputs the DSM signal;

[0074] Reverse transformation module: After the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely transformed into a three-dimensional constellation;

[0075] And, the decision module: makes a decision on the three-dimensional constellation and demodulates to obtain bit data.

[0076] The method of the present invention may be implemented in hardware, firmware, or as software or computer code that may be stored in a recording medium (such as a CDROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded over a network and will be stored in a local recording medium, so that the method described herein may be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that a computer, processor, microprocessor controller, or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, processor, or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A very high-order DSM coding mapping method based on a three-dimensional constellation, characterized in that: The following steps are involved: The bit data is mapped to a three-dimensional constellation, and then a dimensionality reduction process is performed to obtain a two-dimensional constellation, and a QAM signal is obtained; After inverse Fourier transforming the obtained QAM signal, the frequency domain signal is converted into a time domain signal; Perform DSM modulation on the time domain signal, and then use a low-pass filter to cut off the low-frequency signal and high-frequency noise to output the DSM signal; After the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely converted into a three-dimensional constellation; The three-dimensional constellation is judged and demodulated to obtain bit data.

2. The ultra-high-order DSM coding mapping method based on three-dimensional constellation according to claim 1, characterized in that: The process of the dimensionality reduction process is: after converting the coordinates of the three-dimensional constellation into a long sequence, the three-dimensional constellation coordinates are grouped in pairs to form two-dimensional constellation coordinates.

3. The ultra-high-order DSM coding mapping method based on three-dimensional constellation according to claim 1, characterized in that: The expression for inverse Fourier transform of QAM signal is: Among them, F(ω) represents the frequency domain signal, f(t) represents the time domain signal, and e jωt is a complex exponential function, Represents the integral from negative infinity to positive infinity.

4. The ultra-high-order DSM coding mapping method based on three-dimensional constellation according to claim 1, characterized in that: The time domain signal is DSM modulated using a fourth-order delta-sigma modulator based on a cascaded resonator feedback structure.

5. The ultra-high-order DSM coding mapping method based on three-dimensional constellation according to claim 4, characterized in that: The fourth-order delta-sigma modulator based on the cascade resonator feedback structure includes four integrators, and every two integrators are cascaded together to form a resonator.

6. The ultra-high-order DSM coding mapping method based on three-dimensional constellation according to claim 1, characterized in that: In the three-dimensional constellation decision, the received symbol coordinates are compared with the standard symbol coordinates; by comparing the distance between the received symbol coordinates and the standard coordinates, the standard symbol coordinates closest to the received coordinates are selected as the decision result.

7. An ultra-high-order DSM coding mapping system based on a three-dimensional constellation, characterized in that: include: Dimensionality reduction module: performs 3D constellation mapping on the bit data, then performs dimensionality reduction processing to obtain a 2D constellation and obtain a QAM signal; Signal conversion module: After inverse Fourier transform of the obtained QAM signal, the frequency domain signal is converted into a time domain signal; DSM modulation module: performs DSM modulation on the time domain signal, and then uses a low-pass filter to cut off the low-frequency signal and high-frequency noise, and outputs the DSM signal; Reverse transformation module: After the DSM signal is transmitted through the channel, the two-dimensional constellation is reversely transformed into a three-dimensional constellation; And, the decision module: makes a decision on the three-dimensional constellation and demodulates to obtain bit data.

8. A computer storage medium storing a readable program, characterized in that: When the program is running, it can execute the ultra-high-order DSM coding mapping method based on three-dimensional constellation described in any one of claims 1-6.

9. An electronic device, characterized in that: include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the ultra-high-order DSM coding mapping method based on a three-dimensional constellation as described in any one of claims 1-6.

10. A computer program product comprising computer instructions, characterized in that: The computer instructions instruct the computing device to perform operations corresponding to the ultra-high-order DSM coding mapping method based on a three-dimensional constellation as described in any one of claims 1-6.

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