Soft demodulation method, soft demodulation apparatus, and demodulation device for QAM modulation

Abstract

The application provides a QAM modulation soft demodulation method, a soft demodulation device and a demodulation equipment. The method comprises the following steps: obtaining a to-be-demodulated signal and noise variance; IQ decomposition is performed on each to-be-demodulated symbol to obtain a plurality of same-direction components and a plurality of orthogonal components; a same-direction component corresponding to each even bit in the to-be-demodulated symbol is calculated according to the same-direction component and each first bit number to obtain a plurality of same-direction component values; an orthogonal component corresponding to each odd bit in the to-be-demodulated symbol is calculated according to the orthogonal component and each second bit number to obtain a plurality of orthogonal component values; a preset threshold value of each bit is obtained by consulting a threshold table according to the noise variance and a third bit number, the preset threshold value of each bit is compared with the same-direction component value or the orthogonal component value, and a soft information statistical value of the corresponding bit is calculated or a first preset value is determined as the soft information statistical value of the corresponding bit. The problem of waste of calculation resources in the prior art QAM soft demodulation method is solved.

Description

Technical Field

[0001] This invention relates to the field of digital signal processing, and more specifically, to a soft demodulation method, soft demodulation apparatus, computer-readable storage medium, and demodulation device for QAM modulation. Background Technology

[0002] Constellation modulation (CEM) involves generating complex symbols from a bitstream of a certain length according to a specific mapping method and transmitting them over the time-frequency resources of a communication system. This improves the spectral efficiency of baseband signal transmission and is a key technology in communication protocols such as 3G, 4G, 5G, and Wi-Fi. As communication speed requirements gradually increase, more and more higher-order modulation schemes are being introduced into systems. The same complex symbol can carry more bitstream information, further improving the system's spectral efficiency, such as 256QAM, 1024QAM, and 4096QAM.

[0003] Existing constellation soft demodulation methods are based on the characteristic that the received symbols follow a Gaussian distribution centered on standard constellation points. By calculating the probability of each bit being decided as a different set, the probability is input into the decoding system, thereby improving the decoding performance of the system.

[0004] Existing technologies only approximate and simplify the soft demodulation algorithm itself, ignoring the fact that in actual systems, the decoder only needs soft information in the range of ±4 to 16. However, the soft information output by the soft demodulation algorithm exceeds this range by a large amount, and saturation processing is required when inputting it into the decoder. Therefore, calculating soft information that exceeds the saturation range results in a large waste of computing resources. Summary of the Invention

[0005] The main objective of this application is to provide a soft demodulation method, soft demodulation device, computer-readable storage medium, and demodulation equipment for QAM modulation, so as to at least solve the problem in the prior art where the soft information statistical value of each bit is calculated, but the range of soft information required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources.

[0006] To achieve the above objectives, according to one aspect of this application, a soft demodulation method for QAM modulation is provided, comprising: acquiring a signal to be demodulated and a noise variance, wherein the signal to be demodulated is a modulated signal received by a receiver, the signal to be demodulated includes multiple symbols to be demodulated, each symbol to be demodulated includes multiple bits, and the noise variance is used to characterize the degree of variation of the symbols to be demodulated; performing IQ decomposition on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components, wherein the quadrature components correspond one-to-one with each symbol to be demodulated, and the in-direction components correspond one-to-one with each symbol to be demodulated; acquiring multiple first bit positions, and calculating the in-direction component corresponding to each even-numbered bit in the symbol to be demodulated based on the in-direction components and each of the first bit positions to obtain multiple in-direction component values, wherein the multiple first bit positions are used to characterize the order of the bits in the even-numbered bits; acquiring multiple second bit positions, and calculating the odd-numbered bit positions in the symbol to be demodulated based on the quadrature components and each of the second bit positions. The orthogonal components corresponding to the bits are used to obtain multiple orthogonal component values, and the multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits; the third bit position is obtained, and a threshold table is consulted according to the noise variance and the third bit position to obtain a preset threshold value for each bit, and the preset threshold value of each bit is compared with the in-direction component value or the orthogonal component value. The threshold table is a mapping table of the noise variance, the third bit position, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit position is used to characterize the order of the bits in the symbol to be demodulated; if the in-direction component value or the orthogonal component value is less than the preset threshold value, the soft information statistical value of the corresponding bit is calculated; if the in-direction component value or the orthogonal component value is greater than the preset threshold value, the first preset value is determined as the soft information statistical value of the corresponding bit.

[0007] Optionally, obtaining a plurality of first bit positions and calculating the commutative component values ​​corresponding to each even-numbered bit in the symbol to be demodulated based on the commutative component and each of the first bit positions includes: obtaining a modulation order and a plurality of first bit positions, wherein the modulation order is the number of bits included in a symbol to be demodulated; and calculating the commutative component values ​​corresponding to each even-numbered bit based on the modulation order, the commutative component, and each of the first bit positions.

[0008] Optionally, multiple second bit positions are obtained, and multiple quadrature component values ​​are obtained by calculating the quadrature component corresponding to each odd-numbered bit in the symbol to be demodulated based on the quadrature component and each second bit position, including: obtaining the modulation order and the second bit position; calculating the quadrature component value corresponding to each even-numbered bit based on the modulation order, the quadrature component and each second bit position.

[0009] Optionally, before obtaining the third bit length and consulting a threshold table based on the noise variance and the third bit length to obtain the preset threshold value for each bit, the method further includes: obtaining multiple demodulated signals and calculating the average soft information of the bits at different third bit lengths in each demodulated signal; obtaining a preset amplitude, which is the minimum theoretical value of the soft information statistics of each bit input to the decoder without degrading the decoding performance of the decoder; and determining the preset threshold value for each bit corresponding to the third bit length based on the preset amplitude, the average soft information statistics, and the noise variance.

[0010] Optionally, acquiring multiple demodulated signals and calculating the average soft information of bits at different third bit positions in each demodulated signal includes: acquiring multiple first QAM images and multiple second QAM images, wherein the first QAM image is a reference image for QAM modulation, the first QAM image includes a soft information reference value for each bit in the demodulated signal, and the second QAM image is an image representation of the demodulated signal, and the QAM image corresponds one-to-one with the demodulated symbol; determining the positional deviation of each bit in the corresponding demodulated signal based on each second QAM image and the first QAM image, and determining the soft information estimate of the bit based on the positional deviation, the soft information reference value, and Gaussian noise; and calculating the average soft information value corresponding to each bit based on the soft information estimate, the Gaussian noise, and the noise variance.

[0011] Optionally, after determining the preset threshold value of the bit corresponding to each of the third bit positions based on the preset amplitude, the average value of the soft information statistics, and the noise variance, the method further includes: generating a noise variance group based on the noise variance and a preset interval, wherein the difference between any two noise variances in the noise variance group is an integer multiple of the preset interval; calculating the preset threshold value of the bit for each of the third bit positions based on each noise variance in the noise variance group, the preset amplitude, and each average value of the soft information; and generating the threshold table based on the noise variance group, the third bit positions, and the preset threshold value.

[0012] Optionally, calculating the soft information statistics of the bit includes: rounding the corresponding unidirectional component value or quadrature component value to obtain a target unidirectional component value or target quadrature component value; and calculating the soft information statistics of the bit based on the target unidirectional component value or target quadrature component value, the unidirectional component value or quadrature component value, and the noise variance.

[0013] According to another aspect of this application, an engine braking control device is provided, the device comprising: a first acquisition unit, configured to acquire a signal to be demodulated and a noise variance, wherein the signal to be demodulated is a modulated signal received by a receiver, the signal to be demodulated includes a plurality of symbols to be demodulated, each symbol to be demodulated includes a plurality of bits, and the noise variance is used to characterize the degree of variation of the symbols to be demodulated; a decomposition unit, configured to perform IQ decomposition on each symbol to be demodulated to obtain a plurality of in-direction components and a plurality of quadrature components, wherein the quadrature components correspond one-to-one with each symbol to be demodulated, and the in-direction components correspond one-to-one with each symbol to be demodulated; a first calculation unit, configured to acquire a plurality of first bit positions, and calculate the in-direction component corresponding to each even-numbered bit in the symbol to be demodulated based on the in-direction components and each of the first bit positions to obtain a plurality of in-direction component values, wherein the plurality of first bit positions are used to characterize the order of the bits in the even-numbered bits; and a second calculation unit, configured to acquire a plurality of second bit positions, and calculate the in-direction component value based on the quadrature components and each of the second bit positions. Each odd-numbered bit in the symbol corresponds to a quadrature component, resulting in multiple quadrature component values. Multiple second bit positions are used to characterize the order of the bit among the odd-numbered bits. A query unit is used to obtain a third bit position and, based on the noise variance and the third bit position, consult a threshold table to obtain a preset threshold value for each bit. The preset threshold value of each bit is compared with the in-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit position, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing decoding performance. The third bit position is used to characterize the order of the bit in the symbol to be demodulated. A third calculation unit is used to calculate the soft information statistical value of the corresponding bit when the in-direction component value or the quadrature component value is less than the preset threshold value. When the in-direction component value or the quadrature component value is greater than the preset threshold value, a first preset value is determined as the soft information statistical value of the corresponding bit.

[0014] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform any of the methods described.

[0015] According to another aspect of this application, a demodulation device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any one of the methods described.

[0016] Applying the technical solution of this application, in the above-mentioned QAM soft demodulation method, firstly, the signal to be demodulated and the noise variance are obtained. The signal to be demodulated is the modulation signal received by the receiver. The signal to be demodulated includes multiple symbols to be demodulated, and each symbol to be demodulated includes multiple bits. The noise variance is used to characterize the degree of variation of the symbols to be demodulated. Then, IQ decomposition is performed on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the symbols to be demodulated, and the in-direction components correspond one-to-one with the symbols to be demodulated. Afterward, multiple first bit positions are obtained, and the in-direction components corresponding to each even-numbered bit in the symbol to be demodulated are calculated based on the in-direction components and each of the first bit positions to obtain multiple in-direction component values. The multiple first bit positions are used to characterize the order of the bits in the even-numbered bits. Afterward, multiple second bit positions are obtained, and the odd-numbered bits in the symbol to be demodulated are calculated based on the quadrature components and each of the second bit positions. The corresponding quadrature components yield multiple quadrature component values, and the multiple second bits are used to represent the order of the bits in the odd-numbered bits. Then, the third bit is obtained, and a preset threshold value for each bit is obtained by consulting a threshold table based on the noise variance and the third bit. The preset threshold value of each bit is compared with the in-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing decoding performance. The third bit is used to represent the order of the bits in the demodulated symbol. Finally, if the in-direction component value or the quadrature component value is less than the preset threshold value, the soft information statistical value of the corresponding bit is calculated. If the in-direction component value or the quadrature component value is greater than the preset threshold value, the first preset value is determined as the soft information statistical value of the corresponding bit. The soft demodulation method of this application compares the in-direction component value or quadrature component value corresponding to each bit in the signal to be demodulated with a preset threshold during demodulation. If the value exceeds the preset threshold, saturation output is performed. If the value does not exceed the threshold, the soft information statistical value of the bit is calculated. This solves the problem in the prior art that the soft information statistical value is calculated for each bit, but the soft information range required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources. Attached Figure Description

[0017] Figure 1 A hardware block diagram of a mobile terminal performing a soft demodulation method for QAM modulation according to an embodiment of this application is shown.

[0018] Figure 2 A schematic flowchart of a soft demodulation method for QAM modulation provided according to an embodiment of this application is shown;

[0019] Figure 3 A flowchart illustrating the algorithm of a specific QAM modulation soft demodulation method according to an embodiment of this application is shown.

[0020] Figure 4 A structural block diagram of a QAM modulation soft demodulation device provided according to an embodiment of this application is shown.

[0021] The above figures include the following reference numerals:

[0022] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0027] IQ decomposition: refers to a modulation method in digital communication that decomposes an analog signal into components that are in the same direction as the vector direction and orthogonal components that are at 90° to the vector direction in a vector diagram.

[0028] As described in the background section, existing technologies only approximate and simplify the soft demodulation algorithm itself, ignoring the fact that in actual systems, the decoder only needs soft information within a range of ±4 to 16. However, the soft information output by the soft demodulation algorithm exceeds this range significantly, requiring saturation processing when input to the decoder. Therefore, calculating soft information beyond the saturation range results in a significant waste of computational resources. To address the problem of computational resource waste caused by calculating the statistical value of soft information for each bit in existing technologies, where the range of soft information required by the decoder is far lower than the calculated statistical value, embodiments of this application provide a QAM modulation soft demodulation method, a soft demodulation device, a computer-readable storage medium, and a demodulation equipment.

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal using a QAM modulation soft demodulation method according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0031] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the device information display method in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the aforementioned networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0032] This embodiment provides a soft demodulation method for QAM modulation that runs on a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although the logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] Figure 2 This is a flowchart of a soft demodulation method for QAM modulation according to an embodiment of this application. Figure 2 As shown, the method includes the following steps:

[0034] Step S201: Obtain the demodulated signal and noise variance. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0035] Specifically, the above-mentioned signal to be demodulated is acquired, and the corresponding modulation method and the noise variance of the current signal transmission environment are determined.

[0036] Step S202: Perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0037] Specifically, the above-mentioned signal to be demodulated is subjected to IQ decomposition, that is, each symbol to be demodulated in the above-mentioned signal to be demodulated is decomposed to obtain the in-phase component and the quadrature component corresponding to the imaginary part and the real part, respectively. That is, the in-phase component r is obtained by decomposing the symbol to be demodulated r. I and orthogonal components r Q .

[0038] In practical implementation, the CPU is configured to set the same-direction component r I and orthogonal components r Q Assign values ​​to β respectively I and β Q That is, β I =r I ,β Q =r Q .

[0039] Step S203: Obtain multiple first bit positions, and calculate the same-direction component corresponding to each even-number bit in the symbol to be demodulated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-number bits.

[0040] Specifically, the value of the in-direction component obtained by decomposition corresponds to the first even-numbered bit in the symbol to be demodulated. Then, based on the number of bits of the first bit and the in-direction component, the in-direction component corresponding to each even-numbered bit can be recursively deduced, thus obtaining the above multiple in-direction component values.

[0041] Step S204: Obtain multiple second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0042] Specifically, the value of the orthogonal component obtained by decomposition corresponds to the first odd-numbered bit in the symbol to be demodulated. Then, based on the number of bits of the second bit and the orthogonal component, the orthogonal component corresponding to each odd-numbered bit can be recursively derived, thus obtaining the above-mentioned multiple orthogonal component values.

[0043] Step S205: Obtain the third bit length, and look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the demodulated symbol.

[0044] Specifically, during the demodulation and decoding of QAM modulated signals, the actual soft information value obtained by demodulation is much larger than the soft information value required by the decoder to ensure that the decoding performance does not degrade. Therefore, in order to reduce the computational load, this application sets an upper limit for the soft information value of the bit input to the decoder corresponding to different third bits under different noise variance signal transmission environments, namely the preset threshold value.

[0045] Step S206: If the value of the same-direction component or the value of the quadrature component are less than the preset threshold, calculate the soft information statistical value of the corresponding bit; if the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, determine the first preset value as the soft information statistical value of the corresponding bit.

[0046] Specifically, if the value of the same-direction component or the value of the quadrature component are less than the preset threshold, it means that the soft information value after the demodulation of the bit will not exceed the preset threshold. Therefore, in order to ensure the decoding quality, it is necessary to calculate the specific soft information statistics value corresponding to the bit. If the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, saturation output is performed, that is, the soft information statistics value corresponding to the threshold value is output.

[0047] In this embodiment, firstly, the signal to be demodulated and the noise variance are obtained. The signal to be demodulated is the modulated signal received by the receiver. The signal to be demodulated includes multiple symbols to be demodulated, each symbol including multiple bits. The noise variance is used to characterize the degree of variation of the symbols to be demodulated. Then, IQ decomposition is performed on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the symbols to be demodulated, and the in-direction components correspond one-to-one with the symbols to be demodulated. Next, multiple first bit positions are obtained, and the in-direction components corresponding to each even-numbered bit in the symbol to be demodulated are calculated based on the in-direction components and the first bit positions to obtain multiple in-direction component values. The multiple first bit positions are used to characterize the order of the bits in the even-numbered bits. Next, multiple second bit positions are obtained, and the quadrature components corresponding to each odd-numbered bit in the symbol to be demodulated are calculated based on the quadrature components and the second bit positions. Multiple orthogonal component values ​​are obtained, and the multiple second bit values ​​are used to represent the order of the bits in the odd-numbered bits. Then, the third bit value is obtained, and a preset threshold value for each bit is obtained by consulting a threshold table based on the noise variance and the third bit value. The preset threshold value of each bit is compared with the in-direction component value or the orthogonal component value. The threshold table is a mapping table of the noise variance, the third bit value, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit value is used to represent the order of the bits in the demodulated symbol. Finally, if the in-direction component value or the orthogonal component value is less than the preset threshold value, the soft information statistical value of the corresponding bit is calculated. If the in-direction component value or the orthogonal component value is greater than the preset threshold value, the first preset value is determined as the soft information statistical value of the corresponding bit. The soft demodulation method of this application compares the in-direction component value or quadrature component value corresponding to each bit in the signal to be demodulated with a preset threshold during demodulation. If the value exceeds the preset threshold, saturation output is performed. If the value does not exceed the threshold, the soft information statistical value of the bit is calculated. This solves the problem in the prior art that the soft information statistical value is calculated for each bit, but the soft information range required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources.

[0048] In order to recursively deduce the in-direction components corresponding to each bit in the symbol to be demodulated based on the first bit length, in an optional embodiment, step S203 includes:

[0049] Step S2031: Obtain the modulation order and the number of bits of the first bit, wherein the modulation order is the number of bits included in a symbol to be demodulated.

[0050] Specifically, the modulation order and the order of each even-numbered bit in the demodulated symbol are obtained, i.e., the number of bits in the first bit.

[0051] Step S2032: Calculate the value of the same-direction component corresponding to each even-numbered bit based on the modulation order, the same-direction component, and the number of bits of each first bit.

[0052] Specifically, based on the above-mentioned in-direction component corresponding to the first bit with a number of bits, the above-mentioned modulation order, and the above-mentioned number of bits of the first bit, the in-direction components corresponding to the second even-numbered bits, the third even-numbered bits, and so on up to all even-numbered bits can be recursively derived, and the formula is as follows:

[0053] β I，i =-|β I,i-1 +2 (m / 2-i) ,

[0054] Where i is the number of bits in the first bit and m is the modulation order.

[0055] In order to deduce the corresponding in-direction components of each bit in the demodulated symbol based on the second bit length, in an optional implementation, step S204 includes:

[0056] Step S2041: Obtain the modulation order and the number of bits for the second bit.

[0057] Specifically, the modulation order and the order of each odd-numbered bit in the above-mentioned demodulated symbol are obtained, i.e., the number of bits in the second bit.

[0058] Step S2042: Calculate the quadrature component value corresponding to each even-numbered bit based on the modulation order, the quadrature component, and the number of bits of each second bit.

[0059] Specifically, based on the above-mentioned in-direction component corresponding to the first bit with a number of bits, the above-mentioned modulation order, and the above-mentioned number of bits of the first bit, the in-direction components corresponding to the second even-numbered bits, the third even-numbered bits, and so on up to all even-numbered bits can be recursively derived, and the formula is as follows:

[0060] β Q，i =-|β Q,i-1 +2 (m / 2-i) ,

[0061] Where i represents the number of bits in the second bit above.

[0062] In order to obtain the preset threshold value of each bit corresponding to the third bit, in an optional embodiment, before obtaining the third bit and looking up the threshold table based on the noise variance and the third bit, the method further includes:

[0063] Step S301: Acquire multiple signals to be demodulated and calculate the average soft information of the bits of each signal to be demodulated at different third bit positions.

[0064] Specifically, based on the characteristics of QAM modulation, it can be deduced that the lengths of all signals to be demodulated are consistent. By calculating the soft information value corresponding to each bit of each of the above-mentioned signals to be demodulated, the average value of the above-mentioned soft information corresponding to different numbers of the above-mentioned third bit can be determined.

[0065] Step S302: Obtain a preset amplitude value. The preset amplitude value is the minimum theoretical value of the soft information statistics of each bit input to the decoder without reducing the decoding performance of the decoder.

[0066] Specifically, the aforementioned preset amplitude is the decoding limiting requirement of the decoder, which is determined by the different types of decoders. That is, if the soft information value of a single bit exceeds the aforementioned preset amplitude, inputting only the soft information of the aforementioned amplitude will ensure that the decoding quality of that bit is not compromised.

[0067] Step S302: Determine the preset threshold value of the bit corresponding to each of the third bit positions based on the preset amplitude, the average value of the soft information statistics, and the noise variance.

[0068] Specifically, let the above preset amplitude be [-LLR]. mx ,LLR mx The preset threshold value corresponding to each of the above-mentioned third bits can be determined by the statistical average and noise variance of each bit position according to the following formula:

[0069]

[0070] Where D is the data bit width determined based on the performance of the data transmission system itself.

[0071] In order to calculate the average soft information corresponding to different third bit lengths, in an optional implementation, step S301 above includes:

[0072] Step S3011: Acquire multiple first QAM images and multiple second QAM images. The first QAM image is a reference image for QAM modulation. The first QAM image includes the soft information reference value of each bit in the signal to be demodulated. The second QAM image is an image representation of the signal to be demodulated. The QAM images correspond one-to-one with the symbols to be demodulated.

[0073] Specifically, in the QAM modulation process, the discrete modulation state after the analog signal is converted into a digital signal is displayed on the vector diagram as constellation points. The image formed by the constellation points corresponding to the discrete modulation state of a signal to be demodulated is the constellation diagram, namely the first QAM image and the second QAM image mentioned above. The first QAM image is the reference image before signal transmission, and the second QAM image is the image after offset after channel transmission.

[0074] Step S3012: Determine the position deviation of each bit in the corresponding demodulated signal based on each of the second QAM images and the first QAM image, and determine the soft information estimate of the bit based on the position deviation, the soft information reference value and Gaussian noise.

[0075] Specifically, based on the constellation points corresponding to each bit in the first and second QAM images, the positional deviation of each bit after transmission can be determined. Then, the soft information value after transmission can be calculated based on the soft information value of the reference image. Let s be the value at reference coordinate axis p corresponding to the real or imaginary part of the signal to be demodulated. p After passing through Gaussian noise n i The received value is β. ip Then we have β ip =s p +n i , where s p ∈[-(2 m / 2 -1),(2 m / 2 -1)],p∈[-2 m / 2-1 ,2 m / 2-1 Furthermore, when the demodulation position p corresponds to bit b... i The formula for the above soft information estimation value is as follows:

[0076]

[0077] Step S3013: Calculate the average value of the soft information corresponding to each bit based on the soft information estimate, the Gaussian noise, and the noise variance.

[0078] Specifically, based on the demodulation principle of QAM modulation, β is determined. ip The nearest standard constellation point (s0, s1) corresponding to the nearest decision bits of 0 and 1 is determined as follows: Furthermore, the above-mentioned average value of soft information is calculated as follows:

[0079]

[0080] To obtain the aforementioned threshold table, in one optional implementation, after determining the preset threshold value for each of the aforementioned third bit positions based on the aforementioned preset amplitude, the aforementioned soft information statistical average value, and the aforementioned noise variance, the method further includes:

[0081] Step S401: Generate a noise variance set based on the noise variance and the preset interval, wherein the difference between any two noise variances in the noise variance set is an integer multiple of the preset interval.

[0082] Specifically, based on the aforementioned noise variance, multiple noise variances are obtained by taking values ​​at preset intervals, thus obtaining the aforementioned noise variance set.

[0083] Step S402: Calculate the preset threshold value of the bit for each of the third bit bits based on the noise variance, the preset amplitude, and the average value of each of the soft information in the noise variance group.

[0084] Specifically, by substituting each noise variance in the above noise variance group into the above formula, the preset threshold value of each third bit number corresponding to different noise variance environments is obtained.

[0085] Step S403: Generate the threshold table based on the noise variance group, the third bit length, and the preset threshold value.

[0086] Specifically, the threshold table is obtained by drawing a table based on the correspondence between the noise variance, the number of bits of the third bit, and the preset threshold value.

[0087] In one embodiment of this application, the threshold table is shown in Table 1, where the noise variance is expressed in the form of signal-to-noise ratio (SNR), and the conversion relationship is SNR = 10log10(P / σ). 2 ), where P is the signal power.

[0088] Table 1

[0089]

[0090] To simplify the calculation of the aforementioned soft information statistics, in an optional implementation, step S206 includes:

[0091] Step S2061: Round the above-mentioned same-direction component value or the above-mentioned quadrature component value corresponding to the above-mentioned bit to obtain the target same-direction component value or the target quadrature component value.

[0092] Specifically, to simplify the calculation process of the aforementioned soft information statistical values, this application proposes a new simplified calculation method. First, the values ​​of the same-direction components or the orthogonal components corresponding to the aforementioned bits are rounded down, i.e., β... I / QThe integer part is assigned to γ, i.e., γ = |β i | [m / 2-1:1] , where i is the number of bits in the third bit.

[0093] Step S2062: Calculate the soft information statistics of the bit based on the target in-direction component value or the target quadrature component value, the in-direction component value or the quadrature component value and the noise variance.

[0094] Specifically, the formula for calculating the above-mentioned soft information statistics is as follows:

[0095]

[0096] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the soft demodulation method of QAM modulation in this application will be described in detail below with reference to specific embodiments.

[0097] This embodiment relates to a specific soft demodulation method for QAM modulation, such as... Figure 3 As shown, it includes the following steps:

[0098] Step S1: In the decoding device, assign the in-direction component and quadrature component of the symbol r to be demodulated to two internal registers β respectively. I ,β Q :β I =r I ;β Q =r Q .

[0099] Step S2: Configure the QAM modulation pattern order m of the decoding device, and then configure the number of cycles to m / 2. Configure the count i in the counter to 0, obtain the preset threshold value Ai for each bit, and the preset amplitude value LLR corresponding to the decoder. mx .

[0100] Step S3: For the i-th iteration, obtain the sign and absolute value of the input symbol by taking the modulus and the sign, respectively, i.e., S. I =sign(β) I ),S Q =sign(β) Q ),|β I |,|β Q |

[0101] Step S4: Based on the values ​​of the I-path and Q-path, calculate the values ​​for the 2i-th and 2i+1-th bits respectively, and then determine the relationship between the calculated value and the threshold value respectively;

[0102] Step S5: When the calculated value is less than the threshold, assign the integer bits of the calculated value to the internal register γ, and then calculate using the calculator:

[0103] LLR(b 2i )=-2S I / σ 2 (|β I |-γ)(γ+1) or LLR(b 2i+1 )=-2S Q / σ 2 (|β Q |-γ)(γ+1);

[0104] Step S6: When the calculated value is greater than the threshold value, directly output LLR(b) 2i ) = S I *LLR mx or LLR(b 2i+1 ) = S Q *LLR mx ;

[0105] Step S7, update register value β I ,β Q :β I =-|β I +2 m / 2-i and β Q =-|β Q +2 m / 2-i Update counter i: i = i + 1 and check if i meets the loop termination condition i = m / 2 - 1. If not, continue the loop; if so, end the soft demodulation of the current symbol to be demodulated.

[0106] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0107] This application also provides a soft demodulation device for QAM modulation. It should be noted that the soft demodulation device for QAM modulation in this application can be used to execute the soft demodulation method for QAM modulation provided in this application. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0108] The following describes the soft demodulation device for QAM modulation provided in the embodiments of this application.

[0109] Figure 4This is a structural block diagram of a soft demodulation device for QAM modulation according to an embodiment of this application. Figure 4 As shown, the device includes:

[0110] The first acquisition unit 10 is used to acquire the demodulated signal and the noise variance. The demodulated signal is the modulation signal received by the receiving end. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0111] Specifically, the above-mentioned signal to be demodulated is acquired, and the corresponding modulation method and the noise variance of the current signal transmission environment are determined.

[0112] The decomposition unit 20 is used to perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0113] Specifically, the above-mentioned signal to be demodulated is subjected to IQ decomposition, that is, each symbol to be demodulated in the above-mentioned signal to be demodulated is decomposed to obtain the in-phase component and the quadrature component corresponding to the imaginary part and the real part, respectively. That is, the in-phase component r is obtained by decomposing the symbol to be demodulated r. I and orthogonal components r Q .

[0114] In practical implementation, the CPU is configured to set the same-direction component r I and orthogonal components r Q Assign values ​​to β respectively I and β Q That is, β I =r I ,β Q =r Q .

[0115] The first calculation unit 30 is used to obtain a plurality of first bit positions, and calculate the corresponding first bit position of each even bit in the demodulated symbol according to the first bit position and the first bit position to obtain a plurality of first bit position values. The plurality of first bit positions are used to characterize the order of the bit in the even bit position.

[0116] Specifically, the value of the in-direction component obtained by decomposition corresponds to the first even-numbered bit in the symbol to be demodulated. Then, based on the number of bits of the first bit and the in-direction component, the in-direction component corresponding to each even-numbered bit can be recursively deduced, thus obtaining the above multiple in-direction component values.

[0117] The second calculation unit 40 is used to obtain a plurality of second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain a plurality of orthogonal component values. The plurality of second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0118] Specifically, the value of the orthogonal component obtained by decomposition corresponds to the first odd-numbered bit in the symbol to be demodulated. Then, based on the number of bits of the second bit and the orthogonal component, the orthogonal component corresponding to each odd-numbered bit can be recursively derived, thus obtaining the above-mentioned multiple orthogonal component values.

[0119] The query unit 50 is used to obtain the third bit number, and to look up the threshold table according to the noise variance and the third bit number to obtain the preset threshold value of each bit, and to compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit number, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit number is used to characterize the order of the bit in the symbol to be demodulated.

[0120] Specifically, during the demodulation and decoding of QAM modulated signals, the actual soft information value obtained by demodulation is much larger than the soft information value required by the decoder to ensure that the decoding performance does not degrade. Therefore, in order to reduce the computational load, this application sets an upper limit for the soft information value of the bit input to the decoder corresponding to different third bits under different noise variance signal transmission environments, namely the preset threshold value.

[0121] The third calculation unit 60 is used to calculate the soft information statistical value of the corresponding bit when the value of the same direction component or the value of the quadrature component is less than the preset threshold value, and to determine the first preset value as the soft information statistical value of the corresponding bit when the value of the same direction component or the value of the quadrature component is greater than the preset threshold value.

[0122] Specifically, if the value of the same-direction component or the value of the quadrature component are less than the preset threshold, it means that the soft information value after the demodulation of the bit will not exceed the preset threshold. Therefore, in order to ensure the decoding quality, it is necessary to calculate the specific soft information statistics value corresponding to the bit. If the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, saturation output is performed, that is, the soft information statistics value corresponding to the threshold value is output.

[0123] In this embodiment, the first acquisition unit acquires the signal to be demodulated and the noise variance. The signal to be demodulated is the modulated signal received by the receiver. The signal to be demodulated includes multiple symbols to be demodulated, each symbol including multiple bits. The noise variance is used to characterize the degree of variation of the symbols to be demodulated. The decomposition unit performs IQ decomposition on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the symbols to be demodulated, and the in-direction components correspond one-to-one with the symbols to be demodulated. The first calculation unit acquires multiple first bit positions and calculates the in-direction component corresponding to each even-numbered bit in the symbol to be demodulated based on the in-direction components and the first bit positions to obtain multiple in-direction component values. The multiple first bit positions are used to characterize the order of the bits in the even-numbered bits. The second calculation unit acquires multiple second bit positions and calculates the in-direction component corresponding to each odd-numbered bit in the symbol to be demodulated based on the quadrature components and the second bit positions to obtain multiple in-direction component values. The intersection component yields multiple orthogonal component values, and the multiple second bit positions are used to represent the order of the bits in the odd-numbered bits; the query unit obtains the third bit position, and according to the noise variance and the third bit position, consults the threshold table to obtain the preset threshold value of each bit, and compares the preset threshold value of each bit with the same-direction component value or the orthogonal component value, the threshold table is a mapping table of the noise variance, the third bit position, and the preset threshold value, the preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance, and the third bit position is used to represent the order of the bits in the demodulated symbol; the third calculation unit calculates the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is less than the preset threshold value, and determines the first preset value as the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is greater than the preset threshold value. The soft demodulation method of this application compares the in-direction component value or quadrature component value corresponding to each bit in the signal to be demodulated with a preset threshold during demodulation. If the value exceeds the preset threshold, saturation output is performed. If the value does not exceed the threshold, the soft information statistical value of the bit is calculated. This solves the problem in the prior art that the soft information statistical value is calculated for each bit, but the soft information range required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources.

[0124] In order to recursively deduce the in-direction components corresponding to each bit in the demodulated symbol based on the first bit length, in an optional embodiment, the first calculation unit includes:

[0125] The first acquisition module is used to acquire the modulation order and the number of bits of the first bit, wherein the modulation order is the number of bits included in a symbol to be demodulated.

[0126] Specifically, the modulation order and the order of each even-numbered bit in the demodulated symbol are obtained, i.e., the number of bits in the first bit.

[0127] The first calculation module is used to calculate the value of the same-direction component corresponding to each even-numbered bit based on the modulation order, the same-direction component, and the number of bits of each first bit.

[0128] Specifically, based on the above-mentioned in-direction component corresponding to the first bit with a number of bits, the above-mentioned modulation order, and the above-mentioned number of bits of the first bit, the in-direction components corresponding to the second even-numbered bits, the third even-numbered bits, and so on up to all even-numbered bits can be recursively derived, and the formula is as follows:

[0129] β I，i =-|β I,i-1 +2 (m / 2-i) ,

[0130] Where i is the number of bits in the first bit and m is the modulation order.

[0131] In order to recursively deduce the corresponding in-direction components of each bit in the demodulated symbol based on the second bit length, in an optional embodiment, the second calculation unit includes:

[0132] The second acquisition module is used to acquire the modulation order and the second bit number;

[0133] Specifically, the modulation order and the order of each odd-numbered bit in the above-mentioned demodulated symbol are obtained, i.e., the number of bits in the second bit.

[0134] The second calculation module is used to calculate the quadrature component value corresponding to each even-numbered bit based on the modulation order, the quadrature component, and the number of bits of each second bit.

[0135] Specifically, based on the above-mentioned in-direction component corresponding to the first bit with a number of bits, the above-mentioned modulation order, and the above-mentioned number of bits of the first bit, the in-direction components corresponding to the second even-numbered bits, the third even-numbered bits, and so on up to all even-numbered bits can be recursively derived, and the formula is as follows:

[0136] β Q，i =-|β Q,i-1 +2 (m / 2-i) ,

[0137] Where i represents the number of bits in the second bit above.

[0138] In order to obtain the preset threshold value of the bit corresponding to each of the aforementioned third bit positions, in an optional embodiment, the above-mentioned device further includes:

[0139] The second acquisition unit is used to acquire multiple signals to be demodulated and calculate the average soft information of the bits with different numbers of the third bit in each signal to be demodulated before acquiring the third bit number and looking up the threshold table according to the noise variance and the third bit number to obtain the preset threshold value of each bit.

[0140] Specifically, based on the characteristics of QAM modulation, it can be deduced that the lengths of all signals to be demodulated are consistent. By calculating the soft information value corresponding to each bit of each of the above-mentioned signals to be demodulated, the average value of the above-mentioned soft information corresponding to different numbers of the above-mentioned third bit can be determined.

[0141] The third acquisition unit is used to acquire a preset amplitude, which is the minimum theoretical value of the soft information statistics of each bit input to the decoder without reducing the decoding performance of the decoder.

[0142] Specifically, the aforementioned preset amplitude is the decoding limiting requirement of the decoder, which is determined by the different types of decoders. That is, if the soft information value of a single bit exceeds the aforementioned preset amplitude, inputting only the soft information of the aforementioned amplitude will ensure that the decoding quality of that bit is not compromised.

[0143] The fourth calculation unit is used to determine the preset threshold value of the bit corresponding to each of the third bit positions based on the preset amplitude, the average value of the soft information statistics, and the noise variance.

[0144] Specifically, let the above preset amplitude be [-LLR]. mx ,LLR mx The preset threshold value corresponding to each of the above-mentioned third bits can be determined by the statistical average and noise variance of each bit position according to the following formula:

[0145]

[0146] Where D is the data bit width determined based on the performance of the data transmission system itself.

[0147] In order to calculate the average soft information corresponding to different third bit lengths, in one optional implementation, the second acquisition unit includes:

[0148] The third acquisition module is used to acquire multiple first QAM images and multiple second QAM images. The first QAM image is a reference image for QAM modulation. The first QAM image includes the soft information reference value of each bit in the signal to be demodulated. The second QAM image is an image representation of the signal to be demodulated. The QAM image corresponds one-to-one with the symbol to be demodulated.

[0149] Specifically, in the QAM modulation process, the discrete modulation state after the analog signal is converted into a digital signal is displayed on the vector diagram as constellation points. The image formed by the constellation points corresponding to the discrete modulation state of a signal to be demodulated is the constellation diagram, namely the first QAM image and the second QAM image mentioned above. The first QAM image is the reference image before signal transmission, and the second QAM image is the image after offset after channel transmission.

[0150] The third calculation module is used to determine the position deviation of each bit in the corresponding demodulated signal based on each of the second QAM images and the first QAM image, and to determine the soft information estimate of the bit based on the position deviation, the soft information reference value and Gaussian noise.

[0151] Specifically, based on the constellation points corresponding to each bit in the first and second QAM images, the positional deviation of each bit after transmission can be determined. Then, the soft information value after transmission can be calculated based on the soft information value of the reference image. Let s be the value at reference coordinate axis p corresponding to the real or imaginary part of the signal to be demodulated. p After passing through Gaussian noise n i The received value is β. ip Then we have β ip =s p +n i , where s p ∈[-(2 m / 2 -1),(2 m / 2 -1)],p∈[-2 m / 2-1 ,2 m / 2-1 Furthermore, when the demodulation position p corresponds to bit b... i The formula for the above soft information estimation value is as follows:

[0152]

[0153] The fourth calculation module is used to calculate the average value of the soft information corresponding to each bit based on the soft information estimate, the Gaussian noise, and the noise variance.

[0154] Specifically, based on the demodulation principle of QAM modulation, β is determined. ip The nearest standard constellation point (s0, s1) corresponding to the nearest decision bits of 0 and 1 is determined as follows: Furthermore, the above-mentioned average value of soft information is calculated as follows:

[0155]

[0156] To obtain the aforementioned threshold table, in one optional embodiment, the apparatus further includes:

[0157] The first generation unit is configured to, after determining the preset threshold value of the bit corresponding to each of the third bit bits based on the preset amplitude, the above-mentioned soft information statistical average value and the above-mentioned noise variance, generate a noise variance group based on the noise variance and the preset interval, wherein the difference between any two noise variances in the noise variance group is an integer multiple of the preset interval.

[0158] Specifically, based on the aforementioned noise variance, multiple noise variances are obtained by taking values ​​at preset intervals, thus obtaining the aforementioned noise variance set.

[0159] The fifth calculation unit is used to calculate the preset threshold value of each of the third bit bits based on the noise variance of each of the noise variance groups, the preset amplitude and the average value of each of the soft information.

[0160] Specifically, by substituting each noise variance in the above noise variance group into the above formula, the preset threshold value of each third bit number corresponding to different noise variance environments is obtained.

[0161] The second generation unit is used to generate the threshold table based on the noise variance group, the third bit length, and the preset threshold value.

[0162] Specifically, the threshold table is obtained by drawing a table based on the correspondence between the noise variance, the number of bits of the third bit, and the preset threshold value.

[0163] In one embodiment of this application, the threshold table is shown in Table 1, where the noise variance is expressed in the form of signal-to-noise ratio (SNR), and the conversion relationship is SNR = 10log10(P / σ). 2 ), where P is the signal power.

[0164] Table 1

[0165]

[0166] To simplify the calculation of the aforementioned soft information statistics, in an optional implementation, step S206 includes:

[0167] The fifth calculation module is used to round the above-mentioned same-direction component value or the above-mentioned quadrature component value corresponding to the above-mentioned bit to obtain the target same-direction component value or the target quadrature component value.

[0168] Specifically, to simplify the calculation process of the aforementioned soft information statistical values, this application proposes a new simplified calculation method. First, the values ​​of the same-direction components or the orthogonal components corresponding to the aforementioned bits are rounded down, i.e., β... I / Q The integer part is assigned to γ, i.e., γ = |β i |[m / 2-1:1] , where i is the number of bits in the third bit.

[0169] The sixth calculation module is used to calculate the soft information statistical value of the bit based on the target in-direction component value or the target quadrature component value, the in-direction component value or the quadrature component value and the noise variance.

[0170] Specifically, the formula for calculating the above-mentioned soft information statistics is as follows:

[0171]

[0172] The aforementioned QAM modulation soft demodulation device includes a processor and a memory. The first acquisition unit, decomposition unit, first calculation unit, second calculation unit, query unit, and third calculation unit are all stored as program units in the memory. The processor executes these program units stored in the memory to implement their respective functions. All of the above modules reside in the same processor; alternatively, the modules may be located in different processors in any combination.

[0173] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured; adjusting kernel parameters can reduce the complexity of demodulation calculations and decrease computational resource consumption.

[0174] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0175] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the QAM modulation soft demodulation method.

[0176] Specifically, soft demodulation methods for QAM modulation include:

[0177] Step S201: Obtain the demodulated signal and noise variance. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0178] Step S202: Perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0179] Step S203: Obtain multiple first bit positions, and calculate the same-direction component corresponding to each even-number bit in the symbol to be demodulated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-number bits.

[0180] Step S204: Obtain multiple second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0181] Step S205: Obtain the third bit length, and look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the demodulated symbol.

[0182] Step S206: If the value of the same-direction component or the value of the quadrature component are less than the preset threshold, calculate the soft information statistical value of the corresponding bit; if the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, determine the first preset value as the soft information statistical value of the corresponding bit.

[0183] This invention provides a processor for running a program, wherein the program executes the aforementioned soft demodulation method for QAM modulation.

[0184] Specifically, soft demodulation methods for QAM modulation include:

[0185] Step S201: Obtain the demodulated signal and noise variance. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0186] Step S202: Perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0187] Step S203: Obtain multiple first bit positions, and calculate the same-direction component corresponding to each even-number bit in the symbol to be demodulated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-number bits.

[0188] Step S204: Obtain multiple second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0189] Step S205: Obtain the third bit length, and look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the demodulated symbol.

[0190] Step S206: If the value of the same-direction component or the value of the quadrature component are less than the preset threshold, calculate the soft information statistical value of the corresponding bit; if the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, determine the first preset value as the soft information statistical value of the corresponding bit.

[0191] This invention provides a demodulation device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0192] Step S201: Obtain the demodulated signal and noise variance. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0193] Step S202: Perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0194] Step S203: Obtain multiple first bit positions, and calculate the same-direction component corresponding to each even-number bit in the symbol to be demodulated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-number bits.

[0195] Step S204: Obtain multiple second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0196] Step S205: Obtain the third bit length, and look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the demodulated symbol.

[0197] Step S206: If the value of the same-direction component or the value of the quadrature component are less than the preset threshold, calculate the soft information statistical value of the corresponding bit; if the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, determine the first preset value as the soft information statistical value of the corresponding bit.

[0198] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0199] Step S201: Obtain the demodulated signal and noise variance. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols.

[0200] Step S202: Perform IQ decomposition on each of the above-mentioned symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the above-mentioned symbols to be demodulated, and the in-direction components correspond one-to-one with the above-mentioned symbols to be demodulated.

[0201] Step S203: Obtain multiple first bit positions, and calculate the same-direction component corresponding to each even-number bit in the symbol to be demodulated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-number bits.

[0202] Step S204: Obtain multiple second bit positions, and calculate the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated based on the orthogonal components and each of the second bit positions to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits.

[0203] Step S205: Obtain the third bit length, and look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the demodulated symbol.

[0204] Step S206: If the value of the same-direction component or the value of the quadrature component are less than the preset threshold, calculate the soft information statistical value of the corresponding bit; if the value of the same-direction component or the value of the quadrature component are greater than the preset threshold, determine the first preset value as the soft information statistical value of the corresponding bit.

[0205] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0206] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0207] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. 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 apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0208] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0209] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0210] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0211] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0212] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0213] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0214] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0215] 1) The soft demodulation method for QAM modulation of this application firstly acquires the signal to be demodulated and the noise variance. The signal to be demodulated is the modulation signal received by the receiver. The signal to be demodulated includes multiple symbols to be demodulated, each symbol including multiple bits. The noise variance is used to characterize the degree of variation of the symbols to be demodulated. Then, IQ decomposition is performed on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the symbols to be demodulated, and the in-direction components correspond one-to-one with the symbols to be demodulated. Afterward, multiple first bit positions are acquired, and the in-direction component corresponding to each even-numbered bit in the symbol to be demodulated is calculated based on the in-direction components and the first bit positions to obtain multiple in-direction component values. The multiple first bit positions are used to characterize the order of the bits in the even-numbered bits. Afterward, multiple second bit positions are acquired, and the in-direction component corresponding to each odd-numbered bit in the symbol to be demodulated is calculated based on the quadrature components and the second bit positions. The aforementioned quadrature components yield multiple quadrature component values, and the multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits. Then, the third bit position is obtained, and a preset threshold value for each bit is obtained by consulting a threshold table based on the noise variance and the third bit position. The preset threshold value of each bit is then compared with the in-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit position, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without degrading decoding performance. The third bit position is used to characterize the order of the bits in the demodulated symbol. Finally, if the in-direction component value or the quadrature component value is less than the preset threshold value, the soft information statistical value of the corresponding bit is calculated. If the in-direction component value or the quadrature component value is greater than the preset threshold value, the first preset value is determined as the soft information statistical value of the corresponding bit. The soft demodulation method of this application compares the in-direction component value or quadrature component value corresponding to each bit in the signal to be demodulated with a preset threshold during demodulation. If the value exceeds the preset threshold, saturation output is performed. If the value does not exceed the threshold, the soft information statistical value of the bit is calculated. This solves the problem in the prior art that the soft information statistical value is calculated for each bit, but the soft information range required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources.

[0216] 2) The QAM modulation soft demodulation apparatus of this application comprises: a first acquisition unit acquiring a signal to be demodulated and a noise variance, wherein the signal to be demodulated is a modulation signal received by a receiver, the signal to be demodulated includes multiple symbols to be demodulated, each symbol to be demodulated includes multiple bits, and the noise variance is used to characterize the degree of variation of the symbols to be demodulated; a decomposition unit performing IQ decomposition on each symbol to be demodulated to obtain multiple in-direction components and multiple quadrature components, wherein the quadrature components correspond one-to-one with each symbol to be demodulated, and the in-direction components correspond one-to-one with each symbol to be demodulated; a first calculation unit acquiring multiple first bit positions and calculating the in-direction components corresponding to each even-numbered bit in the symbol to be demodulated based on the in-direction components and each of the first bit positions to obtain multiple in-direction component values, wherein the multiple first bit positions are used to characterize the order of the bits in the even-numbered bits; and a second calculation unit acquiring multiple second bit positions and calculating the odd-numbered bits in the symbol to be demodulated based on the quadrature components and each of the second bit positions. The corresponding orthogonal components yield multiple orthogonal component values, and the multiple second bit positions are used to characterize the order of the bits in the odd-numbered bits; the query unit obtains the third bit position, and according to the noise variance and the third bit position, consults the threshold table to obtain the preset threshold value of each bit, and compares the preset threshold value of each bit with the same-direction component value or the orthogonal component value. The threshold table is a mapping table of the noise variance, the third bit position, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit position is used to characterize the order of the bits in the demodulated symbol; the third calculation unit calculates the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is less than the preset threshold value, and determines the first preset value as the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is greater than the preset threshold value. The soft demodulation method of this application compares the in-direction component value or quadrature component value corresponding to each bit in the signal to be demodulated with a preset threshold during demodulation. If the value exceeds the preset threshold, saturation output is performed. If the value does not exceed the threshold, the soft information statistical value of the bit is calculated. This solves the problem in the prior art that the soft information statistical value is calculated for each bit, but the soft information range required by the decoder is much lower than the calculated soft information statistical value, resulting in a waste of computing resources.

[0217] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A soft demodulation method for QAM modulation, characterized in that, include: The demodulated signal and noise variance are obtained. The demodulated signal is the modulated signal received by the receiver. The demodulated signal includes multiple demodulated symbols, each of which includes multiple bits. The noise variance is used to characterize the degree of variation of the demodulated symbols. IQ decomposition is performed on each of the demodulated symbols to obtain multiple in-direction components and multiple quadrature components. The quadrature components correspond one-to-one with the demodulated symbols, and the in-direction components correspond one-to-one with the demodulated symbols. Multiple first bit positions are obtained, and the same-direction component corresponding to each even-numbered bit in the symbol to be demodulated is calculated based on the same-direction component and each first bit position to obtain multiple same-direction component values. The multiple first bit positions are used to characterize the order of the bit in the even-numbered bits. Multiple second bit positions are obtained, and the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated are calculated based on the orthogonal components and each second bit position to obtain multiple orthogonal component values. The multiple second bit positions are used to characterize the order of the bit in the odd-numbered bits. The third bit number is obtained, and the preset threshold value of each bit is obtained by consulting the threshold table according to the noise variance and the third bit number. The preset threshold value of each bit is compared with the in-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit number, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit number is used to characterize the order of the bit in the symbol to be demodulated. If the value of the same-direction component or the value of the quadrature component is less than the preset threshold, the soft information statistical value of the corresponding bit is calculated. If the value of the same-direction component or the value of the quadrature component is greater than the preset threshold, the first preset value is determined as the soft information statistical value of the corresponding bit.

2. The method according to claim 1, characterized in that, Multiple first bit positions are obtained, and the in-direction component corresponding to each even-numbered bit in the symbol to be demodulated is calculated based on the in-direction component and each first bit position to obtain multiple in-direction component values, including: Obtain the modulation order and a plurality of the first bit lengths, wherein the modulation order is the number of bits included in a symbol to be demodulated; The value of the same-direction component corresponding to each even-numbered bit is calculated based on the modulation order, the same-direction component, and the number of bits of each of the first bits.

3. The method according to claim 2, characterized in that, Multiple second bit positions are obtained, and the orthogonal components corresponding to each odd-numbered bit in the symbol to be demodulated are calculated based on the orthogonal components and each second bit position to obtain multiple orthogonal component values, including: Obtain the modulation order and the number of bits of the second bit; The quadrature component value corresponding to each odd-numbered bit is calculated based on the modulation order, the quadrature component, and the number of bits of each second bit.

4. The method according to claim 2, characterized in that, Before obtaining the third bit length and looking up the threshold table based on the noise variance and the third bit length to obtain the preset threshold value for each bit, the method further includes: Acquire multiple symbols to be demodulated and calculate the average soft information of the bits for different third bit positions in each symbol to be demodulated; Obtain a preset amplitude value, which is the minimum theoretical value of the soft information statistics of each bit input to the decoder without degrading the decoding performance of the decoder; The preset threshold value of the bit corresponding to each of the third bit positions is determined based on the preset amplitude, the average value of the soft information, and the noise variance.

5. The method according to claim 4, characterized in that, Acquiring multiple symbols to be demodulated and calculating the average soft information of the bits for different third bit positions in each symbol to be demodulated, including: Multiple first QAM images and multiple second QAM images are acquired. The first QAM image is a reference image for QAM modulation and includes the soft information reference value of each bit in the symbol to be demodulated. The second QAM image is an image representation of the symbol to be demodulated. The QAM images correspond one-to-one with the symbols to be demodulated. The positional deviation of each bit in the corresponding demodulated symbol is determined based on each of the second QAM images and the first QAM image, and the soft information estimate of the bit is determined based on the positional deviation, the soft information reference value and Gaussian noise. The average value of the soft information corresponding to each bit is calculated based on the soft information estimate, the Gaussian noise, and the noise variance.

6. The method according to claim 4, characterized in that, After determining the preset threshold value of the bit corresponding to each of the third bit positions based on the preset amplitude, the average soft information value, and the noise variance, the method further includes: A noise variance set is generated based on the noise variance and a preset interval, wherein the difference between any two noise variances in the noise variance set is an integer multiple of the preset interval; The preset threshold value of each third bit bit is calculated based on the noise variance of each of the noise variance groups, the preset amplitude, and the average value of each of the soft information. The threshold table is generated based on the noise variance group, the third bit length, and the preset threshold value.

7. The method according to any one of claims 1 to 6, characterized in that, Calculating the soft information statistics of the bit includes: The target in-direction component value or the target quadrature component value is obtained by rounding the corresponding in-direction component value or the quadrature component value of the bit. The soft information statistics of the bit are calculated based on the target in-direction component value or the target quadrature component value, the in-direction component value or the quadrature component value, and the noise variance.

8. A control device for engine braking, characterized in that, The device includes: The first acquisition unit is used to acquire the signal to be demodulated and the noise variance. The signal to be demodulated is the modulation signal received by the receiving end. The signal to be demodulated includes multiple symbols to be demodulated, and each symbol to be demodulated includes multiple bits. The noise variance is used to characterize the degree of variation of the symbols to be demodulated. The decomposition unit is used to perform IQ decomposition on each of the symbols to be demodulated to obtain multiple in-direction components and multiple quadrature components, wherein the quadrature components correspond one-to-one with the symbols to be demodulated, and the in-direction components correspond one-to-one with the symbols to be demodulated. The first calculation unit is used to obtain a plurality of first bit positions, and calculate the corresponding first bit position of each even bit in the symbol to be demodulated based on the first bit position and the first bit position to obtain a plurality of first bit position values. The plurality of first bit positions are used to characterize the order of the bit in the even bit position. The second calculation unit is used to obtain multiple second bit positions, and calculate multiple orthogonal component values ​​based on the orthogonal components and each second bit position in the symbol to be demodulated, whereby the multiple second bit positions are used to characterize the order of the bit in the odd-numbered bits. A query unit is used to obtain the third bit length, and to look up the threshold table according to the noise variance and the third bit length to obtain the preset threshold value of each bit, and to compare the preset threshold value of each bit with the same-direction component value or the quadrature component value. The threshold table is a mapping table of the noise variance, the third bit length, and the preset threshold value. The preset threshold value is the minimum allowable soft information statistical value of the bit without reducing the decoding performance. The third bit length is used to characterize the order of the bit in the symbol to be demodulated. The third calculation unit is used to calculate the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is less than the preset threshold value, and to determine the first preset value as the soft information statistical value of the corresponding bit when the same-direction component value or the orthogonal component value is greater than the preset threshold value.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 7.

10. A demodulation device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising methods for performing any one of claims 1 to 7.

Images