Probability shaping method, storage medium, electronic device and apparatus

Abstract

The application provides a probability shaping method, a storage medium, an electronic device and an apparatus. The probability shaping method comprises: dividing a first binary data stream into three parallel data streams; traversing a third amplitude bit data stream and locating a specific bit position satisfying a preset condition; judging a value of a second amplitude bit data stream corresponding to the specific bit position to obtain a judgment result, and determining whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position according to the judgment result; and combining a sign bit data stream, the second amplitude bit data stream after the flip operation and the third amplitude bit data stream to obtain a second binary data stream. The application is based on a single-level flip mechanism, only needs to traverse the data stream once and make a statistical decision based on a single bit, can systematically optimize the probability distribution of PAM8 symbols, reduces the hardware complexity and processing delay, and improves the anti-noise performance of the link.

Description

Technical Field

[0001] This application relates to the field of high-speed optoelectronic hybrid communication and millimeter-wave wireless transmission, and in particular to a probability shaping method, storage medium, electronic device and apparatus for intensity modulation direct detection system. Background Technology

[0002] In the current development of high-speed wireless communication and optical interconnect systems, millimeter-wave communication, especially utilizing the abundant spectrum resources of the W-band (75–110 GHz), is considered a key technological path to break through the existing transmission rate bottleneck. However, millimeter-wave signals face significant path loss and multipath effects during propagation in space, posing a severe challenge to building stable and reliable long-distance high-speed wireless links. To maximize spectral efficiency under conditions of limited bandwidth and channel impairment, the application of higher-order modulation formats has become an inevitable choice. In relatively simple intensity modulation / direct detection (IM / DD) systems, pulse amplitude modulation (PAM) is widely used due to its ease of implementation; among them, 8-level pulse amplitude modulation (PAM8) offers higher spectral efficiency and potentially better noise immunity than the mainstream 4-level format (PAM4), but it also places more stringent requirements on the system signal-to-noise ratio.

[0003] To address millimeter-wave channel loss and improve the robustness of PAM8 signals under harsh channel conditions, probabilistic shaping techniques have been introduced into this field. Probabilistic shaping breaks the assumption of uniform symbol distribution in traditional communication, optimizing the occurrence probability of each symbol in the constellation diagram. This allows low-amplitude internal symbols to appear with a higher probability, thereby concentrating the signal energy distribution while maintaining the same average transmit power, effectively improving receiver sensitivity and anti-interference capabilities. However, classical probabilistic shaping methods (such as constant component distribution matching) typically rely on complex combinatorial mappings or large lookup tables, resulting in high algorithm complexity and large processing delays, making it difficult to meet the low latency and low hardware overhead requirements of real-time communication systems.

[0004] As data center interconnects and high-speed optical access networks continue to evolve towards higher speeds, there is an urgent need for a probabilistic shaping technology that can balance low implementation complexity, low processing latency, and good shaping gain in IM / DD systems to support the practical deployment of high-order modulation formats such as PAM8.

[0005] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a probability shaping method, storage medium, electronic device, and apparatus that have the advantages of low complexity and good transmission performance.

[0007] To achieve the above objectives, the present invention provides a probability shaping method for an intensity modulation direct detection system, comprising: S10. Divide the first binary data stream into three parallel data streams, including a sign bit data stream, a second amplitude bit data stream, and a third amplitude bit data stream; S20. Traverse the third amplitude bit data stream and locate the specific bit position that meets the preset condition. Perform statistical judgment based on the value of the second amplitude bit data stream corresponding to the specific bit position to obtain the judgment result. Determine whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position according to the judgment result. S30. The sign bit data stream, the second amplitude bit data stream after the flipping operation, and the third amplitude bit data stream are combined to obtain a second binary data stream.

[0008] In some embodiments, in step S20, the preset condition is that the value in the third amplitude bit data stream is 0.

[0009] In some embodiments, in step S20, the number of times the second amplitude bit data stream takes the first logical value at the specific bit position is counted. If the number of the first logical values ​​is less than a first threshold, the value of the second amplitude position data stream at the specific bit position is flipped. If the number of the first logical values ​​is greater than or equal to the first threshold, no flipping operation is performed.

[0010] In some embodiments, the statistical judgment is performed within a statistical window of length L, and the first threshold is L / 2.

[0011] In some embodiments, after step S30, step S40 is further included: setting a flag bit; if the number of the first logical values ​​is less than a first threshold, the flag bit is set to a first value; if the number of the first logical values ​​is greater than or equal to the first threshold, the flag bit is set to a second value.

[0012] In some embodiments, step S40 further includes mapping the second binary data stream to probabilistically shaped PAM8 symbols.

[0013] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the probability shaping method for an intensity modulation direct detection system as described above.

[0014] This application also provides an electronic device, including a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, it implements the probability shaping method for a direct intensity modulation detection system as described above.

[0015] This application also provides a probability shaping apparatus for an intensity modulation direct detection system, the probability shaping apparatus being used in the probability shaping method for an intensity modulation direct detection system as described above, the probability shaping apparatus comprising: The data preprocessing module is used to divide the first binary data stream into three parallel sign bit data streams, a second amplitude bit data stream, and a third amplitude bit data stream; A single-level flip processing module is electrically connected to the data preprocessing module. The single-level flip processing module includes a trigger detection unit, a statistical judgment unit, and a flip execution unit. The trigger detection unit is configured to locate a bit position that meets a preset condition using the third amplitude bit data stream as a trigger point. The statistical judgment unit is configured to perform statistical judgment based on the value of the second amplitude bit data stream corresponding to the located bit position to obtain a judgment result. The flip execution unit is configured to determine whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position based on the judgment result.

[0016] In some embodiments, a symbol mapping module is further included, electrically connected to the single-stage inversion processing module, for mapping the second binary data stream into probabilistically shaped PAM8 symbols.

[0017] In summary, compared with the prior art, the probability shaping method, storage medium, electronic device, and apparatus provided by the present invention have the following beneficial effects: The probability shaping method, storage medium, electronic device, and apparatus of this application are based on a single-level flip mechanism. They can systematically optimize the probability distribution of PAM8 symbols by performing only one traversal of the data stream and statistical decision based on a single bit. This reduces hardware complexity and processing latency while improving the noise immunity of the link. The method of this application does not require multi-level iteration or complex distribution matching process. It has the advantages of simple implementation structure, low computational complexity, and low latency, and is suitable for high-speed optical communication and terahertz wireless communication scenarios. Attached Figure Description

[0018] Figure 1 This is a flowchart of the probability shaping method for the intensity modulation direct detection system of this application.

[0019] Figure 2 This is a schematic diagram of the probability shaping device used in the intensity modulation direct detection system of this application.

[0020] Explanation of reference numerals in the attached figures: Probability Shaping Device 10 First binary data stream 110 Data Cache 120 Data preprocessing module 130 Trigger detection unit 140 Statistical Judgment Unit 150 Flip Execution Unit 160 Symbol mapping module 170 PAM8 signal output terminal 180 Detailed Implementation

[0021] The probability shaping method, storage medium, electronic device, and apparatus proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0022] This invention provides a probability shaping method for an intensity modulation direct detection system, the probability shaping method comprising the following steps: S10. In this step, the original input serial first binary data stream is divided into three parallel sub-data streams, including a sign bit data stream, a second amplitude bit data stream, and a third amplitude bit data stream. In this application, Gray code mapping rules are used to map PAM8 (8-level Pulse Amplitude Modulation) to 3-bit binary codes (e.g., 100, 101, ..., 000), where the highest bit is defined as the sign bit, and the remaining two bits are amplitude bits. In the Gray code mapping rules, any two numerically adjacent symbols differ by only one bit in their binary codewords, minimizing serious bit errors caused by minute errors during signal transmission or state switching. For example, when a signal jumps between adjacent amplitude levels due to noise interference, Gray code ensures that the resulting binary error is exactly one bit, thus minimizing the impact of bit errors and significantly improving the system's noise immunity and reliability.

[0023] S20. Traverse the third amplitude bit data stream and locate specific bit positions that meet preset conditions. Perform statistical judgment based on the value of the second amplitude bit data stream corresponding to the specific bit position to obtain a judgment result. Determine whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position based on the judgment result. Specifically, count the number of times the second amplitude bit data stream contains a first logical value at the specific bit position. If the number of first logical values ​​is less than a first threshold, then the value of the second amplitude bit data stream at the specific bit position is flipped; if the number of first logical values ​​is greater than or equal to the first threshold, then no flip operation is performed. In this embodiment, the preset condition is that the value in the third amplitude bit data stream is 0. The statistical judgment is performed within a statistical window of length L, and the first threshold is L / 2.

[0024] In this embodiment, the value of the third amplitude bit data stream is used as the trigger condition. The index positions where the value is "0" are traversed and located as specific positions. The system judges whether the number of "1"s in the corresponding second amplitude bit data stream at these specific positions is greater than half. If the number of "1"s in the second amplitude bit data stream is less than half, the "1"s in the second amplitude bit data stream are flipped to "0", and the "0"s are flipped to "1". If the number of "1"s in the second amplitude bit data stream is greater than half, no flipping is performed. In the technical solution of this application, by flipping the second amplitude bit data stream at positions where the third amplitude bit data stream is "0" when the number of "1"s is less than half, the system systematically converts extreme amplitude symbols with a higher probability of occurrence (such as the lowest and highest levels) into medium amplitude symbols with a lower probability of occurrence. This reconstructs the probability distribution in the PAM8 signal, transforming the overall energy distribution of the signal from a uniform distribution to a shape closer to a Gaussian distribution. During transmission, since the majority of the time the signal being transmitted is a medium-amplitude signal with stronger noise immunity, the effective signal-to-noise ratio against random noise in the channel is improved while keeping the average transmit power strictly constant. The Gaussian distribution of the signal amplitude provides shaping gain. Without increasing power consumption or system complexity, the bit error rate at the receiver is significantly reduced, thus enabling longer-distance or more reliable high-speed data transmission.

[0025] S30. The sign bit data stream, the second amplitude bit data stream after the flipping operation, and the third amplitude bit data stream are combined to obtain the second binary data stream, which is a three-bit binary number used for transmission.

[0026] Following step S30, step S40 is also included: setting a flag bit. If the number of first logical values ​​is less than a first threshold, the flag bit is set to the first value; if the number of first logical values ​​is greater than or equal to the first threshold, the flag bit is set to the second value. By setting the flag bit, reliable state recording and collaborative control are achieved in the hardware system. After the system statistically analyzes the data within the data window, it makes a decision to either flip all or retain all the second amplitude bit data streams. By setting the flag bit to record this decision result, it ensures that the second amplitude bit data streams at all target positions have performed the same operation, avoiding logical errors where some positions are flipped and some are not due to timing or signal transmission deviations. Furthermore, for the receiver, the flag bit determines whether the received signal has been flipped, and the received signal is processed accordingly. For example, a flipped signal is flipped again, while an unflipped signal is received directly without additional processing. By setting the flag bit, the receiver knows whether the transmitter has flipped the current data block, which helps simplify signal processing or decoding algorithms.

[0027] In this embodiment, step S40 further includes: mapping the second binary data stream to probabilistically shaped PAM8 symbols.

[0028] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the probability shaping method for an intensity modulation direct detection system as described above.

[0029] This application also provides an electronic device, including a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, it implements the probability shaping method for a direct intensity modulation detection system as described above.

[0030] like Figure 2 As shown, this application also provides a probability shaping device 10 for an intensity modulation direct detection system. The probability shaping device 10 is used in the probability shaping method for an intensity modulation direct detection system as described above. The probability shaping device 10 includes a data preprocessing module 130, a single-stage inversion processing module, and a symbol mapping module 170.

[0031] The data preprocessing module 130 divides the first binary data stream 110 into three parallel data streams: a sign bit data stream, a second amplitude bit data stream, and a third amplitude bit data stream. The first binary data stream 110 is first stored in a data buffer 120 for processing by the data preprocessing module 130. The data buffer 120 can be implemented using a FIFO (First In First Out) or addressable RAM (Random Access Memory) structure to ensure that subsequent statistical operations are performed on a fixed number of symbols. In the data preprocessing module 130, the input first binary data stream 110 is split into three parallel data streams: a sign bit data stream, a second amplitude bit data stream, and a third amplitude bit data stream.

[0032] The single-stage inversion processing module converts the input three-bit first binary data stream 110 into a probability-shaped PAM-8 signal to increase the probability of intermediate amplitude levels, thereby improving the link's noise immunity. The single-stage inversion processing module is electrically connected to the data preprocessing module 130. The single-stage inversion processing module includes a trigger detection unit 140, a statistical judgment unit 150, and an inversion execution unit 160.

[0033] The trigger detection unit 140 is configured to use the third amplitude bit data stream as a trigger point to locate the bit position that meets preset conditions. The trigger detection unit 140 is used to scan the third amplitude bit data stream ( The positions where the value is "0" are generated, and a trigger index set J is created. A trigger bit of "0" indicates that the symbol belongs to a shapeable target. In the embodiments of this application, only the second amplitude bit data stream of these symbol bits ( (to undergo plastic surgery)

[0034] The statistical judgment unit 150 is configured to base its judgment on the second amplitude bit data stream corresponding to the located bit position. The statistical judgment unit 150 is used to statistically judge the value of the second amplitude bit data stream within a statistical window of length L to obtain the judgment result. The number of times "1" appears in the value cnt is set to a flip threshold of T, where cnt is the number of times "1" appears in the value cnt. .when When the number of "1"s is relatively small, a flip operation is tended to be performed on the amplitude bits to make the overall distribution closer to the shaping target. At this time, the number of "1"s is sufficient, which means that the overall amplitude of the transmitted data is appropriate and can be transmitted under the premise of a high signal-to-noise ratio, so no flipping operation is performed.

[0035] The flip execution unit 160 is configured to determine whether to flip the value of the second amplitude position data stream at a specific bit position based on the judgment result. Specifically, the flip execution unit 160 is used to flip the second amplitude bit data stream in the trigger index set J. Perform a flip operation, the rule of which is that when Then, for all Then for the second amplitude bit data stream ( The value of ) is flipped, that is ;like At that time, the second amplitude bit data stream is maintained. The value of ) remains unchanged. The technical solution of this application performs only one flip operation, requiring no additional secondary flips or complex FPGA (Field-Programmable Gate Array) implementation with matching logic. It only requires a small number of LUTs (Look-Up Tables) and adders, without changing the sign bit data stream or the third amplitude bit data stream. ), to maintain modulation stability.

[0036] The symbol mapping module 170 is electrically connected to the single-stage flip processing module and is used to map the second binary data stream into probabilistically shaped PAM8 symbols. After completing the single-stage bit weighting and flipping processing, the symbol bit data stream, the flipped or unflipped second amplitude bit data stream, and the third amplitude bit data stream are recombine according to their original timing sequence to generate a three-bit second binary data stream. Subsequently, the second binary data stream is input to the Gray mapping unit, mapped into probabilistically shaped PAM8 modulation symbols according to the preset PAM8 Gray mapping rules, and output from the PS-PAM8 signal output terminal 180 for subsequent transmission or signal processing.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 a process, method, article, or apparatus. Without further limitations, 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 said element.

[0038] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A probabilistic shaping method for an intensity modulation direct detection system, characterized in that, The probabilistic shaping method includes: S10, dividing the first binary data stream into three parallel data streams, including a sign bit data stream, a second amplitude bit data stream, and a third amplitude bit data stream; S20, traversing the third amplitude bit data stream and locating specific bit positions that meet preset conditions, performing statistical judgment based on the value of the second amplitude bit data stream corresponding to the specific bit position to obtain a judgment result, and determining whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position according to the judgment result; S30, combining the sign bit data stream, the second amplitude bit data stream after the flip operation, and the third amplitude bit data stream to obtain a second binary data stream.

2. The probability shaping method for a direct intensity modulation detection system as described in claim 1, characterized in that, In step S20, the preset condition is that the value in the third amplitude bit data stream is 0.

3. The probability shaping method for a direct intensity modulation detection system as described in claim 1, characterized in that, In step S20, the number of times the second amplitude bit data stream takes the first logical value at the specific bit position is counted. If the number of the first logical values ​​is less than the first threshold, the value of the second amplitude position data stream at the specific bit position is flipped. If the number of the first logical values ​​is greater than or equal to the first threshold, no flipping operation is performed.

4. The probability shaping method for a direct intensity modulation detection system as described in claim 3, characterized in that, The statistical judgment is performed within a statistical window of length L, and the first threshold is L / 2.

5. The probability shaping method for a direct intensity modulation detection system as described in claim 3, characterized in that, After step S30, the method further includes step S40: setting a flag bit; if the number of the first logical values ​​is less than a first threshold, the flag bit is set to a first value; if the number of the first logical values ​​is greater than or equal to the first threshold, the flag bit is set to a second value.

6. The probability shaping method for a direct intensity modulation detection system as described in claim 3, characterized in that, Step S40 further includes: mapping the second binary data stream to probabilistically shaped PAM8 symbols.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the probability shaping method for a direct intensity modulation detection system as described in any one of claims 1-6.

8. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, which, when executed by the processor, implements the probability shaping method for a direct intensity modulation detection system as described in any one of claims 1-6.

9. A probability shaping device for an intensity modulation direct detection system, characterized in that, The probability shaping device is used in the probability shaping method for a direct detection system for intensity modulation as described in any one of claims 1-6. The probability shaping device includes: a data preprocessing module for dividing a first binary data stream into three parallel sign bit data streams, a second amplitude bit data stream, and a third amplitude bit data stream; and a single-stage flip processing module electrically connected to the data preprocessing module. The single-stage flip processing module includes a trigger detection unit, a statistical judgment unit, and a flip execution unit. The trigger detection unit is configured to locate a bit position that satisfies a preset condition using the third amplitude bit data stream as a trigger point. The statistical judgment unit is configured to perform a statistical judgment based on the value of the second amplitude bit data stream corresponding to the located bit position to obtain a judgment result. The flip execution unit is configured to determine whether to perform a flip operation on the value of the second amplitude bit data stream at the specific bit position based on the judgment result.

10. The probability shaping device for a direct intensity modulation detection system as described in claim 9, characterized in that, It also includes a symbol mapping module, electrically connected to the single-stage inversion processing module, used to map the second binary data stream into probabilistically shaped PAM8 symbols.

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