CN117792509A - PAM signal self-adaptive detection space optical communication method and system - Google Patents
PAM signal self-adaptive detection space optical communication method and system Download PDFInfo
- Publication number
- CN117792509A CN117792509A CN202311866055.6A CN202311866055A CN117792509A CN 117792509 A CN117792509 A CN 117792509A CN 202311866055 A CN202311866055 A CN 202311866055A CN 117792509 A CN117792509 A CN 117792509A
- Authority
- CN
- China
- Prior art keywords
- signal
- symbols
- judgment
- decision
- symbol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 63
- 230000003287 optical effect Effects 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000004891 communication Methods 0.000 title claims abstract description 33
- 230000001427 coherent effect Effects 0.000 claims abstract description 29
- 238000013507 mapping Methods 0.000 claims abstract description 17
- 230000003044 adaptive effect Effects 0.000 claims description 22
- 230000005540 biological transmission Effects 0.000 abstract description 11
- 230000035945 sensitivity Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 102100029469 WD repeat and HMG-box DNA-binding protein 1 Human genes 0.000 description 1
- 101710097421 WD repeat and HMG-box DNA-binding protein 1 Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Abstract
A space optical communication method and system for PAM signal self-adaptive detection relates to the technical field of space optical communication, and comprises the following steps: at a transmitting end, configuring symbols generated by mapping logic bits of PAM signals to obtain symbols with equal intervals of positive and negative types, wherein the interval between adjacent positive and negative symbols is larger than the interval in the positive and negative symbols; at the receiving end, when the receiving distance is smaller than the set value, the signal is received by adopting an intensity detection mode, and corresponding symbols and logic bits are determined to complete signal demodulation; when the receiving distance is larger than the set value, the signal is received by adopting a coherent receiving mode, and corresponding symbols and output bits are determined to complete signal demodulation. The application not only meets the requirement of low cost, but also realizes the extension of the range of the optical wireless transmission system.
Description
Technical Field
The application relates to the technical field of space optical communication, in particular to a space optical communication method and system for self-adaptive detection of PAM signals.
Background
With the development of optical communication technology, high-speed optical transmission applications are becoming more and more widespread. In a spatial light transmission system, information is typically played in the form of broadcasting. Based on cost consideration, a direct detection method is mostly adopted at the receiving end, so that a low-cost direct detection receiving method can be adopted in a range where the received optical power is large enough. However, the method using direct detection has a problem in that its reception power is lower than its reception sensitivity when the transmission distance is large, thereby making the signal impossible to receive.
In order to solve the above-mentioned problems, coherent optical communication is introduced into applications of wireless optical communication, and it is known that optical coherent reception has higher reception sensitivity than direct detection reception, but because of the limitation of coherent reception cost, it cannot be used in a wide range, and thus, a method which satisfies both low cost and enables effective improvement of the optical wireless communication range is lacking at present.
Disclosure of Invention
The application provides a space optical communication method and a system for PAM signal self-adaptive detection, which not only meet the requirement of low cost, but also realize the extension of the range of an optical wireless transmission system.
In a first aspect, an embodiment of the present application provides a spatial optical communication method for adaptive detection of PAM signals, where the spatial optical communication method for adaptive detection of PAM signals includes:
at a transmitting end, configuring symbols generated by mapping logic bits of PAM signals to obtain symbols with equal intervals of positive and negative types, wherein the interval between adjacent positive and negative symbols is larger than the interval in the positive and negative symbols;
at a receiving end, when the receiving distance is smaller than a set value, a signal is received in an intensity detection mode, an output signal is subjected to mean value removal to obtain a first judgment signal, a judgment threshold is set based on two adjacent first judgment signals, and corresponding symbols and logic bits are determined according to the magnitude relation between the first judgment signals and the judgment threshold so as to complete signal demodulation;
when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
In combination with the first aspect, in an implementation manner, the configuring, at the transmitting end, a symbol mapped and generated by a logic bit of a PAM signal, to obtain a symbol with equal intervals between two types of positive and negative symbols, where an interval between adjacent positive and negative symbols is greater than an interval between positive and negative symbols, includes:
when the PAM signal is a PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
With reference to the first aspect, in one embodiment, the signal voltages generated by setting the sign to linearly correspond to the voltage value thereof are 3V, 1V, -2V and-4V, respectively;
and at the transmitting end, the MZ intensity modulator is adopted for modulation, and the bias point of the MZ intensity modulator is set at a zero power point, so that the optical signal and the electric signal generated by modulation are in linear mapping.
In combination with the first aspect, in an implementation manner, when the receiving distance is smaller than a set value, a signal is received by adopting an intensity detection manner, and after the output signal is subjected to mean value removal, a first decision signal is obtained, a decision threshold is set based on two adjacent first decision signals, and corresponding symbols and logic bits are determined according to a size relationship between the first decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 1, 2, 3 and 4 of the intensity detection output by 2.5 to obtain a first judgment signal R1: -1.5, -0.5, 0.5 and 1.5;
taking-1, 0 and 1 as decision thresholds;
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
In combination with the first aspect, in an implementation manner, when the receiving distance is greater than a set value, a coherent receiving manner is adopted to receive the signal, and the output signal is subjected to mean value removal to obtain a second decision signal, a decision threshold is set based on two adjacent second decision signals, and corresponding symbols and output bits are determined according to a magnitude relation between the second decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 3, 1, -2 and-4 of the coherent detection output by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5;
taking-2.5, 0 and 2.5 as decision thresholds;
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
In a second aspect, an embodiment of the present application provides a spatial optical communication system for adaptive detection of PAM signals, where the spatial optical communication system for adaptive detection of PAM signals includes:
the transmitting terminal equipment is used for configuring the symbols generated by mapping the logic bits of the PAM signals at the transmitting terminal to obtain the symbols with equal intervals of positive and negative types, and the interval between the adjacent positive and negative symbols is larger than the interval between the adjacent positive and negative symbols;
the receiving end equipment is used for receiving signals in an intensity detection mode when the receiving distance is smaller than a set value at the receiving end, obtaining first judgment signals after removing the mean value of the output signals, setting judgment thresholds based on two adjacent first judgment signals, and determining corresponding symbols and logic bits according to the size relation between the first judgment signals and the judgment thresholds so as to complete signal demodulation;
when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
With reference to the second aspect, in one embodiment, the transmitting device configures, at a transmitting end, a symbol mapped and generated by a logic bit of a PAM signal to obtain a symbol with equal intervals between two types of positive and negative symbols, where an interval between adjacent positive and negative symbols is greater than an interval between positive and negative symbols, and the method includes:
when the PAM signal is a PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
With reference to the second aspect, in one implementation manner, the sending end device is configured to:
setting signal voltages generated by the symbols linearly corresponding to the voltage values of the symbols to be 3V, 1V, -2V and-4V respectively;
and at the transmitting end, the MZ intensity modulator is adopted for modulation, and the bias point of the MZ intensity modulator is set at a zero power point, so that the optical signal and the electric signal generated by modulation are in linear mapping.
With reference to the second aspect, in one implementation manner, when the receiving distance of the receiving end device is smaller than a set value, the receiving end device receives a signal in an intensity detection manner, and removes an average value of the output signal to obtain a first decision signal, sets a decision threshold based on two adjacent first decision signals, and determines a corresponding symbol and a logic bit according to a size relationship between the first decision signal and the decision threshold, so as to complete signal demodulation, where the method includes:
removing the average value of 1, 2, 3 and 4 of the intensity detection output by 2.5 to obtain a first judgment signal R1: -1.5, -0.5, 0.5 and 1.5;
taking-1, 0 and 1 as decision thresholds;
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
With reference to the second aspect, in one implementation manner, when the receiving distance of the receiving end device is greater than a set value, a coherent receiving manner is adopted to receive a signal, and an output signal is subjected to mean value removal to obtain a second decision signal, a decision threshold is set based on two adjacent second decision signals, and corresponding symbols and output bits are determined according to a size relationship between the second decision signal and the decision threshold, so as to complete signal demodulation, where the method includes:
removing the average value of 3, 1, -2 and-4 of the coherent detection output by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5;
taking-2.5, 0 and 2.5 as decision thresholds;
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
The beneficial effects that technical scheme that this application embodiment provided include at least:
according to the space optical communication method for self-adaptive detection of the PAM signal, symbols which are generated by mapping logic bits of the PAM signal are configured at a transmitting end, so that the symbols with equal intervals of positive and negative types are obtained, and the interval between the adjacent positive and negative symbols is larger than the interval between the adjacent positive and negative symbols; at a receiving end, when the receiving distance is smaller than a set value, a signal is received in an intensity detection mode, an output signal is subjected to mean value removal to obtain a first judgment signal, a judgment threshold is set based on two adjacent first judgment signals, and corresponding symbols and logic bits are determined according to the magnitude relation between the first judgment signals and the judgment threshold so as to complete signal demodulation; when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
The method adopts a self-adaptive receiving mode based on the received power, and on the basis of adopting an original modulation system, the receiving end can adopt different receiving schemes for demodulation according to the situation by changing the modulation scheme of the PAM signal. For receiving points with a relatively short distance and a relatively large number, the system cost is reduced by adopting a scheme of intensity detection, and for receiving points with a relatively long distance and a relatively small number, the system performance is improved under the condition of low receiving power by adopting a scheme of coherent reception. The method is suitable for the optical wireless transmission system, the performance of the optical wireless transmission system is optimized as a whole, the cost is reduced, and the compatibility and stability of the optical wireless transmission system are improved.
Drawings
Fig. 1 is a schematic flow chart of an embodiment of a spatial optical communication method for PAM signal adaptive detection in the present application;
fig. 2 is a schematic diagram of an optical wireless system modulation and adaptive reception scheme in the present application;
fig. 3 is a schematic diagram of a signal modulation and demodulation scheme of the present application.
Detailed Description
In order to make the present application solution better understood by those skilled in the art, the following description will clearly and completely describe the technical solution in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
The terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the foregoing drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus. The terms "first," "second," and "third," etc. are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order, and are not limited to the fact that "first," "second," and "third" are not identical.
In the description of embodiments of the present application, "exemplary," "such as," or "for example," etc., are used to indicate an example, instance, or illustration. Any embodiment or design described herein as "exemplary," "such as" or "for example" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "such as" or "for example," etc., is intended to present related concepts in a concrete fashion.
In the description of the embodiments of the present application, unless otherwise indicated, "/" means or, for example, a/B may represent a or B; the text "and/or" is merely an association relation describing the associated object, and indicates that three relations may exist, for example, a and/or B may indicate: the three cases where a exists alone, a and B exist together, and B exists alone, and in addition, in the description of the embodiments of the present application, "plural" means two or more than two.
In some of the processes described in the embodiments of the present application, a plurality of operations or steps occurring in a particular order are included, but it should be understood that these operations or steps may be performed out of the order in which they occur in the embodiments of the present application or in parallel, the sequence numbers of the operations merely serve to distinguish between the various operations, and the sequence numbers themselves do not represent any order of execution. In addition, the processes may include more or fewer operations, and the operations or steps may be performed in sequence or in parallel, and the operations or steps may be combined.
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
In a first aspect, an embodiment of the present application provides a spatial optical communication method for adaptive detection of PAM signals.
In an embodiment, referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a spatial optical communication method for PAM signal adaptive detection in the present application. As shown in fig. 1, the spatial optical communication method for PAM signal adaptive detection includes:
s1, configuring symbols generated by mapping logic bits of PAM signals at a transmitting end to obtain symbols with equal positive and negative intervals, wherein the interval between adjacent positive and negative symbols is larger than the interval between adjacent positive and negative symbols.
Taking the PAM4 signal as an example, when the PAM signal is the PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
It will be appreciated that the symbols generated by the mapping may also be set to 6, 2, -4, and-8, i.e., proportional, and may be set to other values as desired, and the embodiment is not limited in this regard.
S2, at a receiving end, when the receiving distance is smaller than a set value, a signal is received in an intensity detection mode, the output signal is subjected to mean value removal to obtain first judgment signals, a judgment threshold is set based on two adjacent first judgment signals, and corresponding symbols and logic bits are determined according to the size relation between the first judgment signals and the judgment threshold so as to complete signal demodulation.
Taking PAM4 signal as an example, after the mapped symbols of logical bits 00, 01, 10 and 11 of PAM4 signal are configured to be 3, 1, -2 and-4 in sequence, if the receiving distance is smaller than the set value, the signal is received by adopting an intensity detection mode, and the average value of 1, 2, 3 and 4 of the intensity detection output is removed by 2.5 to obtain a first decision signal R1: -1.5, -0.5, 0.5 and 1.5.
At this time, median values-1, 0 and 1 of two adjacent first decision signals are taken as decision thresholds.
And S3, when the receiving distance is greater than a set value, receiving signals in a coherent receiving mode, removing the average value of the output signals to obtain second judgment signals, setting judgment thresholds based on two adjacent second judgment signals, and determining corresponding symbols and output bits according to the magnitude relation between the second judgment signals and the judgment thresholds so as to complete signal demodulation.
Similarly, if the receiving distance is greater than the set value, a coherent receiving mode is adopted to receive the signal, and the average value of 3, 1, -2 and-4 of coherent detection output is removed by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5.
At this time, median values of two adjacent second decision signals, namely-2.5, 0 and 2.5, are taken as decision thresholds.
The following is a specific example for further explanation:
as shown in fig. 2, in the schematic diagram of the modulation and adaptive receiving scheme of the optical wireless system adopted in the present invention, firstly, the hardware structure of the transmitting end remains unchanged, and still adopts the method of intensity receiving, and the data stream generates probability shaping symbols through mapping, and the rules are as shown in fig. 3, and the PAM4 is taken as an example, and the principle of the modulation signals of other orders is the same, which is not described herein. I.e. the mapping symbols of 00, 01, 10 and 11 are respectively 3, 1, -2 and-4; for simplicity of explanation, it is assumed that the sign of the optical signal is linearly corresponding to the voltage value thereof to generate signal voltages of 3V, 1V, -2V and-4V respectively, and when intensity modulation is performed by using the optical intensity modulator with MZ structure, the bias point is set to be zero power point, so that the optical signal generated by modulation is linearly mapped with the electrical signal, and for convenience of explanation, the modulated optical signals are 3, 1, -2 and-4 respectively. Opposite sign indicates 180 out of phase and intensity is the absolute value of its signal.
At the receiving end, when the distance is relatively close, a scheme of intensity receiving is adopted, so that the cost of receiving hardware is reduced. The optical signals are detected and output to be about 1, 2, 3 and 4; the output signal after taking the average value is a first judgment signal R1, and-1, 0 and 1 are taken as judgment thresholds, and the judgment scheme is as follows:
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
When the distance is far, a scheme of coherent reception is adopted to improve the receiving sensitivity. The optical signal is output to be about 3, 1, -2 and-4 through coherent detection; the output signal after taking the average value is a second judgment signal R2, and-2.5, 0 and 2.5 are taken as judgment thresholds, and the judgment scheme is as follows:
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
The signal demodulation is completed through the demodulation mode, and the system can adaptively allocate the receiving ends at different positions according to different distances of the receiving power, so that the low-cost requirement can be met, and the purpose of long-distance optical wireless transmission can be realized.
In summary, it should be noted that, the scheme in the present application still keeps the original intensity modulation system unchanged, and a set of adaptively receivable PAM signals is generated by changing the position of the polarization point of the light intensity modulator. At the receiving end, the self-adaptive receiving mode combining intensity receiving and coherent receiving is adopted, so that the requirement of low cost is met, and the range extension of the optical wireless transmission system is realized. The cost of the optical wireless transmission system is reduced, and the practicability of the system is improved.
Compared with the original modulation scheme, the bias point of the modulation scheme is set at a zero power point. While the PAM signal amplitude is set to a different value. At the receiving end, the receiving end with a relatively short distance can still adopt an intensity detection mode, and the signal can still be identified through intensity detection due to different PAM signal amplitudes, and the signal is recovered by adopting a coherent detection method for the receiving end with a relatively long distance. Besides the sensitivity improvement brought by coherent reception, the Euclidean distance of the signal is doubled compared with the intensity detection, so that the receiving sensitivity is greatly improved, and the coverage area of the optical wireless signal is also greatly improved.
In a second aspect, embodiments of the present application further provide a spatial optical communication system for adaptive detection of PAM signals, including:
the transmitting terminal equipment is used for configuring the symbols generated by mapping the logic bits of the PAM signals at the transmitting terminal to obtain the symbols with equal intervals of positive and negative types, and the interval between the adjacent positive and negative symbols is larger than the interval between the adjacent positive and negative symbols;
the receiving end equipment is used for receiving signals in an intensity detection mode when the receiving distance is smaller than a set value at the receiving end, obtaining first judgment signals after removing the mean value of the output signals, setting judgment thresholds based on two adjacent first judgment signals, and determining corresponding symbols and logic bits according to the size relation between the first judgment signals and the judgment thresholds so as to complete signal demodulation;
when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
Further, in an embodiment, the transmitting device configures, at a transmitting end, a symbol mapped and generated by a logic bit of a PAM signal to obtain a symbol with equal intervals between two types, and an interval between two adjacent positive and negative symbols is greater than an interval between two adjacent positive and negative symbols, including:
when the PAM signal is a PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
Further, in an embodiment, the sending end device is configured to:
setting signal voltages generated by the symbols linearly corresponding to the voltage values of the symbols to be 3V, 1V, -2V and-4V respectively;
and at the transmitting end, the MZ intensity modulator is adopted for modulation, and the bias point of the MZ intensity modulator is set at a zero power point, so that the optical signal and the electric signal generated by modulation are in linear mapping.
Further, in an embodiment, when the receiving distance is smaller than a set value, the receiving end device receives a signal in an intensity detection manner, and removes an average value of the output signal to obtain a first decision signal, sets a decision threshold based on two adjacent first decision signals, and determines a corresponding symbol and a logic bit according to a size relationship between the first decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 1, 2, 3 and 4 of the intensity detection output by 2.5 to obtain a first judgment signal R1: -1.5, -0.5, 0.5 and 1.5;
taking-1, 0 and 1 as decision thresholds;
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
Further, in an embodiment, when the receiving distance is greater than a set value, the receiving end device receives the signal in a coherent receiving manner, and removes the average value of the output signal to obtain a second decision signal, sets a decision threshold based on two adjacent second decision signals, and determines a corresponding symbol and an output bit according to the magnitude relation between the second decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 3, 1, -2 and-4 of the coherent detection output by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5;
taking-2.5, 0 and 2.5 as decision thresholds;
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
The foregoing description is only of the preferred embodiments of the present application, and is not intended to limit the scope of the claims, and all equivalent structures or equivalent processes using the descriptions and drawings of the present application, or direct or indirect application in other related technical fields are included in the scope of the claims of the present application.
Claims (10)
1. The space optical communication method for the PAM signal self-adaptive detection is characterized by comprising the following steps of:
at a transmitting end, configuring symbols generated by mapping logic bits of PAM signals to obtain symbols with equal intervals of positive and negative types, wherein the interval between adjacent positive and negative symbols is larger than the interval in the positive and negative symbols;
at a receiving end, when the receiving distance is smaller than a set value, a signal is received in an intensity detection mode, an output signal is subjected to mean value removal to obtain a first judgment signal, a judgment threshold is set based on two adjacent first judgment signals, and corresponding symbols and logic bits are determined according to the magnitude relation between the first judgment signals and the judgment threshold so as to complete signal demodulation;
when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
2. The method for adaptive detection of PAM signal spatial optical communication according to claim 1, wherein, at the transmitting end, symbols generated by mapping logic bits of PAM signal are configured to obtain symbols with equal intervals between positive and negative types, and an interval between adjacent positive and negative symbols is larger than an interval between positive and negative symbols, comprising:
when the PAM signal is a PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
3. The spatial optical communication method for PAM signal adaptive detection according to claim 2, wherein:
setting signal voltages generated by the symbols linearly corresponding to the voltage values of the symbols to be 3V, 1V, -2V and-4V respectively;
and at the transmitting end, the MZ intensity modulator is adopted for modulation, and the bias point of the MZ intensity modulator is set at a zero power point, so that the optical signal and the electric signal generated by modulation are in linear mapping.
4. The method for adaptive detection of PAM signal spatial optical communication according to claim 3, wherein when the receiving distance is smaller than a set value, the method for receiving signals by adopting an intensity detection mode, removing an average value of the output signals to obtain first decision signals, setting a decision threshold based on two adjacent first decision signals, and determining corresponding symbols and logic bits according to a size relationship between the first decision signals and the decision threshold to complete signal demodulation comprises:
removing the average value of 1, 2, 3 and 4 of the intensity detection output by 2.5 to obtain a first judgment signal R1: -1.5, -0.5, 0.5 and 1.5;
taking-1, 0 and 1 as decision thresholds;
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
5. The adaptive detection spatial optical communication method of PAM signal according to claim 4, wherein when the receiving distance is greater than a set value, a coherent receiving manner is adopted to receive the signal, and a second decision signal is obtained after an output signal is de-averaged, a decision threshold is set based on two adjacent second decision signals, and corresponding symbols and output bits are determined according to a size relationship between the second decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 3, 1, -2 and-4 of the coherent detection output by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5;
taking-2.5, 0 and 2.5 as decision thresholds;
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
6. A spatial optical communication system for PAM signal adaptive detection, wherein the spatial optical communication system for PAM signal adaptive detection comprises:
the transmitting terminal equipment is used for configuring the symbols generated by mapping the logic bits of the PAM signals at the transmitting terminal to obtain the symbols with equal intervals of positive and negative types, and the interval between the adjacent positive and negative symbols is larger than the interval between the adjacent positive and negative symbols;
the receiving end equipment is used for receiving signals in an intensity detection mode when the receiving distance is smaller than a set value at the receiving end, obtaining first judgment signals after removing the mean value of the output signals, setting judgment thresholds based on two adjacent first judgment signals, and determining corresponding symbols and logic bits according to the size relation between the first judgment signals and the judgment thresholds so as to complete signal demodulation;
when the receiving distance is larger than the set value, a signal is received by adopting a coherent receiving mode, the output signal is subjected to mean value removal to obtain a second judgment signal, a judgment threshold is set on the basis of two adjacent second judgment signals, and corresponding symbols and output bits are determined according to the size relation between the second judgment signal and the judgment threshold so as to complete signal demodulation.
7. The adaptive detection spatial optical communication system of PAM signal according to claim 6, wherein the transmitting device configures, at the transmitting end, symbols mapped by logic bits of PAM signal to obtain symbols with equal intervals between positive and negative types, and an interval between adjacent positive and negative symbols is greater than an interval between positive and negative symbols, and the adaptive detection spatial optical communication system comprises:
when the PAM signal is a PAM4 signal, the mapped generated symbols configuring the logic bits 00, 01, 10, and 11 of the PAM4 signal are 3, 1, -2, and-4 in order.
8. The PAM signal adaptive detection spatial optical communication system according to claim 7, wherein the transmitting device is configured to:
setting signal voltages generated by the symbols linearly corresponding to the voltage values of the symbols to be 3V, 1V, -2V and-4V respectively;
and at the transmitting end, the MZ intensity modulator is adopted for modulation, and the bias point of the MZ intensity modulator is set at a zero power point, so that the optical signal and the electric signal generated by modulation are in linear mapping.
9. The PAM signal adaptive detection spatial optical communication system of claim 8, wherein when the receiving distance is smaller than a set value, the receiving device receives the signal in an intensity detection manner, and removes an average value of the output signal to obtain a first decision signal, sets a decision threshold based on two adjacent first decision signals, and determines a corresponding symbol and a logic bit according to a size relationship between the first decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 1, 2, 3 and 4 of the intensity detection output by 2.5 to obtain a first judgment signal R1: -1.5, -0.5, 0.5 and 1.5;
taking-1, 0 and 1 as decision thresholds;
when R1 is less than or equal to-1, judging to be a symbol 1, and outputting a logic bit to be 01;
when R1 is more than-1 and less than or equal to 0, judging the symbol as symbol 2, and outputting logic bits as 10;
when R1 is more than 0 and less than or equal to 1, judging as a symbol 3, and outputting logic bits as 00;
when R1 > 1, the decision is symbol 4, and the output logic bit is 11.
10. The adaptive PAM signal detection spatial optical communication system of claim 9, wherein when the receiving distance is greater than a set value, the receiving device receives the signal in a coherent receiving manner, and removes an average value of the output signal to obtain a second decision signal, sets a decision threshold based on two adjacent second decision signals, and determines a corresponding symbol and an output bit according to a size relationship between the second decision signal and the decision threshold, so as to complete signal demodulation, including:
removing the average value of 3, 1, -2 and-4 of the coherent detection output by-0.5 to obtain a first judgment signal R2:3.5, 1.5, -1.5 and-3.5;
taking-2.5, 0 and 2.5 as decision thresholds;
when R2 is less than or equal to-2.5, the symbol is judged to be-4, and the output logic bit is 11;
when R2 is more than 2.5 and less than or equal to 0, judging the symbol as symbol-2, and outputting logic bits as 10;
when R2 is more than 0 and less than or equal to 2.5, judging the symbol as 1, and outputting logic bits as 01;
when R2 is more than 2.5, the judgment is 3, and the output logic bit is 00.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311866055.6A CN117792509A (en) | 2023-12-28 | 2023-12-28 | PAM signal self-adaptive detection space optical communication method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311866055.6A CN117792509A (en) | 2023-12-28 | 2023-12-28 | PAM signal self-adaptive detection space optical communication method and system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117792509A true CN117792509A (en) | 2024-03-29 |
Family
ID=90389072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311866055.6A Pending CN117792509A (en) | 2023-12-28 | 2023-12-28 | PAM signal self-adaptive detection space optical communication method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117792509A (en) |
-
2023
- 2023-12-28 CN CN202311866055.6A patent/CN117792509A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7180957B2 (en) | Technique for utilizing spare bandwidth resulting from the use of a transition-limiting code in a multi-level signaling system | |
| US20060126751A1 (en) | Technique for disparity bounding coding in a multi-level signaling system | |
| EP1330083B1 (en) | Digital data transmitter | |
| JP4884959B2 (en) | Optical digital transmission system and method | |
| EP1331776B1 (en) | Digital data transmitter | |
| US7391834B2 (en) | Pulse amplitude modulated system with reduced intersymbol interference | |
| US8976890B2 (en) | Multilevel amplitude modulation device, multilevel amplitude demodulation device, transmission system including these, multilevel amplitude modulation method, and multilevel amplitude demodulation method | |
| CN109842448B (en) | Orthogonal modulation labeling method based on reverse 4PPM line coding | |
| EP1503501A1 (en) | Duobinary to binary decoder | |
| US20030206602A1 (en) | Multivalued FSK modulation system | |
| CN117792509A (en) | PAM signal self-adaptive detection space optical communication method and system | |
| CN105846905B (en) | A kind of optical signal sending, receiving method and device | |
| WO2020095916A1 (en) | Optical transmission system | |
| KR101138630B1 (en) | Duobinary receiver | |
| Dai et al. | Hybrid PPM-BPSK for transmitted reference pulse cluster systems in UWB and 60-GHz channels | |
| CN107852247A (en) | Method, emitter, receiver and the optical network system of receiving and transmitting signal | |
| Islam et al. | A Novel Encoding Scheme for Improving the Bandwidth Efficiency of DPPM | |
| Latha | Performance evaluation of different line Codes | |
| Zamkotsian et al. | Layered offset hierarchical QAM modulation for intersymbol interference reduction | |
| Wei et al. | Noncoherent block-coded TAPSK | |
| US7469022B2 (en) | Methods and apparatus for symmetrical phase-shift keying | |
| EP3954068A1 (en) | Encoding and decoding communications traffic in a pulse amplitude modulation format and optical apparatus for same | |
| Rizwan et al. | Shadow encoding scheme: A smart line coding scheme for network communication | |
| Yang et al. | Minimum Euclidean distance for continuous phase modulation with time-limited phase shaping pulses | |
| JP2017143338A (en) | Light transmission and reception system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |