A method for evaluating bit error rate of an optical communication system using a photon-level energy receiver under periodic pulse interference

Abstract

The application belongs to the technical field of error rate evaluation of optical communication systems. The application provides an error rate evaluation method of an optical communication system with a photon-level energy receiver under periodic pulse interference. The method comprises: obtaining a probability density function of the interference signal and the value of the interference signal and the corresponding probability according to the duty cycle, the periodic coefficient and the asynchronous time difference coefficient of the interference signal; determining the modulation mode and the value of the legal signal; obtaining the average output photon number of the optical receiving end in the legal signal time slot according to the value of the legal signal, the value of the interference signal and the corresponding probability; and obtaining the average error rate of the optical receiving end according to the average output photon number of the optical receiving end in the legal signal time slot. The disclosed embodiment adopts an integer periodic coefficient or an integer reciprocal, can approximate the actual situation, and can obtain a better error rate evaluation effect. Whether the interference signal and the legal signal are synchronous or not, the error rate of the system under interference can be evaluated.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure relates to the technical field of error rate evaluation of optical communication systems, in particular to an error rate evaluation method of an optical communication system with a photon-level energy receiver under periodic pulse interference. BACKGROUND

[0002] When the optical communication system is working, there may be potential illegal users around who want to interfere with the legal receiver and block the communication link. Here, the optical communication system is not limited to wired optical communication (including optical fiber communication) and wireless optical communication (such as free space optical communication, visible light communication, ultraviolet light communication, underwater optical communication, etc.). At this time, the research scenario can be represented as Figure 1 .

[0003] At this time, the optical interference end (J) randomly sends periodic pulse signals to interfere with the optical receiving end (R), expecting to block the link from the optical transmitting end (T) to the optical receiving end (R). In this case, the present application proposes an error rate evaluation method, which lays a foundation for subsequent design of anti-interference methods.

[0004] Assuming that the pulse sent by the optical interference end has a duty cycle of , the method used in the existing literature assumes that the probability of having an interference signal in a signal time slot of the optical receiving end is , and the probability of having no interference signal is . However, this implies two ideal situations: 1. The interference pulse and the legal signal are synchronized, that is, the starting point of the interference pulse is consistent with the starting point of the legal signal; 2. The time length of the pulse in the interference pulse is an integer multiple of the symbol period of the legal signal. In actual situations, the assumption conditions on which the error rate evaluation method under pulse interference is based are too harsh, because the interference users and the legal users are difficult to meet the above two assumptions due to conflicts of interest. Therefore, there is a large difference between the error rate evaluation of the system with the method and the actual situation.

[0005] Therefore, it is necessary to improve one or more problems existing in the related technical solutions.

[0006] It should be noted that this part aims to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art merely because it is included in this part. SUMMARY

[0007] The purpose of the embodiment of the present disclosure is to provide an error rate evaluation method of an optical communication system with a photon-level energy receiver under periodic pulse interference, thereby at least overcoming one or more problems caused by the limitations and defects of the related art.

[0008] According to the embodiment of the present disclosure, a method for evaluating bit error rate of an optical communication system using a photon-level energy receiver under periodic pulse interference is provided, and the method comprises the following steps:

[0009] According to the duty cycle, the periodic coefficient and the asynchronous time difference coefficient of the interference signal, the probability density function of the interference signal is obtained, and the value of the interference signal and the corresponding probability are obtained according to the probability density function of the interference signal;

[0010] The modulation mode is determined, and the value of the legal signal is determined;

[0011] According to the value of the legal signal, the value of the interference signal and the corresponding probability, the average output photon number of the optical receiving end in the legal signal time slot is obtained;

[0012] According to the average output photon number of the optical receiving end in the legal signal time slot, the average bit error rate of the optical receiving end is obtained.

[0013] Further, in the step of obtaining the probability density function of the interference signal according to the duty cycle, the periodic coefficient and the asynchronous time difference coefficient of the interference signal, the step comprises:

[0014] When the periodic coefficient ,

[0015] If ,

[0016]

[0017] If , and ,

[0018]

[0019] If , and ,

[0020]

[0021] When the periodic coefficient ,

[0022]

[0023] wherein, is the probability density function of the interference signal, is the value of the interference signal, is the periodic coefficient, is the asynchronous time difference coefficient, is the duty cycle of the interference signal, represents taking the maximum integer, represents taking the minimum integer, represents taking the integer part.

[0024] Further, in the step of determining the modulation mode and determining the value of the legal signal, comprising:

[0025] determining the modulation mode; wherein the modulation mode at least includes on-off keying modulation, pulse position modulation and quaternary pulse amplitude modulation;

[0026] if the modulation mode is on-off keying modulation and pulse position modulation, the value of the legal signal is 0 or 1;

[0027] if the modulation mode is quaternary pulse amplitude modulation, the value of the legal signal is 0, 1, 2 or 3.

[0028] Further, in the step of obtaining the average output photon number of the optical receiving end in the legal signal time slot according to the value of the legal signal, the value of the interference signal and the corresponding probability, comprising:

[0029] based on the value of the legal signal, the value of the interference signal and the corresponding probability, combining the coefficient of the TR link, the coefficient of the JR link, the peak optical power of the optical transmitting end, the peak optical power of the optical interference end and the average background photon number in the legal signal time slot, obtaining the average output photon number of the optical receiving end in the legal signal time slot; wherein the JR link is the link from the optical interference end J to the optical receiving end R, and the TR link is the link from the optical transmitting end T to the optical receiving end R.

[0030] Further, the expression of the average output photon number of the optical receiving end in the legal signal time slot is:

[0031]

[0032] wherein, is the coefficient of the TR link, is the coefficient of the JR link, and , , is the link gain of the TR link, is the link gain of the JR link, is the energy of one photon, is the time slot of the legal signal, is the Planck constant, is the optical frequency, is the peak optical power of the optical transmitting end, is the peak optical power of the optical interference end, is the average background photon number in the legal signal time slot.

[0033] ​​​​Further, in the step of obtaining the average bit error rate of the optical receiving end according to the average number of output photons of the optical receiving end in the time slot of the legal signal, the step comprises:

[0034] According to the relationship between the average number of output photons of the optical receiving end in the time slot of the legal signal and the actual number of photons received by the optical receiving end, a probability density function and a cumulative distribution function are obtained.

[0035] According to the probability density function, the cumulative distribution function and the value of the legal signal, a conditional bit error rate of the optical receiving end is obtained.

[0036] According to the conditional bit error rate of the optical receiving end, an average bit error rate of the optical receiving end is obtained.

[0037] Further, the expression of the probability density function is:

[0038]

[0039] wherein, the actual number of photons received by the optical receiving end;

[0040] The expression of the cumulative distribution function is:

[0041]

[0042] wherein, is a summation coefficient;

[0043] The expression of the average bit error rate of the optical receiving end is:

[0044]

[0045] wherein, is the conditional bit error rate of the optical receiving end, is the probability density function of the asynchronous time difference coefficient.

[0046] The technical scheme provided by the embodiment of the disclosure can include the following beneficial effects:

[0047] In the embodiment of the disclosure, by using the bit error rate evaluation method of the optical communication system with the photon-level energy receiver under the periodic pulse interference, on the one hand, compared with the existing scheme based on , the probability density function of is directly obtained. This method innovatively introduces an approximate method with an integer periodic coefficient or an integer reciprocal, which is closer to the actual scenario. Through this method, we can obtain a more accurate bit error rate related probability density function, thereby significantly improving the accuracy and reliability of the bit error rate evaluation. On the other hand, this method also deeply considers the antagonistic relationship between the interfering users and the legal users, and specially focuses on the asynchronous step scenario that may exist between the interfering signals and the legal signals. For this complex situation, the proposed The probability density function of the asynchronous time difference coefficient can comprehensively reflect the influence of the asynchronous time difference coefficient on the system bit error rate. This characteristic enables the method to more accurately evaluate the system bit error rate in a complex interference environment, providing strong support for system design and performance optimization. The related content of this method provides an important theoretical basis and practical guidance for the design of optical communication systems in the presence of interference, especially systems using photon-level energy receivers, and the establishment of interference suppression methods. This will help to further promote the development of optical communication technology and improve the anti-interference ability and overall performance of communication systems. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the disclosure. It is to be clearly understood that the drawings are merely representative of some embodiments of the disclosure and that additional drawings can be derived from these drawings by one of ordinary skill in the art without paying creative labor.

[0049] Figure 1 shows a schematic diagram of an optical communication system in an exemplary embodiment of the present disclosure;

[0050] Figure 2 shows a step diagram of a method for evaluating the bit error rate of an optical communication system using a photon-level energy receiver under periodic pulse interference in an exemplary embodiment of the present disclosure;

[0051] Figure 3 shows a schematic diagram of the relationship between the interference signal and the legal signal in an exemplary embodiment of the present disclosure;

[0052] Figure 4 shows the bit error rate of an ultraviolet optical communication system in the presence of interference in an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0053] Example implementations will now be described with reference to the drawings; however, example implementations can be implemented in many different forms and should not be construed as being limited to the examples set forth herein; rather, these implementations are provided so that the disclosure will be more thorough and complete, and will fully convey the concept of example implementations to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more implementations.

[0054] In addition, the accompanying drawings are only schematic diagrams of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities, which do not necessarily have to correspond to physically or logically independent entities.

[0055] This example implementation provides a method for evaluating the bit error rate of an optical communication system employing a photonic-level energy receiver under periodic pulse interference. (Reference) Figure 2 As shown, the bit error rate assessment method for an optical communication system using a photonic-level energy receiver under periodic pulse interference may include steps S101 to S104.

[0056] Step S101: Based on the duty cycle, period coefficient, and asynchronous time difference coefficient of the interference signal, obtain the probability density function of the interference signal, and obtain the value of the interference signal and its corresponding probability based on the probability density function of the interference signal.

[0057] Step S102: Determine the modulation scheme and the value of the valid signal;

[0058] Step S103: Based on the value of the legitimate signal, the value of the interference signal and their corresponding probabilities, obtain the average number of output photons at the optical receiver within the legitimate signal time slot;

[0059] Step S104: Obtain the average bit error rate of the optical receiver based on the average number of output photons of the optical receiver within the valid signal time slot.

[0060] The bit error rate assessment method for optical communication systems using photonic-level energy receivers under periodic pulse interference described above offers advantages over existing solutions. Based on this, directly obtain The proposed method innovatively introduces an approximation method where the period coefficient is an integer or its reciprocal is an integer, to better reflect real-world scenarios. This approach allows us to obtain a more accurate probability density function related to the bit error rate (BER), significantly improving the accuracy and reliability of BER assessment. Furthermore, this method deeply considers the adversarial relationship between interfering and legitimate users, paying particular attention to asynchronous scenarios where interfering and legitimate signals may exist. To address this complex situation, the proposed method… The probability density function can comprehensively reflect the impact of the asynchronous time difference coefficient on the system bit error rate. This characteristic enables the method to more accurately assess the system bit error rate under complex interference environments, providing strong support for system design and performance optimization. The related content of this method provides an important theoretical foundation and practical guidance for the design of optical communication systems under interference conditions, especially systems employing photonic-level energy receivers, and for the establishment of interference suppression methods. This will help promote the further development of optical communication technology and improve the anti-interference capability and overall performance of communication systems.

[0061] Below, we will refer to Figures 1 to 4 The steps of the bit error rate assessment method for an optical communication system using a photonic-level energy receiver under periodic pulse interference described in this example embodiment will be explained in more detail.

[0062] In steps S101 to S103, an optical communication system includes an optical transmitting end and an optical receiving end, as shown in Figure 1 . The communication link between the two is a TR link, and the transmitted is a legal signal, as shown in Figure 3 . The pulse modulation method is used, including but not limited to on-off keying (OOK) modulation, pulse position (PPM) modulation, etc. The time slot of the legal signal is assumed to be . The optical interference end transmits periodic pulses to interfere with the legal user, and the duty cycle of the interference signal is , and the period of a single interference pulse is , where . Since the transmission time of the interference pulse is random, the time difference between the time when the optical receiving end receives the interference signal and the start of the current legal signal time slot is , where . Here, it is assumed that is an integer or the reciprocal is an integer. That is, the period of the interference pulse is an integer multiple of the legal signal time slot, or the legal signal time slot is an integer multiple of the interference pulse period. At this time, this method can accurately evaluate the bit error rate of the system when the above assumption is met, and can be approximated by or its reciprocal for cases that do not meet the above assumption. For example, , take or approximate calculation, , take or approximate calculation.

[0063] Since the receiving end uses a receiving end photon level energy receiver, the signal output by the receiving end in the legal signal time slot is the number of photons reaching the time slot (such as using a photon counting receiver) or the total sum of random electrical signals generated by the photons (such as using a photomultiplier tube (PMT), avalanche diode (APD), etc.). Therefore, the essence is to determine the number of photons reaching the legal signal time slot. For convenience of expression, the present application takes the photon counting receiver as a demonstration. The signal output model using photomultiplier tubes (PMT), avalanche diodes (APD), etc. is also available, and the method is similar, which will not be described in detail here.

[0064] At this time, the average number of photons output by the optical receiving end in the legal signal time slot is:

[0065] (1)

[0066] where and represent the coefficients of the TR link and the JR link, respectively. Where , , and The link gains for the TR and JR links are respectively, including factors such as path loss, transmit antenna gain, receive antenna gain, and detector quantum efficiency. For the energy of a photon, Let be Planck's constant. It represents the frequency of light. The peak optical power at the optical transmitter is determined by the characteristics of the light source at the optical transmitter. The peak optical power at the optical interference end is determined by the light source characteristics of the optical interference section. This refers to the optical signal value transmitted by the optical transmitter within a valid time slot. The specific value depends on the modulation method used and the information being transmitted, such as OOK or PPM. It can be 0 or 1; for quaternary pulse amplitude modulation (4-PAM), then It can be 0, , 1. However, this application is not limited to the above modulation methods. This represents the average background photon count within the valid signal time slot. It is determined by the duration of the high-level interference pulse's influence within the legal time slot.

[0067] This application provides probability density function as follows:

[0068] 1. When hour:

[0069] 1.1 If Then there is

[0070] (2)

[0071] 1.2, if Then there is

[0072] 1.2.1, If

[0073] (3)

[0074] 1.2.2, if

[0075] (4)

[0076] 2. When hour

[0077] (5)

[0078] in, Indicates less than The largest integer, Indicates greater than The smallest integer, Indicates taking The integer part of the above probability density function. The form can be transformed mathematically to other forms without changing the final calculation result. These will not be listed individually in this application.

[0079] So, the actual number of photons received by the optical receiver? Obey The Poisson distribution with mean is as follows:

[0080] (6)

[0081] In step S104, OOK modulation is used as an example to illustrate how to calculate the average bit error rate. The methods for calculating the average bit error rate for other modulation methods are all existing technologies and will not be described in detail here.

[0082] when hour, , The representation is defined as: when hour, Therefore, the conditional bit error rate at the optical receiver is:

[0083] (7)

[0084] in, The decision threshold is determined by the optical receiver and is related to its ability to detect interference signals. It can be set here as follows: This indicates that the optical receiver can accumulate and detect the average power of the interfering optical signal over a period of time. However, The setting is not unique; its setting only affects the calculation result, but does not affect the implementation of this patent. Represented by the natural logarithm. The cumulative distribution function representing the Poisson distribution:

[0085] (8)

[0086] Considering that the jammer, in order to protect itself, will shut down after being powered on for a period of time, and then power on again, repeating this process continuously, therefore, It is also a random variable, and its distribution is assumed to be... Therefore, the average bit error rate at the optical receiver is:

[0087] (9)

[0088] Wherein formula (9) can be calculated by existing numerical integration method, including but not limited to rectangular method, Newton method, Gauss method and other numerical integration formula.

[0089] In a specific embodiment, taking the ultraviolet light communication system as an example, the following is set Each curve ensures comparison under the same conditions, and the calculation result is as shown in Figure 4 The existing approximate method adopts the assumption that the probability of a signal time slot of the light receiving end having an interference signal is The probability of having no interference signal is It can be seen that when continuously increases, the existing approximate method can obtain good results. However, when is small, the existing approximate method has a large difference from the simulation result.

[0090] The method proposed in the application can accurately calculate is an integer or is an integer, the reciprocal of Figure 3 The theoretical and simulation results in the application verify the effectiveness of the theoretical method proposed in the application. When is not an integer or the reciprocal of is not an integer, for example, Figure 3 in the application or , the integer part can be approximately calculated, for example, the BER result of is approximately calculated by , and the difference between them is better than that of the existing approximate method. For example, when , the simulation BER of is about , the BER of the existing approximate method is , and the result of the application is . For example, the BER result of is approximately calculated by , and the difference between them is better than that of the existing approximate method. For example, when , the simulation BER of is almost the same as the result of the application, about , and the BER of the existing approximate method is .

[0091] Through the above method for evaluating the bit error rate of the optical communication system using a photon-level energy receiver under periodic pulse interference, on the one hand, compared with the existing scheme based on , the the probability density function of the bit error rate. This method innovatively introduces an approximation method with an integer periodic coefficient or its reciprocal as an integer, to better fit the actual scenario. Through this method, we can obtain a more accurate bit error rate-related probability density function, thereby significantly improving the accuracy and reliability of the bit error rate evaluation. On the other hand, this method also takes into account the antagonistic relationship between the interfering users and the legitimate users, and pays special attention to the asynchronous scenario that may exist between the interfering signals and the legitimate signals. For this complex situation, the proposed probability density function can comprehensively reflect the influence of the asynchronous time difference coefficient on the system bit error rate. This feature enables the method to more accurately evaluate the system bit error rate in a complex interference environment, providing strong support for system design and performance optimization. The related content of this method provides an important theoretical basis and practical guidance for the design of optical communication systems in the presence of interference, especially systems using photon-level energy receivers, and the establishment of interference suppression methods. This will help to further develop optical communication technology and improve the anti-interference ability and overall performance of communication systems.

[0092] It should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like in the above description indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present disclosure.

[0093] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0094] In the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0095] In the embodiments of the present disclosure, unless specifically defined and limited otherwise, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "over" of a first feature to a second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. "Under", "below" and "underneath" of a first feature to a second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0096] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification.

[0097] Other embodiments of the present disclosure will be apparent to those skilled in the art upon consideration of the specification and practice of the applications disclosed. The present application is intended to cover any variations, uses or adaptive changes of the present disclosure following the general principles of the present disclosure and including known or customary practices in the art not disclosed in the present disclosure. The specification and examples are only considered as exemplary, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A method for evaluating the bit error rate of an optical communication system employing a photonic-level energy receiver under periodic pulse interference, characterized in that, The method includes: Based on the duty cycle, period coefficient, and asynchronous time difference coefficient of the interference signal, the probability density function of the interference signal is obtained, and the value of the interference signal and its corresponding probability are obtained based on the probability density function of the interference signal. Determine the modulation scheme and the value of the valid signal; Based on the values ​​of the legitimate signal, the interference signal, and their corresponding probabilities, the average number of output photons at the optical receiver within the legitimate signal time slot is obtained. The average bit error rate of the optical receiver is obtained based on the average number of output photons within the valid signal time slot; where... When the period coefficient hour, like ,but: like ,and ,but: like ,and ,but: When the period coefficient hour, in, Let be the probability density function of the interference signal. The value of the interference signal. For periodic coefficients, For asynchronous time difference coefficients, The duty cycle of the interference signal. This indicates taking the largest integer. This indicates taking the smallest integer. This indicates taking the integer part.

2. The method for evaluating the bit error rate of an optical communication system using a photonic-level energy receiver under periodic pulse interference as described in claim 1, characterized in that, The steps of determining the modulation scheme and determining the value of the valid signal include: Determine the modulation method; wherein the modulation method includes at least on / off keying modulation, pulse position modulation and quaternary pulse amplitude modulation; When the modulation method is on / off keying modulation and pulse position modulation, the value of the valid signal is... It can be 0 or 1; If the modulation method is quaternary pulse amplitude modulation, the value of the valid signal is... 0, , Or 1.

3. The method for evaluating the bit error rate of an optical communication system using a photonic-level energy receiver under periodic pulse interference as described in claim 2, characterized in that, The step of obtaining the average output photon number at the optical receiver within the time slot of the legal signal, based on the values ​​of the legal signal, the interference signal, and their corresponding probabilities, includes: Based on the values ​​of the legitimate signal and the interference signal and their corresponding probabilities, combined with the coefficients of the TR link, the coefficients of the JR link, the peak optical power of the optical transmitter, the peak optical power of the optical interference end, and the average background photon count within the legitimate signal time slot, the average output photon count of the optical receiver within the legitimate signal time slot is obtained; where the JR link is the link from the optical interference end J to the optical receiver R, and the TR link is the link from the optical transmitter T to the optical receiver R.

4. The method for evaluating the bit error rate of an optical communication system using a photonic-level energy receiver under periodic pulse interference as described in claim 3, characterized in that, The expression for the average output photon number at the optical receiver within a valid signal time slot is: in, For the coefficients of the TR link, Let be the coefficient of the JR link, and , , For the link gain of the TR link, For the link gain of the JR link, For the energy of a photon, To define the time slots for legitimate signals, Let be Planck's constant. For light frequency, This represents the peak optical power at the optical transmitter. This represents the peak optical power at the optical interference end. This represents the average background photon count within the valid signal time slot.

5. The method for evaluating the bit error rate of an optical communication system using a photonic-level energy receiver under periodic pulse interference as described in claim 4, characterized in that, The step of obtaining the average bit error rate of the optical receiver based on the average number of output photons within the valid signal time slot includes: Based on the relationship between the average number of photons output by the optical receiver and the actual number of photons received by the optical receiver within the valid signal time slot, the probability density function and cumulative distribution function are obtained. The conditional bit error rate of the optical receiver is obtained based on the probability density function, cumulative distribution function, and the value of the legitimate signal. The average bit error rate of the optical receiver is obtained based on the conditional bit error rate of the optical receiver.

6. The method for evaluating the bit error rate of an optical communication system using a photonic-level energy receiver under periodic pulse interference as described in claim 5, characterized in that, The expression for the probability density function is: in, The actual number of photons received by the optical receiver; The expression for the cumulative distribution function is: in, For the summation coefficient; The expression for the average bit error rate at the optical receiver is: in, Let be the conditional bit error rate at the optical receiver. This is the probability density function of the asynchronous time difference coefficient.

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