CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging

Abstract

The invention discloses a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging, a sending signal sent by a sending end comprises repeated frames, and the repeated frames comprise a plurality of identical repeated quantum key frames, so that a receiving end can obtain a plurality of corresponding receiving frames to construct an average frame; the signal-to-noise ratio of the average frame is obviously higher than that of a single receiving frame, and correspondingly, the correlation coefficient between the average frame received by the receiving end and the quantum key frame to be sent by the sending end is also obviously higher than that between the single receiving frame received by the receiving end and the quantum key frame to be sent by the sending end. The correlation coefficient of the average frame is obviously improved, and the transmission performance of the signal is effectively enhanced, so that the quantum key distribution is carried out by adopting the repeated frame method, the longer transmission distance can be realized, the accuracy of signal demodulation is effectively improved, the system performance is enhanced, and the communication security is ensured. The method is widely applied to the technical field of quantum communication.

Description

Technical Field

[0001] The invention relates to the technical field of quantum communication, and in particular to a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging. Background Art

[0002] With the rapid development of quantum communication technology, the continuous variable quantum key distribution (CVQKD) system has attracted attention as an effective means to achieve quantum secure communication. The CVQKD system uses the principles of quantum mechanics to generate keys by encoding and transmitting quantum states, thereby achieving secure communication between two communicating parties. However, due to the weak characteristics of quantum signals, the CVQKD system is easily affected by interference factors such as noise in practical applications, and faces limitations in transmission distance and bandwidth, which seriously restricts its communication rate and signal quality. Summary of the invention

[0003] In view of the fact that the current continuous variable quantum key distribution process is easily affected by interference factors such as noise, and faces technical problems such as limitations on transmission distance and bandwidth, the purpose of the present invention is to provide a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging.

[0004] On the one hand, an embodiment of the present invention includes a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging, which is applied to a transmitting end. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes:

[0005] Obtain quantum key frame;

[0006] Generate a repeated frame; the repeated frame includes a plurality of repeated quantum key frames;

[0007] The repeated frame is sent to a receiving end.

[0008] Further, the obtaining of the quantum key frame includes:

[0009] Generate quantum random numbers;

[0010] The quantum key frame is generated according to the quantum random number.

[0011] Further, generating repeated frames includes:

[0012] Determine the number of repetitions;

[0013] Copying the quantum key frame according to the number of repetitions to obtain a plurality of identical quantum key frames;

[0014] Generate synchronization sequence;

[0015] The quantum key frames are sequentially arranged after the synchronization sequence to form the repeated frame.

[0016] Further, determining the number of repetitions includes:

[0017] Obtain the correlation coefficient of the feedback from the receiving end;

[0018] The number of repetitions is dynamically adjusted according to the correlation coefficient.

[0019] Furthermore, the number of repetitions is negatively correlated with the correlation coefficient.

[0020] Further, sending the repeated frame to the receiving end includes:

[0021] Generate single frequency laser;

[0022] Modulating the single frequency laser using the repeated frame to obtain a transmission signal;

[0023] The transmission signal is transmitted to the receiving end through an optical fiber channel.

[0024] On the other hand, an embodiment of the present invention further includes a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging, which is applied to a receiving end. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes:

[0025] A receiving signal is obtained from the transmitting end;

[0026] Acquire multiple reception frames from the received signal;

[0027] Performing averaging processing on each of the received frames to obtain an average frame;

[0028] A quantum key is determined based on the averaged frame.

[0029] Further, the acquiring a plurality of received frames from the received signal comprises:

[0030] Acquire a synchronization sequence from the received signal;

[0031] Performing frame synchronization on the received signal according to the synchronization sequence;

[0032] The received frames are sequentially divided from the received signal after frame synchronization.

[0033] Furthermore, the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging also includes:

[0034] Obtaining the quantum key frame of the sender from the lossless channel;

[0035] A correlation coefficient is determined according to the quantum key frame and the average frame.

[0036] Furthermore, the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging also includes:

[0037] The correlation coefficient is fed back to the sending end.

[0038] On the other hand, an embodiment of the present invention also includes a computer device, including a memory and a processor, the memory is used to store at least one program, and the processor is used to load at least one program to execute the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging in the embodiment.

[0039] On the other hand, an embodiment of the present invention also includes a computer-readable storage medium, which stores a program executable by a processor. When the program executable by the processor is executed by the processor, it is used to execute the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging in the embodiment.

[0040] The beneficial effects of the present invention are as follows: in the embodiment, the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes repeated frames in the transmission signal sent by the transmitting end, and the repeated frames include multiple identical repeated quantum key frames, so that the receiving end can obtain multiple corresponding received frames to construct an average frame; since the average frame is constructed by averaging multiple received frames, the signal-to-noise ratio of the average frame is significantly higher than that of a single received frame, and accordingly, the correlation coefficient between the average frame received by the receiving end and the quantum key frame to be sent by the transmitting end is also significantly higher than the correlation coefficient between the single received frame received by the receiving end and the quantum key frame to be sent by the transmitting end. The correlation coefficient of the average frame has been significantly improved, which effectively enhances the transmission performance of the signal. Therefore, the use of the repeated frame method for quantum key distribution can achieve a longer transmission distance, effectively improve the accuracy of signal demodulation, enhance system performance, and thus ensure communication security. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the structure of a quantum communication system to which the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging can be applied in an embodiment;

[0042] Figure 2 A step diagram of a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging performed by a transmitting end in an embodiment;

[0043] Figure 3 A schematic diagram of the data structure of sending and receiving signals in the embodiment;

[0044] Figure 4 A step diagram of a CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging performed by a receiving end in an embodiment;

[0045] Figure 5Schematic diagram of the effect of the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging in the embodiment. DETAILED DESCRIPTION

[0046] The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging in this embodiment can be applied to Figure 1 In the quantum communication system shown in Figure 1, Figure 1 The quantum communication system includes a transmitting end, a receiving end and an optical fiber channel, wherein the transmitting end needs to send information to the receiving end through the optical fiber channel. The information to be sent is mainly presented in the form of a quantum transmission signal. The content of the information to be sent can be a dual-polarization quantum key, thereby realizing dual-polarization quantum key distribution (also called continuous variable quantum key distribution, Continuous Variable Quantum Key Distribution, CVQKD) from the transmitting end to the receiving end.

[0047] In this embodiment, the complete CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes steps S1A-S3A executed by the transmitting end and steps S1B-S4B executed by the receiving end.

[0048] Reference Figure 1 The transmitting end includes a laser light source, a frame repetition module and a signal modulation module. Specifically, the frame repetition module can perform steps S1A-S3A.

[0049] Reference Figure 2 , the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging performed by the transmitter includes the following steps:

[0050] S1A. Obtain quantum key frame;

[0051] S2A. Generate repeated frames;

[0052] S3A. Send duplicate frames to the receiving end.

[0053] In step S1A, the quantum key frame may be a quantum key that needs to be distributed to a terminal such as a receiving terminal. A quantum random number may be used as a quantum key. Specifically, a quantum random number may be generated, and then the quantum random number may be packaged to obtain a quantum key frame. In this embodiment, it is assumed that the quantum key frame only contains quantum random numbers.

[0054] In this embodiment, when the sending end executes step S2A, that is, the step of generating a repeated frame, the sending end may specifically execute the following steps:

[0055] S201A. Determine the number of repetitions;

[0056] S202A. The quantum key frame is copied according to the number of repetitions to obtain multiple identical quantum key frames;

[0057] S203A. Generate a synchronization sequence;

[0058] S204A. Arrange each quantum key frame in sequence after the synchronization sequence to form a repeated frame.

[0059] In step S201A, the transmitting end determines the number of repetitions N, where N is an integer greater than 1. Specifically, N may be a fixed value, such as N=10.

[0060] In step S202A, the transmitting end copies the quantum key frame according to the number of repetitions to obtain N quantum key frames, namely quantum key frame 1, quantum key frame 2, ... quantum key frame N, and these N quantum key frames are exactly the same as the original quantum key frame.

[0061] In step S203A, the transmitting end generates a synchronization sequence, which may include specific marking information, so that each device can identify repeated frames according to the synchronization sequence and perform frame synchronization and other processing.

[0062] In step S204A, if Figure 3 As shown, the frame repetition module in the transmitter arranges each quantum key frame in sequence after the synchronization sequence to form a large repetition frame. Figure 3 The repeated frames are synchronization sequence, quantum key frame 1, quantum key frame 2...quantum key frame N.

[0063] In this embodiment, when the transmitting end executes step S3A, that is, the step of sending a repeated frame to the receiving end, the transmitting end may specifically execute the following steps:

[0064] S301A. Generate a single frequency laser;

[0065] S302A uses repeated frames to modulate a single frequency laser to obtain a transmission signal;

[0066] S303A. Send a signal to a receiving end through an optical fiber channel.

[0067] In step S301A, a laser light source in the transmitting end generates a single frequency laser beam, which is input into the signal modulation module. In step S302A, the frame repetition module inputs the repeated frame obtained by executing steps S201A-S204A into the signal modulation module, and the signal modulation module modulates the repeated frame into the single frequency laser beam, thereby obtaining a transmission signal, that is, a repeated frame in the form of laser beam. The signal modulation module sends the modulated single frequency laser beam, i.e., the transmission signal, to the optical fiber channel, and the single frequency laser beam carrying the repeated frame information will be transmitted along the optical fiber channel to the receiving end.

[0068] Since the transmission signal in the optical fiber channel will be affected by physical effects such as noise, the form of the signal received by the receiving end from the optical fiber channel may be different from the communication signal sent by the transmitting end in terms of spectrum and signal-to-noise ratio. Therefore, in this embodiment, the signal received by the receiving end from the optical fiber channel is called a received signal to distinguish it from the transmission signal sent by the transmitting end.

[0069] In this embodiment, since the signal is carried by laser, unless otherwise specified, the "transmitted signal" itself and the laser beam carrying the transmitted signal may not be distinguished. Similarly, the "received signal" itself and the laser beam carrying the received signal may not be distinguished.

[0070] Reference Figure 1 The receiving end includes a signal receiving module, a digital signal processing module and a correlation coefficient calculation module.

[0071] In this embodiment, refer to Figure 4 , the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging performed by the receiving end includes the following steps:

[0072] S1B. Receive a received signal from the transmitting end;

[0073] S2B. Obtain multiple received frames from the received signal;

[0074] S3B performs average processing on each received frame to obtain an average frame;

[0075] S4B. Determining the quantum key based on the average frame.

[0076] In step S1B, the signal receiving module in the receiving end receives the laser beam from the optical fiber channel to obtain a received signal. In an ideal situation such as no noise and no dispersion in the optical fiber channel, the received signal is the same as the transmitted signal and contains the same information.

[0077] The signal receiving module sends the received signal to the digital signal processing module, and the digital signal processing module performs digital signal processing on the received signal. Specifically, in step S1B, the digital signal processing module performs down-conversion processing on the received signal.

[0078] In this embodiment, when the receiving end executes step S2B, that is, the step of obtaining multiple received frames from the received signal, the following steps may be specifically performed:

[0079] S201B obtains a synchronization sequence from the received signal;

[0080] S202B performs frame synchronization on the received signal according to the synchronization sequence;

[0081] S203B. Sequentially divide each received frame from the received signal after frame synchronization.

[0082] Steps S201B-S203B may be processed by a digital signal processing module. In step S201B, the digital signal processing module extracts a synchronization sequence from the received signal, executes step S202B, performs frame synchronization on the received signal according to the synchronization sequence, and then executes step S203B.

[0083] In step S203B, refer to Figure 3 , the digital signal processing module can divide the received signal according to the frame length that is the same as the quantum key frame negotiated with the transmitter, thereby dividing multiple receiving frames such as receiving frame 1, receiving frame 2... receiving frame N in sequence. Among them, receiving frame 1 corresponds to quantum key frame 1, that is, in an ideal case, receiving frame 1 is the same as quantum key frame 1 and contains the same information; similarly, receiving frame 2 corresponds to quantum key frame 2... receiving frame N corresponds to quantum key frame N.

[0084] After executing steps S201B-S203B, the digital signal processing module executes step S3B to perform average processing on each received frame. In this embodiment, after obtaining all N received frames such as received frame 1, received frame 2, ... received frame N, the digital signal processing module can perform average processing on all N received frames. In this embodiment, assuming that a single received frame is represented by x1[i], i=1, 2...N, then the following formula can be used

[0085]

[0086] Calculate to obtain the average frame x obtained by averaging all N received frames average [N].

[0087] In step S4B, the digital signal processing module may process the average frame x average [N] performs matching filtering and phase recovery and other processing, and the obtained data is determined as the quantum key assigned by the transmitter, thereby realizing the distribution of quantum keys.

[0088] The principle of the CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging in this embodiment is that: the transmission signal sent by the transmitting end includes repeated frames, and the repeated frames include multiple identical repeated quantum key frames, so that the receiving end can obtain multiple corresponding received frames to construct an average frame; Figure 5, because the average frame is constructed by averaging multiple received frames (corresponding to the quantum key frame), the signal-to-noise ratio (SNR) of the average frame is significantly higher than that of a single received frame. Accordingly, the correlation coefficient between the average frame received by the receiving end and the quantum key frame to be sent by the sending end is also significantly higher than the correlation coefficient between the single received frame received by the receiving end and the quantum key frame to be sent by the sending end. The correlation coefficient of the average frame has been significantly improved, which effectively enhances the transmission performance of the signal. Therefore, the use of repeated frames for quantum key distribution can achieve a longer transmission distance.

[0089] In this embodiment, refer to Figure 1 The receiving end also calculates the correlation coefficient during the reception and processing of the received signal, controls the receiving process according to the correlation coefficient, and feeds back the correlation coefficient to the transmitting end through the optical fiber channel.

[0090] Specifically, when sending repeated frames, the transmitting end may send them in the order of synchronization sequence, quantum key frame 1, quantum key frame 2, etc. In this way, when the receiving end executes step S2B, it does not need to wait for receiving the complete repeated frame before segmenting, but can segment the received data immediately, so that the receiving end can synchronously receive the synchronization sequence, receiving frame 1, receiving frame 2, etc. in sequence.

[0091] In this embodiment, the receiving end can also calculate the total average frame x after receiving N receiving frames, that is, receiving data equivalent to a complete repeated frame. average [N], obtain the quantum key frame from the sender through a lossless channel (for example, a classical optical fiber channel is established between the sender and the receiver, which is almost lossless), and then calculate the average frame x average [N] correlation coefficient with the quantum key frame N . Correlation coefficient definition N It is an indicator to measure the strength of the linear relationship between the data related to the quantum random key received by the receiving end and the quantum key frame of the sending end. N The value of is between -1 and 1, where 1 indicates a perfect positive correlation, -1 indicates a perfect negative correlation, and 0 indicates no linear relationship. N Close to 1.

[0092] In this embodiment, the receiving end can use the correlation coefficient correlation N Feedback to the sending end. The sending end receives the correlation coefficient of the feedback from the receiving end. NAfterwards, the number of repetitions can be dynamically adjusted according to the correlation coefficient when executing step S201A, that is, determining the number of repetitions. N Negative correlation.

[0093] For example, if the sender receives the correlation coefficient N , correlation coefficient N The smaller it is, the sender will increase the number of repetitions N accordingly. In this way, when the sender sends the next repeated frame (a new repeated frame generated by a new quantum random number), the repeated frame sent will be longer because N becomes larger; correlation coefficient N The larger the value, the smaller the number of repetitions N will be. In this way, when the sender sends the next repeated frame (a new repeated frame generated by a new quantum random number), the repeated frame sent will be shorter because N becomes smaller.

[0094] In this embodiment, the receiving end feeds back the correlation coefficient to the transmitting end. The principle of the transmitting end adjusting the number of repetitions according to the correlation coefficient is that if x1[i] represents a quantum key frame in a repeated frame, then x1[i] can be regarded as the sum of the signal s1[i] and the noise n1[i], that is,

[0095] x1[i]=s1[i]+n1[i],1≤i≤,

[0096] Where, is the number of samples. A repeated frame contains N quantum key frames, so the repeated frame x N [i] can be expressed as the sum of these N quantum key frames, that is,

[0097]

[0098] in It represents the addition of N frames of noise. Since the mean of the random noise n[i] is 0, when N approaches infinity, the addition of N frames of noise also approaches 0. The correlation coefficient in this embodiment is an index to measure the strength of the linear relationship between two data frames. The value of the correlation coefficient ranges between -1 and 1, where 1 represents a perfect positive correlation, -1 represents a perfect negative correlation, and 0 represents no linear relationship. Therefore, the correlation coefficient between the signal frame obtained by adding and then averaging N frames of quantum key frames and the signal at the sending end approaches 1. Since the repetition times N cannot be infinity in an actual system, the specific value of the repetition times N will affect the noise level in the received signal. Specifically, the larger the repetition times N, the smaller the noise. However, the larger the repetition times N, the lower the communication efficiency. In the case of a larger correlation coefficient, it indicates that a smaller repetition times N is required. Therefore, the sending end can reduce the number of remaining quantum key frames in transmitting the same repeated frame, or reduce the length of transmitting the next repeated frame, so as to obtain a higher communication efficiency while ensuring the accurate transmission of quantum keys. On the contrary, in the case of a smaller correlation coefficient, it indicates that a larger repetition times N is required. Therefore, the sending end can increase the number of remaining quantum key frames in transmitting the same repeated frame, or increase the length of transmitting the next repeated frame, so as to ensure the accurate transmission of quantum keys.

[0099] In this embodiment, when the receiving end executes step S2B, that is, the step of obtaining multiple received frames from the received signal, the following steps can be specifically executed:

[0100] S204B. When the number of the segmented received frames is equal to or greater than the number threshold, perform an averaging process on all the segmented received frames except the last received frame to obtain an average intermediate frame;

[0101] S205B. Determine the correlation coefficient according to the last received frame and the average intermediate frame among all the segmented received frames;

[0102] S206B. When the correlation coefficient is equal to or greater than the coefficient threshold, interrupt the receiving process of the received signal;

[0103] S207B. When the correlation coefficient is less than the coefficient threshold, continue the receiving process of the received signal.

[0104] Assume that before executing steps S204B - S207B, the receiving end has segmented M received frames such as received frame 1, received frame 2... received frame M (M is an integer and 1 < M < N), and M is equal to or greater than the number threshold (the number threshold can be a fixed value such as 3). Then when currently executing step S204B, the last received frame is received frame M, and the other received frames except the last received frame are received frame 1, received frame 2... received frame M - 1. The digital signal processing module of the receiving end can use the following formula

[0105]

[0106] Calculate to get the average intermediate frame x average [M-1], that is, the average value of the first M-1 received frames.

[0107] In step S205B, a correlation coefficient is determined based on the last received frame of all segmented received frames and the average intermediate frame;

[0108] S206B. When the correlation coefficient is equal to or greater than the coefficient threshold, the receiving process of the received signal is interrupted;

[0109] S207B. When the correlation coefficient is less than the coefficient threshold, continue the receiving process of the received signal.

[0110] In step S205B, the digital signal processing module can calculate the last received frame, that is, the received frame M and the average intermediate frame x average [M-1] correlation coefficient M，averageM-1 ; If the correlation coefficient M，averageM-1 If it is equal to or greater than the coefficient threshold, then the correlation coefficient can be determined. M，averageM-1 is relatively large, the receiving end may execute step S206B to interrupt the receiving process of the received signal, that is, no longer receive the receiving frame M+1 (corresponding to the quantum key frame M+1), the receiving frame M+2 (corresponding to the quantum key frame M+2) ... the receiving frame N (corresponding to the quantum key frame N), etc.; if the correlation coefficient correlation M，averageM-1 If it is less than the coefficient threshold, then the correlation coefficient can be determined. M，averageM-1 The receiving end can execute step S207B to continue the receiving process of the received signal, thereby continuing to receive the receiving frame M+1 (corresponding to the quantum key frame M+1), the receiving frame M+2 (corresponding to the quantum key frame M+2)... the receiving frame N (corresponding to the quantum key frame N), etc.

[0111] In this embodiment, the principle of executing steps S204B-S207B is: M，averageM-1 It represents the correlation coefficient between multiple reception frames currently received by the receiving end. If the correlation coefficient is relatively large, it means that the reception frames currently received can accurately recover the quantum key, so that the reception process of the reception signal can be ended in advance; conversely, if the correlation coefficient is relatively small, then the reception process of the reception signal must be continued to obtain more reception frames.

[0112] In this embodiment, steps S204B-S207B form a loop, and the receiving end can execute steps S204B-S207B once every time a new receiving frame is segmented, thereby ensuring the transmission rate and accuracy of the quantum key.

[0113] For example, in this embodiment, the receiving end can M，averageM-1 Feedback to the sender. The sender receives the correlation coefficient correlation M，averageM-1 , correlation coefficient M，averageM-1 The smaller it is, the sender will increase the number of repetitions N accordingly. In this way, when the sender sends the next quantum key frame M+1, quantum key frame M+2... quantum key frame N in the current repeated frame, more quantum key frames will be sent because N becomes larger; correlation coefficient M，averageM-1 The larger the number, the smaller the number of repetitions N will be adjusted accordingly by the sender. In this way, when the sender sends the next quantum key frame M+1, quantum key frame M+2, and so on in the current repeated frame, fewer quantum key frames will be sent because N becomes smaller.

[0114] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present disclosure are only relative to the relative positional relationship of the components of the present disclosure in the accompanying drawings. The singular forms of "a", "" and "the" used in the present disclosure are also intended to include the plural forms, unless the context clearly indicates other meanings. In addition, unless otherwise defined, all technical and scientific terms used in this embodiment have the same meaning as those generally understood by those skilled in the art. The terms used in the specification of this embodiment are only for describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this embodiment includes any combination of one or more related listed items.

[0115] It should be understood that, although the term first, second, third etc. may be adopted to describe various elements in the present disclosure, these elements should not be limited to these terms. These terms are only used to distinguish the same type of elements from each other. For example, without departing from the scope of the present disclosure, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element. The use of any and all examples or exemplary language ("for example", "such as" etc.) provided by the present embodiment is only intended to better illustrate embodiments of the present invention, and unless otherwise required, the scope of the present invention will not be limited.

[0116] It should be appreciated that embodiments of the present invention may be implemented or enforced by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable memory. The method may be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner - according to the methods and drawings described in the specific embodiments. Each program may be implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, if desired, the program may be implemented in assembly or machine language. In any case, the language may be a compiled or interpreted language. In addition, the program may be run on a programmed dedicated integrated circuit for this purpose.

[0117] In addition, the operations of the process described in this embodiment may be performed in any suitable order, unless otherwise indicated in this embodiment or otherwise clearly contradicted by the context. The process described in this embodiment (or variations and / or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions, and may be implemented as a code (e.g., executable instructions, one or more computer programs, or one or more applications) executed on one or more processors in common, by hardware or a combination thereof. A computer program includes a plurality of instructions that may be executed by one or more processors.

[0118] Further, the method can be implemented in any type of computing platform that is operably connected to a suitable computer, including but not limited to a personal computer, a minicomputer, a mainframe, a workstation, a network or distributed computing environment, a separate or integrated computer platform, or in communication with a charged particle tool or other imaging device, etc. Various aspects of the present invention can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into a computing platform, such as a hard disk, an optical read and / or write storage medium, a RAM, a ROM, etc., so that it can be read by a programmable computer, and when the storage medium or device is read by the computer, it can be used to configure and operate the computer to perform the process described herein. In addition, the machine-readable code, or part thereof, can be transmitted via a wired or wireless network. When such media includes instructions or programs that implement the above steps in conjunction with a microprocessor or other data processor, the invention of this embodiment includes these and other different types of non-transitory computer-readable storage media. When programmed according to the methods and techniques of the present invention, the present invention also includes the computer itself.

[0119] The computer program can be applied to input data to perform the functions of the present embodiment, thereby converting the input data to generate output data stored in a non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the converted data represents a physical and tangible object, including a specific visual depiction of the physical and tangible object produced on the display.

[0120] The above are only preferred embodiments of the present invention. The present invention is not limited to the above embodiments. As long as the technical effects of the present invention are achieved by the same means, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention. Within the scope of protection of the present invention, its technical solutions and / or implementation methods may have various modifications and changes.

Claims

1. A CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging, applied to a transmitting end, characterized in that: The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes: Obtain quantum key frame; Generate a repeated frame; the repeated frame includes a plurality of repeated quantum key frames; The repeated frame is sent to a receiving end.

2. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 1, characterized in that: The obtaining of the quantum key frame comprises: Generate quantum random numbers; The quantum key frame is generated according to the quantum random number.

3. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 1, characterized in that: The generating of repeated frames comprises: Determine the number of repetitions; Copying the quantum key frame according to the number of repetitions to obtain a plurality of identical quantum key frames; Generate synchronization sequence; The quantum key frames are sequentially arranged after the synchronization sequence to form the repeated frame.

4. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 3, characterized in that: Determining the number of repetitions comprises: Obtain the correlation coefficient of the feedback from the receiving end; The number of repetitions is dynamically adjusted according to the correlation coefficient.

5. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 4, characterized in that: The number of repetitions is negatively correlated with the correlation coefficient.

6. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to any one of claims 1 to 5, characterized in that: The sending the repeated frame to the receiving end includes: Generate single frequency laser; Modulating the single frequency laser using the repeated frame to obtain a transmission signal; The transmission signal is transmitted to the receiving end through an optical fiber channel.

7. A CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging, applied to a receiving end, characterized in that: The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging includes: A receiving signal is obtained from the transmitting end; Acquire multiple reception frames from the received signal; Performing averaging processing on each of the received frames to obtain an average frame; A quantum key is determined based on the averaged frame.

8. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 7, characterized in that: The step of obtaining a plurality of received frames from the received signal comprises: Acquire a synchronization sequence from the received signal; Performing frame synchronization on the received signal according to the synchronization sequence; The received frames are sequentially divided from the received signal after frame synchronization.

9. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 7, characterized in that: The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging also includes: Obtaining the quantum key frame of the sender from the lossless channel; A correlation coefficient is determined according to the quantum key frame and the average frame.

10. The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging according to claim 9, characterized in that: The CVQKD signal-to-noise ratio enhancement method based on repeated frame averaging also includes: The correlation coefficient is fed back to the sending end.

Images