Pulse phase modulation method based on quantum Fourier transform

Abstract

The invention discloses a pulse phase modulation method based on quantum Fourier transform, and the method comprises the steps: selecting a corresponding quantum bit to represent the phase of each pulse signal, and enabling the phase state of each quantum bit to correspond to a digit or symbol; the sending end sends out the quantum state subjected to quantum Fourier transform and phase modulation, and the receiving end carries out reverse quantum Fourier transform to decode the received quantum state and recover original digital data. According to the invention, information in a pulse signal is coded on a phase, so that the information is more precisely packaged, the bandwidth efficiency is greatly improved, in addition, quantum Fourier transform is included, pulse phase modulation can work under higher bandwidth efficiency, and meanwhile, through larger data capacity, the characteristic of quantum calculation is finally utilized, so that the bandwidth efficiency is greatly improved. Therefore, phase information and frequency domain conversion are efficiently processed on quantum bits, and the performance and energy efficiency of a digital communication system are optimized.

Description

Technical Field

[0001] The invention relates to the field of communications, and in particular to a pulse phase modulation method based on quantum Fourier transform. Background Art

[0002] With the rapid iteration of communication technology, the requirements for high communication efficiency and big data throughput are gradually increasing, especially in cloud computing and data centers, as well as industries such as the Internet of Things, video streaming, and telemedicine. These scenarios all require a balance between high efficiency and big data throughput to ensure the timeliness, integrity, and security of data while meeting user requirements for service quality and experience.

[0003] In the existing technology, the above problems are usually optimized by using network protocol optimization and network coding technology (FEC and AMC, etc.). However, with the introduction of protocol optimization, the system and network architecture may become more complex, which will increase the complexity of configuration, management and maintenance. In addition, the optimized protocol will be incompatible with old equipment, software or protocol versions, which requires additional conversion equipment or software updates, increasing the cost and workload of deployment and maintenance. Summary of the invention

[0004] The object of the present invention is to provide a pulse phase modulation method based on quantum Fourier transform to solve the above problems.

[0005] The present invention is achieved through the following technical solutions: A pulse phase modulation method based on quantum Fourier transform, comprising: Step 1: Data encoding; Encoding digital data as the amplitude distribution of a quantum state; Step 2: Apply quantum Fourier transform; Applying quantum Fourier transform to the encoded quantum state, quantum Fourier transform converts the original quantum state from the basic representation to the representation in the frequency domain, which contains phase information; Step 3: Phase modulation; According to the result of the quantum Fourier transform in step 2, a corresponding quantum bit is selected to represent the phase of each pulse signal, and the phase state of each quantum bit corresponds to a number or symbol; Step 4: Send and receive; The transmitter sends out the quantum state that has undergone quantum Fourier transform and phase modulation, and the receiver performs an inverse quantum Fourier transform to decode the received quantum state and restore the original digital data.

[0006] The present invention transmits digital information by changing the phase of a pulse signal, encoding the information in the pulse signal in the phase, thereby more accurately packaging the information and greatly improving the bandwidth efficiency. In addition, the present invention includes a quantum Fourier transform, so that pulse phase modulation can work at a higher bandwidth efficiency, while at the same time having a larger data capacity. Finally, the characteristics of quantum computing are utilized to efficiently process phase information and frequency domain conversion on quantum bits, thereby optimizing the performance and energy efficiency of digital communication systems and achieving high-efficiency communication.

[0007] Preferably, the data encoding method is bidirectional amplitude encoding, wherein the bidirectional amplitude encoding converts classical data into quantum states through angle encoding and amplitude encoding.

[0008] Preferably, the specific implementation of angle coding is dense angle coding, wherein the encoded information includes the rotation angle information and phase information of the quantum bit.

[0009] In the present invention, the specific implementation method of angle coding is dense angle coding. Compared with traditional binary coding, dense angle coding can achieve higher coding efficiency and has stronger fault tolerance because information can be quickly transmitted and exchanged with each other through the change of a small number of bits, thereby improving processing speed and efficiency.

[0010] Preferably, the specific implementation of amplitude coding is top-down amplitude coding, which includes the following contents: Process the data vector to obtain the corresponding angle tree structure; Starting from the root node of the angle tree, quantum gate operations are used to encode the quantum state; According to the structure of the angle tree, each node is encoded from top to bottom, and the amplitude information of the entire quantum state is gradually constructed; Through an iterative process, a normalized quantum state is eventually constructed on the quantum bit, the amplitude of which reflects the information of the original data vector.

[0011] Bidirectional amplitude coding has good flexibility and can adjust the coding method according to actual needs. In addition, under top-down amplitude coding, it achieves a higher line speed through a smaller line width, greatly improving the coding efficiency.

[0012] Preferably, in step 2, when applying the quantum Fourier transform, the quantum state encoded in step 1, that is, the standard orthogonal basis state Convert to superposition of another ground state, the conversion formula is as follows: in, is the number of qubits, is the base of natural logarithms, is an imaginary unit. For any quantum state , QFT maps it to ,in yes The discrete Fourier transform result of is pi, and is an integer, where is an integer from 0 to N-1, indicating the index of the input state. It is an integer from 0 to N-1, indicating the index of the output state. Specifically, The meaning is: a cycle is A complex sequence of and The specific terms in the sequence are determined. Each term in this sequence is a point on the complex plane with unit modulus (that is, absolute value 1) but different phase angles. The phase angle is given by OK, when or When changes, the phase angle also changes accordingly, resulting in a rotation in the complex plane.

[0013] Preferably, in step 2, the quantum Fourier transform also includes a Shor algorithm, which includes the following steps: Step 2.1: Choose a random number x and check if x and N are coprime; Where N is a positive integer to be decomposed, which should be the product of two large prime numbers, and a is a randomly selected integer that is coprime with N, used to construct a modular exponential function; Step 2.2: Compute periodic functions using quantum circuits The period r; Where r is the modular exponential function cycle, that is, to satisfy The smallest positive integer of ; Step 2.3: Use quantum Fourier transform to estimate the period r; Step 2.4: Use classical algorithms such as continued fraction expansion to extract prime factors of N from period r.

[0014] The core of Shor's algorithm is to transform the problem of decomposing large numbers into the problem of finding periods. Quantum computing can use superposition states for parallel computing, so the period of a function can be quickly found through quantum algorithms. Shor is used in the present invention mainly to realize quantum secure communication, as well as its stability and bit error rate.

[0015] Preferably, the phase modulation in step 3 is specifically used in a QKD scheme of time and phase hybrid coding; Among them, the communicating parties use single-photon pulses to encode information. Time coding is achieved by imposing different time delays on the pulses, and phase coding is achieved by changing the phase state of photons. The sender of the information will emit a rectangular pulse with a very short duration and randomly apply or not apply a delay to each pulse to generate a time-coded key. At the information receiving end, the sending state of the information sender is inferred by detecting photons in a specific time window.

[0016] The present invention uses a QKD scheme of mixed time and phase coding. In the traditional phase coding scheme, only the pulses that interfere can be used for coding, which usually has only a 50% probability. In the mixed coding scheme, the pulses that do not interfere also carry time coding information, which increases the number of effectively used pulses, thereby improving the coding rate. In addition, the scheme also provides higher security. Since the system generates time coding keys and phase coding keys at the same time, these two sets of keys can be used flexibly: one set is used for communication, and the other set is used to monitor potential eavesdropping, or the two sets of keys are combined into a new key to enhance security.

[0017] Preferably, in the time coding, a timing synchronization method is included, which specifically includes the following contents: The signal pulses are sampled using an unsynchronized local clock source, and the clock offset is estimated using a clock error detection algorithm; After the clock offset is detected, a feedback interpolation algorithm is used to compensate for the influence of the clock offset, wherein the difference algorithm includes a parabolic interpolation algorithm and a Lagrange interpolation algorithm; The peak value of the pulse signal is accurately collected by precisely delaying the rising edge of the clock. The sampling at the receiving end is triggered by the delayed clock to achieve automatic alignment of the data.

[0018] The present invention uses a timing synchronization method, in which the clock offset is estimated by a clock error detection algorithm, such as an early-late gate algorithm based on variance. This algorithm can effectively suppress the influence of shot noise on the detection results in quantum scenarios and improve the detection accuracy.

[0019] Preferably, in step 4, the carrier of the quantum state is photon, and the quantum channel is optical fiber, so as to realize the sending and receiving of the quantum state.

[0020] Preferably, any of the above encoding methods or phase modulation methods includes an anti-interference step for environmental noise.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention transmits digital information by changing the phase of a pulse signal, and encodes the information in the pulse signal in the phase, thereby more accurately packaging the information and greatly improving the bandwidth efficiency. In addition, the present invention includes a quantum Fourier transform, so that pulse phase modulation can work at a higher bandwidth efficiency. At the same time, through a larger data capacity, the characteristics of quantum computing are finally utilized, so that phase information and frequency domain conversion can be efficiently processed on quantum bits, thereby optimizing the performance and energy efficiency of digital communication systems and achieving high-efficiency communication.

[0022] 2. In the present invention, the specific implementation method of angle coding is dense angle coding. Compared with traditional binary coding, dense angle coding can achieve higher coding efficiency and has stronger fault tolerance because information can be quickly transmitted and exchanged with each other by changing a small number of bits, thereby improving processing speed and efficiency.

[0023] 3. Bidirectional amplitude coding has good flexibility and can adjust the coding method according to actual needs. In addition, under top-down amplitude coding, it achieves a higher line speed through a smaller line width, greatly improving the coding efficiency.

[0024] 4. The core of Shor's algorithm is to transform the problem of decomposing large numbers into the problem of finding periods. Quantum computing can use superposition states for parallel computing, so the period of a function can be quickly found through quantum algorithms. Shor is used in the present invention mainly to realize quantum secure communication, as well as its stability and bit error rate.

[0025] 5. The present invention uses a QKD scheme with mixed time and phase coding. In the traditional phase coding scheme, only the pulses that interfere can be used for coding, which usually has only a 50% probability. In the hybrid coding scheme, the pulses that do not interfere also carry time coding information, which increases the number of effectively used pulses, thereby improving the coding rate. In addition, the scheme also provides higher security. Since the system generates time coding keys and phase coding keys at the same time, these two sets of keys can be used flexibly: one set is used for communication, and the other set is used to monitor potential eavesdropping, or the two sets of keys are combined into a new key to enhance security.

[0026] 6. The present invention uses a timing synchronization method, in which the clock offset is estimated by a clock error detection algorithm, such as an early-late gate algorithm based on variance. This algorithm can effectively suppress the impact of shot noise on the detection results in quantum scenarios and improve detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention.

[0028] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention. It should be noted that relational terms such as the terms "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0032] Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a list of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of more restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0033] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0034] Embodiment: A pulse phase modulation method based on quantum Fourier transform, comprising: Step 1: Data encoding; Encoding digital data as the amplitude distribution of a quantum state; Step 2: Apply quantum Fourier transform; Applying quantum Fourier transform to the encoded quantum state, quantum Fourier transform converts the original quantum state from the basic representation to the representation in the frequency domain, which contains phase information; Step 3: Phase modulation; According to the result of the quantum Fourier transform in step 2, a corresponding quantum bit is selected to represent the phase of each pulse signal, and the phase state of each quantum bit corresponds to a number or symbol; Step 4: Send and receive; The transmitter sends out the quantum state that has undergone quantum Fourier transform and phase modulation, and the receiver performs an inverse quantum Fourier transform to decode the received quantum state and restore the original digital data.

[0035] It should be noted that the pulse phase modulation in the present invention is based on the quantum state. It converts the digital signal into a quantum state, processes the quantum state information through quantum Fourier transform, modulates the processed quantum state information and the phase information accordingly, and finally sends the quantum state information out. The present invention combines the pulse conversion of the digital signal with the phase modulation of the quantum state, utilizes the characteristics of quantum, greatly improves the data transmission rate, and has high confidentiality.

[0036] The present invention transmits digital information by changing the phase of a pulse signal, encoding the information in the pulse signal in the phase, thereby more accurately packaging the information and greatly improving the bandwidth efficiency. In addition, the present invention includes a quantum Fourier transform, so that pulse phase modulation can work at a higher bandwidth efficiency, while at the same time having a larger data capacity. Finally, the characteristics of quantum computing are utilized to efficiently process phase information and frequency domain conversion on quantum bits, thereby optimizing the performance and energy efficiency of digital communication systems and achieving high-efficiency communication.

[0037] In this embodiment, the data encoding method is bidirectional amplitude encoding, wherein the bidirectional amplitude encoding converts classical data into quantum states through angle encoding and amplitude encoding.

[0038] In this embodiment, the specific implementation method of angle coding is dense angle coding, in which the encoded information includes the rotation angle information and phase information of the quantum bit.

[0039] In the present invention, the specific implementation method of angle coding is dense angle coding. Compared with traditional binary coding, dense angle coding can achieve higher coding efficiency and has stronger fault tolerance because information can be quickly transmitted and exchanged with each other through the change of a small number of bits, thereby improving processing speed and efficiency.

[0040] In this embodiment, the specific implementation of amplitude coding is top-down amplitude coding, which includes the following contents: Process the data vector to obtain the corresponding angle tree structure; Starting from the root node of the angle tree, quantum gate operations are used to encode the quantum state; According to the structure of the angle tree, each node is encoded from top to bottom, and the amplitude information of the entire quantum state is gradually constructed; Through an iterative process, a normalized quantum state is eventually constructed on the quantum bit, the amplitude of which reflects the information of the original data vector.

[0041] Bidirectional amplitude coding has good flexibility and can adjust the coding method according to actual needs. In addition, under top-down amplitude coding, it achieves a higher line speed through a smaller line width, greatly improving the coding efficiency.

[0042] In this embodiment, in step 2, when applying the quantum Fourier transform, it is necessary to convert the quantum state encoded in step 1, that is, the standard orthogonal basis state Convert to superposition of another ground state, the conversion formula is as follows: in, is the number of qubits, is the base of natural logarithms, is an imaginary unit. For any quantum state , QFT maps it to ,in yes The discrete Fourier transform result of is pi, and is an integer, where is an integer from 0 to N-1, indicating the index of the input state. It is an integer from 0 to N-1, indicating the index of the output state. Specifically, The meaning is: a cycle is A complex sequence of and The specific terms in the sequence are determined. Each term in this sequence is a point on the complex plane with unit modulus (that is, absolute value 1) but different phase angles. The phase angle is given by OK, when or When changes, the phase angle also changes accordingly, resulting in a rotation in the complex plane.

[0043] In this embodiment, in step 2, the quantum Fourier transform also includes a Shor algorithm, which includes the following steps: Step 2.1: Choose a random number x and check if x and N are coprime; Where N is a positive integer to be decomposed, which should be the product of two large prime numbers, and a is a randomly selected integer that is coprime with N, used to construct a modular exponential function; Step 2.2: Compute periodic functions using quantum circuits The period r; Where r is the modular exponential function cycle, that is, to satisfy The smallest positive integer of ; Step 2.3: Use quantum Fourier transform to estimate the period r; Step 2.4: Use classical algorithms such as continued fraction expansion to extract prime factors of N from period r.

[0044] The core of Shor's algorithm is to transform the problem of decomposing large numbers into the problem of finding periods. Quantum computing can use superposition states for parallel computing, so the period of a function can be quickly found through quantum algorithms. Shor is used in the present invention mainly to realize quantum secure communication, as well as its stability and bit error rate.

[0045] In this embodiment, the phase modulation in step 3 is specifically a QKD scheme of time and phase hybrid coding; Among them, the communicating parties use single-photon pulses to encode information. Time coding is achieved by imposing different time delays on the pulses, and phase coding is achieved by changing the phase state of photons. The sender of the information will emit a rectangular pulse with a very short duration and randomly apply or not apply a delay to each pulse to generate a time-coded key. At the information receiving end, the sending state of the information sender is inferred by detecting photons in a specific time window.

[0046] The present invention uses a QKD scheme of mixed time and phase coding. In the traditional phase coding scheme, only the pulses that interfere can be used for coding, which usually has only a 50% probability. In the mixed coding scheme, the pulses that do not interfere also carry time coding information, which increases the number of effectively used pulses, thereby improving the coding rate. In addition, the scheme also provides higher security. Since the system generates time coding keys and phase coding keys at the same time, these two sets of keys can be used flexibly: one set is used for communication, and the other set is used to monitor potential eavesdropping, or the two sets of keys are combined into a new key to enhance security.

[0047] In this embodiment, the time coding includes a timing synchronization method, which specifically includes the following contents: The signal pulses are sampled using an unsynchronized local clock source, and the clock offset is estimated using a clock error detection algorithm; After the clock offset is detected, a feedback interpolation algorithm is used to compensate for the influence of the clock offset, wherein the difference algorithm includes a parabolic interpolation algorithm and a Lagrange interpolation algorithm; The peak value of the pulse signal is accurately collected by precisely delaying the rising edge of the clock. The sampling at the receiving end is triggered by the delayed clock to achieve automatic alignment of the data.

[0048] The present invention uses a timing synchronization method, in which the clock offset is estimated by a clock error detection algorithm, such as an early-late gate algorithm based on variance. This algorithm can effectively suppress the influence of shot noise on the detection results in quantum scenarios and improve the detection accuracy.

[0049] In this embodiment, in step 4, the carrier of the quantum state is photon, and the quantum channel is optical fiber, so as to realize the sending and receiving of the quantum state.

[0050] In this embodiment, any of the above encoding methods or phase modulation methods includes an anti-interference step for environmental noise.

[0051] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pulse phase modulation method based on quantum Fourier transform, characterized in that: include: Step 1: Data encoding; Encoding digital data as the amplitude distribution of a quantum state; Step 2: Apply quantum Fourier transform; Applying quantum Fourier transform to the encoded quantum state, quantum Fourier transform converts the original quantum state from the basic representation to the representation in the frequency domain, which contains phase information; Step 3: Phase modulation; According to the result of the quantum Fourier transform in step 2, a corresponding quantum bit is selected to represent the phase of each pulse signal, and the phase state of each quantum bit corresponds to a number or symbol; Step 4: Send and receive; The transmitter sends out the quantum state that has undergone quantum Fourier transform and phase modulation, and the receiver performs an inverse quantum Fourier transform to decode the received quantum state and restore the original digital data.

2. A pulse phase modulation method based on quantum Fourier transform according to claim 1, characterized in that: The data encoding method is bidirectional amplitude coding, in which bidirectional amplitude coding converts classical data into quantum states through angle coding and amplitude coding.

3. A pulse phase modulation method based on quantum Fourier transform according to claim 2, characterized in that: The specific implementation method of angle coding is dense angle coding, in which the encoded information includes the rotation angle information and phase information of the quantum bit.

4. The pulse phase modulation method based on quantum Fourier transform according to claim 3 is characterized in that: The specific implementation of amplitude coding is top-down amplitude coding, which includes the following: Process the data vector to obtain the corresponding angle tree structure; Starting from the root node of the angle tree, quantum gate operations are used to encode the quantum state; According to the structure of the angle tree, each node is encoded from top to bottom, and the amplitude information of the entire quantum state is gradually constructed; Through an iterative process, a normalized quantum state is eventually constructed on the quantum bit, the amplitude of which reflects the information of the original data vector.

5. The pulse phase modulation method based on quantum Fourier transform according to claim 1, characterized in that: In step 2, when applying the quantum Fourier transform, the quantum state encoded in step 1, that is, the standard orthogonal basis state, needs to be Convert to superposition of another ground state, the conversion formula is as follows: in, is the number of qubits, is the base of natural logarithms, is an imaginary unit; For any quantum state , QFT maps it to ,in yes The discrete Fourier transform result of is pi, and is an integer, where is an integer from 0 to N-1, indicating the index of the input state. It is an integer from 0 to N-1, indicating the index of the output state. Specifically, The meaning is: a cycle is A complex sequence of and The specific terms in the sequence are determined. Each term in this sequence is a point on the complex plane with unit modulus (that is, absolute value 1) but different phase angles. The phase angle is given by OK, when or When changes, the phase angle also changes accordingly, resulting in a rotation in the complex plane.

6. The pulse phase modulation method based on quantum Fourier transform according to claim 5, characterized in that: In step 2, the quantum Fourier transform also includes the Shor algorithm, which includes the following steps: Step 2.1: Choose a random number x and check if x and N are coprime; Where N is a positive integer to be decomposed, which should be the product of two large prime numbers, and a is a randomly selected integer that is coprime with N, used to construct a modular exponential function; Step 2.2: Compute periodic functions using quantum circuits The period r; Where r is the modular exponential function cycle, that is, to satisfy The smallest positive integer of ; Step 2.3: Use quantum Fourier transform to estimate the period r; Step 2.4: Use classical algorithms such as continued fraction expansion to extract prime factors of N from period r.

7. The pulse phase modulation method based on quantum Fourier transform according to claim 1, characterized in that: The specific phase modulation used in step 3 is a QKD scheme of time and phase hybrid coding; Among them, the communicating parties use single-photon pulses to encode information. Time coding is achieved by imposing different time delays on the pulses, and phase coding is achieved by changing the phase state of photons. The sender of the information will emit a rectangular pulse with a very short duration and randomly apply or not apply a delay to each pulse to generate a time-coded key. At the information receiving end, the sending state of the information sender is inferred by detecting photons in a specific time window.

8. The pulse phase modulation method based on quantum Fourier transform according to claim 7, characterized in that: In time coding, a timing synchronization method is included, which specifically includes the following: The signal pulses are sampled using an unsynchronized local clock source, and the clock offset is estimated using a clock error detection algorithm; After the clock offset is detected, a feedback interpolation algorithm is used to compensate for the influence of the clock offset, wherein the difference algorithm includes a parabolic interpolation algorithm and a Lagrange interpolation algorithm; The peak value of the pulse signal is accurately collected by precisely delaying the rising edge of the clock. The sampling at the receiving end is triggered by the delayed clock to achieve automatic alignment of the data.

9. The pulse phase modulation method based on quantum Fourier transform according to claim 1, characterized in that: In step 4, the carrier of the quantum state is photons, and the quantum channel is optical fiber, which realizes the sending and receiving of the quantum state.

10. A pulse phase modulation method based on quantum Fourier transform according to any one of claims 1 to 9, characterized in that: Any encoding method or phase modulation method includes a step of resisting interference with environmental noise.

Images