Delta-Sigma modulation-based radio-over-fiber frequency hopping communication and chaotic encryption integrated method and Delta-Sigma modulation-based radio-over-fiber frequency hopping communication and chaotic encryption integrated system

Abstract

The invention belongs to but is not limited to the technical field of optical communication, and particularly relates to a method and a system for integrating radio frequency hopping communication and chaotic encryption over fiber. At a transmitting end, a chaotic signal and a true random frequency hopping code are generated by utilizing endogenous high-randomness quantization noise in a DSM (Digital Subscriber Modulation) process; dual security enhancement of waveform disturbance and frequency hopping of plaintext signals is realized, and noise-like chaotic encryption signals are converted into low-order digital signals for transmission. At a receiving end, quantization noise is reconstructed from a received signal, chaotic synchronization and frequency hopping code regeneration are achieved, and frequency hopping and chaotic decryption are completed. The problem of high-quality chaos synchronization is fundamentally solved, the performance bottleneck of true random frequency hopping in a high-speed scene is broken through, nanosecond ultrafast frequency hopping and chaos encryption are realized, only a single low-order digital signal needs to be transmitted, the method is perfectly compatible with an existing communication system, and the method is suitable for large-scale popularization and application. And an efficient and feasible physical layer security solution is provided for a high-speed and high-security radio over fiber access network.

Description

Technical Field

[0001] This invention belongs to, but is not limited to, the field of optical communication technology, and particularly relates to an integrated method and system for optical wireless frequency hopping communication and chaotic encryption. Background Technology

[0002] With the development of fifth-generation mobile communication and future networks, Radio over Fiber (ROF) technology has become a key supporting technology for wireless access networks because it can distribute high-frequency wireless signals over long distances through low-loss optical fibers.

[0003] With the increase in access users and access speeds, secure RoF communication should attract attention. While fiber optic physical layer encryption has been extensively studied in RoF systems, wireless channels face increasingly severe security threats due to their open nature. Frequency-Hopping Spread Spectrum (FHSS) technology is an effective solution for ensuring wireless communication security and mitigating the effects of multipath fading. Its security essentially relies on the randomness of the frequency-hopping code. However, in high-speed communication scenarios, the processing speed of Digital Signal Processors (DSPs) is insufficient to meet the requirements of "one-time pad" technology, leading to the use of pseudo-random sequences with short periods as frequency-hopping codes, thus creating security vulnerabilities. Optical chaos, due to its inherent noise-like characteristics and initial value sensitivity, can provide theoretically perfect randomness and is considered an important means to improve communication security. However, achieving high-quality synchronization of chaotic signals between the transmitting and receiving ends in complex RoF channels is extremely challenging; even minor channel disturbances or device parameter mismatches can lead to synchronization failure. Furthermore, complex chaotic synchronization structures increase system cost and implementation difficulty.

[0004] Therefore, existing technologies present a dilemma: frequency hopping schemes lack sufficient security, while chaotic encryption schemes have limited practicality. There is an urgent need in this field for an innovative solution that fundamentally integrates the advantages of both—a solution that must possess the engineering feasibility of frequency hopping technology while introducing high-intensity randomness at the chaotic level; simultaneously, this solution must solve the synchronization problem in ROF scenarios and maintain compatibility with existing communication systems, thereby providing an integrated security solution for future high-speed, high-security RoF networks that combines theoretical sophistication with engineering feasibility.

[0005] Among the existing public technologies closest to the technical subject of this application, existing literature has proposed a scheme combining frequency hopping communication with physical layer chaotic encryption. This scheme utilizes semiconductor laser-driven chaotic synchronization to generate synchronous chaos, performs chaotic masking and frequency hopping modulation on the baseband signal at the transmitting end, transmits it through a wireless channel, and the receiving end recovers the plaintext signal through chaotic synchronization and frequency hopping demodulation. This technology reveals that fusing frequency hopping and chaotic encryption can provide an additional security layer on top of the traditional frequency hopping mode. However, it typically relies on external digital driving signals and independent chaotic synchronization mechanisms, failing to introduce a unified random source to drive encryption and frequency hopping control from the digital-to-analog conversion process itself. Furthermore, existing schemes lack systematic mechanisms for frequency hopping control sequence generation, quantization noise reconstruction, and dynamic closed-loop coordination, resulting in significant deficiencies in randomness utilization efficiency, synchronization robustness, and overall anti-attack capability. Therefore, there is an urgent need for a closed-loop secure transmission mechanism capable of constructing chaotic encryption and frequency hopping control driven by an internal random source to address the core pain points of existing technologies, such as dispersed random resource utilization, independent frequency hopping and encryption updates, and reliance on external signals for synchronization regeneration. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an integrated method and system for optical wireless frequency hopping communication and chaotic encryption.

[0007] This invention is implemented as follows: a method integrating optical wireless frequency hopping communication and chaotic encryption, comprising:

[0008] (1) Chaotic Encryption: The plaintext signal to be transmitted is encrypted using a chaotic signal and another digital chaotic sequence generated by a mathematical formula to produce a ciphertext signal; the chaotic signal is denoted as {C i}, whose encryption depth is denoted as d1; the digital chaotic sequence is denoted as {X}. i The encryption depth is denoted as d2; the plaintext is denoted as {T}. i}, the ciphertext is denoted as {T i The encryption process can be represented as follows: .

[0009] (2) Delta-Sigma Modulation (DSM) and Quantization Noise Generation: The ciphertext signal is input to the DSM. The DSM operates at a set oversampling rate to convert the input ciphertext signal into a low-order digital signal. During the DSM process, out-of-band quantization noise with high randomness is generated synchronously. A high-pass filter is used to extract the quantization noise from the low-order digital signal.

[0010] (3) Generation of chaotic signal and frequency hopping code: A portion of the quantization noise is input to the optical domain nonlinear transformation module to generate a chaotic signal, which is used to encrypt the plaintext signal at the next moment; another portion of the quantization noise is processed by quantization and hash function in sequence to generate a true random number sequence, which is used as the frequency hopping code.

[0011] (4) Generation and transmission of frequency hopping signal: A frequency-hopping radio frequency carrier is generated in the digital domain according to the frequency hopping code; and the low-order digital signal output in step (2) is modulated onto this carrier to form a frequency hopping signal; the frequency hopping electrical signal is modulated onto the optical carrier and converted into an optical signal for transmission on the RoF link.

[0012] (5) Signal reception and frequency hopping de-hopping: The receiving end performs photoelectric detection on the transmitted optical signal and converts it into an electrical signal. Using the locally regenerated frequency hopping code that is exactly the same as that of the transmitting end, the received frequency hopping signal is de-hopped and down-converted to the baseband to recover the low-order digital signal.

[0013] (6) Quantization noise and ciphertext signal reconstruction: The low-order digital signal is filtered to realize the reconstruction of quantization noise and ciphertext signal.

[0014] (7) Chaotic synchronization and frequency hopping code regeneration: A portion of the reconstructed quantization noise is input into a neural network module; the neural network module learns the dynamics of the optical domain nonlinear transformation module of the transmitter and generates the same chaotic synchronization signal as the transmitter; at the same time, another portion of the reconstructed quantization noise is processed by the same quantization and hash function as the transmitter in sequence to regenerate the same frequency hopping code in real time for the next time step of frequency hopping.

[0015] (8) Signal decryption and plaintext recovery: The reconstructed ciphertext is decrypted using the chaotic synchronization signal in step (7) to recover the original plaintext signal.

[0016] Furthermore, the chaotic encryption in the transmitting end employs a hybrid encryption strategy, using a chaotic signal and another digital chaotic sequence generated by a mathematical formula to perform hybrid chaotic encryption on the plaintext signal to be transmitted; the chaotic signal is denoted as {C}. i}, whose encryption depth is denoted as d1; the digital chaotic sequence is denoted as {X}. i The encryption depth is denoted as d2; the plaintext is denoted as {T}. i}, the ciphertext is denoted as {T i The encryption process can be represented as follows: .

[0017] Furthermore, the conversion of quantization noise into frequency hopping code specifically includes: quantizing the quantization noise, then processing it through a hash function to generate a random frequency hopping code sequence.

[0018] Furthermore, the frequency hopping signal generated at the transmitting end has a frequency hopping period greater than or equal to 5ns and a frequency hopping range less than or equal to 10GHz.

[0019] Another objective of this invention is to provide an integrated system for optical radio frequency hopping communication and chaotic encryption that implements the aforementioned integrated method of optical radio frequency hopping communication and chaotic encryption, comprising a transmitting device, a transmitting device, and a receiving device;

[0020] The launching device includes:

[0021] The chaotic encryption module is used to perform mixed chaotic encryption on the input plaintext signal using chaotic signals and digital chaotic sequences;

[0022] The DSM module, connected to the chaotic encryption module, is used to modulate the encrypted signal into a low-order digital signal and generate quantization noise.

[0023] An optical domain nonlinear transformation module, connected to the DSM module, is used to convert quantization noise into a chaotic signal and feed it back to the chaotic encryption module;

[0024] A frequency hopping code generation module, connected to the DSM module, is used to convert quantization noise into random frequency hopping codes and feed them back to the frequency hopping module;

[0025] The frequency hopping module, connected to the DSM module and the frequency hopping code generation module, is used to generate a frequency hopping carrier based on the frequency hopping code and modulate the low-order digital signal to generate a frequency hopping electrical signal; the frequency hopping electrical signal is modulated onto the optical carrier and converted into a frequency hopping optical signal.

[0026] The transmission device includes: a RoF link module for transmitting frequency-hopping optical signals on a RoF link;

[0027] The receiving device includes:

[0028] The frequency hopping de-modification module connects the ROF link module and the frequency hopping code regeneration module. It is used to perform photoelectric detection on the transmitted optical signal, convert it into an electrical signal, and perform frequency hopping de-modification based on the regenerated frequency hopping code.

[0029] The filtering module, connected to the frequency hopping de-hopping module, is used to process the frequency hopping de-hopping signal and reconstruct the quantization noise and ciphertext.

[0030] The neural network module, connected to the filtering module, uses the reconstructed quantization noise to learn the dynamics of the optical domain nonlinear transformation module at the transmitting end through the neural network, generating a chaotic synchronization signal identical to that at the transmitting end. The chaotic synchronization signal is then fed back to the chaotic decryption module.

[0031] The frequency hopping code regeneration module is connected to the filtering module. It regenerates the frequency hopping code using the reconstructed quantization noise and feeds it back to the de-frequency hopping module.

[0032] The chaotic decryption module connects the filtering module and the chaotic synchronization module, uses synchronized chaotic signals to decrypt the ciphertext, and outputs the recovered plaintext signal.

[0033] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, causing the processor to perform the steps of the integrated optical wireless frequency hopping communication and chaotic encryption method.

[0034] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the integrated optical radio frequency hopping communication and chaotic encryption method.

[0035] Another objective of this invention is to provide an information data processing terminal, which includes the aforementioned integrated system of optical wireless frequency hopping communication and chaotic encryption.

[0036] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0037] (1) Enhanced security: The keys for both chaotic encryption and frequency hopping originate from the physical entropy source of DSM quantization noise, which has perfect statistical randomness and unpredictability. Even if the frequency hopping code is intercepted, the signal is still masked by the chaotic signal, providing double protection.

[0038] (2) Simplified chaotic synchronization mechanism: The traditional complex optical chaotic synchronization feedback loop is eliminated. The receiver reconstructs the quantization noise from the low-order communication digital signal and uses machine learning to achieve chaotic synchronization, which is robust and simple to implement.

[0039] (3) High compatibility: It only needs to transmit a low-order format frequency hopping signal, without the need for additional synchronization channels or pilots, and is seamlessly compatible with existing RoF communication systems and digital signal processing algorithms.

[0040] (4) The expected benefits and commercial value of the technical solution of this invention after transformation are as follows:

[0041] This solution seamlessly integrates chaotic secure communication into existing RoF access networks. Its implementation requires no complex modifications to the core network and terminal equipment; simply by introducing the core module of this invention into the centralized processing unit and remote radio frequency unit at the base station front end, physical layer security enhancements can be provided for the entire wireless access link. This not only meets the rigid requirements of 5G / 6G networks for high-speed, high-reliability, and high-security access, but also significantly reduces the deployment and maintenance costs for operators in highly security-sensitive scenarios such as private networks, finance, and government. Its core module is expected to form a standardized security processing chip or unit, possessing broad market prospects and extremely high commercial conversion value, and is a key technology for driving cost reduction and efficiency improvement in next-generation secure wireless infrastructure.

[0042] (5) The technical solution of this invention fills a technical gap in the industry both domestically and internationally:

[0043] Currently, research on RoF security in the industry has long been characterized by two parallel but separate technical approaches: "physical layer encryption" and "frequency hopping." No mature solution has yet been found that can fundamentally and efficiently integrate these two approaches at the source. This invention proposes and experimentally verifies an innovative architecture that utilizes "DSM quantization noise" as a unified physical entropy source, perfectly bridging this technological gap. It creatively constructs an integrated secure channel model that provides both chaotic encryption and nanosecond-level high-speed true random frequency hopping, filling a gap in the international field of "highly compatible physical layer fusion security technology."

[0044] (6) The technical solution of the present invention solves a technical problem that people have long desired to solve but have never been able to solve successfully:

[0045] This invention overcomes two major security challenges in high-speed wireless communication: the frequency hopping security bottleneck, which utilizes the intrinsic physical noise of the DSM to replace the traditional pseudo-random code, achieving true random frequency hopping at the 5ns level; and the chaos practicality barrier, which achieves high-quality synchronization of chaotic signals by replacing complex synchronization circuits with passive reconstruction and machine learning. Simultaneously, it innovatively integrates these two high-security mechanisms, achieving for the first time, while fully compatible with existing systems, both engineering-usable ultrafast frequency hopping and theoretically perfect chaotic encryption, resolving the core contradiction that has long constrained the practical application of physical layer security.

[0046] (7) The technical solution of the present invention overcomes technical bias:

[0047] Traditional technological biases hold that high-strength physical layer security (such as chaotic encryption) inevitably comes with complex system architectures, high hardware costs, and poor compatibility with existing systems; it also believes that the security of high-speed frequency hopping is limited by the computing power of DSP devices, making it difficult to achieve true randomness. This invention breaks these preconceived notions. It demonstrates that through ingenious signal processing architecture design (DSM) and intelligent signal recovery technology (machine learning), it is entirely possible to achieve high-strength dual security protection simultaneously in a minimalist system with low cost and high compatibility. This provides a completely new paradigm for the security design of future communication systems. Attached Figure Description

[0048] Figure 1 This is a flowchart of the integrated optical wireless frequency hopping communication and chaotic encryption method based on Delta-Sigma modulation provided in this embodiment of the invention.

[0049] Figure 2 This is a diagram of the actual transmission link structure of ROF based on optical self-heterodyne detection provided in an embodiment of the present invention.

[0050] Figure 3 This is a measured frequency hopping signal spectrum provided in an embodiment of the present invention.

[0051] Figure 4 This is a constellation diagram provided in an embodiment of the present invention;

[0052] Figure 5 This is a measured chaotic signal synchronization diagram provided in an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0054] like Figure 1 As shown, the integrated method for optical wireless frequency hopping communication and chaotic encryption provided in this embodiment of the invention includes:

[0055] (1) Chaotic Encryption: The plaintext signal to be transmitted is encrypted using a chaotic signal and another digital chaotic sequence generated by a mathematical formula to produce a ciphertext signal; the chaotic signal is denoted as {C i}, whose encryption depth is denoted as d1; the digital chaotic sequence is denoted as {X}. i The encryption depth is denoted as d2; the plaintext is denoted as {T}. i}, the ciphertext is denoted as {T i The encryption process can be represented as follows: .

[0056] (2) DSM and quantization noise generation: The ciphertext signal is input to the DSM. The DSM operates at a set oversampling rate and converts the input ciphertext signal into a low-order digital signal. During the DSM process, out-of-band quantization noise with high randomness is generated synchronously. The quantization noise is extracted from the low-order digital signal using a high-pass filter.

[0057] (3) Generation of chaotic signal and frequency hopping code: A portion of the quantization noise is input to the optical domain nonlinear transformation module to generate a chaotic signal, which is used to encrypt the plaintext signal at the next moment; another portion of the quantization noise is processed by quantization and hash function in sequence to generate a true random number sequence, which is used as the frequency hopping code.

[0058] (4) Generation and transmission of frequency hopping signal: A frequency-hopping radio frequency carrier is generated in the digital domain according to the frequency hopping code; and the low-order digital signal output in step (2) is modulated onto this carrier to form a frequency hopping signal; the frequency hopping electrical signal is modulated onto the optical carrier and converted into an optical signal for transmission on the RoF link.

[0059] (5) Signal reception and frequency hopping de-hopping: The receiving end performs photoelectric detection on the transmitted optical signal and converts it into an electrical signal. Using the locally regenerated frequency hopping code that is exactly the same as that of the transmitting end, the received frequency hopping signal is de-hopped and down-converted to the baseband to recover the low-order digital signal.

[0060] (6) Quantization noise and ciphertext signal reconstruction: The low-order digital signal is filtered to realize the reconstruction of quantization noise and ciphertext signal.

[0061] (7) Chaotic synchronization and frequency hopping code regeneration: A portion of the reconstructed quantization noise is input into a neural network module; the neural network module learns the dynamics of the optical domain nonlinear transformation module of the transmitter and generates the same chaotic synchronization signal as the transmitter; at the same time, another portion of the reconstructed quantization noise is processed by the same quantization and hash function as the transmitter in sequence to regenerate the same frequency hopping code in real time for the next time step of frequency hopping.

[0062] (8) Signal decryption and plaintext recovery: The reconstructed ciphertext is decrypted using the chaotic synchronization signal in step (7) to recover the original plaintext signal.

[0063] The chaotic encryption in the transmitting end employs a hybrid encryption strategy, using a chaotic signal and another digital chaotic sequence generated by a mathematical formula to perform hybrid chaotic encryption on the plaintext signal to be transmitted; the chaotic signal is denoted as {C}. i}, whose encryption depth is denoted as d1; the digital chaotic sequence is denoted as {X}. i The encryption depth is denoted as d2; the plaintext is denoted as {T}. i}, the ciphertext is denoted as {Ti The encryption process can be represented as follows: .

[0064] The process of converting quantization noise into frequency hopping code specifically includes: quantizing the quantization noise, then processing it through a hash function to generate a random frequency hopping code sequence.

[0065] The frequency hopping signal generated at the transmitter has a hopping period greater than or equal to 5ns and a hopping range less than or equal to 10GHz.

[0066] This invention proposes an integrated method for optical wireless frequency-hopping communication and chaotic encryption. By constructing a collaborative closed-loop mechanism with quantization noise as a common random source, chaotic encryption, frequency-hopping control, and synchronous regeneration are organically coupled to achieve deep integration of the physical layer and signal processing layer for secure communication. The transmitting end first performs phase-perturbation type hybrid chaotic encryption on the plaintext signal to be transmitted based on an analog chaotic signal generated by a nonlinear dynamic system and a digital chaotic sequence generated by mathematical mapping. This makes the plaintext highly random in both the phase and statistical domains, destroying the discriminative structure of the signal from the source. The encrypted ciphertext signal is then input into the DSM module. While completing the analog-to-digital conversion and reducing the order representation, highly random out-of-band quantization noise is naturally generated. This noise is no longer considered system interference but is actively introduced as an internal random resource of the system. Part of the quantization noise is fed back to the chaotic system via nonlinear dynamic mapping to drive the chaotic state update at the next moment, making the encryption process continuously evolving and unpredictable. Another part of the quantization noise is extracted into a frequency-hopping control sequence to control carrier frequency hopping in the digital domain, realizing frequency-hopping communication. The low-order digital representation of the ciphertext is modulated onto the generated frequency-hopping carrier and further loaded onto the optical carrier for wireless optical communication transmission, thus introducing time-frequency dual dynamic perturbations into the physical channel. The receiver performs photoelectric conversion and frequency-hopping inversion on the received frequency-hopping optical signal to recover the low-order digital signal and synchronously reconstructs the quantization noise and ciphertext signal from it. The receiver uses the reconstructed quantization noise as a driving input and achieves chaotic system synchronization by learning the nonlinear dynamic characteristics of the transmitter, thereby regenerating the chaotic signal and corresponding frequency-hopping control sequence from the transmitter. Finally, it performs inverse perturbation on the ciphertext signal to recover the original plaintext information.

[0067] This invention is applicable to high-security optical wireless communication, free-space optical communication, military and government confidential communication, unmanned system links, satellite-to-ground links and adversarial communication environments, and is especially suitable for scenarios that counter eavesdropping, replay attacks, statistical analysis attacks and spectrum detection.

[0068] The technical advantages of this invention are as follows: By converting quantization noise into a controllable random source within the system, a unified drive for chaotic encryption updates, frequency hopping control updates, and chaotic synchronization regeneration is achieved. This makes encryption and modulation no longer independent modules, but forms a highly coupled closed-loop security mechanism, thereby significantly improving the system's key space, time invariance violation capabilities, and resistance to synchronization attacks. At the same time, it avoids the predictability and replay risks brought about by introducing external random sources, enhancing the system's self-consistency and security. Furthermore, the use of optical frequency hopping transmission further improves anti-interference and anti-spectral detection capabilities, enabling communication to exhibit randomness simultaneously at the statistical, spectral, and dynamic levels, thereby significantly improving the overall security level and engineering applicability of the communication system.

[0069] The system hardware connection relationships provided in the embodiments of the present invention are as follows: Figure 2 As shown, it mainly consists of three parts: the transmitter, the transmission link, and the receiver.

[0070] Transmitter: First, a chaotic signal is used to encrypt the plaintext at 1.25 Gbaud / s using 16-point Quadrature Amplitude Modulation (16QAM), generating noise-like ciphertext. Then, a DSM is used to convert the generated noise-like ciphertext into a 5 Gbaud / s Quadrature Phase Shift Keying (QPSK) signal, with an oversampling rate set to 4. The generated QPSK digital signal contains both ciphertext and quantization noise. A high-pass filter extracts the out-of-band quantization noise with high randomness. A portion of the quantization noise is converted into a chaotic signal by an intensity modulator (IM), and together with another Logistic digital chaotic sequence generated by a mathematical formula, it performs mixed chaotic encryption on the plaintext at the next time step. This chaotic signal is denoted as {C}. i}, whose encryption depth is denoted as d1; the digital chaotic sequence is denoted as {X}. i The encryption depth is denoted as d2; the plaintext is denoted as {T}. i}, the ciphertext is denoted as {T i The encryption process can be represented as follows: The encryption depths d1 and d2 are both set to 0.375π. Another portion of the quantization noise is sequentially quantized by 8 bits and converted into a random digital sequence using the SHA-256 hash function, serving as the frequency hopping code. A frequency hopping carrier is generated in the digital domain based on the frequency hopping code. The frequency hopping period is set to 5ns, and the frequency hopping range is set to 10GHz. The baseband 5Gbaud / s QPSK signal is up-converted to 10GHz, and a -8GHz virtual frequency hopping carrier is superimposed to generate a frequency hopping communication signal. The frequency hopping communication signal is loaded onto a C-band IQ modulator using a 64 GSa / s arbitrary waveform generator (AWG Keysight M8195A) to generate a transmission optical signal. Figure 3 The spectrum of frequency-hopping signals transmitted in the 18 GHz band was shown, and signals in higher frequency bands were generated using optical self-heterodyne technology.

[0071] Transmission link: The optical signal is transmitted through the ROF link.

[0072] At the receiving end: The transmitted optical signal is detected by a photodiode (PD), and the received signal is acquired and digitized using a 100GSa / s digital sampling oscilloscope (DSO Tektronix DPO 73304D). The acquired data is then imported into a computer for offline digital signal processing using MATLAB. The data undergoes resampling, frequency hopping de-sampling, and constant modulus algorithm (CMA) equalization to achieve perfect QPSK signal recovery. The QPSK constellation diagram after frequency hopping de-sampling is shown below. Figure 4 As shown in (a), its Error Vector Magnitude (EVM) is 16.61%. Further, quantization noise and ciphertext reconstruction are achieved through filtering. A Long Short-Term Memory (LSTM) network is used to learn the nonlinear dynamics of the transmitter's IM to obtain a high-quality chaotic synchronization signal for chaotic decryption. The chaotic signal synchronization diagram is shown below. Figure 5 The synchronization coefficient is calculated to be 0.983. The frequency hopping code is regenerated through quantization and the same hash function, and used for de-frequency hopping at the next time step. By using the chaotic synchronization signal to perform chaotic decryption on the reconstructed ciphertext, the 16QAM plaintext signal can be recovered, as shown below. Figure 4 As shown in (b). Even with correct frequency hopping resolution, the constellation diagram received by the eavesdropper is still subject to chaotic perturbations, such as... Figure 4 As shown in (c), this further reveals the high security of the present invention.

[0073] An application embodiment of the present invention provides a computer device, which includes a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the integrated method of optical radio frequency hopping communication and chaotic encryption.

[0074] An application embodiment of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of an integrated method for optical radio frequency hopping communication and chaotic encryption.

[0075] An application embodiment of the present invention provides an information data processing terminal, which includes an integrated system of optical wireless frequency hopping communication and chaotic encryption.

[0076] Example 1: Co-generation of Hybrid Chaotic Encryption and Quantization Noise

[0077] On the transmitting side, an optical domain nonlinear transformation module first generates an analog chaotic signal, while a digital mapping module generates a digital chaotic sequence. These two modules act as continuous and discrete perturbation sources, respectively, affecting the phase of the plaintext signal to be transmitted. This causes the plaintext signal to experience rapidly changing phase perturbations while maintaining its amplitude information, thus forming a hybrid chaotic encrypted signal. This hybrid approach ensures that the plaintext cannot be recovered even when a single chaotic source fails or is predicted, improving the system's resistance to known-plaintext attacks and statistical attacks.

[0078] The encrypted signal enters the DSM digital modulation process and is quantized at a sampling rate higher than the signal bandwidth, thus naturally generating highly random quantization noise out of band. This quantization noise is separated from the original encrypted signal in the frequency domain, allowing for reliable extraction of the quantization noise through filtering while ensuring that the ciphertext information itself is not destroyed, thereby providing a stable random source for subsequent random driving mechanisms.

[0079] Example 2: Quantization noise-driven chaotic feedback and frequency hopping generation

[0080] The quantization noise extracted from the DSM modulation output is split into two paths. One path is input to the nonlinear dynamics module and transformed into a new chaotic state variable through nonlinear mapping. This variable is used to update the chaotic encryption parameters for the next time step, ensuring that the chaotic system is always in a dynamic evolution state that is closely coupled with the communication process, rather than being an independent fixed chaotic source. This enhances the time-varying security of the system.

[0081] Another portion of the quantization noise is quantized and mapped before being input into a cryptographic hash function to form a frequency hopping control sequence. This sequence controls the rapid switching of the radio frequency carrier between multiple frequency points. Since the frequency hopping sequence originates from naturally generated random noise during communication, rather than an external pseudo-random sequence, attackers cannot predict the frequency hopping behavior without intercepting the entire communication link, thereby simultaneously improving the physical layer's anti-interference and anti-reconnaissance capabilities.

[0082] Example 3: Implementation of Optical Wireless Transmission of Frequency Hopping Signals

[0083] In the digital domain, a frequency-hopping control sequence controls the local carrier source to switch between different center frequencies, forming a frequency-hopping radio frequency carrier. A low-order digital signal is modulated onto this frequency-hopping carrier to form a frequency-hopping electrical signal. This signal is then modulated onto an optical carrier, converted by electro-optical conversion to form a frequency-hopping optical signal, and transmitted through an optical fiber link, enabling long-distance, low-loss transmission of optical wireless signals.

[0084] By using optical domain to carry frequency hopping signals, the bandwidth and low attenuation advantages of fiber optic links can be utilized while maintaining the flexibility of the wireless side. This allows frequency hopping communication to be deployed in distributed antenna systems, centralized base station systems, or fronthaul network environments, making it suitable for large-scale access and long-distance secure communication scenarios.

[0085] Example 4: Receiver-side frequency hopping de-hopping and noise reconstruction

[0086] The receiving side first performs photoelectric conversion on the optical signal to obtain a frequency-hopping electrical signal, and then uses a locally regenerated frequency-hopping control sequence to de-frequency hop the signal, restoring the signal frequency to the original center frequency band. Finally, it performs down-conversion to obtain a low-order baseband digital signal. This process ensures that the receiving and transmitting sides are aligned on the frequency trajectory, thereby avoiding demodulation failures caused by frequency hopping mismatch.

[0087] The recovered low-order digital signal is subjected to frequency domain filtering to separate the in-band ciphertext signal from the out-of-band quantization noise and output them separately. This allows the random noise source to be re-obtained without affecting the information recovery accuracy, providing the basic driving signal for subsequent chaotic synchronization and frequency hopping regeneration.

[0088] Example 5: Machine Learning-Based Chaotic Synchronization Mechanism

[0089] The receiver uses the reconstructed quantized noise as input to drive the dynamics learning module to model the nonlinear dynamics of the transmitter, establishing a mapping relationship between noise and chaotic states through training. This learning process does not rely on explicit sharing of internal parameters of the transmitter, but achieves dynamic synchronization through behavior fitting, thereby avoiding the security risks associated with explicit key transmission.

[0090] Once the learning model converges, its output chaotic signal remains synchronized with the transmitting chaotic signal in terms of statistical characteristics and time evolution trajectory. This allows it to be used to perform inverse perturbation operations on the ciphertext, thereby achieving chaotic decryption and recovering the original plaintext signal.

[0091] Example 6: System Closed-Loop Collaboration and Security Enhancement Effects

[0092] The entire system uses quantized noise as a common random source to form two collaborative security loops: a chaotic feedback loop and a frequency hopping control loop. This allows the encryption state, frequency trajectory, and synchronization process of the communication system to be dynamically driven by the communication itself, rather than relying on external preset keys or fixed random sources. This significantly improves the system's resistance to active attacks, replay attacks, and interference attacks.

[0093] Since quantization noise originates from the real-time communication process, its statistical characteristics change with the signal and environment, giving the system a natural time-varying and unpredictable nature, thereby achieving a synergistic improvement in security and robustness while ensuring communication reliability.

[0094] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0095] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method integrating optical wireless frequency hopping communication and chaotic encryption, characterized in that, The following collaborative closed-loop mechanism steps are included: The transmitting end uses a simulated chaotic signal generated by chaotic dynamics and a digital chaotic sequence generated by mathematical mapping to perform phase perturbation-type hybrid chaotic encryption on the plaintext signal to be transmitted, forming a ciphertext signal. The encrypted signal is input into the Delta-Sigma modulation process, which converts it into a low-order digital signal while generating out-of-band quantization noise with high randomness. The quantization noise is split into at least two paths. One path is transformed by nonlinear dynamics to form a chaotic signal for the next moment and fed back to participate in subsequent encryption. The other path is processed by random number extraction to form a frequency hopping control sequence. Based on the frequency hopping control sequence, a frequency hopping carrier is generated in the digital domain, and the low-order digital signal is modulated onto the frequency hopping carrier to form a frequency hopping electrical signal, which is then modulated onto an optical carrier to form a frequency hopping optical signal for transmission. The receiving end performs photoelectric conversion and frequency hopping inversion on the frequency-hopping optical signal to recover the low-order digital signal; Reconstruct the quantization noise and ciphertext signal from the recovered low-order digital signal; By utilizing the reconstructed quantization noise, a synchronous chaotic signal is generated by learning the nonlinear dynamic characteristics of the transmitter, while simultaneously regenerating the frequency hopping control sequence; The ciphertext signal is inversely perturbed using the synchronous chaotic signal to recover the original plaintext signal. This forms a closed-loop secure transmission mechanism that uses quantized noise as a common random source to collaboratively drive chaotic encryption updates, frequency hopping control updates, and chaotic synchronous regeneration.

2. The method according to claim 1, characterized in that, The hybrid chaotic encryption achieves dual-source phase perturbation superposition chaotic encryption by simultaneously superimposing a continuous perturbation controlled by an analog chaotic signal and a discrete perturbation controlled by a digital chaotic sequence on the phase of the plaintext signal.

3. The method according to claim 1, characterized in that, The quantization noise originates from the out-of-band quantization residual signal of the Delta-Sigma modulation process and is extracted from the low-order digital signal through frequency domain filtering.

4. The method according to claim 1, characterized in that, The frequency hopping control sequence is generated by quantizing and irreversibly compressing the quantization noise.

5. A system integrating optical wireless frequency hopping communication and chaotic encryption that implements the method of any one of claims 1 to 4, characterized in that, include: The transmitting module group includes a chaotic encryption module, a Delta-Sigma modulation module, a nonlinear dynamics module, and a frequency hopping control module. The module group uses quantization noise as the central signal source to form a chaotic feedback loop and a frequency hopping control loop. The transmission module is used to carry frequency-hopping optical signals; The receiver-side module group includes a frequency hopping de-module, a filtering and reconstruction module, a dynamics learning module, a frequency hopping regeneration module, and a chaotic decryption module. This module group utilizes the reconstructed quantization noise to drive the chaotic synchronization loop and the frequency hopping regeneration loop. This creates a dual-loop synchronous secure transmission system between the transmitter and receiver, linked by quantization noise.

6. The system according to claim 5, characterized in that, The dynamics learning module is trained to synchronously reconstruct the nonlinear dynamics behavior of the transmitter by training the mapping relationship between quantization noise and nonlinear dynamics output.

7. The system according to claim 5, characterized in that, The frequency hopping regeneration module achieves synchronous regeneration of the frequency hopping control sequence by performing random number extraction processing on the reconstructed quantization noise in the same way as the transmitting end.

8. The system according to claim 5, characterized in that, The frequency hopping period corresponding to the frequency hopping control sequence is not less than 5 nanoseconds, and the frequency hopping range is not greater than 10 GHz.

9. A device integrating optical wireless frequency hopping communication and chaotic encryption, characterized in that, include: A chaotic perturbation generation unit is used to generate simulated chaotic perturbation sequences and digital chaotic perturbation sequences; Delta-Sigma modulation unit is used to generate low-order digital signals and quantization noise; The dynamic transformation unit is used to map quantization noise into an analog chaotic signal; The random number extraction unit is used to map quantization noise into a frequency hopping control sequence; A synchronization unit is used to synchronize the dynamic transformation behavior based on the reconstructed quantization noise; The de-perturbation unit is used to recover the plaintext by inverse perturbation of the ciphertext based on the synchronous chaotic signal.

10. The apparatus according to claim 9, characterized in that, Each unit forms at least one chaotic feedback closed loop and at least one frequency hopping control closed loop around the quantization noise, and the two closed loops are kept synchronized between the transmitter and receiver through the quantization noise.

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