Quantum communication in free space will be disturbed by natural environment such as fog and dust. However, to build a global quantum satellite wide area communication network, we must solve the problem of 24-h all-weather communication between satellite and earth. With the evolution of time, the degree of interference becomes deeper. In order to improve the performance of quantum communication under such an interference, in this paper we analyze the change of single quantum state channel over time under the background interference, and propose an quantum state-hopping communication strategy based on the kangaroo entanglement hopping model (KEHM), and simulate the performance and parameters of the strategy. Kangaroos are social animals. When they are frightened, they will jump synchronously in the same way with the same step length, height and frequency. According to this model, we make the two communicating parties realize synchronous quantum state jump according to the prearranged pattern. The simulations show that when the ratio between the average power of background quantum noise and the average power of quantum signal is 5, the quantum bit error rate decreases from 0.4524 to 0.1116 with the quantum state hopping frequency increasing from 1 to 15. When the single quantum state transmission success rate is 0.95 and the quantum bit rate is greater than 200 qubit/s, the probabilities of successful transmission of quantum bits at different state hopping frequencies are greater than 0.97. When the quantum reception efficiency of the receiver is 0.8, the quantum state pass rate increases from 0.3667 to 0.9986 with the average quantum number of the source increasing from 1 to 10. When the average quantum number of the source is 6, the passing rate of quantum state increases from 0.6262 to 0.9855 with the quantum receiving efficiency of the receiver increasing from 0.2 to 0.99. However, if the average quantum number of the transmitter is large enough and the receiving efficiency of the receiver is close to 1, the passing rate of the quantum state is also close to 1. The adaptive control strategy of quantum state hopping is based on real-time quantum channel state detection. Its core idea is to remove the quantum states which are seriously disturbed from the quantum state hopping set, and to realize the synchronous hopping of communication parties on the quantum states with low interference. Adopting the strategy of quantum state hopping adaptive control can further reduce the quantum bit error rate of the system. The error rate gain of adaptive control system increases with the increase of the success probability of processing the disturbed quantum state. When the probability of processing the disturbed quantum state is 0.95, the system error rate gain can reach 1.301. The performance of quantum state hopping system is improved obviously. To sum up, the adaptive quantum state-hopping communication strategy based on the kangaroo entanglement hopping model proposed in this paper greatly enhances the comprehensive immunity of the system and ensures the security of quantum information network, and provides an important reference for the healthy development of wide-area quantum satellite communication network in the future.
Quantum communication in free space will be disturbed by natural environment such as fog and dust. However, to build a global quantum satellite wide area communication network, we must solve the problem of 24-h all-weather communication between satellite and earth. With the evolution of time, the degree of interference becomes deeper. In order to improve the performance of quantum communication under such an interference, in this paper we analyze the change of single quantum state channel over time under the background interference, and propose an quantum state-hopping communication strategy based on the kangaroo entanglement hopping model (KEHM), and simulate the performance and parameters of the strategy. Kangaroos are social animals. When they are frightened, they will jump synchronously in the same way with the same step length, height and frequency. According to this model, we make the two communicating parties realize synchronous quantum state jump according to the prearranged pattern. The simulations show that when the ratio between the average power of background quantum noise and the average power of quantum signal is 5, the quantum bit error rate decreases from 0.4524 to 0.1116 with the quantum state hopping frequency increasing from 1 to 15. When the single quantum state transmission success rate is 0.95 and the quantum bit rate is greater than 200 qubit/s, the probabilities of successful transmission of quantum bits at different state hopping frequencies are greater than 0.97. When the quantum reception efficiency of the receiver is 0.8, the quantum state pass rate increases from 0.3667 to 0.9986 with the average quantum number of the source increasing from 1 to 10. When the average quantum number of the source is 6, the passing rate of quantum state increases from 0.6262 to 0.9855 with the quantum receiving efficiency of the receiver increasing from 0.2 to 0.99. However, if the average quantum number of the transmitter is large enough and the receiving efficiency of the receiver is close to 1, the passing rate of the quantum state is also close to 1. The adaptive control strategy of quantum state hopping is based on real-time quantum channel state detection. Its core idea is to remove the quantum states which are seriously disturbed from the quantum state hopping set, and to realize the synchronous hopping of communication parties on the quantum states with low interference. Adopting the strategy of quantum state hopping adaptive control can further reduce the quantum bit error rate of the system. The error rate gain of adaptive control system increases with the increase of the success probability of processing the disturbed quantum state. When the probability of processing the disturbed quantum state is 0.95, the system error rate gain can reach 1.301. The performance of quantum state hopping system is improved obviously. To sum up, the adaptive quantum state-hopping communication strategy based on the kangaroo entanglement hopping model proposed in this paper greatly enhances the comprehensive immunity of the system and ensures the security of quantum information network, and provides an important reference for the healthy development of wide-area quantum satellite communication network in the future.
Quantum communication in free space will be disturbed by natural environment, such as fog, dust, and rain, which is a difficult problem in the construction of quantum communication system. In order to solve this problem and improve the survivability of quantum communication system, we propose an adaptive parameter adjustment strategy for free-space quantum communication based on software-defined quantum communication (SDQC). Firstly, we propose a software-defined quantum communication model based on the idea of software defined networks. The architecture of SDQC is divided into four layers: transport layer, access layer, control layer, and management layer. The SDQC system sends the link information to the preset program at a management level through the real-time monitoring of channel state by the access layer. According to the link information, the management level issues instructions to the control layer to adjust the parameters such as the initial quantum state and the existence time of single quantum state, in order to improve the quantum entanglement and fidelity. Secondly, we analyze the relationship between quantum fidelity and parameters in SDQC system under three noise channels, i.e. depolarization channel, spontaneous amplitude decay channel, and phase damping channel. In the depolarized channel, the quantum fidelity F decreases with the increase of the error probability Pd of the qubit. When the error probability of qubit is certain, the system has the maximum quantum fidelity with the value of parameter x is 0.5. In the spontaneous amplitude decay channel, the quantum fidelity F decreases with the increase of the quantum state transition probability pt. When the transition probability of quantum state is certain, the higher the value of parameter x, the higher the fidelity will be. In the phase-damped channel, the quantum fidelity F decreases with the increase of the probability pc with which the qubit and the background interference equivalent quantum state have complete elastic scattering. When the probability is certain, the larger the value of |1/2 – x|, the higher the quantum fidelity of the system will be. Finally, we study the optimal values of SDQC system parameters under different environmental disturbances. The simulation results show that the optimal parameters of SDQC system are different when the parameters of three noise channels, namely depolarization, spontaneous amplitude decay and phase damping, are different. The system adaptively selects the initial quantum state and the existence time of single quantum state according to the environmental change and business demand, so that the quantum fidelity is always at the peak in the communication process. This strategy effectively improves the adaptability and comprehensive immunity of the quantum communication system.
Quantum satellite communication is an essential part in building a global quantum communication network. In order to cope with the sudden interference brought by snowfall to the quantum satellite communication system, an adaptive adjustment strategy for quantum satellite communication performance based on the optimal average photon number is proposed based on the decoy state protocol and snowfall spectral distribution function for the depolarization channel characteristics. The relationship between snowfall intensity and communication elevation angle and the optimal average number of photons per pulse is established, and the bit error ratio(BER) and survival performance of the system before and after the adoption of this strategy is compared. The simulation results show that the BER of the system decreases from 0.07 and 0.085 to 0.046 and 0.064 for medium and heavy snowfall environments, respectively; if the minimum communication elevation angle is required to be 0.81, the survival capability of the system increases from 0.81 to 0.92 for heavy snowfall environment; if the channel survival capability is required to be 0.8, the minimum communication elevation angle of the satellite link can be adjusted from 26° to 18° for heavy snowfall environment. Therefore, the strategy proposed enables the system to cope with more intense snowfall, improves the transmission quality of small elevation angle communication, further reduces the BER of the quantum satellite communication system, and enhances the reliability of the system in the snowfall context.
Quantum satellite communication has the natural advantages of strong survival reliability and wide coverage, and is currently a research hotspot in the field of communication at home and abroad. The successful launch of the "Mozi" scientific experimental satellite has laid the foundation for the construction of the quantum space-earth integrated communication network. In order to further improve the communication performance of the quantum satellite-ground link, a tuning strategy based on quantum coupled associative feedback control (QCAFC) is proposed in this paper. QCAFC estimates the state information of atoms by measuring the photons leaked in the optical cavity, and adjusts the controller to change the spin state of the atoms in the optical cavity. The evolution of the system is studied, the influence of the QCAFC system on the performance parameters of the satellite-ground quantum communication is analyzed, and the simulation is verified. The simulation results show that in the amplitude damped channel, the QCAFC system can significantly improve the channel capacity and coherence. When transmitting in the plasma environment, when the particle radius is 5, when the transmission distance between the satellite and the earth increases from 50km to 200km, the bit error rate of the system without QCAFC is increased from 7.34×10-3 to 21.93×10-3, and the bit error rate of the system with QCAFC is increased from 4.81×10-3 to 14.72×10-3. Simulation results show that the use of QCAFC system has a significant improvement in the performance of quantum satellite communication.
In quantum satellite communication, when the optical quantum signal is transmitted between satellite and ground links, it will be affected by various natural environments.At the same time, haze has become one of the largest environmental problems in the world.Therefore, it is of great significance to study the communication performance of quantum satellites in haze atmosphere.In this paper, according to the scale distribution and vertical spatial concentration change of large aerosol haze particles, the extinction characteristic model of large aerosol haze particles and the attenuation model of atmospheric haze particle concentration and transmission height on quantum satellite ground link are established.Some important performance parameters in quantum satellite communication are analyzed for amplitude damping channel, depolarization channel and phase damping channel respectively, It includes the quantitative relationship between channel capacity, quantum fidelity, quantum bit error rate and entanglement and large aerosol haze particle concentration and transmission height.The simulation results show that with the increase of transmission distance and haze particle concentration, the channel capacity, quantum fidelity and entanglement of quantum satellite communication in different channels will decrease, and the bit error rate will increase.Therefore, the impact of large haze environment on quantum satellite communication should be fully considered in the actual process of quantum satellite communication, Adaptive adjustment of relevant parameters to ensure the normal operation of quantum satellite communication.
In the atmospheric boundary layer far from the mainland, the complex climate environment, strong sea winds, and intermediate currents pose challenges to ocean satellite and starship communication. Especially in quantum communication, the interference of ionosphere, space plasma, and ice crystal particles can affect the stability and security of communication, which has become a research hotspot in the current field of starship communication. This article proposes an innovative method to optimize starship communication based on Quantum Entanglement Adaptive Control (QEAC). This article establishes the relationship between environmental factors and fidelity, bit error rate, and adaptive adjustment strategies. It compares the system performance parameters before and after the introduction of QEAC. This innovative method can improve the fidelity of quantum satellite communication systems under natural environmental interference through quantum entanglement adaptive control. Especially in the amplitude damping and depolarisation channels, the application of QEAC has significantly improved the stability of quantum starship communication. To verify the effectiveness of the proposed method, this paper conducted performance simulation experiments and achieved satisfactory results. Therefore, the optimization strategy based on quantum entanglement adaptive control proposed in this article is innovative and practical, providing a novel solution for solving the problems faced by ocean satellite communication. This study is of great significance for improving the stability and security of quantum starship communication under complex oceanic and meteorological conditions.
Quantum satellite communication is a research hotspot in the field of quantum communication, which has the characteristics of wide coverage, high communication efficiency and strong security. The construction strategy of the quantum communication network is an essential part of quantum communication. However, the construction strategy of quantum air communication network has not been studied yet so far. In this paper, according to the characteristics of flying goose array and principle of bionics, a simulated wild goose group Λ quantum air communication network topology is proposed, which can be divided into single-head node Λ type and multi-head node Λ type. Based on Greenberger-Horne-Zeilinger (GHZ) state particles, a certifiable QSDC inter-network communication system and a GHZ-EPR quantum teleportation communication system are established. The bit error rate, energy consumption, throughput, and other parameters are studied. After theoretical analysis and experimental measurement, for the single-head node Λ network structure in the environment where the average power spectral density of noise is 2 dB/m, when the communication distance between the head node and the child node is less than 400 m, the bit error rate is less than 0.094; if the communication distance increases from 400 m to 1000 m, the bit error rate increases rapidly, reaching 0.585; when the number of child nodes on one side increases from 2 to 7, the throughput decreases from 110.6 kb/s to 46.45 kb/s. For example, when the total number of nodes is 21, the single-head node Λ network structure saves 32.6% energy but reduces the throughput to 23.9 kb/s. By comparison, the multi-head node Λ network structure with 21 nodes saves 29.3% energy and achieves throughput of 163.4 kb/s. The above studies show that the quantum air network with the structure of imitation goose group array has good network scalability, excellent information security and flexible network structure.