Abstract: As one of the main application directions of quantum technology, underwater quantum communication is of great research significance. In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links, based on the extinction characteristics of marine planktonic algal particles, the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively, the influence of marine planktonic algal particles on the fidelity of underwater quantum links, the generation rate of the security key, and the utilization rate of the channel is analyzed, and simulation experiments are carried out. The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles, quantum communication channel link attenuation shows a gradually increasing trend. In addition, the security key generation rate, channel fidelity and utilization rate are gradually decreasing. Therefore, the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles, and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.
Abstract: As one of the main application directions of quantum technology, underwater quantum communication is of great research significance. In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links, based on the extinction characteristics of marine planktonic algal particles, the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively, the influence of marine planktonic algal particles on the fidelity of underwater quantum links, the generation rate of the security key, and the utilization rate of the channel is analyzed, and simulation experiments are carried out. The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles, quantum communication channel link attenuation shows a gradually increasing trend. In addition, the security key generation rate, channel fidelity and utilization rate are gradually decreasing. Therefore, the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles, and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.
To study the effect of PM2.5 on the communication performance of satellite-ground quantum links, firstly, the effect of PM2.5 particle concentration on channel parameters such as quantum communication link attenuation, channel fidelity, and channel utilization was analyzed, and parametric simulations were carried out based on the PM2.5 particle concentration spectral distribution function and Mie scattering theory to obtain its extinction efficiency factor. The simulation results show that the link attenuation factor increases from 0.221 to 5.085 when the PM2.5 particle concentration increases from 10 to 230 over a transmission distance of 14km. When the transmission distance is 10 km, and the particle concentration increases from 0 to 200, the channel fidelity decreases from 1 to 0.804. When the transmission distance is 5km, and the particle concentration increases from 30 to 200, the channel utilization decreases from 0.51 to 0.36. Therefore, the impact of PM2.5 on the performance of satellite-ground quantum link communication is more significant. According to the PM2.5 concentration, corresponding adjustment strategies can be adopted to improve the reliability of the transmission system and ensure the smooth implementation of quantum communication.
Abstract Soot aerosol is an important part of atmospheric aerosol, which has important influence on the propagation of quantum signal. In order to study the influence of soot aerosol on satellite-ground quantum communication, according to the size distribution parameter and extinction coefficient of the soot aerosol, the influence of the concentration of the soot aerosol particles and the transmission distance on the attenuation of the link is analyzed. The simulation experiments of channel capacity, channel fidelity and channel bit error rate (Ber) are carried out with amplitude-damped channel. The simulation results show that the soot aerosol concentration increases from 2.1×10 6 / m 3 to 3.2 10× 6 / m 3 , the link attenuation factor increases from 0.3dB/ km to 0.46dB/ km, the fidelity decreases from 0.98 to 0.97, and the bit error rate increases from 0.0087 to 0.0122 at a transmission distance of 3km . hhen the transmission distance is 6km and the particle concentration is 2.1×10 6 / m 3 , 2.7 10× 6 / m 3 and 3.9×10 6 / m 3 , the channel capacity increases from 1.078 to 1.0809, and then decreases to 1.0804. Therefore, the soot aerosol has influence on the performance of satellite-ground quantum communication, and the degree of influence is different. In order to ensure the reliability of quantum communication between satellite and ground, the parameters can be adjusted to ensure the normal transmission of quantum signal.
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.
Quantum satellite communication is a communication method with strong security and large coverage area, and it has become a hot research topic at home and abroad. The successful launch of the quantum satellite has laid an important foundation for future integrated quantum communication. When further studying the communication performance between quantum satellite-ground links, it is found that atmospheric particulate matter has a significant impact on quantum satellite communication performance. In this paper, by analyzing the extinction characteristics of atmospheric particles, a mathematical model of particle concentration, transmission distance and satellite-earth quantum energy is established, and the influence of atmospheric particles on communication parameters, bit error rate and entanglement degree is analyzed. The simulation results show that with the increase of particle concentration, the performance indicators of quantum satellite communication are affected to a certain extent. As the concentration of particulate matter in the atmosphere continues to decrease, the energy of the optical quantum signal continues to increase, and the quantum bit error rate increases with the increase in the concentration of atmospheric particulate matter and the transmission distance. The degree of quantum entanglement decreases with the increase of the particle size of atmospheric particles, and increases with the increase of visibility. The luminosity of light quantum will decrease with the increase of transmission height and the increase of surface particle concentration. By studying the optimization and adjustment strategy of quantum signal based on fidelity quantum relay satellite, simulation ensures the feasibility of this strategy. It is observed that the research in this paper can provide the necessary theoretical reference for the development of quantum space-ground integrated communication network.
Quantum communication provides high security and privacy, offering effective protection against eavesdropping and decryption during information transmission. Its inherent unconditional security addresses information security issues effectively. Dust particles, as prevalent environmental factors in the atmosphere, exert negative impacts on both traditional and quantum communication. Due to the higher requirements for signal fidelity and stability in quantum communication, the impact of dust particles may be more significant. To investigate the effect of dust aerosol particles on the performance of satellite-ground quantum communication links, we established quantitative relationships between particle number concentration and transmission distance, and the link attenuation, as well as the channel capacity, system survival function, and error rate of three noise channels: amplitude damping, bit-flip, and depolarizing channels. Using Matlab, we conducted experimental simulations based on the size distribution function of dust aerosol particles and Mie scattering theory. The simulation results indicate that when the transmission distance is 6 km and the particle concentration of dust aerosols increases from20/m3to55/m3, the channel attenuation factor increases from84.35dB/kmto232dB/km. The capacity of the amplitude damping channel decreases from0.6486bit/sto0.3943bit/s, and the survival function of the amplitude damping channel decreases to 0.9059. When the particle concentration is900/m3and the transmission distance increases from 3km to 8km, the bit error rate increases from 0.03 to 0.2. The results indicate that dust aerosols have impacted various aspects of satellite-to-ground communication, each in different ways, highlighting the importance of considering their influence. Therefore, when implementing quantum communication in practice, it is essential to adjust the parameters accordingly to ensure the normal operation of communication.
Quantum communication is brand new way of communication in which quantum entanglement is used to transmit information. It is an interdisciplinary subject combining quantum informatics with modern communication theory. Motivated by the communication requirements for underwater sensor networks, submarines, etc., underwater optical communication has been developing rapidly in recent years due to the ideal information security of quantum communication. However, the research on the performance of underwater quantum communication in sea has not yet been fully developed because of a series of factors such as surge, salinity and seaweed and so on. In this paper, the influence of surge in non-uniform water flow on the underwater quantum communication is studied theoretically and experimentally. Firstly, a new Boussinesq equation with a given flow function is derived based on the horizontal and vertical wave velocity of the free surface to represent the free surface boundary conditions. On the other hand, In view of the nonlinear motion of movement, the complexity of change and the randomness of the distribution, the spectrum is used for numerically calculating the surge. The characteristics of wave motion are described by wave height, period and wavelength. Secondly, the influence of surge on the entanglement of underwater quantum channel is analyzed. It is proved that the wave height of surge and the change of the cycle affect quantum communication due to the destruction of the quantum coherence and the reduction in quantum entanglement degree. Thirdly, the influence of surge motion on the quantum channel capacity is studied. The influence of the relation between the wavelength and the transmission cycle on the quantum channel capacity is simulated. The relationship between the physical characteristics of surge wave and the capacity of depolarized channel is established. Fourthly, the influence of surge motion on error rate in quantum key distribution is studied. The simulation results show that when the sea surface wind speed changes in a range of 0-20.5 m/s, the propagation cycle is increased gradually. The channel entanglement is increased from 0.0012 to 0.8426, and the channel capacity is reduced from 0.8736 to 0.1024. In the key distribution process, the quantum bit error rate increases from 0.1651 to 0.4812. Therefore, in underwater quantum communication, the parameters of the system should be adjusted adaptively according to the varying degree of the surge movement.