Communication reliability analysis of inter-satellite laser link based on transmission parameters

Space Gravitational-wave (GW) detection requires the establishment of an ultra-long-range interplanetary laser communication link. Compared with general inter-satellite laser communication, the power emitted by the laser is relatively small, and only a small part of the power is used to achieve communication. Therefore, higher requirements for communication reliability are put forward. Optical antenna vibrations, on-platform vibrations, and interstellar relative motion can shift the alignment optical path, causing aiming errors at the transmitter and receiver to affect the communication link, while laser wavelength, transmission distance, transmitter and receiver design parameters, and system noise can also have complex effects on the communication link. In this paper, we propose a reliability analysis method for interplanetary laser communication links based on transmission parameters. The basic model of the interstellar laser communication link is first developed in terms of the average received optical power of the detector, and the corrected Rayleigh distribution is used to describe the aiming error. Then, the relationship between the transmitting and receiving signals is analyzed to give a model of the Bit Error Rate (BER) of the communication system, and the link reliability is measured by the error probability. Finally, the effects of changes in parameters such as emitted beam divergence, vibration, communication rate, communication distance, and receiving antenna aperture on the error probability are analyzed, and the optimal beam divergence width is obtained by calculation. Simulation experiments show that the emitted beam scatter and aiming error angle are the main factors affecting the performance of interplanetary laser communication in the space GW detection laser link. Choosing the optimal beam dispersion angle yields the lowest error probability and reduces the requirement for transmitting power. Static deviations in the aiming error angle can reduce the reliability of the link. In this paper, a method for analyzing a system of transmission parameters to improve the reliability of interstellar laser communication links is developed, which provides an effective means for the analysis and design of communication links for space GW detection.