Hybrid modulation and demodulation method for atmospheric laser communication

Abstract

The invention discloses a hybrid modulation and demodulation method for atmospheric laser communication. Multi-pulse pulse position modulation and high-order polarization shift keying modulation are mixed together, a Stokes parameter is extracted for a polarization state of the light during the demodulation, the polarization state is almost constant after atmospheric transmission, the three-dimensional demodulation of the Stokes parameter has a larger coding space and decision space compared with the one-dimensional demodulation or two-dimensional demodulation, therefore the anti-interferenceperformance is high, moreover, the coding space and the decision space are expanded by using the three-dimensional demodulation, so that the PolSK can be pushed to multi-order use on the premise of ensuring the bit error rate performance; whether a time slot receiving signal is an additive white gaussian noise signal is judged by using the extracted Stokes parameter at a receiving end, so that whether a pulse is received within the time slot can be judged, and the demodulation of the pulse position is finally achieved; and by adoption of the method, the use of the signal amplitude demodulationposition in the traditional method is avoided, the demodulation process is simplified, and the demodulation efficiency is also improved.

Description

Technical field [0001] The invention belongs to the technical field of atmospheric laser communication, and particularly relates to a hybrid modulation and demodulation method for atmospheric laser communication. Background technique [0002] Laser communication has the advantages of bandwidth, high speed, and large capacity. As the amount of information in modern society is expanding, how to further improve the communication capacity and bandwidth utilization of laser communication systems has become a new research focus. Atmospheric laser communication is susceptible to atmospheric turbulence, leading to an increase in the bit error rate, which directly affects the communication quality of the laser communication system. Improving the anti-interference performance of the atmospheric laser communication system has also become a top priority. Modulation and demodulation technology is a key technology of laser communication. Researching modulation methods with excellent performanc...

AI Technical Summary

Problems solved by technology

[0004] The existing PPM-PolSK modulation technology uses a single pulse, and the bandwidth utilization rate is low. Generally, two polarization states are used for encoding, and the communication capacity is limited.

Moreover, some people use different arrangements of polarization states to represent the information carried, which increases the technical difficulty of modulation and demodulation.

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