Low-complexity system structure design method based on high-order optical DPSK system

Abstract

The invention discloses a low-complexity system structure design method based on a high-order optical DPSK system, and belongs to the technical field of free space optical communication. According to the design, on the basis of a high-order light DPSK demodulation principle, according to corresponding distribution of each bit sequence on a constellation diagram, the most complex bit in the demodulation process is selected for constellation reconstruction, 0 and 1 of the bit are dispersed as much as possible to simplify a demodulation structure, and meanwhile, auxiliary bits are introduced to mark constellation points for transformation, so that the constellation reconstruction efficiency is improved. And the optical signal is transmitted to a receiving end through amplitude modulation, so that the purpose of assisting in demodulating other bits is achieved, and the system structure is further simplified. According to the high-order light DPSK optimization system, the higher the modulation order is, the simplification degree of the optimization system after constellation mapping reconstruction is higher, and therefore the higher the light power of each demodulated branch is, and the high-order light DPSK optimization system can save the laser emission power and has higher energy efficiency.

Description

technical field [0001] The invention belongs to the technical field of Free Space Optics (FSO), and relates to a low-complexity system structure design based on high-order Differential Phase Shift Keying (DPSK) based on optical communication. Background technique [0002] In recent years, with the explosive growth of network traffic and devices, the traditional radio frequency (Radio Frequency, RF) spectrum has become very congested, and it is difficult to meet the increasing network demands. Free space optical communication technology, as one of the key technologies of my country's space-ground integration development strategy, combines optical communication technology with wireless communication technology, uses laser as the carrier wave and the atmosphere as the transmission medium, realizes high-speed information transmission, and has spectrum resources. Rich, strong anti-electromagnetic interference ability, low power consumption, high security, strong directionality, fl...

AI Technical Summary

Problems solved by technology

However, for the FSO channel, its atmospheric turbulence and attenuation characteristics have a greater impact on the power of the optical signal, and the communication quality of the optical signal is easily affected by atmospheric conditions and weather conditions. Therefore, compared with high-order DPSK modulation, When transmitting the same information, the method of joint amplitude-phase modulation cannot resist the atmospheric influence caused by medium and strong turbulence.

And with the further increase of the modulation order, in order to control the structure of the system is not too complicated, when the joint modulation is used, the order of the signal for phase modulation is not easy to be too high, so the balance is often achieved by increasing the order of the amplitude modulation, which further leading to a decrease in system reliability

In addition, some studies have shown that appropriate changes to the constellation diagram can achieve the purpose of simplifying the system structure, but the cost often leads to the reduction of system reliability

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