Operating method of FSO communication system based on IHDAF protocol

Abstract

The invention provides an operating method of an FSO (Free Space Optical) communication system based on an IHDAF (Incremental Hybrid Decode-Amplify-Forward) protocol, and belongs to the technical field of wireless optical communication. The FSO communication system includes a source node, a relay node and a target node and utilizes a half-duplex operating mode. The operating method of an FSO communication system based on an IHDAF protocol includes three steps: performing M-order pulse amplitude modulation on the source information; transmitting the modulated information to the relay node and the target node through a gauss laser beam, comparing the link instantaneous signal to noise ratio gamma sd from the source node to the target node and the link instantaneous signal to noise ratio gamma sr from the source node to the relay node with the signal to noise ratio threshold SNRsd and SNRsr set by the corresponding link so as to determine selecting the corresponding transmission scheme, that is, direct transmission, Decode and Forward, and Amplify and Forward; and at last, performing recovery and demodulation on the reception signal by means of the target node. The operating method of an FSO communication system based on an IHDAF protocol integrates the relay technology with the free space optical communication technology in the protocol so as to effectively restrain reduction of system performance, caused by path loss, atmospheric disturbance and aiming error and improve the transmission reliability of system.

Description

technical field [0001] The invention relates to a working method of a Free Space Optical (FSO) communication system based on an Incremental Hybrid Decoding Amplification Fronthaul (IHDAF) protocol, and belongs to the technical field of wireless optical communication transmission. Background technique [0002] With the rapid development of my country's communication industry, the number of wireless communication users has increased suddenly, and there are higher requirements for the wireless transmission rate and quality of data. However, in the traditional radio frequency wireless communication field, due to the increasing demand for information transmission, the field Spectrum resources are becoming increasingly scarce. As a supplement to traditional radio frequency communication, wireless optical communication has the advantages of large transmission bandwidth, large communication capacity, fast transmission rate, strong anti-electromagnetic interference ability and good co...

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Problems solved by technology

The above schemes are relatively simple in the selection mode and working mode of the protocol relay node, and are not flexible enough for channel adaptation, which has certain limitations in practical applications.

S.M.Aghajanzadeh et al. (see S.M.Aghajanzadehand M.Uysal, "Performance Analysis of Parallel Relaying in Free-Space Optical Systems," IEEE Transactions on Communications, vol.63, no.11, pp.4314-4326, 2015) proposed the use of parallel in In the relay transmission mode, the sending information can be transmitted through direct transmission, AF relay and DF relay at the same time. This scheme can make the system obtain a certain diversity gain, but the complexity of the system is greatly increased, and the system cannot choose the appropriate transmission depending on the channel condition. mode, it is difficult to exert ideal performance

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