Not Look Directly At The Atmospheric Channel Model Of The Uv Communication Research And Codec Design

Ultraviolet communication bases on atmospheric scattering with center wavelengths(200-280nm) in the solar blind region. An important and potentially large class of applications for ultraviolet non-line-of-sight(NLOS) communication is short-range, secret communication.It can be considered as a supplement of conventional communication.This paper is mainly about atmospheric channel model along with coding and decoding design for NLOS ultraviolet communication.At first, the communication principle,background,key components have all been briefly described.Research on atmospheric channel model is a difficult issue in ultraviolet communication.This issue has been researched in depth.At present, single scattering model developed by Luegtten has been widely used in research on atmospheric channel model for NLOS ultraviolet communication.Although most of the studies are about the energy distribution in fixed angles and distance, the influence of the structure parameters in ultraviolet system has been ignored.This paper also bases on this model,and the effect of the system structure parameters to the value of loss,time delay and so on has been mainly discussed. Qualitative theory researches and simulation experiments have been given. The relationship of transmitter,receiver apex angle,transmitter beam divergence,receiver half-field view with transmission property has been studied.In addition, energy distributions in different distances have been simulated. The results of simulations show:(1)the value of transmission loss can be minimum,while both the transmitter apex angle and the receiver apex angle are no more than 90o in NLOS ultraviolet communication;(2)the value of transmission loss and time-delay will decrease,while the transmitter beam divergence and the receiver half-field view increase;(3)the value of transmission loss,time-delay and pulse broaden will increase as transmission distance grow;(4)the value of time-delay is large,so NLOS ultraviolet communication can only adopt half duplex communication.Generally,the value of transmission loss is more than 100dB,and time-delay is microsecond,and pulse broaden is about 20μs.Therefore, rational selection of structure parameters can avoid intersymbol interference effectively in different distances and transceiver modes.Base on the above research, a new coding scheme(NPPM) has been presented after studying on the scheme of traditional modulation technologies in wireless communication. According to the selected plan, circuit simulation experiment has been made and the requirement of frame synchronization and time slot synchronization has been satisfied.