Research On The Key Technologies Of Hybrid Visible Light Communication In Coal Mine

The existing mine communication system is vulnerable to electromagnetic interference,low anti-interference ability and it can't adapt to the coal mine working face environment which is complex,changeable and mobile.This paper takes the development of visible light communication as an opportunity to put forward the visible light communication system applied to coal mine working face,and the fusion of visible light communication and existing wireless communication systems is expected to provide a new solution for the full coverage of mine communication system.Research is conducted on key technologies of heterogeneous networks in coal mine in this paper.(1)According to the specific environment of coal mine working face,the overall structure of visible light communication system in coal mine working face is proposed and the system configuration and the principle are discussed in detail.(2)The voice communication module of coal mine working face based on visible light communication is designed,including coding and decoding circuit based on the pulse code modulation,LED driver circuit and photoelectric conversion and amplifying circuit.This module can realize duplex communication and multiplex transmission of 32 channels signals.(3)Research is conducted on the layout of visible light communication system in coal mine working face.The space segmentation method is used to transform the narrow and long communication space into a common square communication space.Taking the square communication space as the research object and according to the principle that the illumination distribution of the receiving plane is as uniform as possible,the best lighting distance of LED and LED coverage method in coal mine working face is obtained.(4)Research is conducted on the two handover techniques for the heterogeneous network of visible light communication in the coal mine.For the horizontal handover,a RSI handoff algorithm combined with FFT attenuation detection is proposed in this paper,which can effectively reduce the influence of the table effect.For the vertical handover,the handover process of heterogeneous networks and the existing two handover algorithms of IVHO and DVHO are analyzed.A dynamic dwell timer handover algorithm is proposed by improving the existing handover algorithm and the dwell timer can be adaptively changed according to the user's motion state.The effectiveness of the proposed algorithm is verified by simulation analysis using MATLAB.