Research On Anti-interference Carrier Signal Design And Channel Coding Of Seismic Wave Communication

With the rapid development of national economy,the demand for mineral resources is increasing,the safe production of underground mines has become a top priority.Due to the complex geological structure of underground mines,disasters such as collapse,water inrush and gas leakage often occur.Usually when a major disaster occurs,the wired communication cable is easily damaged,causing trapped people to lose contact with the outside world and hindering the smooth progress of rescue work.The characteristics of the ground channel are relatively stable,so the underground wireless communication system can be used as an emergency communication means to assist post-disaster rescue work.Because the current underground wireless communication systems generally use electromagnetic waves as the communication carrier,the electromagnetic waves attenuate too fast underground,resulting in short communication distances and low reliability.This paper proposes an electromagnetic vibroseis seismic wave communication method,which uses seismic waves as carriers to transmit help and rescue information,and discusses the feasibility of seismic waves used in underground communication.By analyzing the characteristics of seismic waves and the law of propagation and attenuation in underground media,the feasibility of using seismic waves for communication is explored.The electromagnetic vibration source is used as the information sending device,and the data information to be transmitted is loaded onto the seismic carrier signal by digital modulation technology.The electromagnetic vibration source is controlled to excite the corresponding seismic wave signal.The seismic wave is transmitted through underground media and then received by the geophone.The data transmission information can be obtained by demodulating and decoding the received seismic wave signal.For the problem of fast attenuation of underground communication signal and serious noise interference,this paper studies from the perspective of carrier signal,and puts forward two design schemes of anti-jamming carrier signal,namely minimum frequency shift keying modulation(MSK)signal and pseudo random segmented sweep modulation(PRSSM)signal.Through simulation and experimental analysis,both carrier signals can transmit information in underground media,and PRSSM signals have stronger anti-jamming ability than MSK signals,which can effectively suppress random noise interference and improve the effective communication distance of seismic wave communication.Finally,in order to solve the problem of low reliability caused by error codes in seismic wave transmission,this paper studies from the perspective of channel coding,and proposes two channel coding schemes,LBCOOK and CCOOK.Channel encoding can correct errors generated during transmission,reduce communication error rate and improve the reliability of seismic wave communication system.The error correction performance of the two channel coding schemes is studied by numerical simulation.The results show that LBCOOK and CCOOK can effectively reduce the error rate of seismic wave communication.At the same signal-to-noise ratio,CCOOK has stronger error correction ability and can effectively improve the reliability of seismic wave communication system.The electromagnetic vibroseis seismic wave communication scheme proposed in this paper adopts the electromagnetic vibroseis as the information sending device,and uses the digitally modulated seismic wave signal to transmit the command information.Combined with the working principle of electromagnetic vibroseis,two anti-jamming carrier signals are designed,and two channel coding schemes are designed to correct the transmission error of seismic wave communication.The method of seismic wave communication with electromagnetic vibroseis studied in this paper provides some experience for the follow-up study of seismic wave communication system and the rescue after underground mine disaster.In the extreme environment where the existing communication technology fails,seismic wave communication can be used as an emergency communication means to ensure the effective transmission of key information.