Research For The Technology In Well-logging Cable Data Transmission System Based On OFDM

Well logging is one of the most important methods to obtain geological information in oil exploration.Cable logging is a technology in which the cable is used as the main medium of information transmission between the ground and underground.This technology has important research value,and is able to have a huge positive impact of China's oil economy.This thesis will investigate the OFDM system in well-logging cable data communication,and solve the problem of PAPR in OFDM system.OFDM has a strong advantage of many,especially the capability of high-speed data transmission.It has become a key factor in logging cable OFDM high-speed transmission system.However,OFDM system has a serious defect of high PAPR,this problem will cause great negative impact on the superiority of the whole system.This thesis discusses the channel characteristics of the cable and builds up the cable OFDM system model.The process of the OFDM and the key practical technology,including OFDM in practical logging cable system are analyzed.The high PAPR of OFDM and the corresponding reasons,the principle of several common PAPR suppression techniques are studied.The performance of these methods,including the peak clipping method and probability method are simulated.Base on the studies described above,the influence of signal correlation on the PAPR is analyzed,and the method of reducing the PAPR of OFDM system based on the signal correlation is studied in details.In addition for PTS,The performance is enhanced from the point of grouping method and grouping number,iterative methods are used to reduce the computation complexity of PTS with a higher degree of complexity.A suitable PAPR reduction method for well-logging cable data communication,which is in high temperature and complex environment,is found.