High Speed Transmission And Receiving Over Logging Cable Research And Design

The development of well logging technology is toward the high precision,which will yield more and more demand to conveying huge data from down-hole to the control center on the ground.So the technology of high speed communication is very in need.In consideration of the balance of performance and cost,it is relatively ideal scheme that using the logging cable as the transmission medium.OFDM method is applied so that we could reach the high speed transmission over the narrow bandwidth of the cable as long as 7000-9000 meters.By this method,the high speed data stream has been split into multiple parallel data stream that has relatively low speed.Because of this transfer,the communication system has increased its ability to resist the frequency selective and anti-interference.As a physical layer protocol,the communication system is assumed to have two transmission directions of upload and download.The upload transmission is undertaken the abundant data information,while the download system is designed to convey the control signals to the down-hole equipment.During the implementation of the transmitter and receiver,we put forward a self-adaption TCM scheme,which require less computing resource and less running time.We also suggest a frequency domain equalization,which has more convergence speed.A download command control system is been designed in a small cost of resources and bandwidth,which at the same time makes the system became full duplex.