Study Of The Mine Time And Frequency Spread MC-CDMA Wireless Communication System

The mine tunnel has the problems of limited space, rough wall, irregular shape, heavy noise, and also exists moving objects such as electric locomotive.These caused the wireless transceiver can only transport tens to hundreds of meters in underground which originally can transport a few kilometers to tens of kilometers on the ground. To solve this problem Z The paper studies the mine time and frequency spread MC-CDMA technology with good anti-multi-path decline ability as well as resistance of time selective fading.On the basis of the simulation comparison of the three classical OFDM-CDMA systems in sub-carrier symbols on the cycle, chip period, sub-carrier spacing and the bandwidth required, wireless communication system with good anti-multi-path decline ability as well as resistance of time selective fading are studied. Mine time and frequency spread MC-CDMA system is established and the principle, signal frequency and the transceiver structure are proposed.All the users in conventional time and frequency spread MC-CDMA system must have the same transmission rate. However, there is big difference between mine users. In order to study the wireless communication system with different transmission rates according to the different requirements of users, this paper improves the mine time and frequency spread MC-CDMA system above, using carrier block diversity technology through the space block diversity methods, making spread spectrum code length an integral multiple of the sub-carrier number, in order to meet the actual demands of big difference in source rate of different mine users, making the ability to resist multipath fading of the system stronger. The principles and system composition of the improved mine time-frequency expansion MC-CDMA system are proposed.Finally, simulation verifies that time-frequency expansion MC-CDMA system has stronger ability to resist multipath fading. Then the ability to resistant multiple fading of the mine time-frequency expansion MC-CDMA system is analyzed. In addition, simulation verifies that the improved mine time-frequency expansion MC-CDMA system has stronger ability to resist multipath fading.