The Key Technology For Through-the-earth Wireless Communication System

This paper focuses on the key technologies for synchronization and channel estimation for Through-the-earth wireless communication(TWC).In order to solve the key issues and challenges in the design of the existing wireless communication system,two key technologies are discussed: the channel modeling of the wireless communication system and the signal processing scheme of the wireless communication system are synchronous and Channel estimation method.Firstly,the paper introduces the research background and significance of wireless communication,summarizes the advantages and disadvantages of the existing three types of wireless communication and the key research directions.The key problem of wireless communication is: The transmission channel of the communication system is determined by analyzing the electromagnetic parameters of the communication channel and the attenuation characteristics of the electromagnetic wave.The channel model of the communication system is determined by calculating the reflection and transmission coefficient of the electromagnetic wave at the interface.And then analyzes and evaluates some existing system solutions,and analyzes and evaluates the advantages and disadvantages of their respective technologies,such as the other aspects.Based on the problem of poor performance under the condition of low signal-to-noise ratio(Pseudo Noise),a new algorithm is proposed,which is based on the pseudo-random sequence(Pseudo Noise)algorithm.The training sequence is obtained and the received data after the fractional frequency offset correction is correlated with the local training sequence to obtain fine timing synchronization and multipath delay information.(MSE)under low SNR condition can be improved by Matlab simulation,and a higher synchronization acquisition probability can be obtained.In this paper,a new method is proposed to solve the problem of large-carrier frequency difference by introducing differential operation to solve the large carrier frequency offset.In this paper,the algorithm of step The Theoretical analysis and simulation results show that under the condition of low signal-to-noise ratio and large carrier frequency offset,the differential correlation Synchronization algorithm of through-OFDM system can obtain better mean square error performance.Finally,a new method for estimating the performance of the traditional frequency domain channel estimation algorithm is proposed,which is based on the high computational complexity of the traditional frequency domain channel estimation algorithm and its poor performance under low SNR.This method makes use of the training sequence used in the synchronization phase to complete the time domain channel estimation and reduces the system overhead.Furthermore,by using the multipath delay information obtained by the synchronization phase,a cascade synchronization channel estimation method.Theoretical analysis and simulation results show that compared with the traditional channel estimation method,the proposed method can effectively reduce the computational complexity and improve the estimation performance of the channel estimation algorithm at low SNR.