Multi-path Delay Estimation And Its Applications In Multi-Device Communication Systems

In recent years,the time delay estimation(TDE)has received great attention in various applications,including radio localization,radar detection and wireless communication.The estimation accuracy of the regular TDE methods dropped drastically due to the multi-path interference.With the development of the fifth generation mobile communication(5G),the Internet of Things(IoT)is becoming more and more advanced,and the number of devices in a communication system will be more and more.The accurate TDE is a key role to the efficient management of the massive connectivity and information synchronization of devices in multiple device system with multipath environment.However,the performance of the regular TDE methods declined much more severely in multi-device system.Thus,it is of great theoretical significance and application value to study the TDE in multiple devices communication systems.To solve the problems discussed above,this thesis proposed a path integration based delay estimation(PRIDE)method which utilizes the unique delay structure of each device for the first time.The PRIDE method is carried out in two steps to obtain the integer and fractional parts of the delay in sequence.In multi-path multi-devices environment,the multipath delays of each device is represented by the first path delay and the delay structure.The PRIDE method reinforce the energy of the first path signal by adding the energy of the other paths to the firth path based on the delay structure.In addition,the uniqueness of the delay structure can be utilized as an identification for a certain device.This property of the delay structure make the PRIDE method has satisfy performance in multi-device systems.With the purpose of verifying the performance of the proposed method,this thesis applied the PRIDE method in the estimation of angle of arriving(AOA)and obtained the estimation of AOA through the estimated delay information.After that,the performance analysis of the time delay based AOA estimation is presented and the derivation of the closed-form expression for the root mean square error(RMSE)of AOA is also provided.The simulation results show that,compared with the regular methods,the PRIDE method achieves better performance with the expense of a little computational complexity in both single-device and multi-device systems.Compared with the classical estimation of signal parameters via rotational Invariance techniques(ESPRIT)algorithm which is known for its low computational complexity,the PRIDE based AOA estimation method has higher estimation accuracy.Besides,the estimation results of the PRIDE based AOA estimation method is more accurate than the multiple signal classification(MUSIC)algorithm on the condition that the searching precision of these two methods is the same.