Skywave Massive MIMO Channel Characteristic Analysis And Transmission Technique Research

Massive MIMO technique can provide higher data transmission rate,system reliability and power efficiency,so it has become the focus of next-generation mobile communication technique.Skywave communication has become an indispensable part of long-distance communication,and has become synonymous with the use of relatively inexpensive equipment to achieve long-distance communication.Skywave communication is unique in that it can use simple and inexpensive equipment to provide long-distance communication within a country or internationally,and it is particularly suitable for use in remote areas where the communication infrastructure is not accessible due to natural disasters or military conflicts.Skywave communication is the only practical communication method for connecting long distances(thousands of kilometers)without using relay equipment such as satellites.This thesis mainly studies Skywave Massive MIMO communication,designs and implements a Skywave Massive MIMO channel measurement platform,analyzes the Skywave channel propagation characteristics,and studies Skywave Massive MIMO transmission technique.First,the design and implementation of the Skywave massive MIMO channel measurement platform is presented.Starting from the total design of the Skywave massive MIMO channel measurement platform system,the uplink channel measurement system architecture,downlink channel measurement system architecture,and uplink and downlink channel measurement data processing are given.Then,the hardware architecture design and implementation of the channel measurement platform on the terminal side and the base station side are given respectively,and then the software multi-thread architecture design of the measurement platform server and the corresponding software technique support are given.Finally,the types and causes of errors in the channel measurement platform are analyzed.After the error calibration,the working conditions,reliability and stability of the measurement platform are verified.Next,by studying the skywave channel characteristics,skywave massive MIMO channel model and channel measurement methods,the channel measurement plan is designed,and the skywave channel propagation characteristics are analyzed by using the skywave massive MIMO channel measurement platform.Firstly,the characteristics of the skywave channel are analyzed from the aspects of ionospheric characteristics,available frequency window and optimal operating frequency,multipath effect,ionospheric fading and Doppler effect.The characteristics of multipath,fading,Doppler frequency shift and Doppler spread as well as the difference between the generation mechanism and performance mode of skywave channel and other wireless channels,are studied.And on this basis,with the propagation delay,fading and Doppler effect taken into consideration,the skywave massive MIMO channel model is established.Then the channel measurement method of spread spectrum sliding correlation measurement method and the direct of arrival estimation method are studied,and the influence of antenna spacing and ionospheric tilt on the estimation of the angle of arrival is analyzed.Finally,the skywave channel measurement plan is given,and the skywave channel is measured by the sky-wave large-scale channel measurement platform,and the skywave channel propagation characteristics are analyzed based on the channel measurement results.Finally,this thesis studies the skywave massive MIMO transmission technique,and proposes a skywave uplink synchronization method that uses location information at the terminal side.First,the precoding technique and synchronization method in Skywave massive MIMO downlink transmission technique are studied,and the achievable sum rate performances of MF precoding,ZF precoding and RZF precoding are analyzed,and the synchronization sequence generation in the synchronization method as well as the downlink synchronization process are studied.Then the uplink detection method and uplink synchronization method in Skywave's massive MIMO uplink transmission technique are studied,MF detection,ZF detection and MMSE detection methods are studied,the expressions of the detection matrix are given,and the uplink synchronization process is studied.Finally,in view of the long distance between the base station side and the terminal side in the skywave system,a skywave uplink synchronization method that uses location information at the terminal side is proposed to solve the problem of long uplink synchronization sequences and high cross-correlation calculation cost,and ray tracing software is used to verify the method.