Modeling And Implementation Of SDR-TR-MIMO Wireless Communication System In Cabin Environment

In recent years,the increasing human activities in space and the unceasing development of space technology increase the demands for a large capacity data transmission in spacecraft cabins.However,the traditional means of transmitting information through wired cables not only occupy valuable space and weight source,but also increase the design difficulty and manufacturing cost of the space capsule.These has gradually become one of the crucial factors for the limited development of spacecraft.Therefore,it is an urgent problem to be solved in the aerospace field to seek a new wireless communication scheme for spacecraft,replace the traditional data cable bus,and realize large-capacity and high-quality data transmission under the complex multipath channel in the space capsule.Presently,MIMO-OFDM technology is one of the most popular wireless communication technology.It uses both space and frequency resources for space-time coding.MIMO-OFDM can effectively increase the transmission rate of the communication system and reduce the BER without requiring more transmission power or spectrum resource.It is very suitable for multi-node and large-capacity communication in space capsules.However,the transmission paths of electromagnetic waves in the space capsule are complex and variable,which leads to a large increase in multipath delay.The frequency selective fading is obvious,which affects the performance of the MIMO-OFDM system.The unique characters of time reversal such as “super resolution focusing”and “space-time synchronous focusing” can be applied to the complex electromagnetic environment in the space capsule for compression of the channel delay spread.Combining TR with MIMO technology,the communication system capacity can be futher improved and the communication system complexity can be reduced.The main research content includes:Firstly,it reviews the development history of wireless research in space capsules and points out the defects of the current cable communication transmission system in space capsule.The application of TR technology combined with MIMO-OFDM technology in space capsule wireless communication scheme is proposed.The feasibility is proved by formula derivation.Then the performance comparison with other wireless communication systems demonstrates its performance advantages through simulation analysis.The effects of parameters such as modulation order and channel delay on system performance are studied.Also,we analyse the channel capacity of the TR-MIMO-OFDM system.Secondly,a low-complexity and high-speed spatial-domain TR-MIMO wireless communication method based on time reversal in the cabin environment is proposed according to the rich multipath environment in the space capsule.The theoretical derivation and modeling simulation are carried out.The results show that it can achieve good communication performance in dense multipath environment.Finally,this thesis builds a model of TR-MIMO-OFDM system based on software radio platform.After the development process and platform parameters of PicoSDR platform used in this paper are introduced,the Simulink module is developed for its transceiver communication link.An experimental TR-MIMO-OFDM platform in a cabin was built,and the advantages of the TR-MIMO-OFDM system were verified by experimental comparison.The use of software radio platform to implement TR-MIMO-OFDM system lays the foundation for practical applications.