Research And Realization Of Key Technology In MIMO-OFDM Transmitter

With the development of wireless communication,it has attracted a lot of at tentions on how to gain a high-speed and dependable data transmission with restrictions of frequency bandwidth lately.MIMO-OFDM has become a major technology in the future wireless communication for its robust ability against frequency -selective fading, realizing high-speed data transmission,huge system capacity and effectively improving the frequency efficiency.The main content of this thesis is to design a transmitter system which is based on MIMO-OFDM system,for the purpose of the high rate of wireless transmission.It is a great challenge to design the MIMO-OFDM transmitter system at so high transmission rate,which reaches 1.485Gbps,so it has a great practical significance. Four streams of 2048 subband output are designed in the design scheme of the MIMO-OFDM transmitter system.The transmission rate of each stream can reach 371.25Mbps.In order to reduce the data prosessing rate and improve the transmission efficiency,64QAM modulation has been used.In consideration of data protection,synchronization and channel coding,a frame constructing corresponding with the transmission rate has been designed.In this thesis ,a simplified algorithm of space-time code has been proposed.And it has designed a data frame head for synchronization,which is based on the Mody synchronized algorithm.In order to save resourses ,a structure of double buffer stream multiplexing for implement multiple stream IFFT multiplexing has been presented in the FPGA design.In addition,it has analysed the error model of FFT process. A series of simulations of key technology based on MIMO-OFDM transmitter system has been simulated by Matlab, from which a large number of technical requirement has come up.Taking transmission rate,resourses and technical requirement into consideration, the system uses 16 bits fix point, 2048 points to implement FFT and the transmission rate in MIMO system can reach 120MHz.The thesis researched on implementation technology of transmitter based on XC6VLX240T-1FFG1156 of Xilinx company.The designing and implementation of all module in the transmitter,including QAM modulation ,space-time-code ,IFFT algorithm,frame constructing and filter,have been done in ISE with the tool of Verilog HDL.With the stream technology in the FFT,the speed of data processing clock can reach 250 MHz.In order to save resourses, an implementation of multiple stream IFFT multiplexing has been presented by this thesis.At last,this paper has debugged the whole system on the Virtex-6 FPGA ML605 by the ChipScope.After checking the output of the system,the design of transmitter is tested to be right.