Timing Synchronization Scheme And Implementation For Broadband MIMO-OFDM Receiver

With the increasing use of mobile communications applications,people's requirements for communication quality and speed are getting higher and higher.The MIMO-OFDM(Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing)technology can increase channel capacity significantly by using diversity and multiplexing of multiple antennas.It has many advantages,such as high spectrum utilization,fast transmission rate,flexible modulation mode,etc.In the coming 5G(Fifth Generation Mobile Communication Technology),the MIMO-OFDM will serve users as the most important transmission technology.Communication systems with MIMO-OFDM technology consider synchronization and recovery of received data as the key to determine system performance.In order to improve the performance of system receiver in complex channel,this paper focuses on timing synchronization algorithm and frequency offset recovery control scheme,which mainly includes the following parts:Firstly,the background of this research is introduced,and the development of timing synchronization algorithms at home and abroad are summarized.The types of receiver synchronization in MIMO-OFDM system are studied,which are divided into symbol timing synchronization,sampling clock timing synchronization and frequency synchronization.Symbol timing synchronization and sampling clock synchronization constitute timing synchronization.The effects of these synchronization errors on system performance are analyzed,and then,the system model of receiver synchronization is introduced.According to the logic relation of these estimation errors,the system model and overall implementation scheme of receiver timing synchronization are given,and the verification scheme of system synchronization from MATLAB to FPGA is drawn up.Secondly,the implementation algorithm of timing synchronization scheme is deeply studied.For symbol timing synchronization algorithm.Several classical algorithms such as Joint Maximum Likelihood(ML),ML improved algorithm and MPSC(Multiple Point Set Correlation)are introduced.The MATLAB is used to model the synchronization estimation under the bad channel,the advantages and disadvantages of each algorithm are compared through simulation.Finally,some improvements are made for the implementation of the MPSC algorithm.For the sampling clock timing synchronization algorithm,two general realization models are given.The non-synchronous sampling clock timing recovery scheme is introduced in detail.The main body of the scheme is an interpolation filter with Farrow structure,which restores the original data by interpolating the input up-sampling data.The performance of sampling clock timing is verified by MATLAB simulation.Finally,a general architecture of MIMO-OFDM transceiver system is presented.According to the above theory and algorithm,the overall timing synchronization scheme of the system receiver is designed,including coarse symbol timing synchronization,sampling clock timing synchronization and frequency offset control and recovery.Based on the FPGA,the overall hardware structure of each part and the implementation structure of each sub-module are designed respectively.Moreover,the RF interface module of data is designed in combination with the RF agile transceiver chip AD9361,which perfect the transceiver system and gives the resource occupancy rate of the overall synchronization scheme in the FPGA.Finally,the whole MIMO-OFDM system hardware program is downloaded to the FPGA,and the data after synchronization processing is analyzed with MATLAB,which verifies the performance of the receiver synchronization algorithm and the reliability of the hardware implementation structure.