| People's life has changed with the emergence of large number new applications such as ultra-high-definition video,virtual reality,and Internet of Vehicles.The expansion of mobile service types and the increasing smart terminals have present a new challenge to the capacity of existing communication systems.It is urgent to achieve higher spectrum efficiency under limited spectrum resources.Multiple-input Multiple-Output(MIMO)technology has become a core technology of wireless communications,which can achieve a great spectrum efficiency improvement through fully mining spacial resources.In order to achieve high-er data transmission rates,ultra wide bandwidth will be utilized.This article researches the key technolo-gies of broadband MIMO communication systems,including broadband MIMO synchronization technology,low-complexity MIMO signal detection algorithm,ultra-high-speed MIMO transmission system design.We designed a broadband MIMO transceiver system with a high data rate of 10Gbps,and build a high speed hardware platform to verify our technologies.Firstly,we introduce the basic principles and composition of a broadband MIMO communication sys-tem.Due to the advantages of high spectral efficiency and anti-multiple path,broadband MIMO-OFDM is employed as the basic structure of baseband signal processing.We also introduce the MIMO channel model for our simulations.Then we give in brief introduction of a hardware platform based on the software radio architecture for the high speed wireless communications.Furthermore,some performances are tested and the system specifications are analyzed as a reference for the subsequent design.Subsequently,this article carries out research on the synchronization technology of broadband MIMO communication systems.Through analyzing the effect of timing and frequency offset errors on ultra-high-speed MIMO transmission.We design a synchronization frame design scheme with low-overhead,which can complete initial synchronization within one OFDM symbol.This paper also compare the performances of the two synchronization sequences ZC(Zadoff-Chu)and PN(Pseudo-Noise),from the auto-correlation,cross-correlation,and peak-to-average ratio,anti-frequency offset.Based on our analysis,we find that the truncated PN sequences has better performance.Finally,we give the synchronization algorithms,including frame detection and fine symbol synchronization,coarse frequency offset estimation and fine frequency offset estimation.Through the simulations of different antenna configurations,we can show that our proposed synchronization scheme has the advantage of anti-frequency offset,and low complexity,good performance,and is suitable for use in practical systems.Thirdly,this paper studies the MIMO detection algorithms of broadband MIMO communication sys-tem.We give two simplified detection algorithms including algorithms based on interference cancellation and BP(Belief Propagation)detection algorithm based on factor graph.The proposed detection algorithms are suitable for high-speed implementation.For the linear detection algorithms,we investigate the perfor-mance of Zero Forcing(ZF)detection and Minimum Mean-Square Error(MMSE)detection,including serial interference cancellation(Successive interference cancellation,SIC)detection,Parallel interference cancella-tion(Parallel Interference Cancellation,PIC)detection and the combined multi-level interference cancellation detection.For systems with large number of transmitting and receiving antennas,we give the BP detection algorithm based on the factor graph.The performances of the algorithms are simulated under the two channel conditions of weak interference and strong interference,The results show that two detection algorithms are suitable for different channels and antenna configurations.Finally,this paper presents the design and implementation of a broadband MIMO communication sys-tem.In order to achieve a 10Gbps transmission rate on the hardware platform,we give the MIMO-OFDM system transmission scheme,including frame structure design,and overall system structure design.We also give the FPGA design and implementation of the baseband transmission,and explained the algorithm decom-position and timing analysis of the frame detection,carrier frequency offset estimation and compensation.Based on the hardware platform we built,the 4×4 MIMO system was tested offline,and the frame error rate was below 10-4.The test results verified the correctness of the system transmission scheme. |
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