Designandkey Techniquesresearch On High Speed Wireless Communication System Based On Multiple Antennas And SC-FDE Techniques

Recently,the fourth generation mobile communication 4G(LTE)systemsisbeing commercialized,which provides a higher transmission rate,better communication quality for people.The most critical techniquesin its downlink are MIMO and OFDM.By using multiple-input multiple-output communication pattern,MIMO makes effective use of space and spectrum resources,so as to improve the transmission speed of the system and spectrum efficiency.By converting a single path signal into multi-channel signals with orthogonal frequency,OFDM converts frequency selective fading resulted from a signal through multiple path into flat fading,and can effectively overcome inter symbol interference introduced by sending signals through wireless multipath channel.However,OFDM has problems like peak-to-average ratio is too large,it is sensitive synchronization error and frequency offset.Single-carrier frequency domain equalization(SC-FDE)has similar properties in intersymbol interference suppression compared with OFDM,but it can overcome large peak-to-average ratio and reduce synchronization and frequency offset sensitivity,which has been applied in the LTE uplink.According to the requirements of the project,this paper studied multiple antennas and SC-FDE based high-speed digital system design.By combining SC-FDE and MIMO technology,we designed the specific implementation scheme of the system and key algorithms,finished the evaluation of the performance of the whole system by using computer simulation.In this paper,the research work is mainly in the following aspects:(1)According to the characteristics of the UHF frequency band,by combining MIMO and SC-FDE,this paper designed the based implementation scheme of high-speed digital systembased on mutiple antenna SC-FDE,including the choice of modulation mode,the frame structure design and the choice of space-time decoding algorithm.(2)The key algorithms in the receiver were designed in detail,including the channel estimational gorithm,pilot structure design,time synchronization,frequency synchronization,frequency domain equalization,and space-time decoding algorithm,the scheme of realization of the algorithm were presentated,and its implementation complexity is also analyzed.(3)This paper completed the simulation evaluation of the whole system.By using the MATLAB language to build simulation platform,this paper analyzes the bit error rate under different scenarios.Focusing on different antenna numbers,different relative movement speed between transmitter and receiver,different nonlinear amplifier model,etc.,the simulation results are givenand discussed.The simulation results verify the feasibility of the designed scheme.