| The conditions in scatter channel are poor,so how to achieve reliable communication is a challenge in the field of wireless communication.MIMO SC-FDE technology is widely used in communication systems with low signal-to-noise ratio due to its unique advantages.And the design of the synchronization part is an important part of this.The performance of the synchronization part of the receiver directly affects the performance of demodulation and decoding.It's hard to fully exploit the advantages of MIMO SC-FDE system in scatter communication without the support of good synchronization technology.And what's more,we must consider the advantages and disadvantages of the algorithm and the resource consumption.This paper is devoted to the research and implementation of the synchronization technology used in MIMO SC-FDE system in low SNR environment.Firstly,the characteristics of scatter communication channel and the main obstacles to be overcomed are analyzed.Then the advantages and disadvantages of MIMO and single-carrier frequency-domain equalization are briefly discussed.Secondly,it focuses on the key parts of the synchronization technology in MIMO SC-FDE system,including the design principles of acquisition part,tracking part and multipath searching part.Finally,combined with FPGA hardware platform,considering the principle of area and speed in design,the synchronization sub-modules with different time and resource requirements are respectively implemented,and a large number of tests and corresponding improvements are implemented.According to the needs of the laboratory project,this paper designs a synchronization scheme with the characteristics of the project.The main innovations and key technologies are as follows.New capture and tracking mechanisms data are designed and improved for frame structures in different SNR environments.The derivation of the formula shows that the acquisition algorithm is suitable for the separate synchronization of the two antennas at the receiving end and carries out the engineering implementation.Synchronous sequence generation and matched filter design is another innovation of this paper,the iterative formulas are used to generate generalized hierarchical Gray sequence.According to the different signal-to-noise conditions,two novel matched filters with serial and parallel structures are designed.At the same time,innovations and improvements in engineering are realized,then correlation between the long Gray sequence can be calculated quickly and the hardware resources consumption can be reduced rapidly.According to the wireless channel environment of the communication system in the project,a tracking algorithm and a multipath search algorithm which are easy to implement and reliable in performance are designed.In the design,a scheme of combining adaptive threshold and fixed threshold is adopted to enable the system to adapt to lower signal to noise ratio environment.In addition,a new method of estimating the frequency difference between the sender and the receiver by using the sample adjustment mechanism is proposed and implemented.Through the indoor test and outdoor test verification in actual communication system,the synchronous system designed in this paper can cope with harsh channel environment.The synchronization performance is good and the reliability is strong. |
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