| With the commercial landing of 5G technology,the transmission bandwidth of mobile communication technology has been further expanded,and the transmission rate has been correspondingly improved.Synchronization technology,as an important link in the transmission at the end of the communication system,is directly related to the reliability and accuracy of data recovery at the mobile communication receiving end.The generation of a variety of complex baseband standard reference sources is studied,Synchronization technology in the thesis is researched and verified to provide theoretical and technical support for the receiver which can accurately recover a variety of complex baseband modulation signals.A variety of synchronization recovery techniques is mainly implemented and verified.Firstly,the generation of multiple complex baseband reference signal sources is analyzed and realized.Then the synchronization recovery technology based on single/multi-carrier system is discussed.The MPSK synchronization technology is mainly analyzed and verified.In the design of the synchronization loop,the design of the symbol recovery and carrier tracking loop is completed.A composite synchronization loop scheme is proposed,which can match the carrier frequency tracking loop and the phase tracking loop at different sampling rates.The MPSK carrier recovery loop technology is improved and a simple and convenient zero-IF carrier recovery scheme is realized.Carrier tracking performance is improved which is compared with the traditional carrier tracking based on phase-locked loop structure and high hardware design cost is reduced.The synchronization error of the multi-carrier system is analyzed,and the related synchronization algorithm is simulated.Based on the research of the above synchronization technology,a platform based on software and hardware is built to verify the synchronization verification of a variety of complex baseband standard reference sources.The specific research content of the thesis is as follows:Firstly,the synchronization technology of receiving the baseband modulation signal source in the current mobile communication technology is researched and verified.The GSM,EDGE,WCDMA,HSPA+,and LTE standard baseband test signal sources are researched,which are designed by the subject requirements.The baseband signal source is mainly transmitted by a single/multi-carrier system during transmission,so the synchronization technology verification of the baseband signal source under single/multi-carrier modulation is mainly completed.A simple structure and easy-to-implement symbol synchronization scheme for the single-carrier system MPSK synchronization loop design is proposed,and a complex loop synchronization scheme in the loop design of variable sampling rate is implemented.On this basis,a improved structure of a single carrier zero-IF carrier synchronization loop is verified and the corresponding performance is analyzed.A synchronization scheme is designed for frequency division multiplexing OFDM technology under multi-carrier systems and the corresponding synchronization algorithm simulation verification is carried out.The study of the synchronization system design under the baseband modulated carrier system affects the bit error rate of the entire transceiver system and is related to the demodulation performance of the communication transceiver.Secondly,a synchronization verification platform based on multiple signal modulation sources is built.The transmission data receiving constellation diagram and eye diagram are mainly observed to react the corresponding synchronization demodulation performance,The EVM value between standard reference signal source and receiving data is used to determine the synchronization performance,and it is finally verified that it has passed the synchronization test of a variety of baseband modulation signals.The scheme designed in the thesis can quickly extract the corresponding symbol synchronization information,capture and track the carrier and perform corresponding error compensation.The research scheme in the thesis has universal applicability to the synchronization test of a variety of complex baseband signal sources,and can intuitively reflect the performance of the synchronization scheme.It greatly simplifies the test steps of the demodulation performance test at the receiving end in engineering applications.The innovative design on the basis of the existing synchronization structure scheme is carried on,which can make the receiver end have better demodulation performance. |
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