Research And Validation On Key Technology Of Time And Frequency Synchronization In Co-time Co-frequency Full-duplex Microwave Communication Systems

The traditional microwave communication use time division duplex or frequency division duplex, it has basically reached the limit of communication performance. In this paper, we will study the Co-time Co-frequency full-duplex application in microwave relay communication, the spectral efficiency and transmission rate can be doubled compare to the traditional one.In this paper, we focus on the time and frequency synchronization method in the full-duplex microwave communication system. As the full-duplex technique will introduce self-interference to communication system, and self-interference will affect the guide sequence in target signal and then deteriorate the synchronization accuracy in time and frequency estimation. Faced with the challenge, this paper does the following research.Firstly, this paper have a research on the present situation of the self-interference cancellation and time-frequency synchronization. Based on this, we put forward a time-frequency synchronization method that can cancel the self-interference and improve the estimation accuracy of guide sequence. We build the system model, related strategies and conduct the performance simulation. When the interference to signal ratio is 10 d B and the signal to noise ratio is 1d B, the capture probability of time synchronization is 100%. For the frequency synchronization, when the signal to noise ratio is 15 d B, the root mean square error of coarse synchronization is under 30 and the root mean square error of fine synchronization is under 0.2.Then, we conduct the algorithm implementation of signal processing based on the theoretical analysis, the process include the designation of logic module interface and the process flow. in the implementation process, we simplify some calculation and makes it balance between performance and resource.Finally, we test the time and frequency method on a microwave full duplex communication demo, and test separately from the functional and performance by observing the equalized constellation and bit error rate statistics, and fulfill the functional requirements by the prototype. The whole link achieves a performance of 610- bit error rate in the full duplex mode of communication, and also fulfill the demo performance requirements.Through the above research and validation, it can afford the theory and project value for the time-frequency synchronization of full-duplex microwave communication, and support the further research.