Papers by Author: Jing Dai

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier communication system and the system is very sensitive to synchronization errors. The problem that synchronization is not accurate can reduce the system performance largely. Based on the research of Schmidl & Cox and Minn algorithms, the paper proposed an improved timing synchronization algorithm by using the new training sequence in the frequency domain. The improved algorithm eliminates the peak platform problem and side lobe peak problem of the conventional synchronization algorithms in this article. The simulation at MATLAB shows that the improved algorithm overcomes the problems of the conventional algorithms and the timing judgment curve of the improved algorithm also has a very sharp peak at the timing synchronization position, compared with the conventional algorithm. So, the timing synchronization performance of the algorithm is better.

Abstract: A adaptive interference cancellation algorithm was proposed in this paper. The MATLAB simulation results of the performance of five different kinds of adaptive interference cancellation algorithm were presented. According to the comparison of the simulation results, especially the usage of resource, convergence rate and effects of cancellation, the frequency-domain block LMS algorithm was selected suitable for the further design on FPGA. By simulating the functions by modelsim, and analyzing the PSD curve and the constellation of output signals, the adaptive interference cancellation algorithm system based on frequency-domain block LMS achieved expected effect. The better in-band flatness of the PSD curve and the higher convergence rate on constellation were obtained. Therefore, the frequency-domain block LMS adaptive interference cancellation algorithm is chosen as the design with high performance-price ratio.

Abstract: This paper proposed DLMS algorithm which is suitable for real-time signal processing. The algorithm adopts hardware multiplier and pipeline technology to accelerate the operation of the system. By analyzing the time sequence and spectrum of the output signals, the attenuation of the interference signals is about 51dB. It can further demonstrate the high quality and high speed of the DLMS algorithm to filter out the interference signals, and well handle the relationship between the resources and speed of FPGA to meet the requirements of high-speed signal processing.

Abstract: A adaptive interference cancellation algorithm was proposed in this paper，which was based on NLMS algorithm.The NLMS algorithm was achieved on FPGA chips. This paper described the method of the specific implementation. This method introduces bit-shift in terms of subsection instead of division operation, by which the operation speed of FPGA is improved apparently.By Matlab simulating the functions, and analyzing the PSD curve and the constellation of output signals, the adaptive interference cancellation algorithm system based on NLMS achieved expected effect. The better in-band flatness of the PSD curve and the higher convergence rate on constellation were obtained. Therefore, the NLMS adaptive interference cancellation algorithm is chosen as the design with High Performance-price Ratio.