Faster-than-nyquist Interference Cancellation Algorithm And FPGA Implementation

With the advancement and development of technology,better real-time and interactive services at all levels brought by future intelligent emerging technologies must have higher requirements for the spectral efficiency(SE)and system reliability of today 's communication systems.Faster-Than-Nyquist(FTN)increases the symbol transmission rate by compressing the time interval between the shaping pulses to improve the SE,but the use of non-orthogonal transmission will inevitably introduce Inter-Symbol Interference(ISI)thereby reducing the reliability of the system.In order to eliminate self-interference,the FTN system can improve the performance of the system through equalization and precoding algorithms.Therefore,this thesis mainly studies the self-interference of FTN from the perspective of equalization and precoding algorithm,and implements the equalization algorithm in FPGA.First of all,in view of the high complexity of the equalization algorithm in the FTN transmission system,this thesis studies two low-complexity Turbo equalization algorithms,which are Successive Interference Cancellation(SIC)and Minimum Mean-Squared Error(MMSE)algorithm,and so on this basis,a new turbo equalization method based on MMSE-SIC is proposed.The main idea is to mix and iterate the two equalization algorithms,MMSE and SIC at the receiving end,so as to reduce the total iterative complexity and alleviate the error propagation problem of the SIC algorithm.Computer simulation experiments show that the proposed new Turbo equalization method can effectively eliminate the ISI introduced by FTN technology,and its bit error rate performance is close to Nyquist orthogonal transmission.Secondly,in view of the problem of residual interference when using TomlinsonHarashima Precoding(THP)in the FTN transmission system based on the Ungerboeck model,this thesis proposes two detection algorithms at the receiver,which are the detection algorithm based on Backward serial interference cancellation(BSIC)and the An improved Turbo equalization algorithm based on Successive Interference cancellation(SIC).It uses the known filter information and the data of the symbol at the later time to eliminate the interference of the symbol at the previous time.The computer simulation shows that under the selected extended modulo interval,the BSIC detection algorithm can effectively eliminate the ISI introduced by FTN when the acceleration factor is 0.9,and the gap is only 0.7dB compared with the Nyquist transmission.In addition,the improved Turbo equalization algorithm based on SIC has obvious improvement in bit error rate performance compared with the original algorithm,and its bit error rate performance is close to Nyquist orthogonal transmission when the acceleration factors are 0.9 and 0.8.Finally,FPGA is designed and simulated for the BSIC detection algorithm proposed in this thesis.The computer simulation results verify the correctness of the FPGA implementation of the detection algorithm.