Research On Frequency Offset Estimation Technology And FPGA Implementation Of SC-FDMA System

Single carrier frequency division multiple access(SC-FDMA)has been adopted for Long Term Evolution(LTE)uplink transmission due to its low peak to average power ratio property.Similar to Orthogonal Frequency Division Multiplexing(OFDM)based systems,SC-FDMA is also very sensitive to carrier frequency offset(CFO).It happens due to oscillator mismatch or Doppler shift.In the case of a multi-user uplink SC-FDMA system,the received signal is a combination of multiple signals from different users,where each user may experience different CFO due to different hardware setup or different transmission environments.It results in inter-subcarrier interference(ICI)for the same user and multiple access interference(MAI)with other users,deterioration of overall system performance.Therefore,estimation and compensation of multi-user carrier frequency offset estimation are crucial task at the base station to improve the system performance.In this paper,the SC-FDMA system frequency offset estimation algorithm is first studied.The paper introduces the background and significance of this research,analyzes and summarizes the research status at home and abroad.Then the principle and model of SC-FDMA system are elaborated,and the theoretical analysis and simulation of the influence of CFO on SC-FDMA system are carried out.Then,based on the uplink multi-user simulation system,the simulation and performance comparison of the frequency domain and time-domain carrier frequency offset estimation algorithms are completed.It also shows the influence of the sub-carrier allocation method on the frequency offset estimation performance by simulation.A multi-user frequency offset estimation scheme for FPGA implementation was finalized.Another research work of this paper focus on the FPGA implementation of the SC-FDMA system frequency offset estimation algorithm.The paper separately introduces the hardware circuit design and detailed description of the multi-user separation,frequency offset estimation and compensation module,including the internal circuit design,interface design and timing design of each module.Finally,the function and timing of the whole system and each module are verified by the joint simulation of Modelsim and Matlab,and the error and hardware resource consumption are analyzed.This design improves the accuracy of the frequency offset estimation result through algorithm simulation analysis,and greatly improves the operation speed by parallel processing of data by FPGA.