Research And Implementation Of Frequency Domain Equalization Technology In Single Carrier Transmission System

The rapid development of broadband wireless communication enriches people’slife. How to overcome the multipath delay spread and doppler effect has been achallenging problem in high data rate wireless communication. How to eliminate theinterference of these effect and ensure the quality of communication is an issue that hasbeen continuously discussed. At the present stage, Orthogonal Frequency DivisionMultiplexing (OFDM) is a transmission technology which is widely used in wirelesscommunication that can deal with these interferences. However, the single carrierfrequency domain equalization (SCFDE) has similar anti-multipath performance andsimilar complexity. Moreover, SCFDE overcomes several disadvantages of OFDM,such as high Peak-to-Average Power Ratio (PAPR) and frequency offect sensitive,gradually becomes a strong competitor of OFDM in various standards, often as OFDMoptions appear in the same protocol. As one of the most important key technologies ofthe single carrier frequency domain equalization transmission system, frequency domainequalization technology effectively overcome the time-varying fading characteristics ofwireless channel to bring, and resistance to inter symbol interference (ISI) system in thereceiving end.First of all, this paper introduces the SCFDE principle, and analyzes the influencewireless channel brings to the transmission. Base on this basis, this paper built theExtend Pedestrian A (EPA) and Typical Urban6(TU6) channel software simulationplatform. At the meantime, this paper briefly introduces the composition of the singlecarrier frequency domain equalization transmission system, frame format and channelestimation problem.Secondly, this paper deduced the basic principle of frequency domainequalization，and linear equalization performance is analyzed in two kinds of channelconditions. After the research of the traditional time-frequency mixed decision feedbackequalization (HDFE) algorithm and the noise prediction decision feedback equalization(NPDFE) algorithm, and the optimized structure and performance analysis. Thirdly, this paper studies the iterative block decision feedback equalization(IBDFE) algorithm. Two improved algorithms and a simplified IBDFE is designed onthe basis of the original algorithm in Unique Word frame format. The simulation resultsshow that two improved methods’ performance is improved obviously. At the sametime, the simplified IBDFE algorithm greatly reduces the system complexity while justtake a little sacrifice of performance for cost.In the last part of article, we designed frequency domain equalization circuit ofsingle carrier portable broadband wireless communication system baseband receivingterminal. The designing is under the development environment for Xilinx ISE andModelsim by using Verilog hardware description language.The chosen implementationscheme linear equalization scheme. At last, the designing is downloaded to FPGAdevelopment board, and the simulation waveforms and the output data verifies thefunctional correctness of design circuit, so as to meet the design requirements.