Desing And Implementation Of Single Carrier Frequency Domain Equalization System

Single Carrier Frequency Domain Equalization(SC-FDE) technology maintaining high-speed, large-capacity communication can confront frequency selective fading channel productively. Compared with the time domain equalizer technology, frequency domain equalization technology has the advantage of computational complexity; compared with Orthogonal Frequency Division Multiplexing(OFDM), SC-FDE can reduce the peak to average power ratio, so reduce the receiving end of the power amplifier requirements. Currently, single carrier frequency domain equalization system as a powerful competitor of OFDM in the broadband wireless systems are increasingly used.Firstly, this paper expounds the basic characteristic of wireless channel and discusses the SUI-3 channel model, the model provide a condition for follow-up study. Then this paper describes the mathematical description of single carrier frequency domain equalization system, analyses the computational complexity of frequency domain equalization and time domain equalization, the peak average power ratio and channel capacity of single carrier frequency domain equalization system and OFDM. This paper discusses the system of transfer mode and channel estimation algorithm in SC-FDE.Secondly, linear equalizer in single carrier frequency domain equalization system is introduced in detail. the zero-forcing equalizer compares with the MMSE equalizer in the advantages and disadvantages and the bit error performance. The paper analyzes the carrier tracking performance of the single carrier frequency domain equalization system, specially, the carrier frequency offset and phase noise influence on the performance of the system. And a system adopting the linear equalizer implemented on FPGA under the condition of SUI-3 channel obtained the certain effect.The last key is the introduction nonlinear equalizer, which respectively details the basic principle, structure and the bit error performance of the time-frequency mixed decision feedback equalizer, MMSE-RISIC equalizer, iterative block decision feedback equalizer(IBDFE), and compare the computational complexity of various kinds of equalizer. IBFDE uses iteration to eliminate inter-symbol interference effectively, which the feed-forward and feedback filter work in frequency domain. But feed-forward filter and feedback filter coefficient need to compute the related factors, and each iteration needs computing new correlation factor and update coefficient, as the growth of the number of iterations, calculation also increases. This article obtains a improve IBFDE equalizer form the derivation process of the IBFDE equalizer coefficients, corresponding filter coefficients are obtained by minimum mean square error criterion, withdrew the related factors of calculation, the performance is similar to traditional algorithm and reduces the complexity.