在本篇論文，我們將單載波頻域等化器系統運用在上行的分碼多工系統上，並提出將解展頻放於頻域等化器前，其好處為可以使頻域等化器的離散傅利葉與離散反傅利葉點數減少，可大幅降低系統複雜度。分碼多工系統可提升系統容量，但隨使用者增加，使用者間干擾也會越嚴重，這種干擾稱為多使用者干擾，本篇論文使用一個去除多使用者干擾疊代法，可有效的將干擾消除。最後，我們將判別回授等化器結合在單載波頻域等化器分碼多工系統，可更進一步提升系統效能。模擬結果顯示去除多使用者干擾疊代法加上判別回授等化器可有效消除多使用者干擾並提升系統效能。In this thesis, we consider the single-carrier frequency domain equalizer (SC-FDE) system used for the uplink of code division multiple access (CDMA) systems in which the code despreading is performed in front of the equalizer. The main advantage of the new despreading scheme is to reduce the number of the discrete Fourier and inverse Fourier transform points required in the FDE compared to the conventional CDMA dispreading scheme. Although the CDMA system can enhance system capacity, as the number of users increases, the multiuser interference (MUI) problem needs to be carefully dealt with. In our study, an iterative multiuser interference removal method in a combination of decision feedback equalization is applied. Simulation results show that the proposed despreading scheme significantly reduces the FFT size and the proposed iterative MUI removal method can majorly eliminate MUI with only a small number of iteration.
