In this paper, a new interleaving scheme for an interleaved frequency division multiple access (IFDMA) system is proposed. The proposed scheme combines the advantages of code division multiple access (CDMA) with maximal length sequence (m-sequence) and orthogonal frequency division multiple access (OFDMA). Multiaccess interference (MAI) among users is eliminated by employing orthogonal carriers, and the intersymbol interference (ISI) due to multipath channels is minimized by using cyclic interleaving. Diversity gain is achieved in the proposed method with maximal ratio combining (MRC) in the case of a Rayleigh environment. Compared to complex multiuser (MU) detection, the detection process in the proposed method is relatively simple. Multipath orthogonality is achieved in the proposed method, avoiding the need for channel equalization. The proposed method is compared with the conventional interleaving employing well-known minimum mean square error frequency domain equalization (MMSE-FDE). The Monte Carlo simulation results prove the superiority of the proposed interleaving over conventional interleaving with MMSE-FDE, showing that the present scheme is suitable for both uplink and downlink mobile radio transmissions.

中文翻译：

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IFDMA系统的循环交织方案

本文提出了一种新的交织频分多址（IFDMA）系统的交织方案。所提出的方案结合了码分多址（CDMA）与最大长度序列（m序列）和正交频分多址（OFDMA）。通过使用正交载波消除了用户之间的多址干扰（MAI），并且通过使用循环交织将由于多径信道而引起的符号间干扰（ISI）降至最低。在瑞利环境下，该建议方法通过最大比率合并（MRC）实现了分集增益。与复杂的多用户（MU）检测相比，该方法的检测过程相对简单。该方法实现了多径正交性，避免了信道均衡的需要。将该方法与采用众所周知的最小均方误差频域均衡（MMSE-FDE）的常规交织进行了比较。