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多载波直接扩频序列码分多址 (DS- CDMA)是一种结合正交频分复用 (OFDM)的调制方式和 DS- CDMA的多址方式而产生的宽带 CDMA传输方式。该文结合下行多载波 DS- CDMA的特点 ,提出了最优交织器的设计准则 ,推导出了它的最优解和相应的最优性能。给出了一种只需排序操作就可以实现次最优交织器的设计方法。理论分析和仿真结果表明 ,当频域分集数 P小于信道阶数 L 时 ,优化后的交织器能有效地提高系统的分集增益 ,并使系统的性能逼近P=L 时的最优性能。当 P≥ L 时 ,等间距交织器就是最优交织器。
Multi-Carrier Direct Spread Spectrum Code Division Multiple Access (DS-CDMA) is a wideband CDMA transmission method that combines the modulation method of Orthogonal Frequency Division Multiplexing (OFDM) and the multiple access method of DS-CDMA. Based on the characteristics of downlink multi-carrier DS-CDMA, this paper presents the design criteria of the optimal interleaver and derives its optimal solution and the corresponding optimal performance. A design method of suboptimal interleaver can be realized by just sorting operation. The theoretical analysis and simulation results show that the optimized interleaver can effectively improve the system diversity gain and make the system performance approach the optimal performance at P = L when the frequency diversity number P is less than the channel order L. When P ≥ L, the equally spaced interleaver is the optimal interleaver.