Rayleigh衰落信道中带限DS-CDMA系统的最佳Chip波形设计

理论分析表明CDMA系统中多址干扰的统计特性取决于Chip波形的形状和能量，而Chip波形不仅影响系统的频谱特性还影响系统的误码性能。Chip波形的优化问题一直是近年来移动通信系统研究中的热点。目前研究人员对AWGN信道中CDMA系统的Chip波形已进行了广泛研究，设计出多种限制条件下的最佳Chip波形。而实际的移动信道都是有衰落的，到目前为止，有关衰落信道中CDMA系统Chip波形优化的研究见诸于文献的并不多。讨论了衰落信道中带限CDMA系统的最佳Chip波形的设计问题，给出了无Chip间串扰的最佳Chip波形的自相关函数的表达式。

Optimal Chip Waveform Design for Band -limited Asynchronous DS -CDMA Communications in Rayleigh Fading

For direct sequence code division multiple access (DS CDMA) systems with matched filter receivers, the statistical properties of the multiple access interference depend on the actual shape of the chip waveform as well as its energy, therefore, the chip waveform affects not only the spectral efficiency of the system, but also the error performance. Recently, the problem of chip waveform optimization is a hotspot in mobile communication research. Much work has been reported on the design of the optimal chip waveform for CDMA system in an additive white Gaussian noise (AWGN) channel, while few work on that in fading channel can be seen in literatures. The practical channel is usually fading one. The problem of optimal chip waveform design in Rayleigh fading channel is considered and the time autocorrelation function of the optimal chip waveform with zero interchip interference is presented in the paper.