时分复接码分多址系统中预瑞克与空时编码技术

提出了一种适用于时分复接码分多址系统的发射分集，即预瑞克与空时格状编码调制相结合方案。采用预瑞在代替瑞克，在接收机中采用单径瑞克就可实现多径分集，可以简化接收机结构和节约费用。计算机仿真结果表明，在多径衰落下，所提出方案的性能比仅采用空时码好。在最小均方误差意义下预瑞克抽头数应与多径数相同。所提出新型星座图－8APK（振幅相位键控）可以用来构造了一个空时码，此空时码性能比由8PSK构造的具有相同结构的空时码好。

Pre-RAKE Combining with Space-Time Coding for TDD/CDMA Systems

A novel synthetically transmit diversity, Pre-rake joint with space-time trellis coded modulation (STTCM), for TDD DS-CDMA system is proposed. Space-time code (STC) is applied for the multi-path fading circumstance. Pre-rake is used in stead of Rake to overcome multi-path fading for the simplicity of the receiver configuration. Through computer simulation, the performance of our proposed scheme in multi-path fading is better than that of STC only, the taps of the Pre-rake should be chosen to be equal to the multi-path number in the sense of minimum mean square error. A new constellation--8APK is presented to construct a kind of STC that achieves better performance than that of 8PSK.