相关多径衰落信道下MIMO-CDMA系统容量研究

Capacity of MIMO-CDMA System in Correlated Multipath Fading Channels

在瑞利衰落信道下使用多输入多输出(M IMO:Mu ltip le InputMu ltip le Output)技术将大大增加信道容量。从理论来说,一个M发M收系统信道容量至少为一个单发单收系统信道容量的M倍。贝尔分层空时(BLAST:Bell Layer Space Tim e)结构和多码CDMA(Code D ivision Mu ltip le Access)都支持高速数据传输,为取得更高的速率,提出一种结合这两种技术的模型,给出了接收机没有干扰协方差信息时的ML(M aximumL ikelihood)检测器和解相关检测器,计算并比较了在相关多径衰落时基于LS码和基于W alsh码的系统的容量。结果表明,基于LS码的系统在性能上远远优越于基于W alsh码的系统。

Recent research indicates that using multiple input and multiple output can increase capacity greatly, in principle a system with M transmit antennas and M receive antennas can achieve M times capacity of traditional system with single antenna. Both BLAST （Bell Layer Space Time） and multioode CDMA （Code Division Multiple Access） can support high rate transmission, a model combined both to acquire higher data rate is proposed. We give ML （ Maximum Likelihood） detector without interference covariance knowledge and decorrelator detector, calculate the capacity in correlated muhipath fading and compare system based on LS code with that based on Walsh code. We conclude that system based on LS code performs better than that based on Walsh code.