垂直分层空时编码(V-BLAST)是一种将空间复用和空间分集相结合的技术,它具有极高的频谱利用效率和传输速率,因此将垂直分层空时编码技术应用于自由空间光通信。在研究了大气信道的特性之后,提出了一种基于垂直分层空时编码的自由空间光通信系统的信道模型。介绍了垂直分层空时编码的编码原理,并分析了该系统的信道容量。利用仿真实验比较了采用垂直分层空时编码前后系统信道容量及误码性能的变化。结果表明,当接收天线数大于或等于发送天线数时,系统的信道容量与发送天线数成正比例增长,误码性能被有效改善。说明该系统具有垂直分层空时编码所提供的信道容量和良好的误码性能,且能有效克服大气湍流所产生的闪烁效应。

Vertical bell labs layered space-time (V-BLAST) is a technology combining space multiplexing with space diversity. It has the high spectrum efficiency and the transmission speed, so the technology is applied to free space optical communication. In this paper, after researching the characteristic of atmosphere channel, a free space optical communication channel model based on V-BLAST is proposed. Code principle of V-BLAST is introduced, and channel capacity of this system is analyzed. The difference of the channel capacity and error rate of the system with and without V-BLAST structure is compared through simulation experiment. As a result, when receiving antenna number is larger than the transmitting antenna number, the channel capacity is improved directly proportional with transmitting antenna number, and the error code performance of system coded V-BLAST is improved effectively. It shows that the system has channel capacity supplied by V-BLAST structure and well error code characteristic, and the scintillation effect caused by atmosphere turbulence is effectively overcome.