提出了一种双跳混合射频(RF)和多输入多输出(MIMO)自由空间光通信(FSO)放大转发中继通信系统。RF链路和MIMO FSO链路分别考虑Rayleigh衰落分布模型和Gamma-Gamma大气湍流信道模型,多孔径接收端采用等增益合并方式。在中继分别为固定增益和变增益放大转发下,推导出关于混合系统信噪比的累计分布函数和概率密度函数,进一步得到混合RF和MIMO FSO系统的中断概率、遍历容量及在不同二进制调制方式下的平均误码率的闭合表达式。仿真分析了不同增益模式下大气湍流、调制方式及空间分集对混合RF/MIMO FSO双跳中继通信系统性能的影响。

This paper presents a dual-hop mixed radio frequency (RF) and multiple-input multiple-output (MIMO) free-space optical (FSO) amplify and forward (AF) relay communication system. The RF link and MIMO FSO link consider the Rayleigh fading distribution model and the Gamma-Gamma atmospheric turbulence channel model, respectively. The multi-aperture receiver adopts equal gain combination mode. Under the relays with fixed gain and variable gain AF, the cumulative distribution function of the signal-to-noise ratio of the hybrid system and its probability density function are derived. Closed-form mathematical formulas of the outage probability, ergodic capacity, and average bit error rate for different binary modulation modes of the mixed RF/MIMO FSO system are obtained. The effects of the atmospheric turbulence, modulation mode, and space diversity on the performance of the mixed RF/MIMO FSO dual-hop relay communication system under different gain modes are simulated and analyzed.