Djordjevic Ivan B, Djordjevic Goran T
Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ 85721, USA.
Opt Express. 2009 Sep 28;17(20):18250-62. doi: 10.1364/OE.17.018250.
The free-space optical (FSO) communications can provide any connectivity need at high-speed. However, an optical wave propagating through the atmosphere experiences the variation in amplitude and phase due to scintillation. To enable high-speed communication over strong atmospheric turbulence channels, we propose to transmit the encoded sequence over both FSO and wireless channels, feedback channel state information of both channels by RF-feedback, and adapt powers and rates so that total channel capacity is maximized. The optimum power adaptation policy maximizing total channel capacity is derived. We show significant spectral efficiency performance improvement by employing this approach. We further show that deep fades in the order 35 dB and above can be tolerated by proposed hybrid communication scheme.
自由空间光（FSO）通信能够高速满足任何连接需求。然而，光波在大气中传播时会因闪烁而经历幅度和相位变化。为了在强大气湍流信道上实现高速通信，我们建议通过FSO和无线信道同时传输编码序列，通过射频反馈来反馈两个信道的信道状态信息，并调整功率和速率，以使总信道容量最大化。推导了使总信道容量最大化的最优功率适配策略。我们展示了采用这种方法能显著提高频谱效率性能。我们还进一步表明，所提出的混合通信方案能够容忍高达35dB及以上的深度衰落。
