混沌与湍流大气中的光通信  

Optical communication in turbid and turbulent atmosphere

作　　者：冒添逸 陈钱[1] 何伟基[2] 庄佳衍[1] 邹云浩 戴慧东 顾国华[1] 

机构地区：[1]南京理工大学电子工程与光电技术学院,南京210094 [2]南京理工大学,江苏省光谱成像与智能感知重点实验室,南京210094

出　　处：《物理学报》2016年第8期178-185,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61271332;61101196)资助的课题~~

摘　　要：目前,光无线通信的质量主要受到大气信道环境的制约,大气信道中混沌介质与湍流的强烈扰动使得通信质量很差,甚至通信中断.提出了一种面到点的光无线通信机理:利用面阵各单元的光信号在混沌介质中传输通道的空间非相干性,通过桶探测器收集通过混沌介质的光信号的能量和,平均各传输通道的交叉干扰,降低混沌介质对光无线通信的影响;利用随机噪声与随机编码的空间非相干性,经过二阶相关运算,构建新的信号传输方程,减弱大气湍流及背景光对信号解码的干扰,使得接收端并不需要窄带光学滤波器.数值仿真和演示实验表明,该光无线通信机理在混沌与湍流大气中的误码率为4—2,能够实现复杂大气环境中的光通信,在军事、抢险救援等方面具有重要应用价值.Free space optical-communication（FSO） has gained significant importance due to its unique features： large bandwidth, license free spectrum, high data rate, easy and quick deployability, less power and low mass requirement. However,the performance of FSO is degraded in the turbid and turbulent atmosphere, dramatically. Various techniques are proposed to cope with the turbid media and turbulence in atmosphere, e. g. aperture averaging, diversity, adaptive optics,modulation and coding and orbital angular momentum. However, in the above systems with point-to-point optical communication structure, there exist obvious drawbacks or they are complex and expensive, and thus difficult to use in practice. In this article, array-to-point optical communication（APOC） with good performance in turbid and turbulent atmosphere is demonstrated. The strongly disturbed communication channel can be expressed as a circular complex Gaussian transmission matrix, and the transmitted field is described as a linear combination of the fields coming from different and independent segments of the digital micro-mirror device（DMD）, so that the cross terms are averaged on the surface of bucket detector. Instead, the contributions of all segments for each light field nearly becomes equally weighted.Turbulence and other noises are reduced for the incoherence with sampling matrix based on the second-order correlation which has widely been used in ghost imaging and LIDAR. Consequently, narrow-band optical filter is not required at the receiver. The decoding algorithm is a new signal processing strategy from information technology, compressed sensing,which discards low frequency components in sampling process and recovers the signal by conducting convex optimization.Numerical simulations and experiments with binary and multi-bits level signals are demonstrated to show that the bit error rate of the proposed method APOC is approximately 10^-4–10^-2, which is feasible for the optical communication in such complex communication channels.

关 键 词：光无线通信 混沌介质 二阶关联 压缩感知 

分 类 号：TN929.1[电子电信—通信与信息系统]