关键词: 光无线通信/
混沌介质/
二阶关联/
压缩感知
English Abstract
Optical communication in turbid and turbulent atmosphere
Mao Tian-Yi1,Chen Qian1,
He Wei-Ji2,
Zhuang Jia-Yan1,
Zou Yun-Hao1,
Dai Hui-Dong1,
Gu Guo-Hua1
1.School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
2.Jiangsu Key Laboratory of Spectral Imaging and Intelligent Sense, Nanjing University of Science and Technology, Nanjing 210094, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61271332, 61101196).Received Date:04 November 2015
Accepted Date:28 December 2015
Published Online:05 April 2016
Abstract: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. The communication rate, limited by the frequency of the DMD and the sampling rate of the receiver, could reach hundreds of kbit/s, and with improved technology a rate of Mbit/s should be attainable. This proposed APOC could realize optical communication in turbid and turbulent atmosphere and thus offers a very effective approach to promoting the implementation in military and rescue.
Keywords: optical communication/
turbid media/
second-order correlation/
compressed sensing
