We experimentally demonstrated a long-range, large-capacity-featured, airship-based, free-space optical transmission system by using key technologies, such as GPS/INS real-time precision laser pointing, coarse and fine compound high-bandwidth laser tracking, avalanche photodiode detector adaptive control turbulence channel compensation, and the aurora laser fifth-generation (5G) interface protocol, to solve the problems of laser tracking and targeting based on an airship motion platform, high-speed signal transmission under atmospheric channel perturbation, and interface protocol between a wireless laser link and 5G base station signal, respectively. To the best of our knowledge, the first FSO transmission of 5G base station signals between airship platforms with a rate of 2.5 Gbps and a distance of 12 km was realized, and channel turbulence jitter was also recorded for laser links of different altitudes, from 200 to 1000 m, which provides technical and data support for the application of wireless laser links in 5G floating base stations.

The booming crowdsourced delivery leverages networks of local, part time couriers to meet growing customer demands for increasingly speedy shipping. By conducting city-wide low-cost delivery networks, crowd-sourced enabled instant delivery platforms have fought to figure out a way to offer instant shipping at low price. Nevertheless, limited ubiquitous computing infrastructures impede the discovery of equilibrium between cost reduction and sufficient shipping capacity. In this article, we present our endeavor towards understanding and designing a dynamic pricing framework based on a large-scale food-delivery platform. To reduce delivery fees in capacity overload regions and resolve the decline of service quality caused by insufficient shipping capacity, we address the challenge of quantifying the inter-regional shipping capacity disparities by accordingly applying a variety of techniques, including cooperative game theory, probability analysis and address entity recognition. In particular, we provide an $O(n^{2})$ algorithm for the cooperative game based cost allocation, of which the exponential computational complexity $O(n^{2}2^{n})$ is generally considered a major challenge in real-world applications. City-wide experiments in Nanjing and Shenzhen illustrate that we achieve a 10% decrease in delivery fees under overload shipping capacity and a 3% increase in completion rates in customer locations with poor service quality.

The mean-square angle-of-arrival (AOA) difference between two counter-propagating spherical waves in atmospheric turbulence is theoretically formulated. Closed-form expressions for the path weighting functions are obtained. It is found that the diffraction and refraction effects of turbulent cells make negative and positive contributions to the mean-square AOA difference, respectively, and the turbulent cells located at the midpoint of the propagation path have no contributions to the mean-square AOA difference. If the mean-square AOA difference is separated into the refraction and diffraction parts, the refraction part always dominates the diffraction one, and the ratio of the diffraction part to the refraction one is never larger than 0.5 for any turbulence spectrum. Based on the expressions for the mean-square AOA difference, formulae for the correlation coefficient between the angles of arrival of two counter-propagating spherical waves in atmospheric turbulence are derived. Numerical calculations are carried out by considering that the turbulence spectrum has no path dependence. It is shown that the mean-square AOA difference always approximates to the variance of AOA fluctuations. It is found that the correlation coefficient between the angles of arrival in the x or y direction of two counter-propagating spherical waves ranges from 0.46 to 0.5, implying that the instantaneous angles of arrival of two counter-propagating spherical waves in atmospheric turbulence are far from being perfectly correlated even when the turbulence spectrum does not vary along the path.

The non-uniform response in infrared focal plane array (IRFPA) detectors inevitably produces corrupted images with a fixed-pattern noise. In this paper, we present a novel and adaptive scene-based non-uniformity correction (NUC) method called Correction method with Statistical scene-based and Interframe Registration (CSIR), which realizes low delay calculation of correction coefficient for infrared image. This method combines the statistical method and registration method to achieve a better NUC performance. Specifically, CSIR estimates the gain coefficient with statistical method to give registration method an appropriate initial value. This combination method not only reduces the need of interactive pictures, which means lower time delay, but also achieves better performance compared to the statistical method and other single registration methods. To verify this, real non-uniformity infrared image sequences collected by ourselves were used, and the advantage of CSIR was compared thoroughly on frame number (corresponding to delay time) and accuracy. The results show that the proposed method could achieve a significantly fast and reliable fixed-pattern noise reduction with the effective gain and offset.

Networking is an inevitable trend in developing free-space optical communications. The demand for multiple optical terminals to simultaneously establish links with and transmit to a single optical terminal has driven the integration of optical terminals. Phased arrays and rotating parabolic mirrors have been employed for beam control. However, achieving codomain detection of multiple optical spots with a single quadrant detector (QD) remains challenging in integrated detection. This paper proposes a codomain detection method for multiple beacons using a single QD based on pseudorandom code spread-spectrum modulation. This method realizes multiple beacons through code division multiple access (CDMA) by leveraging the orthogonality of pseudorandom sequences. The impact of different spread-spectrum gains on detection sensitivity and accuracy variation law under the interaction of multiple optical spots with different powers is investigated using simulation and experimental verification. The results demonstrate that when the spread spectrum gain is 1023, the detection sensitivity can reach −30 dBm@1 μm. Under conditions of equal-power interaction between two optical spots, the system deviation of position detection is less than ±60 μm, a reduction of 87.8% compared to the ±493 μm disturbance error without using CDMA. Finally, a simultaneous three spots tacking detection system was validated, achieving a detection accuracy of 1 μm, thereby proving the feasibility of CDMA multibeacon detection.

In pure seawater, the transmission window is in the blue-green light band, and blue light has good transmission characteristics. This paper proposes an underwater wireless optical communication system that uses a 470 nm LED array stitching structure, increasing the diverging angle. At the same time, we use Fresnel lens as the optical antenna realizing the wide field of view receiving. At an underwater distance of 20 m, this system could successfully achieve reliable communication at a rate of 5 Mbit/s (data rate) and a BER of 10(-6), which lays a foundation for subsequent underwater dynamic laser communication systems.