Design of Automatic Operated Modular Underwater Vehicle System for Marine Ranch BreedingDesign of Automatic Operated Modular Underwater Vehicle System for Marine Ranch Breeding

As terrestrial resources gradually cannot meet people's needs, Countries around the world gradually increase the development and utilization of marine resources. The emergence of marine ranching overcomes many disadvantages of traditional fishery, but there is still a distance from unattended intelligent marine ranch. In this paper, designed a kind of unattended modular underwater robot system which used in marine ranch, including the main body for cage monitoring, the robot module for cleaning and repairing of net clothes and recycling of dead fish, while designed a underwater interfacing apparatus for the main body and root module,This paper introduces the underwater vehicles system of marine ranching, and designs the main body and working module in detail. This paper simply describes the interfacing process of the underwater workstation with the main body and modules.The research results of this paper compensate for the gaps in marine ranch engineering equipment and technology, and meantime proposed an underwater vehicle for cage repairing and dead fish recycling, which uses modular ideas, it can reduces costs and this paper strongly promotes the development of intelligence and automation level of marine ranching.

2 × 20 Gbit/s OFDM-based FSO transmission system for HAP-to-ground links incorporating mode division multiplexing with enhanced detection

In this work, the integration of free-space optics (FSO) technology for implementing long-haul high-altitude platform (HAP)-to-ground transmission system is proposed. Mode division multiplexing (MDM) and orthogonal frequency division multiplexing (OFDM) are incorporated for carrying high-speed signals without interference. The impact of increasing input power, divergence angle, antenna diameter, and attenuation on the system performance is further investigated. In addition, the performance of the MDM-OFDM-HAP-to-ground FSO transmission system is improved by using a square root module at the receiver for link reach enhancement. The results exhibit a reliable transportation of 40 Gbps information over 20 km FSO distance with good quality of the received signal.

Improved Performance Investigation of 10 Gb/s–10 GHz 4-QAM Based OFDM-Ro-FSO Transmission Link

In this work, a 10 Gb/s–10 GHz hybrid orthogonal frequency division multiplexing (OFDM)-radio-over-free space optics (Ro-FSO) transmission link using 4-level quadrature amplitude modulation (QAM) has been modeled and its performance is investigated under different atmospheric conditions and system parameters. A link distance of 4000 m at 10 Gb/s was achieved using the proposed link. Also, an improved performance by using a square root module (SRm) at the receiver end has been demonstrated. The results show a significant improvement in SNR and total received power using the proposed detection technique.