We consider a two-phase decode-and-forward (DF) relay network assisted by an unmanned aerial vehicle (UAV), where the UAV performs energy harvesting and information decoding simultaneously with a power splitting (PS) receiver structure. For the network, we optimize the PS and time allocation (TA) factors to minimize the outage probability in transferring the data from a source to a destination suffering from blockages in the direct link. The optimal solution is found in two steps, optimization of the PS factor for given TA and then optimization of the TA factor using the conditionally optimized PS factor given in a closed-form. To reduce the complexity of the optimal method, we next propose a suboptimal method using a fixed TA determined by the transmission rate only and a fixed PS ffactor given by a function of the average power of the UAV-to-destination channel. The outage probability of the proposed method is analyzed in a generalized UAV channel model including path-loss, shadowing, and Nakagami-m fading, which is shown to agree with the simulation results and is close to the optimal performance. In addition, the optimal UAV position is investigated in various channel environments, which reveals that the optimal altitude depends on the deployment scenarios and the optimal ground position is the center-point between the source and destination in general. INDEX TERMS Decode-and-forward, energy harvesting, lognormal shadowing, Nakagami-m fading, simultaneous wireless information and power transfer, unmanned aerial vehicles.

Environment is the key factor in the greenhouse system. To provide monitoring and controlling facility inside the greenhouse, IoT based system is more flexible and suitable solution. To maintain the proper environment inside the green- house, we have designed the system with heating, cooling and water supply facility by integrating the system with heater, cooling fan and water pump. The temperature, humidity and    the soil moisture inside the greenhouse continuously monitored and controlled over online platform.

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In the recent era, unmanned aerial vehicle (UAV) plays an important role in numerous application fields related to the wireless communication system. Due to its precise control, efficient deployment, and affordable cost, UAV-assisted communication attracts significant attention to all the sectors including the defense sector, agriculture sector, and security purpose, and so on. Though UAVassisted relaying has enormous advantages but there are potential challenges while UAV deploys as a relay. For example, deploying UAV in the wireless communication field, its battery life is the main concern due to its limited battery size and storage capacity. To get significant benefits from UAV while deployed in the cooperative communication network, the battery status of the UAV is an unavoidable issue. To minimize the aforementioned problem, energy harvesting (EH) techniques can be an efficient solution. The UAV can harvest energy from the transmitted power by the source and with the help of this harvested energy UAV can retransmit the signal to the destination. However, there are several parameters that also significantly influence the UAV-based cooperative system performance such as UAV’s position, time allocation factor and power allocation factor, and UAV’s height. Considering the importance of the aforementioned parameters, in this paper, we have considered simultaneous wireless information and power transfer (SWIPT) enabled UAV-assisted relaying network and evaluate the system outage performance with different parameters aspects. We have provided some insight about the parameters such as the UAV’s position, the power allocation factor and the time allocation factor and the UAV’s height by providing simulation results such as the outage probability versus transmit power in the different urban scenario, the outage probability versus time allocation factor and power allocation factor and the outage probability versus UAV’s height. These simulation results clearly show the significance of the abovementioned parameters in wireless-powered UAVassisted cooperative communication. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

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