Today, with scientific and technological advances in the field of robotics, artificial intelligence, control and computers, land, air and sea vehicles, they have been considered. Unmanned Aerial Vehicles (UAVs) have also significantly improved and are very useful for many important applications in the business, urban and military environment. One of the important uses of UAVs in Wireless Sensor Networks (WSNs) is that these devices may not be able to communicate in large areas due to their energy constraints. In this case, a UAV can play mobile collectors for WSN networks. In this paper, we survey the work done towards all of practical applications of UAVs as mobile collectors for wireless sensor networks. We first examine the proposed UAV applications and compared their weaknesses with each other. We also examine the technical challenges we have about the applications of UAVs in the Wireless Sensor Network in detail. Then, in this paper, we provide an energy efficient data gathering with a deadline for wireless sensor networks using the UAV and a series of virtual grid points, named virtual grid energy efficient deadline based data gathering (VGEEDDG), to determine the optimal virtual grid points, optimal sojourn time for deploying multiple UAVs with the minimum time required in a predetermined deadline time to collect buffer data from cluster heads. In fact, in many applications, especially in practical applications, the deadline is limited to the critical level of application, and as a result, this deadline time for collecting data is not enough, and single UAV cannot collect data from cluster head with minimal energy. In this situation, this paper presents seven strategies for solving the problem of inadequate deadline time is provided by multiple UAVs for deadline based WSN applications. The results obtained in the simulation section show that the proposed framework is able to provide efficient data collection with satisfactory energy constraints and a deadline when dependent on the critical level of the application.

Keywords