RESEARCH ARTICLE Prolong network lifetime and improve efficiency in WSN- UAV systems using new clustering parameters and CSMA modification Reza Tarighi 1 | Kamran Farajzadeh 2 | Hooman Hematkhah 3 1 Department of Control Engineering, Faculty of Electrical Engineering, Islamic Azad University, South Tehran Branch (IAUSTB), Tehran, Iran 2 Department of IT Management, Islamic Azad University, Science and Research Branch (SRBIAU), Tehran, Iran 3 Faculty of Electrical Engineering, Shahid Chamran University (SCU), Ahwaz, Iran Correspondence Reza Tarighi, Department of Control Engineering, Faculty of Electrical Engineering, Islamic Azad University, South Tehran Branch (IAUSTB), Tehran 15847-43311, Iran. Email: st_r_tarighi@azad.ac.ir Summary Since unmanned aerial vehicles (UAVs) have been introduced as mobile nodes for data gathering, wireless sensor networks (WSNs) have progressed considerably. The resulting WSN-UAV systems are employed for emergency applications and also for remote monitoring purposes. WSN-UAV systems yield an optimum data gathering method using the WSN. In the proposed method, the nodes' data are transferred using a remotely operated vehicle (drone) rather than the conventional data transferring methods like the direct and hop-to-hop data transmission approaches. Then, the gathered data are delivered in the pre-determined destination point. WSN-UAV systems, in fact, are a special case of the systems with the mobile sink in which the sink path is previously specified and controlled. In this paper, the effects of clustering parameters on the WSNs are studied; then, the network's lifetime is prolonged by applying some parameters. In addition, the network's performance is enhanced to some extent by assigning some changes in the media access control (MAC) layer. Also, the effect of drone's path pattern on the lifetime of the network is studied. KEYWORDS clustering, MAC, mobile sink, unmanned aerial vehicle (UAV), wireless sensor network (WSN), WSN-UAV 1 | INTRODUCTION Extensive applications and high levels of compatibility in wireless sensor networks (WSNs) on one hand and the advances in the communication and low-power circuits on the other hand make the WSNs an interesting subject of research, 1 such that various applications in the traffic control, monitoring the environmental parameters, controlling the production line of the factories, and also in the military fields are proposed for WSNs. 2 These systems are a network composed of several sensor nodes (SNs) which are distributed in the region of interest. SNs, as the smallest components of the network, sense the data from the environment and send them to the base station (BS). These nodes, however, have specific limitations in memory, processing capacity, radio communication range, and particularly energy. It should be noted that the nodes are supplied with batteries, but these batteries cannot be replaced or recharged due to harsh environmental conditions. 3 Received: 20 November 2017 Revised: 19 November 2018 Accepted: 28 December 2019 DOI: 10.1002/dac.4324 Int J Commun Syst. 2020;e4324. wileyonlinelibrary.com/journal/dac © 2020 John Wiley & Sons, Ltd. 1 of 29 https://doi.org/10.1002/dac.4324