**Seongjoon Park †, Hyeong Tae Kim † and Hwangnam Kim \***

School of Electrical Engineering, Korea University, Seoul 02841, Korea; psj900918@korea.ac.kr (S.P.); kevink97@korea.ac.kr (H.T.K.)

**\*** Correspondence: hnkim@korea.ac.kr; Tel.: +82-02-3290-4821

† These authors contributed equally to this work.

Received: 24 October 2019; Accepted: 25 November 2019; Published: 27 November 2019

**Abstract:** Following striking developments in Unmanned Aerial Vehicle (UAV) technology, the use of UAVs has been researched in various industrial fields. Furthermore, a number of studies on operating multiple autonomous networking UAVs suggest a potential to use UAVs in large-scale environments. To achieve efficiency of performance in multi-UAV operations, it is essential to consider a variety of factors in UAV network conditions, such as energy efficiency, network overhead, and so on. In this paper, we propose a novel scheme that improves the energy efficiency and network throughputs by controlling the topology of the network. Our proposed network topology control scheme functions between the data link layer (L3) and the network layer (L2). Accordingly, it can be considered to be layer 2.5 in the network hierarchy model. In addition, our methodology includes swarm intelligence, meaning that whole topology control can be generated with less cost and effort, and without a centralized controller. Our experimental results confirm the notable performance of our proposed method compared to previous approaches.

**Keywords:** UAV network; topology control; space division; energy efficiency
