摘要 : Unmanned aerial vehicles (UAVs) have been widely used in wireless communication in recent years and are a promising component of future wireless systems. UAVs are easily deployable and can provide reliable, robust, and cost-effect... 展开 Unmanned aerial vehicles (UAVs) have been widely used in wireless communication in recent years and are a promising component of future wireless systems. UAVs are easily deployable and can provide reliable, robust, and cost-effective communication to any desired location. However, the performance parameters of UAV cannot attain the desired level due to additional path loss caused by diffraction in non-line of sight (NLOS) propagation during atmospheric turbulence. In this paper, UAV operated communication system with multihop radio frequency (RF)-free-space optical (FSO) link is proposed. In order to provide better network connectivity and coverage, relays which also act as low altitude platform are configured between source and destination. These relays are modeled using RF and FSO technologies and also maintain decode and forward protocol and linear network coding. Based on this setup, communication channel is classified into three segments namely, ground to UAV, UAV to UAV, and UAV to ground channel. Initially, the optimal altitude of UAVs is derived using RF and FSO channel parameters for reliable system performance. The proposed model is verified using Monte Carlo simulation method, and the performance of the model is measured in terms of outage probability and symbol error rate, assuming that coherent detection takes place at receiver which employs M-ary phase shift keying modulation techniques. Numerical results demonstrate that the proposed multihop RF-FSO link outperforms the relevant benchmark schemes for a given signal to noise ratio value. 收起