Joint Trajectory Design and User Scheduling for Secure Aerial Underlay IoT Systems

Abstract

Unmanned aerial vehicles (UAVs) have been widely employed to enhance the end-to-end performance of wireless communications since the links between UAVs and terrestrial nodes are line-of-sight (LoS) with high probability. However, the broadcast characteristics of signal propagation in LoS links make them vulnerable to being wiretapped by malicious eavesdroppers, which poses a considerable challenge to the security of wireless communications. In this work, we investigate the security of aerial underlay Internet of Things (IoT) systems by jointly designing trajectory and user scheduling. An airborne base station transmits confidential messages to secondary users utilizing the same spectrum as the primary network. An aerial jammer transmits jamming signals to suppress the eavesdropper to enhance secrecy performance. The uncertainty of eavesdropping node locations is considered, and the average secrecy rate of the secondary user is maximized by optimizing multiple users' scheduling, the UAVs' trajectory, and transmit power. To solve the non-convex optimization problem with mixed multi-integer variable problem, we propose an iterative algorithm based on block coordinate descent and successive convex approximation. Numerical results verify the effectiveness of our proposed algorithm and demonstrate that our scheme is beneficial in improving the secrecy performance of aerial underlay IoT systems.

Physical layer security‐oriented energy‐efficient resource allocation and trajectory design for UAV jammer over 5G millimeter wave cognitive relay system

“…While the aforementioned works that considered the case where the UAV is used as a mobile relay or BS, [8][9][10][11][12][13][14][15][16][17][19][20][21][22][23] the works of Li et al [24][25][26][27] regarded the UAV as a mobile and friendly jammer to enhance the PL security by injecting the jamming signals over wiretap channels, which is also a promising application direction of UAVs. Specially, the work of Li et al 24 considered the case where two UAVs transmit confidential messages to their special ground destinations in the presence of a ground Eve.…”

“…This work introduced an improvement scheme of PL security because the two UAVs inherently act as mutually cooperative jammers for each other. However, the EE was not exploited in the work of Li et al 24 The dual-UAV system was also investigated in the work of Lei et al 25 The difference from the work of Li et al 24 is that the work of Lei et al 25 considered an aerial IoT system under underlay CR. Therefore, by considering the interference temperature at primary receiver, the work of Lei et al obtained the optimal UAV trajectory and user scheduling scheme.…”

“…Therefore, by considering the interference temperature at primary receiver, the work of Lei et al obtained the optimal UAV trajectory and user scheduling scheme. 25 However, the EE was not investigated in this work, too. The dual-function UAV system was also investigated in the work of Duo et al, 26 where the uplink was investigated.…”

“…In addition, while the first direction has been investigated widely in the works and references therein, 27 the second direction has been done in limited works. [24][25][26][27] Moreover, although for the second direction, both the security and UAV onboard energy problems have been investigated, [24][25][26][27] these works only focused on sub-6GHz spectrum band, without on the millimeter wave (mm-Wave). At the same time, besides the work of Lei et al, 25 these works did not exploit the high spectrum-efficient CR scheme.…”

“…[24][25][26][27] Moreover, although for the second direction, both the security and UAV onboard energy problems have been investigated, [24][25][26][27] these works only focused on sub-6GHz spectrum band, without on the millimeter wave (mm-Wave). At the same time, besides the work of Lei et al, 25 these works did not exploit the high spectrum-efficient CR scheme. In practice, from Table 1, we see that the two key techniques, mm-Wave and CR, were not fully exploited in the literature of the first direction, too.…”