Weighted Secrecy Coverage Analysis and the Impact of Friendly Jamming over UAV-Enabled Networks

Abstract

In 5G and beyond networks, Unmanned Aerial Vehicles (UAV) are an attractive solution to enhance the secrecy of a wireless systems by exploiting their predominant LOS links and spacial manoeuvrability to introduce a friendly jamming. In this work, we investigate the impact of two cooperative UAVbased jammers on the secrecy performance of a ground wireless wiretap channel by considering secrecy-area related metrics, the jamming coverage and jamming efficiency. Moreover, we propose a hybrid metric, the so-called Weighted Secrecy Coverage (WSC) that can be used as a metric for gaining insights on the optimal deployments of the UAV jammers to provide the best exploration of jamming signals. For evaluating these metrics, we derive a closed-form position-based metric, the secrecy improvement, and propose an analogous computationally simpler metric. Our simulations show that a balanced power allocation between the two UAVs leads to the best performances, as well as a symmetrical positioning behind the line of sight between the legitimate transmitter and receiver. Moreover, there exist an optimal UAV height for the jammers. Finally, we propose a suboptimal and simpler problem for the maximisation of the WSC.

Positioning And Power Optimization For UAV-Assisted Networks In The Presence of Eavesdroppers: A Multi-Armed Bandit Approach

“…As previously mentioned, E is located within a circular area S around A, but no further knowledge on the exact position of E is assumed, i.e. E can be in whichever point inside S. Therefore, to evaluate the secrecy performance of the proposed system, we consider the area-based secrecy metrics proposed in [16], namely jamming coverage (JC) and jamming efficiency (JE), and a new hybrid metric, the WSC, introduced in [17]. These metrics' definition is based on the secrecy outage probability (SOP), which is derived for the proposed system as described below.…”

“…Then, ∆ > 1 values imply a reduction on the SOP by the presence of the UAV jammers while ∆ < 1 is the opposite. For mathematical tractability purposes, in [17] we proposed an analogous secrecy improvement metric that provides the same general idea with the criteria of secrecy achievement (1 − SOP) instead of SOP, thus given by…”

“…To dive into the characterization of the effectiveness of friendly jamming in wireless networks, the authors in [16] proposed two novel areabased metrics, the jamming coverage and the jamming efficiency, in order to provide insights into the design of optimal jamming configurations by considering different levels of CSI knowledge. Later, in [17], we considered a UAV-assisted friendly jamming scheme in a wireless network in the presence of eavesdroppers. Based on the area-based metrics in [16], a novel metric, the weighted secrecy coverage (WSC), was proposed to give a better insight into the impact of friendly jamming.…”

“…Inspired by [16] and based on [17], we will advance on the state-of-the-art by studying a UAV-assisted wireless network, where two UAVs assist a legitimate ground communication between a pair of ground nodes in a confined region on a fading environment, and the 3D positioning of the UAVs is optimized in order to maximize the WSC metric. For that purpose, we model our optimization problem as a multi-armed bandit (MAB) problem and provide a RL-based solution [1] .…”

“…For that purpose, we model our optimization problem as a multi-armed bandit (MAB) problem and provide a RL-based solution [1] . The main contributions that carry on from the previous paper [17] are the following:…”