Motivated by the advancing computational capacity of wireless end-user equipment (UE), as well increasing concerns about sharing private data, a new machine learning (ML) paradigm has emerged, namely federated (FL). Specifically, FL allows decoupling data provision at UEs and ML model aggregation central unit. By training locally, is capable avoiding direct leakage from UEs, thereby preserving privacy security to some extent. However, even if raw are not disclosed an individual's information...

Vehicle-to-vehicle (V2V) communication applications face significant challenges to security and privacy since all types of possible breaches are common in connected autonomous vehicles (CAVs) networks. As an inheritance from conventional wireless services, potential eavesdropping is one the main threats V2V communications. In our work, anti-eavesdropping scheme CAVs networks developed through use cognitive risk control (CRC)-based vehicular joint radar-communication (JRC) system. particular,...

This paper studies the physical layer security of an unmanned aerial vehicle (UAV) network, where a UAV base station (UAV-B) transmits confidential information to multiple receivers (IRs) with aid jammer (UAV-J) in presence eavesdroppers. We formulate optimization problem jointly design trajectories and transmit power UAV-B UAV-J order maximize minimum average secrecy rate over all IRs. The is non-convex variables are coupled, which leads being mathematically intractable. As such, we...

In this letter, we study an unmanned aerial vehicle (UAV)-mounted mobile edge computing network, where the UAV executes computational tasks offloaded from terminal users (TUs) and motion of each TU follows a Gauss-Markov random model. To ensure quality-of-service (QoS) TU, with limited energy dynamically plans its trajectory according to locations TUs. Towards end, formulate problem as Markov decision process, wherein UAV-TU association are modeled parameters be optimized. maximize system...

Covert communications hide the transmission of a message from watchful adversary while ensuring certain decoding performance at receiver. In this paper, wireless communication system under fading channels is considered where covertness achieved by using full-duplex More precisely, receiver covert information generates artificial noise with varying power causing uncertainty adversary, Willie, regarding statistics received signals. Given that Willie's optimal detector threshold test on power,...

In this paper, a random frequency diverse array-based directional modulation with artificial noise (RFDA-DM-AN) scheme is proposed to enhance physical layer security of wireless communications. Specifically, we first design the RFDA-DM-AN by randomly allocating frequencies transmit antennas, thereby achieving 2-D (i.e., angle and range) secure transmissions, outperforming state-of-the-art 1-D angle) phase array (PA)-based DM scheme. Then derive closed-form expression lower bound on ergodic...

Covert wireless communication aims to hide the very existence of transmissions in order guarantee a strong security networks. In this paper, we examine possibility and achievable performance covert amplify-and-forward one-way relay Specifically, is greedy opportunistically transmits its own information destination covertly on top forwarding source's message, while source tries detect transmission discover illegitimate usage resource (e.g., power spectrum) allocated only for purpose...

This work considers covert communications in the context of unmanned aerial vehicle (UAV) networks, aiming to hide a UAV for transmitting critical information out scenario that is monitored and where communication not allowed. Specifically, as transmitter intends transmit legitimate receiver (Bob) covertly order avoid being detected by warden (Willie) with location uncertainties at Bob and/or Willie. In enhance considered performance, we prefer jointly optimize UAV's trajectory power terms...

This work examines the performance gain achieved by deploying an intelligent reflecting surface (IRS) in covert communications. To this end, we formulate joint design of transmit power and IRS reflection coefficients taking into account communication covertness for cases with global channel state information (CSI) without a warden's instantaneous CSI. For case CSI, first prove that perfect is achievable aid even single-antenna transmitter, which impossible IRS. Then, develop penalty...

A large-scale fully digital receive antenna array can provide very high-resolution direction of arrival (DOA) estimation, but resulting in a significantly high RF-chain circuit cost. Thus, hybrid analog and (HAD) structure is preferred. Two phase alignment (PA) methods, HAD PA (HADPA) (HDAPA), are proposed to estimate DOA based on the parametric method. Compared (APA), they reduce complexity phases. Subsequently, fast root multiple signal classification HDAPA (root-MUSIC-HDAPA) method...

Directional modulation (DM) is a secure transmission technology that able to retain the original constellation of transmitted signals along desired direction, while distort in undesired directions at same time. In this letter, we develop novel and robust DM synthesis methods for enhancing performance. Specifically, first propose low-complexity dynamic method. method, derive closed-form expression null space conjugate transpose steering vector direction. Based on derived, construct projection...

In this paper, a practical wireless transmission scheme is proposed to transmit confidential messages the desired user securely and precisely by joint use of multiple techniques, including artificial noise (AN) projection, phase alignment/beamforming, random subcarrier selection (RSCS) based on orthogonal frequency division multiplexing (OFDM), directional modulation (DM), namely RSCS-OFDM-DM. This RSCS-OFDM-DM provides an extremely low-complexity structure for receiver makes secure precise...

In this letter, we consider delay-constrained covert communications with the aid of a full-duplex (FD) receiver. Without delay constraints, it has been shown that transmit power artificial noise (AN) at FD receiver should be random in order to enhance communications. show transmitting AN fixed indeed improve since limited time period warden cannot exactly learn its received power. This explicitly shows one benefit considering practical constraints context We analyze optimal for either or...

Recently, directional modulation has become an active research area in wireless communications due to its security. Unlike existing work, we consider a multi-beam (MBDM) scenario with imperfect desired direction knowledge. In such setting, robust synthesis scheme is proposed for MBDM broadcasting systems. order implement the secure transmission of confidential message, beamforming vector message designed preserve power as possible directions by minimizing leakage eavesdropper while...

In a multicast scenario, all desired users are divided into K groups. Each group receives its own individual confidential message stream. Eavesdropper aims to intercept streams. To achieve secure transmission, two schemes proposed: Maximum receive power plus null-space (NS) projection (Max-GRP NSP) and leakage. The former obtains precoding vector per by maximizing subject the orthogonal constraint, AN matrix consist of bases NS steering vectors from latter attains driving current space...

In this letter, an intelligent reflecting surface (IRS)-aided secure wireless information and power transfer system is studied. To maximize the harvested of energy harvesting receiver (EHR), we optimize transmit beamforming at access point (AP) phase shifts IRS subject to secrecy rate (SR) constraints. Due non-convexity optimization problem coupled variables, convert into a semidefinite relaxation (SDR) sub-optimal solution obtained. reduce high-complexity proposed SDR method, low-complexity...

Mobile edge computing (MEC) provides computational services at the of networks by offloading tasks from user equipments (UEs). This letter employs an unmanned aerial vehicle (UAV) as server to execute offloaded ground UEs. We jointly optimize association, UAV trajectory, and uploading power each UE maximize sum bits all UEs UAV, subject energy constraint quality service (QoS) UE. To address non-convex optimization problem, we first decompose it into three subproblems that are solved with...

In this work, we adopt channel inversion power control (CIPC) to achieve covert communications aided by a full-duplex receiver. Specifically, the transmitter varies and phase of transmitted signals as per receiver, such that receiver can decode these without knowing state information. This eliminates required feedback from which aids hiding warden. The truncated CIPC conventional schemes are proposed examined, where for transmission ceases when quality is low, while always occurs regardless...

This work examines the possibility, performance limits, and associated costs for a self-sustained relay to transmit its own covert information destination on top of forwarding source's information. Since source provides energy information, does not allow relay's transmission is detect it. Considering time switching (TS) power splitting (PS) schemes harvesting, where all harvested used at relay, we derive minimum detection error probability $\xi^{\ast}$ source, based which determine maximum...

In this letter, we develop a new framework to jointly characterize covertness and timeliness of short-packet communications, in which metric named covert age information (CAoI) is first proposed then closed-form expression for the average CAoI derived. Our examination explicitly reveals tradeoff between communication affected by block-length, transmit power prior transmission probability. Multiple designs are tackled order minimize subject constraint, where resultant differences relative...

This work considers unmanned aerial vehicle (UAV) networks for collecting data covertly from ground users. The full-duplex (FD) UAV intends to gather critical information a scheduled user (SU) through wireless communication and generate artificial noise (AN) with random transmit power in order ensure negligible probability of the SU’s transmission being detected by unscheduled users (USUs). To enhance system performance, we jointly design UAV’s trajectory its maximum AN together scheduling...

Intelligent reflecting surface (IRS) is of low-cost and energy-efficiency will be a promising technology for the future wireless communications like sixth generation. To address problem conventional directional modulation (DM) that Alice only transmits single confidential bit stream (CBS) to Bob with multiple antennas in line-of-sight channel, IRS proposed create friendly multipaths DM such two CBSs can transmitted from Bob. This significantly enhance secrecy rate (SR) DM. maximize SR...

As a low-cost and low-power-consumption passive reflector, intelligent reflecting surface (IRS) can make significant rate improvement by building programmable wireless environment. To improve the performance coverage range of networks, an IRS-aided decode-and-forward (DF) relay network is proposed with multiple antennas at station (RS). achieve high rate, alternately iterative structure (AIS) maximizing receive power (Max-RP) RS to jointly optimize beamforming vectors phase shifts IRS....

Intelligent reflecting surface (IRS) is a promising solution to build programmable wireless environment for future communication systems, in which the reflector elements steer incident signal fully customizable ways by passive beamforming. In this paper, an IRS-aided secure spatial modulation (SM) proposed, where IRS perform beamforming and information transfer simultaneously adjusting on-off states of elements. We formulate optimization problem maximize average secrecy rate (SR) jointly...

Extremely large-scale reconfigurable intelligent surface (XL-RIS) has recently been proposed and is recognized as a promising technology that can further enhance the capacity of communication systems compensate for severe path loss. However, pilot overhead beam training in XL-RIS-assisted wireless enormous because near-field channel model needs to be taken into account, number candidate codewords codebook increases dramatically. To tackle this problem, we propose two deep learning-based...