Over-the-air computation (AirComp) based federated learning (FL) is capable of achieving fast model aggregation by exploiting the waveform superposition property multiple access channels. However, performance severely limited unfavorable wireless propagation In this paper, we propose to leverage intelligent reflecting surface (IRS) achieve yet reliable for AirComp-based FL. To optimize performa...

Covert transmission is studied for an intelligent reflecting surface (IRS) aided communication system, where Alice aims to transmit messages Bob without being detected by the warden Willie. Specifically, IRS used increase data rate at under a covert constraint. For considered model, when equipped with single antenna, power and phase shift are jointly optimized maximize either instantaneous or p...

This paper focuses on securing confidential communication in multiple intelligent reflecting surfaces (IRS) assisted terahertz (THz) systems, where a potential eavesdropper can intercept either the base station (BS)-IRS link or IRS-user link. Notably, secure transmission may be intercepted and blocked by due to blockage-prone nature THz bands. To characterize blocking effects of eavesdropper, b...

Besides improving communication performance, intelligent reflecting surfaces (IRSs) are also promising enablers for achieving larger sensing coverage and enhanced quality. Nevertheless, in the absence of a direct path between base station (BS) targets, multi-target is generally very difficult, since IRSs incapable proactively transmitting beams or analyzing target information. Moreover, echoes ...

This letter investigates a device-to-device (D2D) cooperative computing system, where user can offload part of its computation task to nearby idle users with the aid an intelligent reflecting surface (IRS). We propose minimize total delay via jointly optimizing assignment, transmit power, bandwidth allocation, and phase beamforming IRS. To solve formulated problem, we devise alternating optimiz...

Cognitive radio (CR) is an effective solution to improve the spectral efficiency (SE) of wireless communications by allowing secondary users (SUs) share spectrum with primary (PUs). Meanwhile, intelligent reflecting surface (IRS), also known as reconfigurable (RIS), has been recently proposed a promising approach enhance energy (EE) communication systems through intelligently reconfiguring chan...

in this work, sio2 –zro2 mixed oxides was prepared by the polymeric sol–gel route. the characterization of pore structure, which determines the permeation process of membrane, is of great importance. so far, most investigations have focused on such pore structure as specific surface area and pore size distribution, but the surface fractal, the important parameter reflecting the roughness of por...