Implementation of Resonant Electric Based Metamaterials for Electromagnetic Wave Manipulation at Microwave Frequencies

In this paper, we present the application of a resonant electric based metamaterial element and its two-dimensional metasurface implementation for a variety of emerging wireless applications. Metasurface apertures developed in this work are synthesized using sub-wavelength sampled resonant electric-based unit-cell structures and can achieve electromagnetic wave manipulation at microwave frequencies. The presented surfaces are implemented in a variety of forms, from absorption surfaces for energy harvesting and wireless power transfer to wave-chaotic surfaces for compressive sensing based single-pixel direction of arrival estimation and reflecting surfaces. It is shown that the resonant electric-synthesized metasurface concept offers a significant potential for these applications with high fidelity absorption, transmission and reflection characteristics within the microwave frequency spectrum.

Resource Allocation for Intelligent Reflecting Surfaces Assisted Federated Learning System with Imperfect CSI

Due to its ability to significantly improve the wireless communication efficiency, the intelligent reflective surface (IRS) has aroused widespread research interest. However, it is a challenge to obtain perfect channel state information (CSI) for IRS-related channels due to the lack of the ability to send, receive, and process signals at IRS. Since most of the existing channel estimation methods are developed to obtain cascaded base station (BS)-IRS-user devices (UDs) channel, this paper studies the problem of computation and communication resource allocation of the IRS-assisted federated learning (FL) system based on the imperfect CSI. Specifically, we take the statistical CSI error model into consideration and formulate the training time minimization problem subject to the rate outage probability constraints. In order to solve this issue, the semi-definite relaxation (SDR) and the constrained concave convex procedure (CCCP) are invoked to transform it into a convex problem. Subsequently, a low-complexity algorithm is proposed to minimize the delay of the FL system. Numerical results show that the proposed algorithm effectively reduces the training time of the FL system base on imperfect CSI.

Processing of data streams in the detection of retroreflective objects

This work is devoted to the study of methods for detecting retroreflective objects (RRO), including optical and optoelectronic observation devices, based on the search for spatial anomalies in images formed in pulse laser location systems. Algorithms and software for detecting RRO have been developed. At the same time, special attention is paid to various methods of forming difference frames with periodic illumination, including preliminary replacing each pixel of the background images with the maximum value for the corresponding neighborhood. The effectiveness of the proposed methods for detecting retroreflective objects in conditions of intense sunlight, despite the presence of specular and diffuse reflecting surfaces in the field of view, is demonstrated.

Performance Analysis of Large Intelligent Reflecting Surface Aided Moderate MIMO for 5G Communication

The recently completed 5G framework is the outcome of a few advanced technologies. Massive Multiple Input Multiple Output (MIMO), millimeter wave communication, and network densification are examples of these technologies. However, there are two disadvantages to this technology.1) the lack of control over the wireless channel, and 2) the wireless interface’s excessive power consumption. The concept of re-configurable Intelligent Reflecting Surfaces has emerged to answer the need for green and cost-effective future cellular networks. In this study, we’ll look at how using an Intelligent Reflecting Surface (IRS) improve the performance of moderate MIMO communication in terms of the rate, SINR, Energy efficiency and transmit power metrics. Despite the fact that the underlying issue is non-convexity, we use Lagrangian dual transform and Quadratic Transform to change and rearrange the original issue. After that, active and passive beam forming improved alternatively using an alternating Direction method of multiplier algorithm (ADMM.The IRS-aided system with a reasonable number of antennas at the access point (AP) outperforms the massive MIMO without IRS in terms of sum rate, SINR, Energy efficiency and transmit power metrics.