Rate optimization using low complex methods with reconfigurable intelligent surfaces

With the help of a developing technology called reconfigurable intelligent surfaces (RIS), it is possible to modify the propagation environment and boost the data rates of wireless communication networks. In this article, we optimized the phases of the RIS elements and performed a fair power allocation for each subcarrier over the full bandwidth in a single-input-single-output (SISO) wideband system where the user and the access point (AP) are provided with a single antenna. The data rate or its equivalent channel power is maximized by proposing different low-complex algorithms. The strongest tap maximization (STM) and power methods are compared with the semidefinite relaxation (SDR) method in terms of computational complexity and data rate performance. Runtime and complexity analysis of the suggested methods are computed and compared to reveal the actual time consumption and the required number of operations for each method. Simulation results show that with an optimized RIS, the sum rate is 2.5 times higher than with an unconfigured surface, demonstrating the RIS's tremendous advantages even in complex configurations. The data rate performance of the SDR method is higher than the power method and less than the STM method but with higher computational complexity, more than 6 million complex operations, and 50 ​min of runtime calculations compared with the other STM and power optimization methods

Configuring reconfigurable intelligent surfaces using a practical codebook approach

It is proven that the scattering, reflection, and refraction properties of electromagnetic signals can be adapted and managed by using reconfigurable intelligent surfaces (RISs). In this paper, we have investigated the performance of a single-input-single-output (SISO) wideband system in terms of achievable data rate by optimizing the phases of RIS elements and performing a fair power allocation for each subcarrier over the entire bandwidth. A new beamforming codebook is developed from which the maximizing signal-to-noise (SNR) configuration is selected. The channel state information (CSI) along with the selected maximizing SNR configuration is then used by the proposed power algorithm to obtain the optimal configuration of the RIS. To validate our proposed method, it is compared with state-of-the-art semidefinite relaxation (SDR) scheme in terms of performance, complexity and run-time consumption. Our method shows dramatically lower computational complexity than the SDR method and achieves an order of 2.5 increase in the achievable data rate with an optimized RIS compared with an un-configured surface

A survey on reconfigurable intelligent surfaces: wireless communication perspective

Using reconfigurable intelligent surfaces (RISs) to improve the coverage and the data rate of future wireless networks is a viable option. These surfaces are constituted of a significant number of passive and nearly passive components that interact with incident signals in a smart way, such as by reflecting them, to increase the wireless system's performance as a result of which the notion of a smart radio environment comes to fruition. In this survey, a study review of RIS-assisted wireless communication is supplied starting with the principles of RIS which include the hardware architecture, the control mechanisms, and the discussions of previously held views about the channel model and pathloss; then the performance analysis considering different performance parameters, analytical approaches and metrics are presented to describe the RIS-assisted wireless network performance improvements. Despite its enormous promise, RIS confronts new hurdles in integrating into wireless networks efficiently due to its passive nature. Consequently, the channel estimation for, both full and nearly passive RIS and the RIS deployments are compared under various wireless communication models and for single and multi-users. Lastly, the challenges and potential future study areas for the RIS aided wireless communication systems are proposed

Reconfigurable Intelligent Surfaces Aided Wireless Communications with Electromagnetic Interference

No abstract available

Investigating the Data Rate of Intelligent Reflecting Surfaces with Mutual Coupling and EMI

No abstract available

Discrete Phase Shifts for Intelligent Reflecting Surfaces in OFDM Communications

Reconfigurable intelligent surface (RIS) in wireless communications allows the network provider to control the scattering, reflection, and refraction characteristics of the electromagnetic signals. Different research results have shown (RIS) can effectively control the properties of the wireless waves like Amplitude and Phase without complex equalization and decoding at the receiver. Nevertheless, configuring the surface under practical frequency selective fading channel must be considered over the whole bandwidth consequently we took into consideration the wideband orthogonal frequency division multiplexing (OFDM) communication system based on practical (RIS) setup with different phase shifts per each element in the surface. We used the communication setup considered in the IEEE signal processing Cup 2021 to investigate the user data rate enhancement of such (RIS) surfaces using different discrete phase shifts with equal spacing. Simulation results have shown that the data rate improved when using high resolution of discrete phase shifts per each RIS element

A study on the applicability of bismuth film plated carbon paste electrodes in highly alkaline media

A silicone oil-based carbon paste electrode plated "in situ" with a bismuth film, BiF(C/SO), has been tested for differential pulse anodic stripping voltammetry of heavy metal ions in highly alkaline media. First, the BiF(C/SO) was examined with respect to its polarisability in solutions of either NaOH or KOH with varying concentration. Further, strpping characteristics of selected metals (Zn, Cd, Pb, and Tl) were investigated in order to define analytical performance of the BiF(C/SO) in 0.1 M KOH chosen as optimal medium. The study has revealed some specifics of measurements in solutions with high pH due to complex-forming capabilities of the OH- ions, contributing thus to the continuing characterisation of bismuth film-based electrodes

Intelligent reflective surfaces (IRSs) for green networks

Power efficiency is a critical aspect of green communication as it aims to reduce the carbon footprint of telecommunication networks. Numerous challenges and problems need to be addressed to achieve energy-efficient wireless networks. The deployment and operation of wireless network infrastructure, including base stations (BSs) and access points, demand significant energy resources. Signal propagation poses another challenge, as wireless signals experience attenuation and interference, necessitating higher transmission power to maintain reliable communication. Therefore, developing environmentally friendly solutions for wireless communication is essential. Intelligent reflective surfaces (IRSs) are a novel passive technology that can improve the efficiency of wireless networks. The integration of IRSs into the wireless network reduces the number of active transceivers, enhances coverage, and improves the quality of wireless signals. In contrast to the active technologies such as multiple-input multiple-output (MIMO), active beamforming, and relay networks, which demand extra energy and complicated hardware, IRS is a passive solution, that does not need any radio frequency (RF)-chains, thus, it can be easily integrated into the network, leading to lower energy consumption and a smaller carbon footprint of the network. This chapter aims to present a comprehensive study on applications and design aspects of the IRS in future wireless networks focussing on promoting the use of IRS in green communication and achieving sustainable development goals. The concept of IRS technology and its architecture is presented, and then we highlight the advantages and possible use cases for integrating IRSs into the wireless network. Finally, the IRS is compared with active solutions in terms of its benefits in terms of signal quantity, power efficiency, and sustainability

Investigating the Data Rate of Intelligent Reflecting Surface Under Different Deployments

No abstract available