ABSTRACT Reconfigurable Intelligent Surface (RIS) is emerging as a potential solution for Tera Hertz communication. It supports a re‐configurable and smart wireless environment by enhancing the signal strength and reflecting it to the desired receiver which aids in improving energy efficiency. This article presents a novel mathematical framework of a mixed integer nonlinear programming (MINLP) problem to maximize the energy efficiency (EE) of a RIS‐based multi‐user network having a multi‐antenna base station (BS). The formulated problem is a concave fractional programming problem (CFP) which is transformed into a concave program using the proposed Charnes–Cooper transformation (CCT). MINLP problems are generally NP‐hard in nature and their complexity increases with the number of users, therefore, an outer approximation algorithm (OAA) is applied which gives.

Edge computing improves the performance of Internet of Things (IoT) devices by moving cloud services closer to where these devices operate, thereby reducing delays and saving bandwidth. However, the IoT devices communicate wirelessly with edge servers, which creates a significant challenge in keeping the devices' locations private, especially when they use different methods. To address this, researchers have proposed various methods. However, these methods require a lot of computational power and storage, which makes them unsuitable for edge computing environments. To address these challenges, we propose a certificateless cryptography (CLC) and identity-based cryptography (IBC) based heterogeneous deniable authentication (CI-HDA) scheme. It enables an IoT device operating CLC to securely communicate with an edge server using IBC. The server verifies the devices authenticity without proving its participation to third parties, which ensures location privacy in edge computing environments. Additionally, our scheme supports batch verification, which enables the server to efficiently validate multiple authenticators simultaneously. The security of CI-HDA scheme is formally proven in the random oracle model, and performance evaluations demonstrate reduced computational and communication/storage overheads compared to existing methods. We also explored its application in military surveillance, which highlights its practicality in privacy-sensitive edge computing environments.

Edge computing brings cloud services closer to Internet of Things (IoT) devices by processing data at the edge of the network, reducing latency and bandwidth usage. However, preserving the location privacy of IoT devices is a major challenge due to the heterogeneous, open wireless, and dynamic nature of the edge computing environments. The authentication process in this context may potentially disclose the device’s location, as IoT devices and edge server often rely on different security mechanisms. To address this concern, researchers have proposed various schemes to preserve location privacy. However, these schemes often incur high computational and communication overhead, making them unsuitable for IoT devices, which have limited processing power and storage capacity. In response to this challenge, we present a heterogeneous deniable authentication scheme based on certificateless cryptography (CLC) and public-key infrastructure (PKI), abbreviated as CP-HDA. This scheme enables an IoT device in a CLC to securely transmit messages to an edge server in a PKI. Using the CP-HDA scheme, the edge server can verify the legitimacy of the IoT device but cannot provide evidence to third parties regarding the device’s involvement in communication, thereby preserving the location privacy of the IoT device. It also supports batch verification, which enables faster verification of multiple deniable authenticators. The security of the CP-HDA scheme is formally proven in the random oracle model based on the assumption that the elliptic curve computational Diffie-Hellman problem is hard. In comparison to alternative schemes, our scheme enhances performance by reducing both computational and communication costs.

The Internet of Vehicles (IoV), which is an extension of traditional vehicular ad hoc networks (VANETs), ensures the provision of safe and efficient vehicular communications. However, the burgeoning IoV faces several challenges in terms of traffic information security and vehicle identity privacy during wireless transmission. Generally, vehicles move faster on the highway necessitating the use of reliable technology to communicate with infrastructure on the roadside efficiently and securely. Lately, researchers have proposed several different message dissemination methods for vehicle-to-infrastructure (V2I) communications. However, they suffer from different concerns (i.e., security weaknesses, computationally heavy, and high communication/storage overhead); therefore, they are unreliable for delay-sensitive communications. To cope with this, we come up with an enhanced certificateless and identity-based offline/online heterogeneous signcryption (CIOOHSC) protocol for V2I communications in edge computing-based IoV to simultaneously achieve confidentiality, integrity, authentication, non-repudiation, and identity anonymity in a logically single step. The CIOOHSC protocol allows a vehicle in certificateless cryptography to transmit a message to an edge node in identity-based cryptography. In the online phase, there are no point multiplication operations as they are already carried out in the offline phase. This reduces the computational load considerably in the online phase. Furthermore, our protocol enables the edge node to aggregate multiple messages and process them simultaneously to boost performance. The CIOOHSC protocol’s security is proved in the random oracle model under the hard problems’ assumptions. Our protocol outperforms recent similar schemes in terms of computational complexity, communication/storage overhead, and average transmission delay, according to the performance evaluation findings.

This manuscript addresses peak-to-average ratio (PAR) reduction in orthogonal frequency division multiplexing (OFDM) based multiple-input multiple-output (MIMO) systems. A new technique for PAR reduction in point-to-point scenarios is proposed. Singular value decomposition (SVD) algorithms usually sort the singular values of a MIMO channel in descending order. The last singular value and the associated eigenchannels of a MIMO-OFDM channel are often very weak. Not using them for data transmission will offer redundancy for PAR reduction. These eigenchannels are used to approximate the peaks which exceed a given target value in a least-squares fashion. This approximated exceedence model is then subtracted from the original signal in time domain for PAR reduction. It has been shown that a remarkable gain can be obtained with the proposed algorithm with a negligible increase in the average power and capacity loss.

This paper addresses peak-to-average ratio (PAR) reduction in orthogonal frequency division multiplexing (OFDM) based large-scale multiple-input multiple-output (MIMO) systems. We propose a new technique for PAR reduction in point-to-point scenarios. The last eigenchannels of a massive MIMO channel are often very weak. Not using them for data transmission will offer redundancy for PAR reduction. These eigenchannels are used to approximate the peaks which exceed a given target value in a least squares fashion. This approximate exceedence model is then subtracted from the original signal in time domain for PAR reduction. It has been shown through simulation results that a considerable gain can be obtained with the proposed method with marginal increase in the average power and almost negligible loss in the channel capacity.