The rapid evolution of mobile technologies presents a formidable security challenge, as traditional cryptographic methods struggle to keep pace. Integrating physical layer security (PLS) solutions with cutting-edge technologies such as in-band full-duplex (IBFD) and reconfigurable intelligent surfaces (RISs) holds promise for addressing these challenges effectively. This study introduces a novel RIS-driven protected zone (PZ) formation approach that employs artificial noise (AN) to safeguard legitimate users without requiringa prioriknowledge of eavesdropper locations, channels, or numbers. The proposed methodology partitions the RIS into two distinct segments: while the former segment enhances the achievable data rate for legitimate signal, the latter segment concurrently amplifies AN to jam illegitimate users within the PZ.We present formulations and solutions for maximizing secrecy capacity (SC) and minimizing power consumption through optimized transmit power allocation factors, RIS segmentation, and beams’ directions, all subject to stringent quality-of-service (QoS) constraints. Closed-form expressions are derived to facilitate efficient implementation and performance optimization. Simulation results validate closed-form solutions and demonstrate that the proposed scheme can significantly enhance SC compared to benchmarks where RIS and AN are used separately, with the proposed scheme achieving approximately 81% greater capacity than the “RIS-Only” approach and a substantial advantage over the “AN-Only” approach, which results in no secrecy. Additionally, this work includes an analysis of energy efficiency, emphasizing the critical importance of optimizing power consumption in practical applications. This dual focus on improving security while effectively managing energy resources underscores the scheme’s practical relevance and efficiency.

The rapid proliferation of mobile technologies introduces substantial security vulnerabilities, with conventional cryptographic approaches increasingly inadequate. Physical layer security (PLS) approaches, especially when paired with advanced methods like full-duplex (FD) communication and reconfigurable intelligent surfaces (RISs), offer substantial potential for enhanced security. This work proposes a novel RIS-aided inband FD (IBFD) framework that employs artificial noise (AN) to establish a protected zone (PZ) around the legitimate user, operating independently of any a priori knowledge regarding the number, positions, or channels of potential eavesdroppers. To achieve this, the RIS is functionally partitioned into two distinct segments: one enhances the legitimate user's data rate, while the other simultaneously intensifies AN to jam any unauthorized users within the PZ. We formulate a secrecy capacity (SC) maximization problem that optimizes both the legitimate user's transmission power and the RIS configuration, while meeting quality-of-service (QoS) requirements. Simulation results indicate the superior efficacy of the proposed technique in enhancing SC compared to benchmarks that employ RIS and AN independently. In particular, the proposed approach achieves an approximate SC improvement of 80% and 49% over the “RISonly” and “AN-only” approaches, respectively, underscoring its significant potential to enable robust PLS in next-generation communication networks.

Spreading codes are the core of the spread spectrum transmission. In this paper, a novel channel-dependent code allocation procedure for enhancing security in multi-carrier code division multiple access (MC-CDMA) system is proposed and investigated over frequency-selective fading. The objective of the proposed technique is to assign the codes to every subcarrier of active/legitimate receivers (Rxs) based on their channel frequency response (CFR). By that, we ensure security for legitimate Rxs against eavesdropping while preserving mutual confidentiality between the legitimate Rxs themselves. To do so, two assigning modes; fixed assigning mode (FAM) and adaptive assigning mode (AAM), are exploited. The effect of the channel estimation error and the number of legitimate Rxs on the bit error rate (BER) performance is studied. The presented simulations show that AAM provides better security with a complexity trade-off compared to FAM. While the latter is more robust against the imperfection of channel estimation.

This work aims to address the timing synchronization issue which limits the applicability of coordinated multipoint schemes, specifically joint transmission, in practical wireless networks. Following a brief description of the issue itself, and its repercussions on the network performance, the various conditions/solutions that mitigate this problem are recapped. Following this, we provide the background of the proposed approach to be used for mitigating the timing synchronization issues, namely, common cyclic prefix (CP) technique. Then, a clustering algorithm is proposed aimed at balancing the cell load with timing synchronization as a constraint. In load balancing stage, the first priority is given to users with higher received power and lower number of base stations in the candidate set. The results obtained via simulations indicate that heterogeneous network (HetNet) deployments suffer from timing synchronization when smaller CP duration is used, and this performance degradation can be resolved quite effectively using the common CP configuration.

In this paper, a novel, yet efficient, multi-user scheduling scheme based on mode selection and power allocation is presented for 5G and beyond networks. The proposed scheme schedules the users in co-existence (CE) and non coexistence (NCE) modes to maximize the connectivity under signal separability and reliability constraints. In addition, two multi-user scheduling mechanisms; check requirements before scheduling (CRBS) and check requirements after scheduling (CRAS), are proposed for practical scenarios to study the impact of quality of service (QoS) on multi-user scheduling in terms of users' reliability requirements. Analytical results show that CRBS outperforms CRAS and orthogonal multiple access (OMA) schemes in terms of connectivity and system throughput with a complexity trade-off.

Development of green telecommunication systems is already being considered highly attractive by standard bodies and recently is attracting research attention. While most of the research focuses on modeling and simulation, in this work we implement a lab setup to test an energy aware wireless system based on software defined radio and solar energy power system. In addition, we proposed an energy aware adaptive modulation algorithm that considers the state of charge of the solar energy batteries before setting up the modulation order. Moreover, the algorithm adapts to user preferences between the connectivity mode and the quality mode.