This paper proposes a secure wireless system that integrates rate-splitting multiple access (RSMA), intelligent reflecting surfaces (IRS), and full-duplex relaying (FDR) to enhance secrecy performance against multiple colluding eavesdroppers. Closed-form expressions for the secrecy outage probabilities (SOPs) and average secrecy capacities (ASCs) of both common and private messages are derived. Comparative analysis with a baseline RSMA-FDR system (without IRS) demonstrates the benefits of IRS in improving secrecy. Numerical results reveal that RSMA-IRS-FDR achieves superior secrecy performance, with SOPs and ASCs strongly influenced by transmission power, particularly differing between message types. Moreover, the adverse effect of residual self-interference (RSI) is substantially mitigated in the IRS-aided system. The secrecy performance is further enhanced by increasing the number of IRS elements. The study also investigates the impact of key parameters such as power allocation, target secrecy rate, fading order, Wi-Fi frequency, and number of eavesdroppers, offering practical insights for secure RSMA-IRS-FDR system design.

Friendly jamming and relay are effective schemes in physical layer security (PLS) for enhancing security in wireless communication . By deploying unmanned aerial vehicle (UAV)-assisted Non-Orthogonal Multiple Access (NOMA) transmission can extend coverage and enhancing spectrum efficiency. This paper studies the physical layer security of an UAV-based relay NOMA system, consisting of a source, multiple users, and an eavesdropper. To enhance secrecy performance, an additional UAV is employed to transmit jamming signals to the eavesdropper. Moreover, for a more practical approach, we also consider the imperfect collaboration between the jammer device and the legitimate user. The minimum average secrecy rate (MASR) of the users is maximized, assuming that the eavesdropper is capable of intercepting signals both from the source and from the relay UAV. An efficient iterative algorithm is proposed to solve the MASR maximum problem by optimizing UAV trajectories, transmit power, and power allocation coefficients. Simulation results demonstrate that the proposed system achieves 238% better MASR than the system without friendly jamming signals and 633% better than the non-optimal system. In addition, the ability to decode the received signal using successive interference cancellation also significantly affects the MASR of users in the system.

This article proposes an integration of multiple reconfigurable intelligent surfaces (RISs) with a relay to enhance the performance of a low-power wide-area (LPWA) network. Specifically, besides using the traditional relaying approach to assist the transmission between an Internet of Things (IoT) sensor and a gateway, multiple RISs are also utilized to boost the intermediate links between the IoT sensor and the relay and between the relay and the gateway. We mathematically derive the analytical expressions of average outage probability (AOP) and average symbol error probability (ASEP) of this multiple-RIS-relay aided LPWA network over Nakagami-$m$fading channels. The performance of the proposed network is also compared with the performance of the relay-aided LPWA network without using RISs. The analytical results show that the exploitation of RISs can greatly enhances the performance of the LPWA network. Thus, the multiple-RIS-relay aided LPWA network can operate at the high frequency band for long range transmission. Moreover, the effect of various important factors such as the location of the RISs, the Nakagami-$m$parameters, the data transmission rate, and the modulation scheme on the performance of the multiple-RIS-relay aided LPWA network are also investigated in practical scenarios.

In this paper, the performance of a wireless system, which is beneficial from utilization of multiple reconfigurable intelligent surfaces (RISs) and the direct link between the source node and the mobile user, is analyzed. Especially, the effect of transceiver hardware impairments (HIs) are taken into consideration. We successfully derive the outage probability (OP), throughput, achievable data rate (ADR), and symbol error probability (SEP) expressions of this multiple-RIS assisted wireless systems with and without HIs (referred as RIS-HI and RIS-ID system, respectively) over Nakagami-$m$fading channels. The above performance factors are also benchmarked with the case that only a point-to-point (P2P) link without RIS is considered (denotes as as P2P-HI and P2P-ID systems for HI and ideal hardware conditions, respectively). All obtained formulas are verified by Monte-Carlo simulations. It is observed that the RIS-HI system significantly outperforms the P2P-HI system at low transmit power regime, while the performance of the RIS-ID system is always better than that of P2P-ID system. On the other hand, HIs show more severe effect for higher data transmission rates or high modulation orders.

In this paper, we propose and evaluate performance of multihop multipath underlay cognitive radio networks. In a primary network, an uplink nonorthogonal multiple access method is employed to allow primary transmitters to simultaneously transmit their data to a primary receiver. Using an underlay spectrum‐sharing method, secondary source and secondary relays must adjust their transmit power to guarantee quality of service of the primary network. Under the limited transmit power, cochannel interference from the primary transmitters, and hardware noises caused by impairments, we propose best‐path selection methods to improve the end‐to‐end performance for the secondary network. Moreover, both multihop decode‐and‐forward and amplify‐and‐forward relaying protocols are considered in this paper. We derive expressions of outage probability for the primary and secondary networks and propose an efficient method to calculate the transmit power of the secondary transmitters. Then, computer simulations employing the Monte‐Carlo approach are realized to validate the derivations.

In this paper, a combination of energy harvesting (EH) and cooperative nonorthogonal multiple access (NOMA) has been proposed for full-duplex (FD) relaying vehicle-to-vehicle (V2V) networks with two destination nodes over a Rayleigh fading channel. Different from previous studies, here both source and relay nodes are supplied with the energy from a power beacon (PB) via RF signals, and then use the harvested energy for transmitting the information. For the extensive performance analysis, the closed-form expressions for the performance indicators, including outage probability (OP) and ergodic capacity of both users, have been derived rigorously. Additionally, the effect of various parameters, such as EH time duration, residual self-interference (RSI) level, and power allocation coefficients, on the system performance has also been investigated. Furthermore, all mathematical analytical results are confirmed by Monte-Carlo simulations, which also demonstrate the optimal value of EH time duration to minimize the OP and maximize the ergodic capacity of the proposed system.

In this paper, we derived the analytical expressions of the system performance (in term outage probability and throughput) of the power splitting half-duplex power beacon-assisted energy harvesting relay network in both amplify-and-forward and decode-and-forward modes. Moreover, the analytical results are also demonstrated and convinced by using Monte-Carlo simulation. The numerical results demonstrated and convinced the analytical and the simulation results are matched well with each other in connection with all possible system parameters.

The energy harvesting amplify-and-forward full-duplex relaying network over the dissimilar fading environments in imperfect CSI condition is investigated. In this system model, the energy, and information are transferred from the source to the relay nodes by the power splitting protocol with helping of the full-duplex relay node. Firstly, the outage probability, achievable throughput, and the optimal power splitting factor in terms of the analytical mathematical expressions were proposed, analyzed, and demonstrated. Furthermore, the system performance of the proposed model on the connection with all system parameters is rigorously studied. Finally, the numerical results demonstrated and convinced one that the analytical and the simulation results are matched well with each other for all system parameter values using Monte-Carlo simulation. The results show that the system performance degrades significantly but is still in a permissible interval while the channel estimation error increases and the system performance of the mixing scenarios is better in comparison with the Rayleigh-Rayleigh scenario.

We investigate the system performance of a two‐way amplify‐and‐forward (AF) energy harvesting relay network over the Rician fading environment. For details, the delay‐limited (DL) and delay‐tolerant (DT) transmission modes are proposed and investigated when both energy and information are transferred between the source node and the destination node via a relay node. In the first stage, the analytical expressions of the achievable throughput, ergodic capacity, the outage probability, and symbol error ratio (SER) were proposed, analyzed, and demonstrated. After that, the closed‐form expressions for the system performance are studied in connection with all system parameters. Moreover, the analytical results are also demonstrated by Monte Carlo simulation in comparison with the closed‐form expressions. Finally, the research results show that the analytical and the simulation results agree well with each other in all system parameters.

We consider the wireless relay network in which a base station communicates with multiple subscribers, each of which has the ability to act as a relay to forward information to a base station. Here, we propose an algorithm for joint optimization of power allocation, time scheduling, and relay selection when there is imperfect channel state information (CSI). We show that the algorithm converges with probability one to the optimal solution when a condition is satisfied. Otherwise, it converges with probability one to a solution in some neighborhood of the optimal solution.