This paper proposes and analyzes a downlink multi-antenna multi-user system with rate-splitting multiple access (RSMA) scheme. In this framework, we consider the error probability when the base station (BS) transmits both long and short packet information to multiple cell-edge users. Our approach begins with the beamforming vector analysis, and employs the cumulative distribution functions (CDF) of signal-interference noise ratio (SINR). To map the dependencies of common and private streams of RSMA for the SINR, we adopt a two-dimensional signal constellation, which revealed the relationship between power allocation factors and modulation types. This relationship affects the decision boundaries of the modulation schemes. To evaluate the system performance, exact and asymptotic expressions for the block error rate (BLER) and bit error rate (BER) are derived over Nakagami fading channels. The optimal power allocation coefficient to minimize BLER under varying channel uses is formulated and detected through optimization problem and numerical results. Fairness in BER among all users is considered by accounting for the number of antennas and the adopted power allocation strategy. The advantages of RSMA are further verified through comparisons of BLER/BER with non-orthogonal multiple access (NOMA) systems. These findings underscore the potential of RSMA to significantly enhance reliability. The derived expressions are tractable, validated through comparisons with Monte Carlo simulation results, and offer reduced computational complexity and faster execution compared to the simulation-based outcomes. The results show the closest alignment between simulations and the derived analytical expressions.

This paper considers and analyzes the performance of a non-orthogonal multiple access (NOMA) system using finite-size data packets with the assistance of active reconfigurable intelligent surfaces (ARISs) mounted on an unmanned aerial vehicle (UAV). This work aims to enhance communication efficiency in scenarios that require low latency and high reliability. The exact and asymptotic closed-form expressions for the block error rate (BLER) and average achievable rate (AAR) of the considered UAV-ARIS-NOMA system with short packet communication under imperfect successive interference cancellation (SIC) are derived. The results analysis indicates that the number of reflection elements strongly influences the diversity order. The considered system meets ultra-reliable and low-latency communications (URLLC) demands with 99.999% reliability, and the ARIS model's BLER reduces by 290% compared to the passive RIS (PRIS). Moreover, the gap between the AAR of ARIS and PRIS is up to 40% when configuring eight reflection elements. The system's AAR reaches saturation by adjusting the ARIS amplification factor to three power units. When channel uses exceed 300, the system's transmission rate meets the Shannon rate. Moreover, simulation results are introduced to verify the theoretical analysis and offer insights into optimizing power allocation and UAV altitude to minimize BLER.

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.

In this paper mathematically studies utilizing finite block length in a full-duplex (FD) relay network with multiple antennas and non-orthogonal multiple access (NOMA). Specifically, the block error rate (BLER) and age-of-information (AoI) of the investigated system with residual self-interference and imperfect successive interference cancellation are derived. Moreover, the power allocation coefficient is optimized to minimize the average BLER and the influences of various parameters on system's performance are examined. We enhance the BLER and AoI performance by employing the maximal-ratio combining and maximal-ratio transmission techniques at multiple antennas of source and destination nodes. Simulation results validate our analytical frameworks. Numerical results indicate that employing multi-antennas for a NOMA system with FD relay gives exceptionally low average BLER that fulfils the targets of high reliability and latency of the wireless systems. Furthermore, the optimal AoI of the investigated system can be achieved by selecting a suitable block length. In particular, the minimum AoI is obtained when SNR = 10 dB and the block length is 300. Also, the average BLER and average AoI of the considered NOMA-FD system outperform conventional orthogonal multiple access and half-duplex (HD) systems. Especially when the block length is less than 250, the AoI of the FD system is reduced by 90% compared to that of the HD system.

In this paper, we investigate the performance of a full-duplex (FD) relay system where multi-antennas are exploited at source and destination. Unlike previous works, the impacts of imperfect channel state information (I-CSI), transceiver hardware noise (THN), and residual self-interference (RSI) are taken into account. We mathematically derive the exact closed-form expressions of the outage probability (OP), symbol error rate (SER), and ergodic capacity (EC) of the FD relay system with I-CSI, THN, and RSI over Nakagami-$m$fading channels. From the derived expressions, the performance of the considered system under the effects of three negative factors (I-CSI, THN, and RSI) is compared with that system in the case of all ideal factors (perfect channel state information (P-CSI), perfect transceiver hardware (P-TH) and perfect self-interference cancellation (P-SIC)), two ideal factors (P-CSI and P-TH, P-CSI and P-SIC, P-TH and P-SIC), or one ideal factor (P-CSI or P-TH or P-SIC). Numerical results show a strong impact of three negative factors on the OP, SER, and EC of the considered FD relay system, especially when the data transmission rate of the system and signal-to-noise ratio (SNR) are high. In particular, OP, SER, and EC go to the floors in the high SNR regime due to the three negative factors. Therefore, when I-CSI, THNs, and RSI exist in the FD relay system, we should use suitable source and relay transmission power to obtain excellent performance while saving energy consumption. Moreover, when two of the three negative factors are large enough, the remaining factor’s impact becomes weaker and may be neglected in certain circumstances.

This paper studies the ergodic capacity (EC) of full‐duplex (FD) amplify‐and‐forward (AF) and decode‐and‐forward (DF) relay system with energy harvesting (EH) for vehicle‐to‐vehicle (V2V) communications. Unlike previous works on FD‐EH systems, we consider the case that both relay and destination are mobile vehicles while the source is a static base station. We mathematically derive the exact closed‐form expressions of ECs of both AF and DF protocols of the considered FD‐EH‐V2V relay system over cascade (double) Rayleigh fading. Our numerical results show that the ECs in the case of the V2V communication system are reduced compared to those in the case of stationary nodes. Also, with a specific value of residual self‐interference (RSI), the ECs of the considered FD‐EH‐V2V relay system can be higher or lower than those of half‐duplex‐ (HD‐) EH‐V2V system, depending on the average transmission power of the source. Furthermore, when the transmission power of the source and RSI are fixed, the ECs of the considered system can achieve peak values by using optimal EH time duration. On the other hand, the ECs of both AF and DF protocols reach the capacity floors in the high signal‐to‐noise ratio (SNR) regime due to the RSI impact. Also, the effect of RSI dominates the impact of cascade Rayleigh fading in the high SNR regime. Finally, we validate our analysis approach through Monte‐Carlo simulations.

In this paper, we evaluate the performance of a vehicle-to-vehicle (V2V) system where full-duplex relay (FDR) harvests the energy from source and uses decode-and-forward (DF) protocol to forward data from source to destination. Unlike existing works about FDR systems, we consider the scenario that both relay and destination are moving vehicles, leading to the channel between relay and destination characterized by double (cascade) Rayleigh fading. We successfully obtain the closed-form mathematical expressions of the outage probability (OP) and throughput of the considered energy harvesting- (EH-) FDR-V2V system. Based on these expressions, the system performance is investigated through various scenarios. Numerical results indicate that the performance of the considered system is reduced compared with that of the system over Rayleigh fading channels. We also observe that there is an optimal EH time duration that minimizes the OP and maximizes the throughput. This value depends on the transmission power of source. Furthermore, the OP goes to outage floor faster due to the impact of the residual self-interference (RSI), especially when RSI is high. All analysis results are verified by Monte-Carlo simulations.

In this paper, we evaluate a two-way relay system consisting of two terminals and an intermediate relay. In this model, two terminals do not have a direct link but exchange data with each other via the relay in three phases. The relay utilizes energy harvesting technology to collect energy from the received signals of two terminals in the first two phases and then uses the obtained energy for signal transmission in the third phase. Each node is equipped with a single antenna and operates under a half-duplex mode. All wireless channels are influenced by reversible independent flat Rayleigh fading. Using analytical methods, we provide the exact and approximate closed-form expressions of user outage probability and system outage probability. The approximate expressions of these outage probabilities are more explicit and straightforward, providing a better understanding of the influences of network parameters on the system quality. Monte-Carlo simulations are used to confirm the correctness of mathematical analyses.

Summary In this paper, we propose a Stability‐aware Cooperative Routing scheme for Reliable high‐speed data transmission in Multi‐rate mobile ad hoc wireless networks, called SCRRM, to provide high data transmission with stable and reliable routes. The main features and contributions of our proposed routing scheme are as follows: First, we use the cross‐layer concept with network layer, media access control (MAC) layer, and physical (PHY) layer. Second, a stable routing path based on link lifetime calculated from node mobility information is selected as the main routing path. Third, we use the received signal strength indicator (RSSI), PHY delay, and MAC delay for adaptively choosing relay and appropriate data rate. Fourth, we derive mathematical models to investigate the tradeoff between point‐to‐point transmission rates and the corresponding effective transmission ranges. The performance evaluation through analysis and simulation demonstrates that our proposed routing scheme can adaptively select optimal data rate and outperforms single‐rate routing protocol in terms of packet delivery ratio, network throughput, and average end‐to‐end delay in all settings of node density and node mobility. Copyright © 2014 John Wiley & Sons, Ltd.

The number of hops between source node and destination node is one of key parameter in studying multi-hop ad-hoc networks. Although hop count in conventional ad-hoc networks has been well studied, to the best of our knowledge, there have no works that intensively investigate the hop count of multi-hop path in cognitive environment. This paper presents detail simulation analysis on the hop count of multi-hop path in Cognitive Radio Ad-hoc Networks (CRAHNs). The effect of network parameters such as node density of Secondary User (SU) and Primary User (PU), operating frequencies, average activating rate of PUs, in the networks are studied. Simulation experiments with different network parameters are conducted to clarify the features of hop count in cognitive ad-hoc networks.