The secrecy outage probability (SOP) of cooperative communication systems with optimal relay selection (ORS) scheme in the presence of an eavesdropper is investigated by implementing decode-and-forward-based full-duplex (FD) two-way relayingmode. Under Rayleigh fading assumptions, the closed-form expressions for the distributions of end-to-end signal-to-interference-plus-noise ratio in each wireless link are derived. Furthermore, the closed-form expression for the exact SOP of the proposed ORS scheme is given out. Numerical results show that the SOP of the proposed system can be substantially impacted by several parameters involved, including the number of relays, the average signal-to-noise ratio (SNR) of eavesdropper links, and the average residual self-interference (SI) imposed on the FD relays. In particular, the impact of residual SI is shown to be more obvious in terms of eroding the system’s secrecy performance in a low-to-medium SNR regime than in a high-SNR regime. As long as the residual SI power is not beyond the background noise level, the proposed FD-TWC scheme can always outperform the conventional half-duplex mode in terms of SOP.

A bi-node full-duplex communications system, in which both nodes are assumed to have the capability of energy harvesting (EH), is investigated. In the proposed model, node B harvests radio frequency energy that dissipated by node A, to which the former will transmit its signal back simultaneously. Furthermore, by exploiting node B's critical information, including its channel state information and the usage of its battery, a minimum transmission protocol is proposed by employing two kinds of EH-manners. Note that node B is allowed to always transmit, provided that its residual energy is high enough to ensure a successful decoding at node A. In addition, the proposed protocol with capabilities of both EH and signal transmission can be developed by employing a Markov-chain model, following which we can derive both the stationary distribution and the outage probability of node A. Finally, numerical results validate the proposed theoretical analysis.

KSII Transactions on Internet and Information Systems TIIS Paper Details

This article investigates the transmission characteristics of Laguerre–Gaussian (LG) beams under cosine modulation, power function modulation and linear modulation based on the variable coefficient fractional Schrödinger equation (FSE), respectively. In the absence of modulation, the LG beam undergoes diffraction-induced expansion as the transmission distance increases, with the degree of spreading increasing with a rising Lévy index. Under the cosine modulation, the evolution of the beam exhibits a periodic inversion, where the higher modulation frequency leads to a shorter oscillation period. The oscillation amplitude enlarges with a higher Lévy index and lower modulation frequency. When taking a power function modulation into account, the beam gradually evolves into a stable structure over propagation, with its width broadening with a growing Lévy index and modulation coefficient. In a linear modulation, the propagation of the LG beam forms a “trumpet-like” structure due to an accelerated diffraction effect. Notably, the transmission of the beam is not affected by the radial and azimuthal indices, but its ring number and phase singularity are changed correspondingly. The beam behaves in a similar evolutionary law under different modulations when the Lévy index is below 1. These findings offer valuable insights for applications in optical manipulation and communication.

Considering energy harvesting, the ergodic data rates for both in band full-duplex (FD) and half-duplex (HD) wireless communications were studied. The analytic expressions of downlink and uplink ergodic rates for the proposed system were first derived with independent and identically distributed (i.i.d.) Rayleigh fading link. It was revealed that the uplink data rate can be improved by decreasing the downlink data rate. Furthermore, the uplink/downlink data rates are also shown to be influenced by some significance parameters, for example, the power split parameter and signal-to-noise ratio (SNR) (i.e., P_S/σ²) of each link. Additionally, unlike the HD, the proposed FD node is capable of harvesting energy during the communication process; however, this is at the cost of performance loss induced by the residual self-interference (RSI), which is caused by the essence of simultaneous uplink and downlink transmissions in a single frequency band.

With the increasing size of the power grid, maintaining the frequency stability of the power grid is becoming more and more challenge, Model Predictive Control is one of the promising solutions to this problem. In this paper, we propose a Distributed Model Predictive Control (DMPC) method for the load-frequency control (LFC) of an interconnected multi-area grid, which incorporates the terminal states into the cost function and considers the non-zero steady-state error, thereby improving the convergence speed and effectiveness. First, the traditional multi-area LFC model is adapted and simplified into a new model suitable for the proposed DMPC method and discretized. Then, the design of the new cost function is given with a detailed derivation and a system stability analysis is performed. Finally, simulations are performed in Simulink to verify the effectiveness of the proposed method.