Time Switching Receiver Architectures Research Articles

Outage Probability and Throughput of Multirelay SWIPT-WPCN Networks With Nonlinear EH Model and Imperfect CSI

This article investigates the simultaneous wireless information and power transfer-wireless powered communication network systems, where a multiantenna source transmits information to a multiantenna destination with the assistance of multiple single-antenna energy-constrained relays. For such a system, a transmission protocol is presented based on the $J$ th best relay selection and the transmit antenna selection such that the information and power are transferred over the channel with the largest instantaneous power gain. Time switching receiver architecture is adopted at the relays for information decoding and energy harvesting (EH). The system information transmission performances in Rayleigh fading are analyzed with the nonlinear EH model and imperfect channel state information (CSI), and the closed-form expressions of the system outage probability and reliable throughput are derived. In order to provide more concise results, the corresponding approximate expressions are also derived at low and high signal-to-noise ratio. Numerical results show that our obtained theoretical results match Monte Carlo simulation results very well, demonstrating the effectiveness of our obtained analytical results. Besides, it also shows that the imperfect CSI of the source-to-relay link has greater impact on the system performance than that of the relay-to-destination link. Additionally, by using the nonlinear EH model, the false performance caused by the linear EH model can be reduced.

Performance Evaluation of Relay Selection Schemes in Beacon-Assisted Dual-Hop Cognitive Radio Wireless Sensor Networks under Impact of Hardware Noises.

To solve the problem of energy constraints and spectrum scarcity for cognitive radio wireless sensor networks (CR-WSNs), an underlay decode-and-forward relaying scheme is considered, where the energy constrained secondary source and relay nodes are capable of harvesting energy from a multi-antenna power beacon (PB) and using that harvested energy to forward the source information to the destination. Based on the time switching receiver architecture, three relaying protocols, namely, hybrid partial relay selection (H-PRS), conventional opportunistic relay selection (C-ORS), and best opportunistic relay selection (B-ORS) protocols are considered to enhance the end-to-end performance under the joint impact of maximal interference constraint and transceiver hardware impairments. For performance evaluation and comparison, we derive the exact and asymptotic closed-form expressions of outage probability (OP) and throughput (TP) to provide significant insights into the impact of our proposed protocols on the system performance over Rayleigh fading channel. Finally, simulation results validate the theoretical results.

Regularized Channel Inversion for Simultaneous Confidential Broadcasting and Power Transfer: A Large System Analysis

We propose for the first time new transmission schemes based on linear precoding to enable simultaneous confidential broadcasting and power transfer in a multiuser multi-input single-output network, where a base station with $N$ antennas simultaneously transmits power and confidential messages to $K$ single-antenna users. We first design two transmission schemes based on the rules of regularized channel inversion (RCI) for both power splitting (PS) and time switching (TS) receiver architectures, namely, RCI-PS and RCI-TS schemes. For each scheme, we derive channel-independent expressions to approximate the secrecy sum rate and the harvested power in the large-system regime where $K,N\rightarrow \infty$ with a fixed ratio $\beta =K/N$ . Based on the large-system results, we jointly optimize the regularization parameter of the RCI and the PS ratio or the TS ratio such that the secrecy sum rate is maximized subject to an energy-harvesting constraint. We then present the tradeoff between the secrecy sum rate and the harvested power achieved by each scheme, and find that neither scheme always outperforms the other one. Motivated by this fact, we design an RCI-hybrid scheme based on the RCI and a newly proposed hybrid receiver architecture. The hybrid receiver architecture takes advantages of both the PS and TS receiver architectures. We show that the RCI-hybrid scheme outperforms both the RCI-PS and RCI-TS schemes.