Optimal precoders and power splitting factors in multiuser multiple‐input multiple‐output cognitive decode‐and‐forward relay systems with wireless energy harvesting

Author(s):  
Ha Hoang Kha
Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 182 ◽  
Author(s):  
Xiaoqing Liu ◽  
Zhigang Wen ◽  
Dan Liu ◽  
Junwei Zou ◽  
Shan Li

We consider a multiple-input multiple-output amplify-and-forward wireless multiple-hop sensor network (WMSN). The simultaneous wireless information and power transfer technology is deployed to potentially achieve an autonomous system. We investigate two practical receiver schemes, which are the power splitting (PS) and the time switching (TS). The power splitting receiver splits received signals into two streams, one for information decoding (ID) and the other for energy harvesting (EH). On the other hand, the time switching receiver only serves in ID mode or energy harvesting mode during a certain time slot. Subject to transmit power constraints and destination harvested energy constraint, we aim to obtain a joint beam-forming solution of source and relay precoders to maximize the maximum achievable rate of the WSN. In order to make the non-convex problem tractable, diagonalization-based alternating optimization algorithms are proposed. Numerical results show the convergence and good performance of the proposed algorithms under both PS and TS protocols.


2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Jinxin Zhu ◽  
Jun Shao

In this work, a reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output (MIMO) system is studied with wireless energy harvesting (EH). Specifically, we focus on maximizing the harvested power at the receiver by joint optimization of the signal covariance, the phase shifter, and the power splitting factor, subject to the information rate and transmit power constraints. The formulated problem is hard to address due to the nonconcave objective and the nonconvex constraints. To tackle these challenges, an alternating optimization (AO) framework is proposed, where the phase shifter is solved by the penalty-based method. Simulation results validate the performance of the proposed approach.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Syed Tariq Shah ◽  
Daniel B. da Costa ◽  
Kae Won Choi ◽  
Min Young Chung

Wireless energy harvesting has emerged as an efficient solution to prolong the lifetime of wireless networks composed of energy-constrained nodes. In this paper, we consider a multipoint-to-multipoint relay network, where multiple source nodes communicate with their respective destination nodes via intermediate energy-constrained decode-and-forward (DF) relay. The performance of two different transmission modes, namely, delay tolerant and delay nontolerant, is studied. Based on power-splitting relaying protocol (PSR), optimal energy harvesting and distribution schemes for both transmission modes are provided. In addition, for more realistic and practical analysis, we consider a nonlinear energy conversion model for energy harvesting at the relay node. Our numerical results provide useful insights into different system parameters of a nonlinear energy harvesting-based multipair DF relay network.


2018 ◽  
Vol 2 (1) ◽  
pp. 18
Author(s):  
Miroslav Voznak ◽  
Hoang Quang Minh Tran ◽  
N. Tan Nguyen

In recent years, harvesting energy from radio frequency (RF) signals has drawn significant research interest as a promising solution to solve the energy problem. In this paper, we analyze the effect of the interference noise on the wireless energy harvesting performance of a decode-and-forward (DF) relaying network. In this analysis, the energy and information are transferred from the source to the relay nodes in the delay-limited transmission and Delay-tolerant transmission modes by two methods: i) time switching protocol and ii) power splitting protocol. Firstly, due to the constraint of the wireless energy harvesting at the relay node, the analytical mathematical expressions of the achievable throughput, outage probability and ergodic capacity of both schemes were proposed and demonstrated. After that, the effect of various system parameters on the system performance is rigorously studied with closed-form expressions for system throughput, outage probability, and ergodic capacity. Finally, the analytical results are also demonstrated by Monte-Carlo simulation. The results show that the analytical mathematical and simulated results agree with each other.  This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


2011 ◽  
Vol 225-226 ◽  
pp. 1225-1229
Author(s):  
Rui Zhe Yang ◽  
Li Zhang ◽  
Peng Bo Si ◽  
Zhi Kun Song ◽  
Yan Hua Zhang

For the classic three-node multiple-input multiple-output (MIMO) relay channel, a capacity enhanced transmission is proposed, using simple half-duplex tow-hop relaying based on symbol level decode-and-forward (DF) mode. For higher capacity to the destination, we assume the source node equipped with more antennas and propose the transmission strategy, where using channel precoding, the source transmits the data to the relay and destination respectively in the first hop and retransmits part of data to destination jointly with relay in the second hop. Additionally, the power allocation is designed to maximize the system capacity. Simulation results are then presented for illustration of the capacity enhancement.


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