Joint Power Splitting Research Articles

Performance Analysis of Wireless Powered Cooperative NOMA-Based CDRT IoT Networks

This article investigates the outage performance of a wireless powered cooperative nonorthogonal multiple access-based coordinated direct and relay transmission (CDRT) Internet-of-Things (IoT) network with simultaneous wireless information and power transfer capable IoT master node. A method to remedy the high outage situation of a near user by exploiting information from earlier communication phase is proposed and analyzed. The competency of this method and the closed form of the outage probability for the users under practical variations, such as imperfect successive interference cancellation and different incentive transmission power levels for the IoT master node, are derived analytically and confirmed via simulation. In addition to that, our asymptotic analysis shows that it is not mandatory to enhance the outage performance of the near user in the final phase of CDRT by using many antennas in the high signal-to-noise-ratio regime. Moreover, a modified particle swarm optimization algorithm is introduced to solve a joint power splitting, time splitting, and power allocation for the proposed system. Numerical results from our analysis exemplify significant tradeoff between near user performance and the quality of service of the master node’s client.

Secrecy rate maximisation for non‐linear energy harvesting relay networks with cooperative jamming and imperfect channel state information

The secrecy performance of a wireless-powered relaying system is investigated in the presence of imperfect channel state information. To improve the system secrecy performance, the destination splits a part of power to transmit the cooperative interference signal while the source transmits confidential information to the relay. The relay is assumed to be equipped with a non-linear energy harvester and to harvest energy from the source and destination for information processing. A joint power splitting and time allocation scheme is studied to maximise the system secrecy rate. The joint optimisation problem is dealt with by the interior-point method. For the sake of comparison, the equal time allocation scheme and the equal power splitting scheme are also investigated. The numerical results verify that the proposed scheme could achieve higher secrecy rate.

Optimal Power Allocation and Relay Location for DF Energy Harvesting Relaying Sensor Networks.

This paper considers a simultaneous wireless information and power transfer (SWIPT) based decode-and-forward (DF) relaying sensor network, where the “save-and-forward” strategy is utilized at the relay sensor node. We investigate a joint power splitting (PS) and relay location (RL) optimization scheme for delay-sensitive transmission mode using the instantaneous channel state information (CSI). In particular, two optimization problems are formulated to minimize the outage probability and maximize the average capacity, respectively. For the two optimization problems, the optimal solutions to the PS ratio and RL are obtained based on the instantaneous CSI. On the basis of optimal solutions, the analytical expressions for outage probability and average capacity are derived, and the corresponding achievable throughputs are obtained. Numerical results verify the correctness of theoretical derivations and validate the advantages of our proposed scheme.

Joint power splitting and power allocation for two-way OFDM relay networks with SWIPT

This paper studies power-splitting relaying (PSR) in an orthogonal-frequency-division-multiplexing (OFDM) amplify-and-forward (AF) two-way relay network (TWRN) which implements simultaneous wireless information and power transfer (SWIPT), with the goal of maximizing information exchanging rates of two terminals in the network. To achieve this, we investigate the joint optimization of power-splitting (PS) ratio of the relay and power allocation over subcarriers. The formulated optimization problem not only bears a non-convex energy-harvesting constraint of the relay but also tightly couples the PS ratio and power allocation variables in the non-convex objective function. To tackle this challenging problem, we show that it can be transformed into a problem which fits well in the d.c.(difference of two convex functions) programming framework by two different approaches, and thus can be effectively solved by two constrained concave-convex procedure based algorithms, respectively. Simulation results show that the performance of the PSR-based OFDM AF TWRN employing our proposed schemes is not only better than that of the existing time-switching based relaying OFDM AF TWRN, but also superior over that of the PSR-based OFDM AF TWRN employing the simple scheme with fixed PS ratio.

Energy efficiency optimisation for SWIPT AF two‐way relay networks

A joint power splitting ratio optimisation and power allocation scheme is proposed to maximise the energy efficiency in amplify-and-forward two-way relay networks with the simultaneous wireless information and power transfer scheme. Both the locally optimal solution and simplified equal power allocation scheme with closed-form expressions are derived. Simulation results show the effectiveness of the proposed schemes.

An Efficiency Maximization Design for SWIPT

A joint power splitting and beamforming design for multiuser multiple-input single-output (MISO) systems where receivers have capability of decoding information and harvesting energy simultaneously from received signals is considered. The objective is to maximize the ratio of the achieved utility to the total power consumption subject to harvested power requirements and power budget at a base station (BS). The utility function of interest combines the sum rate and the total harvested power. The design problem is nonconvex, and thus, global optimality is difficult to achieve. To solve this problem locally we first convert the problem into a more tractable form, and then propose an iterative algorithm which is guaranteed to achieve a Karush–Kuhn–Tucker solution. Numerical results are provided to demonstrate the superior performance of the proposed method.