Energy efficiency in energy harvesting cooperative networks with self-energy recycling

Cooperative communication has been identified as an important component in the 5G system. This paper considers a decode-and-forward (DF) relaying wireless cooperative network, in which the self-energy recycling relay is powered by radio-frequency (RF) signal from the source and its transmitted power from the loop-back channel. The harvested energy is used to support the relay transmissions. Based on a self-energy recycling relaying protocol, we study the optimization of energy efficiency in wireless cooperative networks. Although the formulated optimization problem is not convex, it can be re-constructed to a parametric problem in the convex form by using the non-linear fractional programming, to which closed form solutions can be found by using the Lagrange multiplier method. The simulation results are presented to verify the effectiveness of this solution proposed in this paper

Beamforming optimisation in energy harvesting cooperative full-duplex networks with self-energy recycling protocol

This study considers the problem of beamforming optimisation in an amplify-and-forward relaying cooperative network, in which the relay node harvests the energy from the radio-frequency signal. Based on the self-energy recycling relay protocol, the authors study the beamforming optimisation problem. The formulated problem aims to maximise the achievable rate subject to the available transmitted power at the relay node. The authors develop a semidefinite programming (SDP) relaxation method to solve the proposed problem. They also use SDP and the full search to solve the beamforming optimisation based on a time-switching relaying protocol as a benchmark. The simulation results are presented to verify that the self-energy recycling protocol achieves a significant rate gain compared with the timeswitching relaying protocol and the power-splitting relaying protocol

Optimal Power Allocation for Energy Recycling Assisted Cooperative Communications

We investigate the problem of optimal power allocation for energy recycling cooperative communications systems, employing full duplex relays, based on the criterion of maximizing the rate, or equivalently the Signal to Noise Ratio (SNR), of the system. A system model is investigated where each time slot is split into an information transmission phase, during which the Source (S) transmits information to the destination (D) and a full-duplex Relay (R), and an energy harvesting phase. During the energy harvesting phase, R relays information to D, while concurrently it performs energy harvesting, exploiting a signal transmitted by S and energy recycling, exploiting its own transmission. For this system model, we formulate a rate/SNR maximization problem, in order to compute the optimal source power levels for both information transfer and energy transfer phases. The cost function of this optimization problem is then substituted by a sharp approximation, which allows for obtaining an analytically tractable power allocation. The performance of the resulting power allocation is then assessed by means of Monte Carlo simulations, and it is found that it outperforms existing solutions. It is therefore shown that our proposed solution can contribute towards increasing the range of IoT networks