Abstract
In this paper, we investigate an energy harvesting scheme in a smart grid based on the cognitive relay protocol, where a primary transmitter scavenges energy from the nature sources and then employs the harvested energy to forward the primary signal. Depending on the intensity of the energy harvesting from nature, a secondary user dynamically acts as a relay node to assist the primary transmission or does not. When the energy is not enough powerful to support the direct transmission between two primary users, the secondary users share the spectrum by assisting the primary transmission. For the relaying scheme, both amplify-and-forward (AF) and decode-and-forward (DF) protocols are investigated. We analytically obtain the exact transmission rates for both primary and secondary networks and derive the exact expressions of the system outage probabilities for both primary and secondary users in the smart grid. Moreover, we develop the analytically optimal bandwidth allocation strategy to maximize the total sum rate of the proposed scheme. Numerical results are presented to demonstrate the performance gain of the proposed scheme over the nonoptimal scheme.
Highlights
Spectral efficiency has attracted much attention in wireless smart grid communications networks due to the increasing demands of wireless services [1]
Due to the fluctuation of energy harvesting from nature sources, we model and propose an energy harvesting and relaying protocol with dynamic bandwidth allocation in cognitive relay networks. e protocol enables a secondary user dynamically sharing the primary spectrum by assisting the primary transmission if the direction transmission between two primary users cannot be effectively realized
We propose the following energy harvesting and relaying protocol: (i) When the harvesting energy is powerful enough to support the direct transmission between two primary nodes, the primary network operates in the direct transmission mode and w1 spectrum will be allocated to the primary network while the rest to the secondary network. erefore, the transmission consists of only one phase which lasts for one slot time T
Summary
Spectral efficiency has attracted much attention in wireless smart grid communications networks due to the increasing demands of wireless services [1]. As a result, combining energy harvesting technology with cognitive radio networks offers a new opportunity to improve both spectral and energy efficiency for the smart grid [8]. Park and Hong [13] provided an optimal spectrum sensing policy for an energy harvesting cognitive radio which is in purpose of maximizing the expected total throughput. In this paper, considering the massive potential of harvesting energy from nature resources, we adopt this technique to cognitive radio network where we assume the primary user lacks of energy and harvests energy from the nature resources. If the direct transmission data rate meets the basic threshold requirement, the direct transmission between two primary users occurs and some bandwidth is allocated to the secondary network.
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