Opportunistic Wireless Energy Harvesting in Cognitive Radio Networks

Abstract

Abstract-Wireless networks can be self-sustaining by harvesting energy from ambient radio-frequency (RF) signals. Recently, researchers have made progress on designing efficient circuits and devices for RF energy harvesting suitable for low-power wireless applications. Motivated by this and building upon the classic cognitive radio (CR) network model, this paper proposes a novel method for wireless networks coexisting where low-power mobiles in a secondary network, called secondary transmitters (STs), harvest ambient RF energy from transmissions by nearby active transmitters in a primary network, called primary transmitters (PTs), while opportunistically accessing the spectrum licensed to the primary network. We consider a stochastic-geometry model in which PTs and STs are distributed as independent homogeneous Poisson point processes (HPPPs) and communicate with their intended receivers at fixed distances. Each PT is associated with a guard zone to protect its intended receiver from ST's interference, and at the same time delivers RF energy to STs located in its harvesting zone. Based on the proposed model, we analyze the transmission probability of STs and the resulting spatial throughput of the secondary network. The optimal transmission power and density of STs are derived for maximizing the secondary network throughput under the given outage-probability constraints in the two coexisting networks, which reveal key insights to the optimal network design. Finally, we show that our analytical result can be generally applied to a non-CR setup, where distributed wireless power chargers are deployed to power coexisting wireless transmitters in a sensor network.

Maximization of Throughput in Wireless Powered Communication Networks

“…That increase energy and spectrum efficiency demand. [5] To maximize energy efficiency, we proposed a new method with co-existence of primary and secondary transmitters in which low carrier form a secondary network.…”

“…It has been reported that 3.5mW and 1uW of wireless power can be harvested from radio-frequency (RF) signals at distances of 0.6 and 11 meters, respectively, using Powercast RF energy Harvester operating at 915MHz [1].Furthermore, recent advance in designing highly efficient rectifying antennas will enable more efficient wireless energy harvesting from RF signals in the near future [2]. It is worth noting that there has been recently a growing interest in studying wireless powered communication networks (WPCNs), where energy harvested from ambient RF signals is used to power wireless terminals in the network, e.g., [3]- [5]. In [3], a wireless powered sensor network was investigated, where a mobile charging vehicle moving in the network is employed as the energy transmitter to wirelessly power the sensor nodes.…”

“…In [4], the wireless powered cellular network was studied in which dedicated power-beacons are deployed in the cellular network to charge mobile terminals. Moreover, the wireless power-driven cognitive radio network has been measured in [5], where active primary users are utilized as energy transmitters for charging their nearby secondary users that are not allowed to transmit over the same channel due to strong interference. furthermore, as radio signals transmit energy as well as information at the equal instant, a joint examination of simultaneous wireless information and power transfer (SWIPT) has recently tense a important attention (see e.g.…”

Optimal Paring of Spectrum Sensing Duration and Threshold for Energy-Harvesting CRNS

“…To perform its own local spectrum sensing measurements independently, every cognitive radio user makes decision on whether the primary user is present or not [9]. To enhance the SNR a matched filter is often used at the receiver front end.…”

Energy harvesting empowered cognitive metro-cellular networks

“…Thus definition of cognition must be extended and harvesting aware algorithms must be devised for the deployment of the self-sustainable networks. Energy harvesting and microwave power transfer have been extensively explored in context of cellular networks in [2], [3], [4], [5], [6], [7], [8] However, most of these studies assume the stochastic energy arrival models. In practice, energy harvested from the natural sources such as sun has a deterministic behavior.…”