31 research outputs found
Optimal Spectrum Access for a Rechargeable Cognitive Radio User Based on Energy Buffer State
This paper investigates the maximum throughput for a rechargeable secondary
user (SU) sharing the spectrum with a primary user (PU) plugged to a reliable
power supply. The SU maintains a finite energy queue and harvests energy from
natural resources, e.g., solar, wind and acoustic noise. We propose a
probabilistic access strategy by the SU based on the number of packets at its
energy queue. We investigate the effect of the energy arrival rate, the amount
of energy per energy packet, and the capacity of the energy queue on the SU
throughput under fading channels. Results reveal that the proposed access
strategy can enhance the performance of the SU.Comment: arXiv admin note: text overlap with arXiv:1407.726
Optimal time sharing in underlay cognitive radio systems with RF energy harvesting
Due to the fundamental tradeoffs, achieving spectrum efficiency and energy
efficiency are two contending design challenges for the future wireless
networks. However, applying radio-frequency (RF) energy harvesting (EH) in a
cognitive radio system could potentially circumvent this tradeoff, resulting in
a secondary system with limitless power supply and meaningful achievable
information rates. This paper proposes an online solution for the optimal time
allocation (time sharing) between the EH phase and the information transmission
(IT) phase in an underlay cognitive radio system, which harvests the RF energy
originating from the primary system. The proposed online solution maximizes the
average achievable rate of the cognitive radio system, subject to the
-percentile protection criteria for the primary system. The
optimal time sharing achieves significant gains compared to equal time
allocation between the EH and IT phases.Comment: Proceedings of the 2015 IEEE International Conference on
Communications (IEEE ICC 2015), 8-12 June 2015, London, U
On Spectrum Sharing Between Energy Harvesting Cognitive Radio Users and Primary Users
This paper investigates the maximum secondary throughput for a rechargeable
secondary user (SU) sharing the spectrum with a primary user (PU) plugged to a
reliable power supply. The SU maintains a finite energy queue and harvests
energy from natural resources and primary radio frequency (RF) transmissions.
We propose a power allocation policy at the PU and analyze its effect on the
throughput of both the PU and SU. Furthermore, we study the impact of the
bursty arrivals at the PU on the energy harvested by the SU from RF
transmissions. Moreover, we investigate the impact of the rate of energy
harvesting from natural resources on the SU throughput. We assume fading
channels and compute exact closed-form expressions for the energy harvested by
the SU under fading. Results reveal that the proposed power allocation policy
along with the implemented RF energy harvesting at the SU enhance the
throughput of both primary and secondary links
RF-Powered Cognitive Radio Networks: Technical Challenges and Limitations
The increasing demand for spectral and energy efficient communication
networks has spurred a great interest in energy harvesting (EH) cognitive radio
networks (CRNs). Such a revolutionary technology represents a paradigm shift in
the development of wireless networks, as it can simultaneously enable the
efficient use of the available spectrum and the exploitation of radio frequency
(RF) energy in order to reduce the reliance on traditional energy sources. This
is mainly triggered by the recent advancements in microelectronics that puts
forward RF energy harvesting as a plausible technique in the near future. On
the other hand, it is suggested that the operation of a network relying on
harvested energy needs to be redesigned to allow the network to reliably
function in the long term. To this end, the aim of this survey paper is to
provide a comprehensive overview of the recent development and the challenges
regarding the operation of CRNs powered by RF energy. In addition, the
potential open issues that might be considered for the future research are also
discussed in this paper.Comment: 8 pages, 2 figures, 1 table, Accepted in IEEE Communications Magazin