1 research outputs found
Joint Power Splitting and Relay Selection in Energy-Harvesting Communications for IoT Networks
In this paper, we consider an energy-harvesting (EH) relay system consisting
of a source, a destination, and multiple EH decode-and-forward (DF) relays that
can harvest the energy from their received radio signals. A power-splitting
ratio is employed at an EH DF relay to characterize a trade-off between an
energy used for decoding the source signal received at the relay and the
remaining energy harvested for retransmitting the decode outcome. We propose an
optimal power splitting and relay selection (OPS-RS) framework and also
consider the conventional equal power splitting and relay selection (EPS-RS)
for comparison purposes. We derive closed-form expressions of outage
probability for both the OPS-RS and EPS-RS schemes and characterize their
diversity gains through an asymptotic outage analysis in the high
signal-to-noise ratio region. We further examine an extension of our OPS-RS
framework to an energy-harvesting battery (EHB) enabled cooperative relay
scenario, where the EH relays are equipped with batteries used to store their
harvested energies. We propose an amplify-and-forward (AF) based EHB-OPS-RS and
a DF based EHB-OPS-RS schemes for AF and DF relay networks, respectively.
Numerical results show that the proposed OPS-RS always outperforms the EPS-RS
in terms of outage probability. Moreover, the outage probabilities of AF and DF
based EHB-OPS-RS schemes are much smaller than that of OPS-RS and EPS-RS
methods, demonstrating the benefit of exploiting the batteries in EH relays.
Additionally, the DF based EHB-OPS-RS substantially outperforms the AF based
EHB-OPS-RS and such an outage advantage becomes more significant, as the number
of EH relays increases.Comment: 14 page