2 research outputs found
Coexistence of RF-powered IoT and a Primary Wireless Network with Secrecy Guard Zones
This paper studies the secrecy performance of a wireless network (primary
network) overlaid with an ambient RF energy harvesting IoT network (secondary
network). The nodes in the secondary network are assumed to be solely powered
by ambient RF energy harvested from the transmissions of the primary network.
We assume that the secondary nodes can eavesdrop on the primary transmissions
due to which the primary network uses secrecy guard zones. The primary
transmitter goes silent if any secondary receiver is detected within its guard
zone. Using tools from stochastic geometry, we derive the probability of
successful connection of the primary network as well as the probability of
secure communication. Two conditions must be jointly satisfied in order to
ensure successful connection: (i) the SINR at the primary receiver is above a
predefined threshold, and (ii) the primary transmitter is not silent. In order
to ensure secure communication, the SINR value at each of the secondary nodes
should be less than a predefined threshold. Clearly, when more secondary nodes
are deployed, more primary transmitters will remain silent for a given guard
zone radius, thus impacting the amount of energy harvested by the secondary
network. Our results concretely show the existence of an optimal deployment
density for the secondary network that maximizes the density of nodes that are
able to harvest sufficient amount of energy. Furthermore, we show the
dependence of this optimal deployment density on the guard zone radius of the
primary network. In addition, we show that the optimal guard zone radius
selected by the primary network is a function of the deployment density of the
secondary network. This interesting coupling between the two networks is
studied using tools from game theory. Overall, this work is one of the few
concrete works that symbiotically merge tools from stochastic geometry and game
theory
Joint Energy and SINR Coverage in Spatially Clustered RF-powered IoT Network
Owing to the ubiquitous availability of radio-frequency (RF) signals, RF
energy harvesting is emerging as an appealing solution for powering IoT
devices. In this paper, we model and analyze an IoT network which harvests RF
energy and receives information from the same wireless network. In order to
enable this operation, each time slot is partitioned into charging and
information reception phases. For this setup, we characterize two performance
metrics: (i) energy coverage and (ii) joint signal-to-interference-plus-noise
(SINR) and energy coverage. The analysis is performed using a realistic spatial
model that captures the spatial coupling between the locations of the IoT
devices and the nodes of the wireless network (referred henceforth as the IoT
gateways), which is often ignored in the literature. In particular, we model
the locations of the IoT devices using a Poisson cluster process (PCP) and
assume that some of the clusters have IoT gateways (GWs) deployed at their
centers while the other GWs are deployed independently of the IoT devices. The
level of coupling can be controlled by tuning the fraction of total GWs that
are deployed at the cluster centers. Due to the inherent intractability of
computing the distribution of shot noise process for this setup, we propose two
accurate approximations, using which the aforementioned metrics are
characterized. Multiple system design insights are drawn from our results. For
instance, we demonstrate the existence of optimal slot partitioning that
maximizes the system throughput. In addition, we explore the effect of the
level of coupling between the locations of the IoT devices and the GWs on this
optimal slot partitioning. Particularly, our results reveal that the optimal
value of time duration for the charging phase increases as the level of
coupling decreases.Comment: To appear in IEEE Transactions on Green Communications and Networkin