Performance Enhancement for Multihop Harvest-to-Transmit WSNs With Path-Selection Methods in Presence of Eavesdroppers and Hardware Noises

Energy-harvesting-based physical layer security
(PLS) has become a promising technique, as it not only secures
information from eavesdropping without upper layer data encryption,
but it also improves the energy efficiency of wireless
networks. However, it imposes new challenges, as adversary
parties can overhear the transmission of confidential information
between the source and destination via a relay. Therefore, the
transmit power of the signals must be large enough for energy
harvesting, but it must also be small enough to avoid eavesdropping.
This is even more challenging with multi-hop multi-path
wireless networks. Motivated by these observations, this paper
proposes three innovative protocols, namely, the shortest path
selection (SPS) protocol, random path selection (RPS) protocol,
and best path selection (BPS) protocol. These will enhance the
security of multi-hop multi-path randomize-and-forward (RF)
cooperative wireless sensor networks (WSNs) under the presence
of eavesdroppers and hardware impairment, wherein the source
node and relay nodes are capable of harvesting energy from
beacon for data transmission. Furthermore, we derive exact
closed-form expressions and the asymptotic outage probability
for each protocol under multiple eavesdropping attacks. The
simulation results validate the theoretical results.