We focus on a scenario where two wireless source nodes wish to exchangeconfidential information via an RF energy harvesting untrusted two-way relay.Despite its cooperation in forwarding the information, the relay is considereduntrusted out of the concern that it might attempt to decode the confidentialinformation that is being relayed. To discourage the eavesdropping intention ofthe relay, we use a friendly jammer. Under the total power constraint, tomaximize the sum-secrecy rate, we allocate the power among the sources and thejammer optimally and calculate the optimal power splitting ratio to balancebetween the energy harvesting and the information processing at the relay. Wefurther examine the effect of imperfect channel state information at bothsources on the sum-secrecy rate. Numerical results highlight the role of thejammer in achieving the secure communication under channel estimation errors.We have shown that, as the channel estimation error on any of the channelsincreases, the power allocated to the jammer decreases to abate theinterference caused to the confidential information reception due to theimperfect cancellation of jammer's signal.
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