This paper investigates a wireless-powered two-way relay network (WP-TWRN),in which two sources exchange information with the aid of oneamplify-and-forward (AF) relay. Contrary to the conventional two-way relaynetworks, we consider the scenario that the AF relay has no embedded energysupply, and it is equipped with an energy harvesting unit and rechargeablebattery. As such, it can accumulate the energy harvested from both sources'signals before helping forwarding their information. In this paper, we developa power splitting-based energy accumulation (PS-EA) scheme for the consideredWP-TWRN. To determine whether the relay has accumulated sufficient energy, weset a predefined energy threshold for the relay. When the accumulated energyreaches the threshold, relay splits the received signal power into two parts,one for energy harvesting and the other for information forwarding. If thestored energy at the relay is below the threshold, all the received signalpower will be accumulated at the relay's battery. By modeling thefinite-capacity battery of relay as a finite-state Markov Chain (MC), we derivea closed-form expression for the system throughput of the proposed PS-EA schemeover Nakagami-m fading channels. Numerical results validate our theoreticalanalysis and show that the proposed PS-EA scheme outperforms the conventionaltime switching-based energy accumulation (TS-EA) scheme and the existing powersplitting schemes without energy accumulation.
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