  The various wireless networks have made the ambient radio frequency signals
around the world. Wireless information and power transfer enables the devices
to recycle energy from these ambient radio frequency signals and process
information simultaneously. In this paper, we develop a wireless information
and power transfer protocol in two-way amplify-and-forward relaying channels,
where two sources exchange information via an energy harvesting relay node. The
relay node collects energy from the received signals and uses it to provide the
transmission power to forward the received signals. We analytically derive the
exact expressions of the outage probability, the ergodic capacity and the
finite-SNR diversity-multiplexing trade-off (DMT). Furthermore, the tight
closed-form upper and lower bounds of the outage probability and the ergodic
capacity are then developed. Moreover, the impact of the power splitting ratio
is also evaluated and analyzed. Finally, we show that compared to the
non-cooperative relaying scheme, the proposed protocol is a green solution to
offer higher transmission rate and more reliable communication without
consuming additional resource.
