  In this paper we consider wireless energy transfer for a point-to-point link.
The energy transmitter sees a finite number of independent channel
realizations, and, armed with (causal) knowledge of the channels, must decide
how much energy to transmit in each time slot. The objective is to maximize the
expected energy transferred to the receiver at the end of the time period. We
show that the optimal energy allocation policy is binary: the transmitter sends
no energy or all energy in a slot with this decision based on a simple
threshold on the channel. As intuition demands, this threshold for transmission
decreases as we move closer to the last available time slot. The performance of
the optimal scheme is studied both analytically and numerically.
