  This letter deals with the opportunistic beamforming (OBF) scheme for
multi-antenna downlink with spatial randomness. In contrast to conventional
OBF, the terminals return only 1-bit feedback, which is powered by wireless
power transfer through a rectenna array. We study two fundamental topologies
for the combination of the rectenna elements; the direct-current combiner and
the radio-frequency combiner. The beam outage probability is derived in closed
form for both combination schemes, by using high order statistics and
stochastic geometry.
