  The link misalignment and high susceptibility to blockages are the biggest
hurdles in realizing 60GHz based wireless local area networks (WLANs). However,
much of the previous studies investigating 60GHz alignment and blockage issues
do not provide an accurate quantitative evaluation from the perspective of
WLANs. In this paper, we present an in-depth quantitative evaluation of
commodity IEEE 802.11ad devices by forming a 60GHz WLAN with two docking
stations mimicking as access points (APs). Through extensive experiments, we
provide important insights about directional coverage pattern of antennas,
communication range and co-channel interference and blockages. We are able to
measure the IEEE 802.11ad link alignment and association overheads in absolute
time units. With a very high accuracy (96-97%), our blockage characterization
can differentiate between temporary and permanent blockages caused by humans in
the indoor environment, which is a key insight. Utilizing our blockage
characterization, we also demonstrate intelligent handoff to alternate APs
using consumergrade IEEE 802.11ad devices. Our blockage-induced handoff
experiments provide important insights that would be helpful in integrating
millimeter wave based WLANs into future wireless networks.
