  60GHz wireless local area networks (WLANs) standards (e.g., IEEE 802.11ad and
IEEE 802.15.3c) employ hybrid MAC protocols consisting of contention based
access using CSMA/CA as well as dedicated service periods using time division
multiple access (TDMA). To provide the channel access in the contention part of
the protocol, quasi omni (QO) antenna patterns are defined which span over the
particular spatial directions and cover a limited area around access points. In
this paper, we propose an algorithm to determine the beamwidth of each QO
level. The proposed algorithm takes into account the spatial distribution of
nodes to allocate the beamwidth of each QO level in an adaptive fashion in
order to maximizes the channel utilization and satisfy the required link budget
criterion. Since the proposed algorithm minimizes the collisions, it also
minimizes the average time required to transmit total packets in a QO level.
Proposed algorithm improves the average channel utilization up to 20-30% and
reduces the time required to transmit total packets up to 40-50% for the given
network parameters.
