  The K-user multiple-input and multiple-output (MIMO) broadcast channel (BC)
with no channel state information at the transmitter (CSIT) is considered,
where each receiver is assumed to be equipped with reconfigurable antennas
capable of choosing a subset of receiving modes from several preset modes.
Under general antenna configurations, the sum linear degrees of freedom (LDoF)
of the K-user MIMO BC with reconfigurable antennas is completely characterized,
which corresponds to the maximum sum DoF achievable by linear coding
strategies. The LDoF region is further characterized for a class of antenna
configurations. Similar analysis is extended to the K-user MIMO interference
channels with reconfigurable antennas and the sum LDoF is characterized for a
class of antenna configurations.
