Based on reconfigurable antenna and hidden Markov model, this paper proposes an uplink spectrum sharing for co-channel operation heterogeneous networks, consisting of macro- and femtocells. The femtocell base station (fBS) is designed to observe the occurrence of interference from a closely-located neighbor macrocell user, which is modeled as a hidden Markov process. When expecting an incoming interference, the fBS proactively reconfigures its receiving antenna pattern for interference suppression. Simulations show that user throughput on cell edge can be increased from 0.75 Mbps to 1.58 Mbps.