An effective interference management is essential for cognitive radio (CR) network to operate in the spectrum sharing environment in order to increase the spectrum utilization. In this paper, we propose a single carrier adaptive array for space time block coding (STBC) transmission over underlay CR network. Here, two approach will be constructed, namely, STBC subband adaptive array (STBC-SBAA) and STBC tapped delay line adaptive array (STBC-TDLAA) that performs joint interference suppression and equalization of the received signals. The optimal weight determination for both schemes to perform joint suppression and equalization were presented. Simulation in an interference intensive environment with the presence of primary users was conducted and, the results show that STBC-SBAA achieved a better performance compared to STBC-TDLAA due to exploitation of frequency diversity gain.