Systems and methods for using clear channel assessment (CCA) on a channel prior to transmitting the channel are disclosed. A wireless transmission system may perform omnidirectional CCA using a CCA power threshold that is calculated based on a number of synchronization signal blocks (SSBs) transmitted by the wireless transmission system per SSB burst or per synchronization signal/physical broadcast channel (SS/PBCH) block measurement timing configuration (SMTC) window, or on a number of transmit (Tx) antennas used. A wireless transmission system may perform directional CCA on one or more Rx beams that correspond to one or more intended Tx beams using CCA power thresholds calculated based on an equivalent isotropic radiated power (EIRP) of the one or more intended Tx beams to determine directional availability of the channel. A wireless transmission system may determine a CCA power threshold based on a scaling between an actual CCA bandwidth and a nominal CCA bandwidth.