During the S′ subframe 435, a downlink CCA (DCCA) 440 may be performed by one or more base stations, such as one or more of the base stations 105, 205, and/or 205-a described with reference to FIGS. 1 and/or 2, to reserve, for a period of time, the channel over which the wireless communication 410 occurs. Following a successful DCCA 440 by a base station, the base station may transmit a channel usage beacon signal (CUBS) 445 to provide an indication to other base stations and/or apparatuses (e.g., UEs, Wi-Fi access points, etc.) that the base station has reserved the channel. In some examples, a CUBS 445 may be transmitted using a plurality of interleaved resource blocks. Transmitting a CUBS 445 in this manner may enable the CUBS 445 to occupy at least a certain percentage of the available frequency bandwidth in the unlicensed radio frequency spectrum band and satisfy one or more regulatory requirements (e.g., a requirement that the CUBS 445 occupy at least 80% of the available frequency bandwidth). The CUBS 445 may in some examples take a form similar to that of an LTE/LTE-A cell-specific reference signal (CRS) and/or channel state information reference signal (CSI-RS). Following the transmission of the CUBS 445, an LTE/LTE-A based waveform 447 may be transmitted, from a base station to a UE, over the unlicensed radio frequency spectrum band.
