In the case of synchronous operators, the sharing of an unlicensed radio frequency spectrum band by different synchronous operators may be facilitated by providing fair access to the number of CCA opportunities described with reference to FIGS. 4A and/or 4B, where FIG. 4A shows a number of CCA opportunities in which a DCCA 440 may be performed and FIG. 4B shows a number of CCA opportunities in which a UCCA 490 may be performed. However, in the case of asynchronous operators, in which transmissions of a first base station of a first operator are asynchronous to transmissions of a second base station of a second operator, the sharing of an unlicensed radio frequency spectrum band may be facilitated by use of an N/K protocol, in which a base station that successfully performs CCA for N consecutive LBT frames does not participate in an LBT procedure over the next K LBT frames. In this manner, for example, the second base station of the second operator may be provided with an opportunity to gain access to a channel of the unlicensed radio frequency spectrum band despite there being no procedure to synchronously change the temporal order in which the CCAs of the first operator and the second operator are performed (i.e., the CCA timing of the first operator and the second operator) from one LBT frame to a next LBT frame. Values of N may be, for example, 2, 3, 4, or 5 LBT frames, and values of K may be, for example, 0 or 1 LBT frame. The duration of an LBT frame may be, for example, ten, five, or two milliseconds, as represented, respectively, by the first gating interval 305, the second gating interval 315, and the third gating interval 325 (see, e.g., FIG. 3). A ten millisecond first gating interval 305 or LBT frame corresponds to the duration of the LTE/LTE-A radio frame 310.
