Systems and methods for multidimensional beam refinement procedures and signaling for millimeter wave WLANs. In some embodiments, there are multi-dimensional enhanced beam refinement protocol MAC and PHY frame designs that extend the MAC packet and the PPDU format with or without backwards compatibility. The multiple dimensions may be supported jointly or separately. In other embodiments, the increased data signaled in the eBRP frame designs may be more efficiently signaled with reduced BRP frame sizes, such as through a training type dependent BRP minimum duration selection procedure or use of null data packet BRP frames. In further embodiments, the maximum duration of the interframe spacing between BPR packets may be varied to improve the efficiency of BRP operation.