An Evanescent Cell (EC) refers to a WTRU-centric cell exploiting highly directional transmissions. An EC may comprise one or more beams from one or more BSs/gNBs/TRPs that may be operated by the same or different operators. An EC may be created utilizing knowledge of radio planning having detected the presence of one or more WTRU. A Beam-Group (BG) refers to a group of beams associated with an EC. All beams associated with an EC may be categorized into multiple BGs. Each BG may be made up of one or more beams from multiple BSs/gNBs/TRPs. Multiple BGs within an EC may be enabled to ease the burden of cell management. In one or more embodiments, there may be systems, procedures, and/or devices for EC/BG detection, deactivation, activation, selection, reselection, and augmentation. Further, there may be one or more embodiments for hierarchical system information acquisition as they relate to ECs/BGs.