Systems, methods, and instrumentalities are disclosed for processing a multi-level transmission sent on a common set of resources using superposition coding, comprising determining a first group radio network temporary identifier (GRNTI), wherein the GRNTI is associated with a broadcast transmission to a plurality of wireless transmit/receive units (WTRUs), determining a second GRNTI, wherein the second GRNTI is associated with a transmission to a subset of the plurality of WTRUs that received the first GRNTI, receiving the multi-level transmission, wherein the multi-level transmission comprises a first level message and a second level message, decoding the first level message from the multi-level transmission using the first GRNTI and preconfigured control information, and decoding the second level message from the multi-level transmission using the second GRNTI.