A wireless transmit receive unit (WTRU) may receive a set of candidate resources, which may be used for transmission. The WTRU may periodically perform CCA on a channel (e.g., before transmitting on the channel). When the channel is determined to be free, the WTRU may determine a resource for transmission from the candidate resources. The resource may be determined based on the time remaining in the time period. For example, when the time remaining in the time period is shorter, the WTRU may determine to transmit on a resource that comprises more frequency resources. The WTRU may determine a Multiple Input Multiple Output (MIMO) scheme based on the number of frequency resources. The WTRU may send a transmission on the resource, which may include a demodulation reference signal (DM-RS). The DM-RS may indicate the resource used from transmission to a receiver of the transmission.