Abstract: A method performed by a wireless transmit/receive unit (WTRU) may include receiving configuration information for reporting a power headroom (PH) associated with each of a plurality of cells, wherein a first cell uses first time intervals each having a first length and a second cell uses second time intervals each having a second length. The method may include transmitting a first uplink transmission using a first carrier frequency associated with the first cell and transmitting, in one of the second time intervals that is fully overlapped by the one of the first time intervals, based on the received configuration information, a report including information indicating a first PH corresponding to the one of the first time intervals and a second PH corresponding to the earliest one in time of the second time intervals that is fully overlapped by the one of the first time intervals.