is lower than PRACHs. If there is a PRACH that has started already in the earlier sub-frame, that transmis- sions can continue without changes in the transmit power. In PCM2, the same priority order as in PCM1 is used to allocate uplink power. The PRACH transmissions typically take place only in subset of all UL sub-frames and UE may be able to determine the required power for PRACH transmission well before the actual transmission takes place. So in PCM2, UE should, in some cases, be able to prioritize the PCell PRACH over some lower priority transmission also in the case that PCell PRACH overlaps the latter part of some other transmission in the other cell group. If PRACH transmissions overlap and maximum UE transmission power is exceeded, it is up to UE implementation whether power of the lower priority PRACH is scaled down or PRACH is dropped. In this case, depending on physical layer indication to MAC, power ramping may not be done for the retransmission of the preamble. When UE sends power headroom report to the eNodeB, it includes power headroom infor- mation of all the cells in the report. For the own cell group, that is, when UE reports Power Headroom (PH) of MCG transmissions to MeNodeB, or PH of SCG transmissions to SeN- odeB, the reporting mechanism defined in Release 11 is used. When UE reports PH of SCG transmissions to the MeNodeB or PH of MCG to SeNodeB, type 2 power headroom of the PUCCH cell is always included in the report. In addition, depending on configuration power headroom in all the cells in the other cell group is based on reference format calculation (virtual power headroom) or it is calculated based on actual transmission in the cells, where PUSCH/PUCCH transmission takes place. In asynchronous dual connectivity, it is up to UE implementation, whether PHR of the cells in the non-scheduling eNodeB is calculated based on the first or the latter overlapping sub-frame. The performance with dual connectivity is covered Chapter 8. Small Cell Enhancements in Release 12/13 Other Small Cell Phys