ization to process the uplink grant that schedules overlapping transmission to the latter part of the current sub-frame in the other cell group. This means that when UE determines the transmit power for MeNodeB PUSCH/PUCCH in sub-frame P in Figure 4.9, UE does not know, how much power is required for SeNodeB transmission in sub-frame Q. Therefore, in the PCM2, the remaining power is allocated simply to the transmission that starts in the earlier sub-frame. So in the case depicted in Figure 4.9, PUSCH/PUCCH to MeNodeB in sub-frame P can use all the UE power except the power that is guaranteed for transmissions to SeNodeB. If UE knows based on higher layer configuration (e.g. TDD UL/DL configuration) that there is no overlapping transmission in the other cell group, UE can use all the power in one of the cell groups. The rule that earlier sub-frame can use the remaining power is applicable also in the case that only SRS is transmitted in the earlier sub-frame and the actual transmission in the other cell group in fact takes place prior to the SRS transmission. In dual connectivity, both contention-based and non-contention-based random access pro- cedures are supported in the SCG. Because it is difficult to coordinate PRACH transmissions to the MeNodeB and SeNodeB, it has been agreed that UEs have to support simultaneous PRACH transmissions to the MeNodeB and SeNodeB. In the PRACH power control, two principles have to be taken into account. The first thing is that PRACH transmission in the PCell is the highest priority channel of all the UE transmissions. The second thing is that, if UE has PRACH transmission that span over multiple sub-frames, the power of that transmis- sion should not change in the middle of the transmission. In PCM1, if UE is power limited when sending PRACHs and the two PRACHs are intended to start at the same sub-frame, the priority order to allocate uplink power is such that PCell PRACH has the highest priority, other PRACHs have the second highest priority and the priority of other channels 