A radio access network node and method of allocating cell downlink power to a set of channels (e.g., DPCH channels) and to a high-speed shared channel such as a high-speed downlink shared channel (HS-DSCH) or a high-speed shared control channel (HS_SCCH). After allocating part of the cell downlink power to the set of channels, the node allocates only a portion of the remainder of the cell downlink power to the high-speed shared channel. The node reserves a power margin for possible use during a future timeslot of a channel of the set.