 downlink power allocation is fully controlled by the eNode B, SO the power alloca- tion algorithm does not need to be specified in the standard. However, to control the UL transmission power, the eNode B needs to send power control commands to the UE, which needs to be specified in the standard. Similarly, the behavior of the UE in response to receiving such a power control command also needs to be specified. This means that the UL power control algo- rithm needs to be specified in the standard. According to this algorithm, the UE transmit power is set as follows: min (Pmax) 10 log10 (M) +Po+axPL+AMcs+f(A)) where Pmax is the maximum allowed power; M is the number of resource blocks assigned to the UE; P is a UE-specific parameter; a is a cell-specific path loss compensation factor; PL is the downlink path loss calculated in the UE based on reference power measurements; AMCS is a modulation- and coding scheme-specific parameter (the table of AMCS values is configured in the UE via RRC signaling; MCS is signaled in the scheduling assignment); and function f() is also signaled via RRC, while is the actual transmit power com- mand signaled in each scheduling assignment. 4.2.4 Handover Control Handover control is responsible for maintaining the radio link of a UE in active mode as the UE moves within the network from the coverage area of one cell to the coverage © 2009 by Taylor & Francis Group, LLC Architecture and Protocol Support for RRM area of another. In LTE, the handovers are hard handovers (similarly to global system for mobile communications [GSM] systems) with preparation at the target cell. The handover is network controlled and UE assisted. Hard handover means that the switch from one cell to the other happens in a "break-before-make" fashion; that is, the UE has connectivity to only one cell at a time. This is in contrast to the 3G wideband code divi- sion multiple access (WCDMA) system, which employs soft handover and fast power control and in which the UE can be associated with multiple cells at the sa