ayer Design 4.3.6.2 Compressed Mode Power Control The compressed mode, which has compressed frames containing transmission gaps, uses the same transmit power control function outlined in the preceding section, but with additional features aiming for fastest recovery of the signal-to-interference ratio (SIR) close to the target SIR after each transmission gap. In this mode, compressed frames may exist either in the uplink or the downlink or both. In the first case, the DPDCH(s) and DPCCH uplink transmissions stop during the gaps. In the 2nd case, if the gaps cause the absence of downlink TPC commands, the corresponding TPC_cmd derived by the UE goes to zero. A transmit power change of the uplink DPCCH compensates the variation in the total pilot energy in both compressed and non-compressed frames in the uplink DPCCH due the different number of pilot bits per slot. Thus, at the start of each slot the UE derives a power offset APILOT value. The compensation uses the value in the most recently trans- mitted slot; APILOT (in dB) follows: APILOT (4.34) where Npilot,prev is the number of pilot bits in the most recently transmitted slot, and Npilot,curr is the number of pilot bits in the current slot. If no compensation takes place during transmission gaps in the downlink, APILOT = zero. Furthermore, during com- pressed mode the UE will adjust the transmit power of the uplink DPCCH with a step of ADPCCH (in dB) as follows: (4.35) The latter may not occur if otherwise specified. After an uplink transmission gap, the UE applies a change in the transmit power of the uplink DPCCH by an amount ADPCCH (in dB) at the beginning the 1st slot, with respect to the uplink DPCCH power in the most recently transmitted uplink slot, where: ADPCCH = ARESUME + (4.36) The UE determines the ARESUME value (in dB) according to the Initial Transmit Power (ITP) mode, which is a UE specific parameter signalled by the network with other com- pressed mode parameters. Table 4.15 summarizes the ITP mode. If a downlink TPC command is transmitted in t