in The UMTS Network and Radio Access Technology cell, each cell gets a temporary identification (ID) and the UE periodically informs a primary cell ID to the connecting cells via the uplink FBI field. The non-primary cells selected by the UE, switch off their transmission power. Upper layer signalling carries out SSDT activation, termination and ID assignment. See [11] for details on cell identi- fication. 4.3.13.4 Power Control in The PDSCH, AICH, PICH, and S-CCPCH The network can select inner(fast) loop power control based on the power control commands sent by the UE on the uplink DPCCH or slow power control to realize the PDSCH power control. The UE gets information about the relative transmit power of the AICH4, , compared to the primary CPICH transmit power by the higher layers. The UE gets also information about the relative transmit power of the PICH5, com- pared to the primary CPICH transmit power by the higher layers. The TFCI and pilot fields may have time-varying offset relative to the power of the data field. 4.3.14 The Compressed Mode Procedure In the compressed mode we do not use TGL slots from Nfirst to N1ast for data transmis- sion. As shown in Figure 4.36 the instantaneous compress-frame transmit power in- creases to keep quality (e.g. BER, FER, etc.) despite reduced processing gain. The power increase depends on the transmission time reduction method under the network decision. Compressed frames may occur periodically or on demand. Compressed-frame rate and type varies and depends on the environment and the measurement require- ments. Power One frame (10 ms) Transmission gap available for inter-frequency measurements Figure 4.36 Compressed mode transmission (after [10]). Measured as the power per transmitted acquisition indicator. The UTRA Physical Layer Design 4.3.14.1 Uplink Frame Structure Figure 4.37 illustrates the UL compressed mode structure showing the control slots and data transmission slots. Slot # (Nfirst 1) transmission gap Slot # (N 1ast + 1) Pilot Pilot Figure 4.37 Uplink compress