ed frame structure. 4.3.14.2 Downlink Frame Structure We have two different types of downlink frame structures. Type A maximizes the TGL and type B optimizes power control. In type A we transmit the pilot field of the last slot in the transmission gap, and transmission gets turned off during the remaining of the transmission gap, see Fig- ure 4.38a. In type B we transmit the TPC field of the first slot and the pilot field of the last slot in the transmission gap. As in type A, transmission gets turned off during the remaining of the transmission gap, see Figure 4.38a. Slot # (Nfirst 1) transmission gap Slot # (Nlast + 1) Datal Data2 Data1 Data2 (a) Frame structure type A Slot # (Nfirst - 1) transmission gap Slot # (N 1ast + 1) Data1 Data2 Datal Data2 (b) Frame structure type B Figure 4.38 Frame structure types in downlink compressed transmission. 4.3.14.3 Transmission Time Reduction Method In compressed mode we transmit in less time the information typically transferred in 10 ms frames. We achieve the latter through puncturing, halving spreading factor, and higher layer scheduling. The DL compression supports all methods, while the DL ex- Measured as the power over the transmitted paging indicators, excluding the undefined part of the PICH frame. The UMTS Network and Radio Access Technology cludes compression by puncturing. We define the maximum idle length as 7 slots per one 10 ms frame. By puncturing. Puncturing compression takes place through rate matching while using the rate matching or puncturing algorithm for rate matching. By halving the SF. In this mode we halve the SF during one radio frame to enable the transmission of the information bits in the remaining time slots of a compressed frame. In the DL the UTRAN may also command the UE to use a different scrambling code than the usual one. If the latter occurs then there exists a one-to-one mapping between the scrambling code used in normal mode and the one used in compressed mode. Compression through higher layer scheduling. Higher layers set conditions 