en by ciation firstly, and j, secondly, with the constraint that the midamble for a spreading SF factor is the same as in the upper branch for the spreading factor 2SF. The index j = 1 or 2 indicates whether we use the original basic midamble sequence (j = 1) or the time-inverted basic midamble sequence (j = 2) [6]. Data Symbols: Midamble: Data Symbols: GP: 192 976 Chips 512 Chips 880 Chips Chips 2560*T Figure 4.44 PRACH burst configuration. 4.4.6 The Synchronization Channel (SCH) The synchronization channel provides the code group of a cell. To prevent uplink/ downlink asymmetry limitations we map the SCH on one or two downlink slots per frame only. The two cases of SCH and P-CCPCH allocation include: first, SCH and P- CCPCH allocated in TS#k, k = 0, ,14; and second SCH allocated in two TS (TS#k and TS#k + 8, k = 0, 6; P-CCPCH allocated in TS#k). The position of SCH (value of k) in the frame can change in the long term in either of the two cases and allow knowledge of the position of P-CCPCH from the SCH. Specifications in [6] and [7] give more details for the SCH. The UTRA Physical Layer Design 4.4.7 Physical Uplink/Downlink Shared Channels The Physical Uplink Shared Channel (PUSCH), which provides uplink TFCI transmis- sion possibilities, uses the DPC burst structure, where user specific physical layer pa- rameters, e.g. power control, timing advance or directive antenna settings come from the associated channel (i.e. FACH or DCH). The Physical Downlink Shared Channel (PDSCH), which provides downlink TFCI transmission possibilities, uses the DPCH burst structure. As in the PUSCH, specific parameters, e.g. power control or directive antenna settings come from the associated channel (FACH or DCH). The DSCH utilizes three signalling methods to inform the UE that it has data to decode: (a) using the TFCI field of the associated channel or PDSCH; (b) using the DSCH user specific midamble derived from the set of midambles used for that cell; and (c) using higher layer signalling. In the last method, the UE decodes t