sults available. System Information After the mobile has decoded PCPICH it can also decode PCCPCH, which is the physical channel that carries BCCH. In BCCH the network information is sent on system information blocks (SIBs). Different system information blocks carry different information elements. For example, system information block 7 (SIB7) carries information about the uplink interference situation, which is needed to estimate trans- mission power in open loop power control. Due to the fact that the radio environment changes constantly SIB7 needs to be transmitted often. As another example, SIB11 carries information about neighbours needed for cell re-selection and handovers. The mobile needs to read SIB11 after cell re-selection, but after that it does not need to update neighbour information. The master information block (MIB) carries reference and scheduling information to all SIBs; different SIBs have different characteristics regarding their repetition rate and requirements. The MIB also indicates whether the information in one of the SIBs has changed and the mobile needs to read that SIB again in order to update an information element. Connection Setup Random Access Procedure The random access procedure is used to establish the RRC connection setup when the mobile wants to move from idle mode to connected mode or if the mobile is in connected mode (Cell_FACH, Cell_PCH, URA_PCH) and it is to transmit information on uplink. The PRACH and AICH channels are involved the PRACH procedure. In the random access procedure the UE sends a trial transmission burst called preamble (see Fig- ure 2.42). The transmission power of a preamble is estimated using open loop power control. If the mobile does not receive an indication from the BTS that it has received the preamble, the mobile will ramp up the transmission power and send another preamble. The power ramp-up step size is configured by a parameter. Only after receiving confirmation on the AICH that the BTS has received the preamble does the mobile send the RACH m