UMTS uses logical, transport, and physical channels to transmit data over the air interface. The Broadcast Control Channel (BCCH) broadcasts general system information to mobile devices in idle state. The Paging Control Channel (PCCH) informs users of incoming calls or messages. The Common Control Channel (CCCH) is used to establish new connections between mobile devices and the network. Transport channels like the Broadcast Channel (BCH) and Dedicated Channel (DCH) carry data from the logical channels. Physical channels such as the Primary Common Control Physical Channel (P-CCPCH) and Dedicated Physical Data Channel (DPDCH) provide the transmission medium and perform channel coding.