ment for broadcast in the entire cover- age area of the cell, and is mapped to physical resources which can also be used dynam- ically for traffic or other control channels. This channel is used for paging when the network does not know the location of the UE. Common control channel (CCCH) can be mapped to DL-SCH and represents a logical channel for transmitting control information between UEs and gNBs. This channel is used for UEs that have no RRC connection with the network. Dedicated control channel (DCCH) can be mapped to DL-SCH and is a point-to-point bidirectional channel that transmits dedicated control information between a UE and the network. It is used by UEs that have already established RRC connection. Dedicated traffic channel (DTCH) can be mapped to DL-SCH and represents a point-to- point bidirectional channel dedicated to a single UE for the transfer of user information. In the uplink, the logical channels and the transport channels are mapped as follows: CCCH can be mapped to uplink shared channel(s) (UL-SCH), which is characterized by possibility to use beamforming, support for dynamic link adaptation by varying the transmit power and modulation and coding schemes, support for HARQ, support for both dynamic and semistatic resource allocation. DCCH can be mapped to UL-SCH. DTCH can be mapped to UL-SCH. Random access channel(s) (RACH), which is characterized by limited control informa- tion and collision risk. The RLC sublayer is used to format and transport traffic between the UE and the gNB. The RLC sublayer provides three different reliability modes for data transport: acknowledged mode (AM), unacknowledged mode (UM), and transparent mode (TM). The UM is suitable for transport of real-time services since such services are delay-sensitive and cannot 5G Network Architecture tolerate delay due to ARQ retransmissions. The acknowledged mode is appropriate for non- real-time services such as file transfers. The transparent mode is used when the size of SDUs are known in advance such as for broadcastin