5G‐NR Radio Interface – Data Link Layer

The data link layer is made up of four sublayers: service data adaptation protocol, packet data convergence protocol (PDCP), radio link control (RLC), and medium access control (MAC). Connectivity to a data network through 5G‐NR radio access and the 5G Core network is provided by a packet data unit session. PDCP is used for radio resource control (RRC) signaling messages, relative to dedicated control data, and for traffic Internet Protocol (IP) packets. The PDCP provides the following functions: the security of RRC traffic and signaling data, and sequence numbering and sequential delivery of RRC messages and IP packets. The IP packet may be subject to the robust header compression header compression to reduce the relative weight of headers. The RLC protocol provides control of the radio link between the mobile and the gNB entity. The MAC protocol defines a header for multiplexing RLC frames from different instances and from MAC protocol control elements.